-
PREFACE
Every aspect of human activity is closely connected with the
natural environment. Whether or not we are aware, or care, every
day each of us interacts with and affects our environment. The
rapid development of technology, especially at the end of 20th
century, has increased enormously man's ability to produce goods
which, in turn, have enhanced his standard of living. On the other
hand, this development has also generated a secondary phenomenon,
the environment pollution. Such effect led to deterioration of life
quality. Thus, improvement of the life quality owing to innovative
technologies caused negative effects for the environment.
In order to keep the balance between technology development and
main components of the man's environment the appropriate
technologies should be used which appear to be a powerful force for
the improvement of the environment. The relevant activities for
upgrading the quality of ground water, drinking water, soil and air
have to be developed. The environmental changes affect also the
human health. Only few chemical compounds present in the human
close surrounding may be considered as beneficial for health. The
majority of them act harmfully on humans, even in minimal doses.
They occur in our environmental media - air, water and soil and
that is why we observe the increasing efforts devoted to the human
environmental protection. One of the most important factors in this
field are the possibilities and results of modern chemical analyses
of pollutants in biological fluids to maintain human health.
Water is one of the most important components of our
environment. Nowadays, the drinking water is becoming more and more
scarce, but our demand for water is becoming greater and greater. A
very important problem is concerned with the rising levels of
nutrients such as nitrates and phosphates in the surface water.
Their presence has caused a serious deterioration in the water
quality of many rivers, lakes and reservoirs. Therefore the
attention has to be given to the removal of nutrients originating
from sewages and fertilizers by adsorption methods, ion-exchange
and relevant biotechnological techniques. Phosphorous and its
compounds dissolved in the ground waters are responsible for the
eutrophication in the closed water system, especially in lakes and
highly enclosed bays where water is stagnant. Slag media, wasted by
- products from steel industries, are effective adsorbents for
phosphorous and its compounds.
The earth atmosphere along with water, is the main component of
our environment. One essential cause of pollution of the air is the
tendency to decrease the cost of manufacturing goods by the use of
contaminated raw materials without purifying or enriching them
before their application. A preliminary desulfurization of coal is
still rare. When air is used as a source of
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oxygen, nitrogen in the air is a diluent which, after the oxygen
consumption, is discharged into the atmosphere together with other
impurities. Dusts and smogs are another group of air contaminants.
The modern technologies should restrict emissions of carbon dioxide
to prevent from increasing the amount of heat being dispersed into
the atmosphere. This increase, leading to a change of climate, is
the greenhouse effect. The other fundamental problem is connected
with the removal of volatile organic chloride (VOC) compounds from
ground water and recovery of chlorofluorocarbons (CFCs), which are
still used in refrigeration and cooling systems. Emission control
of ozone depletion by CFCs is very urgent.
The pressure on industry to decrease the emission of various
pollutants into the environment is increasing. A broad range of
methods is available and developed to control and remove both
natural and anthropogenic, municipal, agricultural and other
pollutants. In relation to the price/performance, adsorption
technologies are the most important techniques to overcome the
degradation of environmental quality. They play a significant role
both in environmental and human health control and in prevention
from global warming and ozone layer depletion. The neccessity to
reduce the ozone depletion gases like CFCs and the demand for
primary energy diversification in the air conditioning sector, are
the main reasons for the increasing interest in adsorption devices
considered as alternative to the traditional compressor heat pumps
in the cooling systems. Adsorption processes are the ,,heart" of
several safety energy technologies which can find suitable
applications in the domestic sectors as reversible heat pumps, and
in the industrial sectors as refrigerating systems and heat
trasnformers using industrial waste heat as the primary energy
source. They can also be used for technologies to be applied in the
transportation sectors, for automobile air conditioning or for food
preservation in trucks. The adsorption dessicant dehumidification
technology is also emerging as an alternative to vapour compression
systems for cooling and conditioning air for a space. Dessicant
base systems can improve indoor air quality and remove air
pollutants due to their coadsorption by the dessicant materials.
Moreover, a number of microorganisms are removed or killed by the
dessicant. Other problems are production of drinking water, removal
of anthropogenic pollutants from air, soil and water as well as
removal of microorganisms from the indoor air and other important
tasks to solve in terms of adsorption technologies. Adsorption can
also be expected to play a significant role in the environmental
control and life supporting systems or planetary bases, where
sorbents may be used to process the habitat air or to recover
useful substances from the local environments. Another
environmental dilemma deals with the removal of thermal SOx and NOx
from hot combustion gases. The above mentioned problems may be
solved by advanced adsorption techniques. Among them, the rapid
pressure swing adsorption (PSA) methods are very efficient for
solving both global and local environmental issues. By the term of
global environmental problem is meant emission of ozone depletion
gases like CFCs, VOC and emission of green-house gases (CO2, CH4,
N20, etc.), but the term local environmental problem deals with
flue gas recovery (SOx and NOx),
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vii
solvent vapour fractionation and solvent vapour recovery,
wastewater treatment and drinking water production. Other
environmental issues concern the industrial solid aerosols, which
are the incomplete combustion products. They are harmful as
precursors to the synthesis of strong toxins, carcinogenes and
mutagenes. Automobiles contribute substantially to man-made
hydrocarbon emissions. A new type of activated carbon filtres for
the application in Evaporative Loss Central Devices (ELCD) were
developed by NORIT. Automobiles had to pass the so-called SHED
emission test, which was legislated in Europe in 1992.
Adsorption of metals into living or dead cells has been termed
biosorption. Biosorption dealing with the metal - microbe
interactions include both terrestrial and marine environments.
Biosorption by the sea bacteria plays a significant role in
detoxification of heavy metals in the aqueous systems. The
literature on the influence of biosorption in metal crystal
formation is rather scant. The subject of microbe participation in
nucleation and halite crystal growth is important with regard to
the influence of cell surface layer (S-layer) components on the
crystal habit.
As follows from the above considerations, the subject of utility
of modern adsorption technologies has enormous environmental,
economic and legal importance and constitutes a serious challenge
with the prospects for further intense development. Likwise to
volume I which contains the most important industrial applications
of adsorption, this volume includes the chapters written by
authoritative specialists on the broad spectrum of environmental
topics to find a way for intense anthropogenic activities to
coexist with the natural environment. Some of the topics presented
in this volume were mentioned above. However, I would like to
highlight a wide spectrum of themes referring to the environmental
analysis and environmental control, molecular modelling of both
sorbents and adsorption environmentally friendly processes, new
trends in applications of colloidal science for protecting soil
systems, purification and production of drinking water, water and
ground water treatment, new environmental adsorbents for removal of
pollutants from waste waters and sewages, selective sorbents for
hot combustion gases, some corrosion aspects and ecological
adsorption of heating and cooling pumps.
This book is divided into two volumes, consisting of chapters
arranged in a consistent order, though some chapters could be
connected with the industrial (volume I) or environmental (volume
II) fields. In order to highlight for readers all topics and
considerations each volume of the monograph comprises the complete
contents and the complete list of authors, but ncludes its own
subject index only. It should be emphasized that all contributions
were subjected to a rigorous review process, with almost all papers
receiving two reviews from a panel of approximately fifty
reviewers.
The presented chapters give not only brief current knowledge
about the studied problems, but are also a source of topical
literature on it. Thus each chapter constitutes an excellent
literature guide for a given topic and encourages
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viii
the potential reader to get to know a problem in detail and for
further specialistic studies. At the end of the volume the
comprehensive bibliography on adsorptive separations, environmental
applications, PSA, parametric pumping, ion-exchange and
chromatography is presented which includes the period 1967-1997.All
the articles give both the scientific background of the phenomena
discussed and indicate practical aspects to a great extent.
Consequently, this monograph is addressed to a large group of
research workers both in academic institutions and industrial
laboratories, whose professional activities are related to widely
understood surface environmental problems, including environmental
analysis, environmental catalysis and biocatalysis,modern
adsorption ecologically- friendlly technologies, etc. This book is
meant also for students of graduate and postgraduate courses.
I am aware, that the panorama of the researches presented is
incomplete.On the other hand, I believe that this monograph is a
substantial step presenting the current trends and the state of the
art. I would like to express my warmest thanks to all the
contributors for their efforts to develop the topical environmental
fields of great importance. Finally, I wish acknowledge the great
help I had my wife, Mrs. Iwona D@rowska, during all stages of the
growth of the monograph.Her patience, encouragment and support made
it possible to appear this book in present form.
Lublin, September, 1998. A.Dqbrowski (ed.)
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Complete L is t o f Authors
1. A lexandratos S.D. Department of Chemistry, University of
Tennessee at Knoxville, Knoxville, TN 37996-1600, USA
2. Andrushkova O.V. Department of Total and Bioorganic
Chemistry, Novosibirsk Medical Institute, Krasny Prospekt 52,
Novosibirsk 630091, Russia
3. Baldini F. Instituto di Ricerca sulle Onde Elettromagnetiche
,,Nello Carrara", CNR, Via Panciatichi 64, 50127 Firenze, Italy
4. Bandosz T.J. Department of Chemistry, City College of New
York, New York, NY 10031, USA
5. Blom J. Tauw Milieu P.O.Box 133, 7400 AC Deventer, The
Netherlands
6. Bl~dek J. Institute of Chemistry, Military University of
Technology, Kaliskiego 2, 01-489 Warsaw, Poland
7. Boere J.A. NORIT N.V., Research & Development,
Nijverheidsweg - Noord 72, P.O.Box 105, 3800 AC Amersfoort, The
Netherlands
8. Bogillo V.I. Institute of Surface Chemistry, National Academy
of Sciences, Prospekt Nauki 31, 252022 Kiev, Ukraine
9. Bracc iS. Centro di Studio sulle Cause di Deperimento e
Metodi di Conservazione Opere d'Arte, CNR, Via G.Capponi 9, 50121
Firenze, Italy
10. Billow M. The BOC Group Gases Technical Center, 100 Mountain
Ave., Murray Hill, NJ 07974, USA
11. Buczek B. Faculty of Fuels and Energy, University of Mining
and Metallurgy, 30-059 Cracow, Poland
-
12. Burke M. University of Arizona, Old Chemistry Bldg., Tucson,
AZ 85721, USA
13. Cacciola G. National Council of Research, Institute for
Research on Chemical Methods and Processes for Energy Storage and
Transformation, S.Lucia sopra Contesse, 98126 Messina, Italy
14. Carey T.R. Radian International, LLC, 8501 N.Mopac Blvd.,
Austin, TX 78759, USA
15. Cerofolini G.F. SGS-THOMSON Microelectronics, 20041 Agrate
MI, Italy
16. Chang R. Electric Power Research Institute, 3412 Hillview
Ave., Palo Alto, CA 94403, USA
17. Chen J. Georgia Institute of Technology, School of Civil and
Environmental Engineering, Atlanta, GA 30332-0512, USA
18. Chen S. Illinois State Geological Survey, 615 E. Peabody Dr.
Champaign, IL 61820, USA
19. Dabou X. Chemical Process Engineering Laboratory, Department
of Chemical Engineering, Aristotle University of Thessaloniki and
Chemical Process Engineering Research Institute, PO Box 1520,
Thessaloniki 54006, Greece
20. Dal lBauman L.A. NASA Johnson Space Center, Houston, TX
77058, USA
21. D~browski A. Faculty of Chemistry, M.Curie-Sktodowska
University, 20031 Lublin, Poland
22. Deka R.C. India Catalysis Division, National Chemical
Laboratory, Pune - 411008, India
23. Deng S.G. USA Department of Chemical Engineering, University
of Cincinnati, Cincinnati, Ohio 45221, USA
24. Dobrowolski R. Faculty of Chemistry, M.Curie-Sklodowska
University, 20031 Lublin, Poland
25. Domingo-Garcia M. Grupo de InvestigaciSn en Carbones, Dpto.
de Quimica Inorganica, Fac. de Ciencias, Universidad de Granada,
18071 Granada, Spain
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26. Dybko A. Department of Chemistry, Warsaw University of
Technology, Noakowskiego 3, 00-664 Warsaw, Poland
27. Fadoni M. Department of Physical Chemistry and
Electrochemistry, University of Milan, Via Golgi 19, 20133 Milan,
Italy
28. Fernandez-Mora les I. Grupo de InvestigaciSn en Carbones,
Dpto. de Quimica Inorganica, Fac. de Ciencias, Universidad de
Granada, 18071 Granada, Spain
29. F inn J.E. NASA Ames Research Center, Moffett Field CA,
USA
30. F leming H. Cochrane Inc., 800 3 nd Avenue, King of Prussia,
19406 PA, USA
31. Ghosh T.K. Particulate Systems Research Center, Nuclear
Engineering Program, E 2434 Engineering Building East, University
of Missouri-Columbia, Columbia, MO 65211, USA
32. Ghzaoui A.E1. UM II LAMMI ESA 5079, Case 015, Place Eugene
Bataillon, 34095 Montpellier Cedex 5, France
33. Golden T.C. Air Products and Chemicals, Inc., 7201 Hamilton
Boulevard, Allentown, PA 18195-1501, USA
34. Groszek A.J. MICROSCAL LTD, 79 Southern Row, London W 10 5
AL, UK
35. Haukka S. Microchemistry Ltd., P.O.Box 132, FIN-02631 Espoo,
Finland
36. Hei jman S.G.J. KIWA Research and Consultancy, P.O.Box 1072,
3430 BB Nieuwegein, The Netherlands
37. Hines A.L. Honda of America Mfg.Inc., 24 000 Honda Parkway,
Marysville, OH 43040, USA
38. Hopman R. KIWA Research and Consultancy, P.O.Box 1072, 3430
BB Nieuwegein, The Netherlands
39. Horvath G. University of Veszprem, H-8201 Veszprem, P.O.Box
158, Egyetem u.10, Hungary
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40. Hsi H-C. University of Illinois, Environmental Enegineering
Program, 205 N.Mathews Ave., Urbana, IL 61801, USA
41. Hubicki Z. Faculty of Chemistry, M.Curie-Sktodowska
University, 20031 Lublin, Poland
42. Isupov V.P. Institute of Solid State Chemistry and Raw
Mineral Processing Kutateladze-18, 630128, Novosibirsk, Russia
43. Iverson I. Department of Chemistry, University of Nevada,
Reno, NV 89557, USA
44. Izmailova V.N. Moscow State University, Department Colloid
Chemistry, Vorob'evy Gory, 119899 Moscow, Russia
45. Jakowicz A. Faculty of Chemistry, M.Curie-Sklodowska
University, 20031 Lublin, Poland
46. Janusz W. Faculty of Chemistry, M.Curie-Sktodowska
University, 20031 Lublin, Poland
47. Kalvoda R. J.Heyrovsky Inst.Phys.Chem., Czech Acad. Scis,
Dolejskova 3, 18223 Prague 8, Czech Republic
48. Kaneko K. Chiba University, Department of Chemistry, Faculty
of Science, 1-33 Yayoi, Inage, Chiba 263, Japan
49. Kanellopoulos N. Institute of Physical Chemistry NCSR
,,DEMOKRITOS", Aghia Paraskevi Attikis, GR- 153 10, Athenes,
Greece
50. Kikkinides E.S. Institute of Physical Chemistry NCSR
,,DEMOKRITOS", Aghia Paraskevi Attikis, GR- 153 10, Athenes,
Greece
51. Kir ichienko O.A. Institute of Solid State Chemistry, SB
RAS, Kutateladze 18, Novosibirsk 630128, Russia
52. Kleut D.v.d. NORIT N.V., Research & Development,
Nijverheidsweg - Noord 72, P.O.Box 105, 3800 AC Amersfoort, The
Netherlands
53. Kobal I. Department of Physical and Environmental Chemistry,
J.Stefan Institute, 61000 Ljubljana, Slovenia
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54. Kotsupalo N.P. Ekostar - Nautech Company, B.Chmielnitsky 2,
630075 Novosibirsk, Russia
55. Krebs K.-F. Merck KGaA, LAB CHROM Synthese, D-64271
Darmstadt, Germany
56. Kubo M. Department of Molecular Chemistry and Engineering,
Faculty of Engineering, Tohoku University, Sendai 980-77, Japan
57. Lakomaa E.-L. Neste Oy, Technology Center, P.O.Box 310,
FIN-06101 Porvoo, Finland
58. Lemcoff N.O. The BOC Group, 100 Mountain Avenue, Murray
Hill, NJ 07974, USA
59. Lin Y.S. USA Department of Chemical Engineering, University
of Cincinnati, Cincinnati, Ohio 45221, USA
60. Liu Y. Department of Chemical Engineering, Swearingen
Engineering Center, University of South Carolina, Columbia, SC
29208, USA
61. Long R. Department of Chemical Engineering, The University
of Michigan, Ann Arbor, Michigan 48109-2136, USA
62. Lopez-Cortes A. Center for Biological Research, P.O. Box
128, La Paz 23000, BCS, Mexico
63. Lopez-Garzon F.J. Grupo de Investigaci6n en Carbones, Dpto.
de Quimica Inorganica, Fac. de Ciencias, Universidad de Granada,
18071 Granada, Spain
64. Lucarelli L. ThermoQuest Italy S.p.A., Strada Rivoltana,
20090 Rodano (Milan), Italy
65. Luo R.G. Department of Chemical Engineering, Chemistry and
Environmental Science, New Jersey Institute of Technology,
University Heights, Newark, NJ 07102-1982, USA
66. Lutz W. Holzmarktstrasse 73, D-10179 Berlin, Germany
67. Lodyga A. Fertilizers Research Institute, 24110 Putawy,
Poland
68. Lukaszewski Z. Poznafl University of Technology, Institute
of Chemistry and Technical Electrochemistry, Piotrowo 3, 60-965
Poznafl, Poland
69. MacDowall J.D. NORIT United Kingdom Ltd., Clydesmill Place,
Cambuslang Industrial Estate, Glasgow G32 8RF, Scotland
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70. Matyska M. Department of Chemistry, San Jose State
University, San Jose, CA 95192 USA
71. Matijevic E. Center for Advanced Materials Processing,
Clarkson University, P.O.Box 5814, Potsdam, New York 13699-5814,
USA
72. Meda L. EniChem - Istituto Guido Donegani, 28100 Novara NO,
Italy
73. Menzeres L.T. Ekostar - Nautech Company, B.Chmielnitsky 2,
630075 Novosibirsk, Russia
74. Meyer K. Bundesanstalt ffir Materialforschung und -prfifung
(BAM), Zweiggelande Adlershof, Rudower Chaussee 5, D-12489 Berlin,
Germany
75. Mitropoulos A.Ch. Institute of Physical Chemistry NCSR
,,DEMOKRITOS", Aghia Paraskevi Attikis, GR- 153 10, Athenes,
Greece
76. Miyamoto A. Department of Molecular Chemistry and
Engineering, Faculty of Engineering, Tohoku University, Sendai
980-77, Japan
77. Mizukami K. Department of Molecular Chemistry and
Engineering, Faculty of Engineering, Tohoku University, Sendai
980-77, Japan
78. Moon H. Department of Chemical Technology, Chonnam National
University, Kwangju 500-757, Korea
79. Moreno-Castilla C. Grupo de Investigaci6n en Carbones, Dpto.
de Quimica Inorganica, Fac. de Ciencias, Universidad de Granada,
18071 Granada, Spain
80. Neffe S. Institute of Chemistry, Military University of
Technology, Kaliskiego 2, 01-489 Warsaw, Poland
81. Nemudry A.P. Institute of Solid State Chemistry and Raw
Mineral Processing, Kutateladze-18, 630128, Novosibirsk, Russia
82. Nijdam D. Tauw Milieu, P.O.Box 133, 7400 AC Deventer, The
Netherlands
83. Ochoa J.L. Center for Biological Research, P.O.Box 128, La
Paz 23000, BCS, Mexico
84. Pan G. Department of Earth Sciences, University of Leeds,
Leeds LS2 9JT, UK
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85. Par tyka S. UM II LAMMI ESA 5079, Case 015, Place Eugene
Bataillon, 34095 Montpellier Cedex 5, France
86. Patel D.C. Department of Chemical Engineering, Chemistry and
Environmental Science, New Jersey Institute of Technology,
University Heights, Newark, NJ 07102-1982, USA
87. Pesek J. Department of Chemistry, San Jose State University,
San Jose, CA 95192, USA
88. Pokrovskiy V.A. Institute of Surface Chemistry, National
Academy of Sciences, Prospekt Nauki 31, 252022 Kiev, Ukraine
89. Raisglid M. University of Arizona, Old Chemistry Bldg.,
Tucson, AZ 85721, USA
90. Ramarao B.V. Syracuse University, Faculty of Paper Science
and Engineering and Engineering, SUNY, College of Environmental
Science and Forestry, Syracuse, NY 13210, USA
91. Rao M.B. Air Products and Chemicals, Inc., 7201 Hamilton
Boulevard, Allentown, PA 18195-1501, USA
92. Ray M.S. Department of Chemical Engineering, Curtin
University of Technology, GPO Box U1987, Perth 6845, Western
Australia
93. Reimerink W.M.T.M. NORIT N.V., Research & Development,
Nijverheidsweg - Noord 72, P.O.Box 105, 3800 Ac Amersfoort, The
Netherlands
94. Restuccia G. National Council of Research, Institute for
Research on Chemical Methods and Processes for Energy Storage and
Transformation, S.Lucia sopra Contesse, 98126 Messina, Italy
95. Richardson C.F. Radian International, LLC, 8501 N.Mopac
Blvd., Austin, TX 78759, USA
96. Ripperger K.P. Department of Chemistry, University of
Tennessee at Knoxville, Knoxville, TN 37996-1600, USA
97. Ritter J.A. University of South Carolina, Department of
Chemical Engineering, Swearingen Engineering Center, Columbia,
South Carolina 29208, USA
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98. Robens E. Institut ffir Anorganische Chemie und Analytische
Chemie der J.Gutenberg-Universitat D-55099 Mainz, Germany
99. Rodrigues A.E. Laboratory of Separation and Reaction
Engineering, University of Porto, 4099 Porto Codex, Portugal
100. Rood M. University of Illinois, Environmental Engineering
Program, 205 N.Mathews Ave., Urbana, IL 61801, USA
101. Rosenhoover W. CONSOL, 4000 Brownsville Rd., Library, PA
15129, USA
102. Rostam-Abadi M. Illinois State Geological Survey, 615 E.
Peabody Dr. Champaign, IL 61820, USA
103. Rule J. College of Sciences, Old Dominion University,
Norfolk, VA 23529-0163, USA
104. Saba J. Faculty of Chemistry, M.Curie-Sklodowska
University, 20031 Lublin, Poland
105. Sakellaropoulos G.P. Chemical Process Engineering
Laboratory, Department of Chemical Engineering, Aristotle
University of Thessaloniki and Chemical Process Engineering
Research Institute, PO Box 1520, Thessaloniki 54006, Greece
106. Samaras P. Chemical Process Engineering Laboratory,
Department of Chemical Engineering, Aristotle University of
Thessaloniki and Chemical Process Engineering Research Institute,
P.O. Box 1520, Thessaloniki 54006, Greece
107. Sh in tan i H. National Institute of Hygienic Sciences,
18-1 Kamiyoga 1-Chome, Setagaya-ku, Tokyo 158, Japan
108. Silva da F.A. Laboratory of Separation and Reaction
Engineering, University of Porto, 4099 Porto Codex, Portugal
109. Silva J.A.C. Laboratory of Separation and Reaction
Engineering, University of Porto, 4099 Porto Codex, Portugal
110. Sircar S. Air Products and Chemicals, Inc., 7201 Hamilton
Boulevard, Allentown, PA 18195-1501, USA
111. Sivasanker S. Catalysis Division, National Chemical
Laboratory, Pune - 411008, India
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112. Stubos A.K. Institute of Nuclear Technology and Radiation
Protection, NCSR ,,DEMOKRITOS", 15310 Aghia Paraskevi Attikis,
GR-15310, Athenes, Greece
113. Subramanian D. University of South Carolina, Department of
Chemical Engineering, Swearingen Engineering Center, Columbia,
South Carolina 29208, USA
114. Suckow M. Fachhochschule Lausitz, Grossenhainer Strasse,
D-01968 Senftenberg, Germany
115. Suntola T. Microchemistry Ltd., P.O.Box 132, FIN-02631
Espoo, Finland
116. Suzuki M. Institute of Industrial Science, University of
Tokyo, 7-221 Roppongi, Minato-ku, Tokyo 106, Japan
117. Szczypa J. Faculty of Chemistry, M.Curie-Sktodowska
University, 20031 Lublin, Poland
118. Sykut K. Faculty of Chemistry, M.Curie-Sklodowska
University, 20031 Lublin, Poland
119. Swi~ttkowski A. Institute of Chemistry, Military Technical
Academy, Kaliskiego 2, 01-489 Warsaw, Poland
120. Takaba H. Department of Molecular Chemistry and
Engineering, Faculty of Engineering, Tohoku University, Sendai
980-77, Japan
121. Tam-Chang S.-W. Department of Chemistry, University of
Nevada, Reno, NV 89557, USA
122. Tarasevich Yu.I. Institute of Colloid Chemistry and
Chemistry of Water, 42 Vernadsky avenue, Kiev 252680, Ukraine
123. TSth J. Hungarian Academy of Sciences, Research Laboratory
for Mining Chemistry, 3515 Miskolc-Egyetemvaros, P.O. Box 2,
Hungary
124. Tzevelekos K.P. Institute of Physical Chemistry NCSR
,,DEMOKRITOS", Aghia Paraskevi Attikis, GR-153 10, Athenes,
Greece
125. Unger K.K. Institut ffir Anorganische Chemic und
Analytische Chemic der J.Gutenberg-Universitat, D-55099 Mainz,
Germany
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126. Ushakov V.A. Institute of Solid State Chemistry, SB RAS,
Kutateladze 18, Novosibirsk 630128, Russia
127. Vansant E.F. Laboratory of Inorganic Chemistry, University
of Antwerpen (U.I.A.), Universiteitsplein 1, 2610 Wilrijk,
Belgium
128. Vetrivel R. Catalysis Division, National Chemical
Laboratory, Pune - 411008, India
129. Vigneswaran S. University of Technology, Sydney, Faculty of
Engineering, Building 2, Level 5 P.O.Box 123 Broadway, NSW 2007,
Australia
130. Waghmode S.B. Catalysis Division, National Chemical
Laboratory, Pune - 411008, India
131. Wr6blewski W. Department of Chemistry, Warsaw University of
Technology, Noakowskiego 3, 00-664 Warsaw, Poland
132. Yampolskaya G.P. Moscow State University, Department
Colloid Chemistry, Vorob'evy Gory, 119899 Moscow, Russia
133. Yang R.T. Department of Chemical Engineering, The
University of Michigan, Ann Arbor, Michigan 48109-2136, USA
134. Y iacoumi S. Georgia Institute of Technology, School of
Civil and Environmental Engineering, Atlanta, GA 30332-0512,
USA
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Contents of Volume I
Preface v
Complete List of Authors IX
Fundamentals of Adsorption 1. Adsorption - its development and
applications for practical purposes
(A.D@rowski) 3 2. Industrial carbon adsorbents (A.Swi~tkowski)
69 3. Standarization of sorption measurements and reference
materials for
dispersed and porous solids (E.Robens, K.-F.Krebs, K.Meyer,
K.K.Unger) 95 4. Spectroscopic characterization of chemically
modified oxide surfaces
(J.Pesek, M.Matyska) 117 5. Advances in characterisation of
adsorbents by flow adsorption
microcalorimetry (A.J.Groszek) 143 6. Temperature programmed
desorption, reduction, oxidation and flow
chemisorption for the characterisation of heterogeneous
catalysts. Theoretical aspects, instrumentation and applications
(M.Fadoni, L.Lucarelli) 177
7. Adsorption with soft adsorbents and adsorbates. Theory and
practice (G.F.Cerofolini, L.Meda, T.J.Bandosz) 227
Application in Industry 1. Advanced technical tools for the
solution of high capacity adsorption
separation (G.Horvath, M.Suzuki) 275 2. The mutual
transformation of hydrogen sulphide and carbonyl sulphide
and its role for gas desulphurization processes with zeolitic
molecular sieve sorbents (M.B(ilow, W.Lutz, M.Suckow) 301
3. Nitrogen separation from air by pressure swing adsorption
(N.O.Lemcoff) 347 4. Methodology of gas adsorption process design.
Separation of
propane/propylene and rgiso- paraffins mixtures (Jose A.C.Silva,
F.Avelino da Silva, Alirio E.Rodrigues) 371
5. Fractionation of air by zeolites (S.Sircar, M.B.Rao,
T.C.Golden) 395 6. Production, characterization and applications of
carbon molecular sieves
from a high ash Greek lignite (P.Samaras, X.Dabou,
G.P.Sakellaropoulos) 425 7. Development of carbon-based adsorbents
for removal of mercury
emissions from coal combustion flue gas (M.Rostam-Abadi,
H-C.Hsi, S.Chen, M.Rood, R.Chang, T.R.Carey, C.F.Richardson,
W.Rosenhoover) 459
8. Sorption properties of gas/coal systems, degasification of
coal seams (J.TSth) 485
9. The influence of properties within particles of active
carbons on selected adsorption processes (B.Buczek) 507
-
Adsorption and its Applications in Industry and Environmental
Protection Studies in Surface Science and Catalysis, Vol. 120 A.
Dabrowski (Editor) 9 1998 Elsevier Science B.V. All rights
reserved.
Environmental pollutants and application of the adsorption
phenomena for their analyses
J. Btadek and S. Neffe
Institute of Chemistry, Military University of Technology,
00-908 Warsaw, Kaliskiego St., 2, Poland
1. INTRODUCTION
Human activity is now altering the global environment on an
unprecedented scale and thus contributes to the environmental
change affecting human health. Only few of chemical compounds
present in direct human surrounding may be considered as beneficial
for health; the majority of them act harmfully on humans, even in
minimal doses. They occur in all environmental media (air, water
and soil) and that is why we observe the increasing attention to
the environmental protection. One of the most important factors in
this field are the results of chemical analysis of pollutants. It
is obvious that only reliable analytical data obtained during
monitoring can be a base for environmental protection
activities.
The term monitoring means systematic and planned collection of
analytical activities realised in any space to define the quality
of air, water and soil. Volatile organic compounds, pesticides,
polycyclic aromatic hydrocarbons, polycyclic aromatic heterocycles,
phenols, polychlorinated biphenyls, organotins, chemical warfare
agents and inorganic pollutants belong to the most important
environmental pollutants. The need of monitoring leads to the
development of independent branch of instrumental analysis -
environmental analysis. It is a discrete, and sophisticated branch
of instrumental analysis which concerns the treatment of
environmental samples from their sampling to receiving the final
result of analysis. The fundamental requirement of environmental
analysis is for a fast, modern and reliable methodology, especially
as the data produced are increasingly drawn upon as the decisive
basis for regulatory measures. Consequently, specific conditions
need to be fulfilled for the detection of pollutants in trace and
ultra-trace quantities, within a short time and with a high degree
of precision.
To define the analytical process, Skoog and co-workers [1]
mention the following steps: selecting method of sampling,
obtaining representative samples, preparing laboratory samples,
defining replicate samples, dissolving samples,
-
eliminating interference and measuring features of analyses. The
aims of these activities are: 9 making the sample suitable physical
parameters, removing interference and
transferring the analytes to matrix being compatible with
analytical technique; liquid, gas, solid phase and supercritical
fluid extraction is usually applied for transferring analytes
directly from samples into media being subjected to final
instrumental analysis, as well as to liberate analytes trapped on
sorbents during preconcentration steps;
9 cleaning-up the analytical samples and analytes enrichment;
liquid-liquid partitioning, solid phase extraction, preparative
column and thin layer chromatography are usually applied as
clean-up and preconcentration techniques,
9 separation of sample components to obtain the chemical
individuals; in environmental analyses the partition of analysed
mixtures is most often realised by chromatographic methods,
9 detection, identification and quantitation; detectors which
are parts of chromatographic apparatus or can co-operate with them
in on-line mode are predominantly used. There are many various
methods of sampling, sample preparation and
analyses, which warrant correctness of obtained analytical
results. Extraction, chemisorption, absorption, adsorption,
distillation or freezing are used in them inter alia. Features and
applications of these methods are presented in numerous
compilations and monographs. In this elaboration we present only
these techniques in which phenomena of adsorption are used. They
are applied mainly to the sampling of pollutants in fluid, sample
preparation and such analytical techniques, which warrant
separation of components of analysed mixture (mainly
chromatographic techniques of analyses). In these processes
compounds of interest are selectively removed from the bulk sample
matrix, preconcentrated, cleaned-up~ separated into individual
substances and analysed.
2. SHORT CHARACTERISTIC OF MONITORED SUBSTANCES
The term environmental pollution means any physical, chemical,
or biological change disturbing ecological equilibrium in the
environment. It may be a result of random, accidental events,
emission of certain pollutants due to activity of nature itself, or
human activities. As a result of the activity of nature, natural
pollutants are emitted into atmosphere; human activity leads to the
emission of pollutants called anthropogenic pollutants. Natural and
anthropogenic pollutants emitted from a given source are called
primary pollutants. A number of primary pollutants can undergo some
changes due to reactions with other pollutants, as well as with
some components of the environment. In this way, new compounds,
often of higher toxicity, can be formed. They are called secondary
pollutants. Primary as well as secondary pollutants occur in all of
the environment media:
-
atmosphere, hydrosphere, and soil. The following groups of
substances are considered as the most important environmental
pollutants: 9 Volatile organic compounds. Volatile organic
compounds (VOCs), originating
from anthropogenic sources, are the monocyclic aromatic
hydrocarbons and the volatile chlorinated hydrocarbons. Both groups
of compounds are considered as priority pollutants; they are
present in all parts of the environment. Monocyclic aromatic
hydrocarbons are mainly emitted by industrial processes and
combustion of fossil fuels, while chlorinated hydrocarbons are
widely applied as solvents for dry cleaning, as degreasing agents
in metal industries or as fumigants [2]. Due to their lipophilic
properties, they can be taken up in lipophilic matrices. Uptake of
xenobiotic VOCs in plants used for human nutrition (vegetables and
fruits), results in an exposure of man through the food chain, next
to a direct exposure to air pollutants through inhalation. VOCs are
also the most frequently encountered contaminants at hazardous
waste sites.
9 Pesticides comprise a group of compounds that are given great
attention in environmental studies. They are introduced into
environment due to wilful human activity; economic production in
the cultivation of vegetables and fruits, as well as in
agriculture, can not be achieved without pesticides. Pesticides
belong to different chemical groups of compounds; the most
important of them are: organophosphorous, organochloride,
carbamate, triazine compounds and chlorophenoxy acids. With respect
to the biological activity they are classified as insecticides,
herbicides and fungicides. Well known compounds such as DDT,
lindane or aldrin belong to the organochloride group which, in the
past, was widely used all over the world. Although their
manufacture and application are now largely prohibited, they can
still, due to their persistence, be found in the soil, in animals,
plants and food products. Pesticides are poisons; some of them or
their degradation products also demonstrate carcinogenic potential
and teratogenic activity. They are present in all parts of the
environment.
9 Polycyclic aromatic hydrocarbons (PAHs) are compounds whose
molecules can contain 2-13 aromatic rings arranged in linear,
cluster, or angular shapes. They may contain some number of alkyl
substituents. PAHs arouse much interest mainly due to their
carcinogenic and mutagenic properties. They are widespread
environmental contaminants emitted from a variety of sources,
including industrial combustion and discharge of fossil fuels,
residential heating, or motor vehicle exhaust. In processes of
monitoring, PAHs have been measured in a variety of environmental
matrices including air, water, soil, sediments and tissue
samples.
9 Polycyclic aromatic heterocycles. In the environment, carbon
atoms in PAHs rings can be substituted with oxygen, sulphur, or
nitrogen atoms. In this way polycyclic aromatic heterocycles are
formed, and they usually occur together with PAHs. The most
dangerous of these, polychlorinated dibenzo-p-dioxins and
polychlorinated dibenzofurans, are by-products formed during
the
-
manufacture of chlorophenols and related products; other sources
include the pulp and paper industry and accidental fires that
release polychlorinated biphenyls. Dibenzotiophene and some of its
methyl-substituted compounds are persistent residues in sea
environment after oil accidents. In the natural environment,
polychlorinated thianthrenes and polychlorinated dibenzothiophenes
also exist. As with their oxygen analogues, they are hazardous
substances. Azaarenes, mainly benz(c)acridine and many of its
related compounds, have been shown to exhibit carcinogenic
activity. Nitro- related compounds are mutagenic and carcinogenic.
Polycyclic aromatic heterocycles are continually found in many
natural and environmental samples.
9 Pheno ls form a group of aromatic compounds with one or more
hydroxyl groups. Phenols and substituted phenols are products of
manufacturing processes used in plastics, dyes, drugs,
antioxidants, and pesticides industries. They pose the serious
danger to the environment, especially when they enter the food
chain as water pollutants. Even at very low concentration phenols
affect the taste and odour of fishes and drinking water. Because of
this, many phenol derivatives (mainly nitrophenols and
chlorophenols, which are also poisons) are considered as priority
pollutants of the environment.
9 Po lych lor inated b iphenyls (PCBs) are a group of compounds
derived from biphenyl by substituting one to ten hydrogen atoms
with chlorine. There are 209 possible PCB configurations. They have
extensive application because of high chemical and thermal
stability, low or no flammability, low vapour pressure at ambient
temperature and high permeability. PCBs are utilised alone or in
mixtures as heat-transfer fluids, dielectrics for capacitors and
transformers, hydraulic fluids, lubricants, additives in plastics
and dyes, etc. PCBs are different in their physical and chemical
properties as well as toxic potencies; some of them are inducers of
drug-metabolising enzymes also being able to affect various
physiological processes such as reproduction, carcinogenesis or
embryonic development.
9 Organot ins . These compounds have been widely used as
biocides incorporated in antifouling paints, and are accumulated by
the biota, especially by filtrating organisms. The organotins are
much more toxic than inorganic tin. Contamination of the marine
environment by organotins has been well documented. Tributyltin is
the most often used organotin compound, followed by triphenyltin.
In water these substances can be step-wise decomposed to less
substituted and down to inorganic tin, absorbed by lipid fraction
of organisms or adsorbed onto particulate matter.
9 Chemica l warfare agents. The need of the monitoring on the
presence of these substances in the environment results not only
from the need of the verification of the Chemical Weapon Convention
[3] but also because certain chemical warfare agents can be spread
in the environment as the old or abandoned chemical warfare agents.
Out of this group of compounds organophosphorous (O-ethyl
S-2-diisopropylaminoethyl methyl phosphono-
-
thiolate, O-pinacolyl methylphosphono-fluoridate, etc.) and
bis(2-chloroethyl) sulfide (mustard gas), tris(2-chloroethyl) amine
(nitrogen gas), 10-chloro-5,10- dihydrophenarsazine (adamsite) have
importance due to their toxicity or persistence in the
environment.
9 Explosives. 2,4,6-trinitrotoluene (TNT) is known first of all
as an explosive, but it appears that this compound and its
degradation products have been found as contaminants in water and
soil. TNT and its degradation products have been identified in the
blood and urine of the explosives manufacturing plants personnel.
Because of the mutagenity of these compounds, environmental t
reatment of TNT and its degradation products (2- and 4-monoamino-
dinitrotoluenes as well as 2,4- and 2,6-diaminonitrotoluenes) is an
important issue.
9 Inorganic po l lutants . Among inorganic environmental
pollutants aerosols, heavy metals, radionuclides and some anions
are monitored. Aerosol or particulate matter refer to any
substance, except pure water, that exists as a liquid or solid in
the atmosphere under normal conditions and is in microscopic or
submicroscopic size. Even non-toxic aerosols are harmful; they can
cause eye or throat irritation, bronchitis or lung damage. Heavy
metals (mainly As, Cd, Cr, Cu, Se, Ni, Mo, Hg and Pb) can pose
serious threats to the human health even at very low concentrations
in air and water. For instance, lead causes damage of brain,
mercury affects several areas of the brain, as well as the kidneys
and bowels, arsenic causes cancer etc. After pollution of soil they
can be incorporated into the food cycle via vegetables or,
alternatively, be washed towards surface or underground water.
Farming, industrial and urban activities are most often mentioned
as pollution sources of heavy metals. The radioactivity in
environment originates from both natural sources and human
activities. The latter include operations concerned with the
nuclear fuel cycles, from mining to reprocessing, medical uses etc.
Radionuclides cause cancer. The common anions, such as cyanides
(CN-), halides (Br-, CI-, F-) or the oxy-ions (SO3-, 304-, NO2-or
NO3-) are monitored mainly in water and wastewaters. When listing
the most important environmental pollutants it is impossible to
forget industrial gases such as SO2, NOx, CO2, etc., which are
emitted in huge quantities to the atmosphere. First two of them
cause respiratory illness and lung damage. They also cause the acid
rains which are responsible for corrosion of metals, acidification
of soil and surface waters, as well as degradation of forests. NO2
and CO2 are, like as CH4, tropospheric 03 and chlorofluorocarbons,
greenhouse gases. These gases absorb in the spectral range where
thermal energy radiated from the earth is at a maximum. All of
them, analogically as above mentioned organic and non-organic
pollutants must be systematically monitored.
-
3. ADSORPT ION IN SAMPLING AND SAMPLE PREPARATION
Basic feature which distinguishes environmental analysis is the
need of sampling and sample preparation of substances existing in
matrix on trace levels. Monitoring of polychlorinated
dibenzo-p-dioxins and polychlorinated dibenzofurans can be a good
example of such needs. Because of high toxicity the level of
quantitation of these substances equals 10 -~2 g/kg; it is also
important that these substances usually exist in natural
environment in neighbourhood of other organic chlorine compounds
whose concentration can be twice or three times higher. So to cope
with the demands of environmental analyses such as techniques of
sampling, sample preparation and analyses, which have proper
ability to separation, high sensitivity, good selectivity, ability
to generate reliable identification data should be applied.
Adsorption phenomena play an important, if not decisive, role in
many of these processes.
3.1. Sampl ing The term sampling is used for the description of
the process by which a
representative fraction of matrix is acquired. In environmental
analyses various sampling techniques (and equipment submitting
them) are used; adsorption phenomena are usually applied for the
sampling of air, surface water and wastewater; in these processes
sampling is realised together with the enrichment of analytes.
Owing to the adsorption processes compounds of interest are
selectively removed from the bulk sample matrix and preconcentrated
(an enrichment factor of 103-107 can be usually obtained).
There are two main groups of sampling and preconcentration
methods of air samples: passive and aspirative (denudatic or
dynamic) [4]. The idea of passive method is diffusion or permeation
of analytes to the trapped medium surface. Analytes which are
present in the nearest surrounding of the enriching device
(dosimeter) are transferred due to the molecular diffusion forces
towards the semipermeable membrane and are penetrating through it.
Phenomena of absorption, chemisorption and adsorption are used in
aspirative methods. Passive samplers are suitable for large scale
measurements. As they do not require pumping of air during sampling
they can be employed at virtually every location. Passive samplers
can be sent by mail and stored before and after sampling for
periods of several months. On the other hand, passive samplers
require at least 24-hour exposure and therefore cannot be used for
short-term sampling.
Aspirative denudatic method of preconcentration consist in a
junction of a forced gas stream flow and diffusive transfer of
analytes in the direction of denuder wall which acts as an analyte
trap. The advantage of denudating techniques is the possibility of
differentiation of so called physical speciation of analytes, it
means differentiation between gaseous and aerosol form of
preconcentrated substances. Aspirative dynamic enrichment is the
oldest method of air sampling. It allows to determine the time
weighted average concentration or short term exposure level.
Absorption in liquid solutions, freezing out in
-
cryogenic traps and adsorption belongs to these methods.
Adsorption aspirative dynamic methods are used to separate the
volatile and non-volatile organic pollutants. The applied
techniques differ from each other in volume of sample, shape of
sorbent container, and first of all in dissimilarity of used
sorbents (usually they are carbonaceous, inorganic or polymeric
sorbents). The scheme of the set for sampling and preconcentration
of atmospheric air pollutants on adsorbent is presented in Figure
la. In Figure lb the crossection of adsorption tube is shown.
1 5
6 7
8 r
Figure la. The set for collecting samples. 1-probe, 2-
adsorption tube, 3- filter, 4-capillary tubes 5-vacuum-gauge,
6-flow controller, 7-pressure reducing valve, 8-vacuum pump.
Reprinted from [4].
1 2 .~/3 #y5. ~_.#6#'L.~ 8 1
Figure lb. Adsorption tube. 1-plastic caps, 2-fused ends of tube
(they are broken before using), 3-glass sorption tube, 4- spring,
5-glass wool, 6-adsorbent layer, 7-polyurethane plug, 8-adsorbent
protective layer. Reprinted from [4].
Among carbon sorbents active carbons and carbon molecular sieves
with specific surface area between 600 and 1200 me/g, and
relatively high adsorption
-
10
capacity for most organic compounds are used. For specific
non-polar analytes graphitized carbon blacks with a small specific
surface area are used. Disadvantage of carbon adsorbents is an
irreversible adsorption of many analytes and substantial
variability of adsorption properties between different batches of
the same product. Detailed description of application of carbon
adsorbents in analyses of organic environmental pollutants is
presented in work of Matiskowa and Skrabakov~ [5].
Among the inorganic sorbents, silica is the most widely used.
Chromatographic silica is amorphous, porous solid which can be
prepared in a wide range of surface areas and average pore
diameters. Variation of solution pH during the acid gelation of
sodium silicate yields silica with surface areas varying from about
200 m2/g (pH ~ 10) to 800 m2/g (pH < 4). Silica may be treated
as a typical polar adsorbent. The raw material for the production
of chromatographic alumina (aluminium oxides) are different
aluminium hydroxides, e.g. hydrargillite. Like silica, alumina can
be regarded as a typical polar adsorbent, and sample separation
order on alumina and silica is generally similar. The presence of
carbon-carbon double bonds in a pollutant molecule generally
increases adsorption energy on alumina more than on silica.
Aromatic hydrocarbons which contain different numbers of aromatic
carbon atoms are much better separated on alumina than on silica.
Adsorption sites are used for the selective adsorption of
unsaturated or polar molecules onto a hydroxylated silica surface.
Three distinct site types can be recognised on the alumina surface:
acidic or positive field sites, basic or proton acceptor sites and
electron acceptor (charge transfer) sites [6]. Each of these is
important in the adsorption of certain samples on alumina. Florisil
is co-precipitate of silica and magnesia and this is why the
retention and separation on its surface is generally intermediate
between alumina and silica. Inorganic adsorbents have a high
adsorption capability, even to polar and volatile organic
compounds. This property is limited in the case of moisture samples
(adsorption of water vapours cause the deactivation of adsorption
centres and lowers the retention of analytes).
Porous polymers and co-polymers are the most universal group of
adsorbents used for sampling of air; they are synthesised in the
processes of the bead polymerisation. A suitable selection of
cross-linking polymers and other polymerisation parameters allows
to control polymerisation processes. Therefore it is possible to
obtain adsorbents with desirable specific surface area, porosity
and polarity (for example Tenax | Porapak | Chromosorb | or XAD|
Tenax is a porous polymer based on 2,6-diphenyl-p-phenylene oxide.
The high thermal stability and its compatibility with alcohols,
amines, amides, acids and bases together with good recovery
characteristics make Tenax very suitable as sorbent medium in air
and water analysis [7]. Porapak is a series of cross-linked porous
polymers, for example divinylbenzene/ethylene glycol dimethacrylate
(Porapak N). That sorbent is used for preconcentration of many
substances [8]. Porapaks have the following polarity:
N>S>P>Q, T>R. Chromosorbs or XAD are produced by
copolymerising monofunctional monomers with bifunctional monomers.
For
-
11
instance Chromosorb 102 is a styrene/divinylbenzene copolymer
with specific surface area in the range of 300-400 m2/g; the
surface is non-polar. Chromosorb 108 is moderately polar acrylic
ester resin with the specific surface area between 100 and 200
m2/g. They are also commonly used for air sampling and
preconcentration of analytes [9, 10]. Disadvantage of polymeric
adsorbents is their sensibility to oxidative action of ozone or
chlorine.
Among the adsorption methods applied for isolating analytes from
liquid matrixes (mainly from water) and for their preconcentration,
practical importance has the solid phase extraction (SPE)
technique. The idea of this technique consists in retention of
analytes from a large sample volume on a small bed of adsorbent
(placed in cartridge or shaped in the disk form), and following
elution of analytes, with a small volume of solvent. The selection
of appropriate parameters of adsorbents and solvents is the basic
condition for successful employment of this method. Details on the
SPE are presented in chapter 23, vol. 2 of this book.
An alternative to the SPE, solvent-free sampling technique is a
solid phase microextraction [SPME]. Typically, a fused-silica
fibre, which is coated with a thin layer of polymeric stationary
phase, is used to extract analytes from fluid (for analysis the
retained analytes are thermally desorbed). The application of the
SPME for sampling of polycyclic aromatic hydrocarbons [PAHs] from
aqueous samples is presented in the work of Yu Liu et al. [11]. The
porous layer coatings were prepared by the use of silica particles
(5 ~m diameter) bonded with phenyl, Cs, and monomeric or polymeric
Cls stationary phases. It was proved that several factors affected
the selectivity for extraction of PAHs, including functional group
in the bonded phase, and phase type (monomeric or polymeric). The
distribution coefficients of PAHs in the porous layer increased
with an increasing number of carbon atoms. A greater selectivity
towards solute molecular size and shape were obtained using a
polymeric Cls porous layer. The effect of solution ionic strength
on recovery was also investigated.
There are many papers describing the testing of usefulness of
various adsorbents for fluid sampling [12, 13]. Adsorption capacity
for the defined groups of the analytes, breakthrough capacity and
influence of adsorbent bed length, as well as enrichment conditions
on these parameters were investigated. The recovery of analytes by
their thermal or liquid desorption is an essential element of such
investigations.
3.2. Sample preparation Only few analytical methods provide the
possibility for examination of samples
in their original state, without preliminary preparation. In
case of the environmental analysis such examinations are in
practice almost impossible. Complexity of environmental samples is
the reason why analytical processes are very difficult and usually
multistages. Analytes need to be determined at extremely low
concentrations over a wide polarity range, and frequently there is
little or no information about the analysed sample. This is why the
sample
-
12
preparation is the most important and often the most difficult
step of analysis in environmental studies.
The experiment described by Falcon et al. [14] can be a very
good example of complications of sample preparation process. They
developed the procedure for trace enrichment of benzo(a)pyrene in
extracts of smoked food products. All steps of this analysis are
presented in Figure 2. As it was mentioned above, the
[ Lyophilization [
[ Ultrasound I
I 50 ml hexane extract I
] Centrifugation I
[ Supernatant !
I Concentration to 5 ml
I ] Silica purification
[ Extraction DMSO [
30 ml DMSO extract I
[ C- 18 purification [
[ Hexane evaporation I
] Filtration I I
[ HPLC [
25/15/10 ml hexane (lh)
Elution 10 ml hexane
15/10/5 ml DMSO (5 min)
75 ml water
Elution 5 ml hexane
1 ml acetonitryle
Figure 2. Flow-chart summarising treatment sample prior to the
HPLC analysis of benzo(a)pyrene. Reprinted from [ 13].
-
13
transfer of analytes to matrix being compatible with analytical
technique, usually by means of liquid, gas or supercritical fluids
extraction, is one of the steps of sample preparation process.
Unfortunately, in this process very undesirable substances
(interferences) penetrate to the matrix. This is why a cleaning-up
of analytical samples, connected usually with preconcetration of
analytes, is a very essential step of environmental analyses. Among
the adsorption methods, preparative column chromatography and thin
layer chromatography are commonly used. Aluminium oxide, cellulose
powder or microcrystalline cellulose, silica, diatomaceous earth
(Kieselguhr), polyamide and Florisil | are employed in column or
layer preparation.
Nowadays, a large variety of chemicaly bonded stationary phases
are applied. Such phases are prepared by anchoring specific organic
moieties to inorganic oxides (mainly silica), under defined
reaction conditions. Organic moieties can be attached to the silica
by mono-, di-, or trifunctional silane reaction. After
derivatisation of the silica substrate to yield a bonded phase, a
network of so- called structure elements can be distinguished at
the silica surface. This includes organic moieties bound to the
surface, like cyano-, NH2-, phenyl-, octyl-, or octadecyl groups.
The residual silanols, approximately 50% of the originally present
silanols, have different properties as they consist of lone,
vicinal and geminal groups. Consequently, besides the attached
organic ligands, also the residual silanols play an important role
in the final properties of the chemically bonded stationary
phases.
Carlsson and Ostman [15] presented a method for the isolation of
polycyclic aromatic nitrogen heterocyclic (PANHs) compounds from
complex sample matrix. They are known to be mutagenic and /or
carcinogenic. PANHs with a single endocyclic nitrogen heteroatoms
can be divided into two classes: acridines (containing a pyridine
ring) and carbazoles (containing a pyrrole ring). They were
isolated and separated as carbazole and acridine type PANHs with an
absolute recovery in the range between 79-98%. The open column
chromatography was used as an initial step for isolating a PANH
fraction. By applying a normal-phase liquid chromatography using a
dimethylaminopropyl silica stationary phase and utilising
back-flush technique it was possible to separate the PANHs fraction
into two fractions containing acridine type and carbazole type
PANHs respectively. The method applied on a sample of solvent
refined coal heavy distillate; acridines and carbazoles were
identified by gas chromatography (GC).
Rimmer's and co-workers work [16] is a good example of
application of high- resolution gel permeation chromatographic
clean-up technique (prior to GC). The method for the determination
of phenoxy acid herbicides in vegetable samples was presented.
Macerated samples were extracted with acetone, filtered and
acidified; the herbicides were then partitioned into
dichloromethane, cleaned-up using high-resolution gel permeation
chromatography before undergoing rapid and efficient methylation
using trimethyl-silyldiazomethane. The resultant methyl esters were
than selectively and sensitively analysed by GC/MS
-
14
technique. The procedure has been applied for grass samples
spiked with four phenoxy acid herbicides: 2,4-D, dichlorprop, MCPA
and mecroprop.
Environmental monitoring is often realised by using the
non-direct methods; in such investigations the results of
contamination, e.g. presence of pollutants or products of their
transformation in food are determined. For example milk; being at
one of the highest levels of the tropic chain and due to its
lipophilic nature, milk has been usually studied as an indicator of
the bioconcentration process of environmentally persistent organic
micropollutants. Di Muccio and co-workers [17] developed a rapid
procedure that allows a single step selective extraction and
clean-up of organophosphate pesticide residues from milk, dispersed
on solid matrix diatomaceous material into disposable cartridges by
means of light petroleum saturated with acetonitrile and ethanol.
Recovery experiments were carried out on homogenised commercial
milk spiked with solutions of 24 pesticides. Bernal and co-workers
[18] presented a method for determination of vinclozolin
(agrochemical fungicide) in honey and bee larvae. LL or SPE
extraction techniques were used and two clean-up procedures
(chromatography on Florisil or Cls column) were assayed after the
solvent extraction. A clean-up method for organochloride compounds
in fatty samples based on normal-phase liquid chromatography is
described in work of van der Hoff et al. [19]. The use of liquid
chromatography column packed with silica enables complete
fat/organochloride pesticide separation in total fraction volume of
12 ml and results in a fully automated clean-up procedure.
Adsorption phenomena in the soil sampling and sample preparation
is rarely applied; it is used mainly to the clean-up of
extracts.
4. TIIE CHROMATOGRAPHIC METHODS
The detection and determination of pollutants in complex
environmental systems by conventional and biochemical methods is
difficult and time- consuming, and the results are often doubtful.
These methods are now being systematically replaced by instrumental
analytical methods, among which adsorption procedures play an
imporatan role; crucial meaning have the chromatographic
methods.
The idea of all chromatographic methods is the partition of
components of analysed mixture between two phases. One of these
phases is stationary; the second is the mobile phase which moves
along the stationary phase. Gas, liquid or supercritical fluid can
be the mobile phase; the separation techniques which use these
phases are called respectively: gas chromatography (GC), liquid
chromatography (LC) and supercritical fluid chromatography (SFC). A
solid or liquid can be the stationary phase; in the first case it
is adsorption chromatography (GSC), in the second one -
partitioning chromatography (GLC). If the stationary phase is in a
column we call it column chromatography (GC or High Performance
Liquid Chromatography - HPLC). In the case when adsorbent
-
15
is spread on a solid carrier plate in the form of thin layer and
attached to it we call it thin-layer chromatography (TLC). In every
case the separation is achieved by repeating distribution of
analytes between two phases of given chromatographic system.
In the column chromatography the compounds are eluted with the
mobile phase to a detector (universal or selective), which produces
a signal proportional to the amount of a particular substance in
this phase. The proper choice of column, injection technique and
temperature program will ensure the separation of interesting
substances from the background ones. Good separation efficiency is
one of the most critical parameters for reliable identification of
pollutants by a detector. Pollutants can be identified by means of
the absolute or relative retention times; a very useful parameter
of identification is also retention index. Quantitation can be
realised by internal or external standards. In cases of
environmental analyses very frequently compounds cannot be
separated from each other. These problems can often be solved by
chromatographic technique utilising two or more columns. In
multicolumn chromatography the columns may have widely varying
measurements and separation characteristics. The columns may be
connected either off-line or, nowadays much more often, on-line
technique.
Volatile or semi-volatile environmental pollutants which are the
subject of monitoring are usually analysed by GC. In this technique
sensitive and selective detectors such as the electron capture
detector (ECD) or the mass spectrometer (MS) are used. They enable
identification and quantitation of trace components in complex
mixtures. HPLC has been recommended for the analyses of thermally
labile, non-volatile and highly polar compounds. Application of
high performance adsorbents in TLC and sophisticated equipment
(apparatus for automatically spotting and developing chromatograms,
scanning densitometry) caused, that present instrumental TLC can
compete with the HPLC in terms of analytical efficiency,
sensitivity, and precision. Other chromatographic methods such as
SCFC and capillary electromigration have been currently developed
but for the time being their application in environmental analysis
is limited.
The studies on applications of chromatographic methods for
environmental investigation can be classified on the criteria of
goals of experiments. According to this criterion they can be
divided into three groups. These ones which refer to the monitoring
are represented the most frequently. The reports which can be
entitled "behaviour" are relatively numerous too. They refer to
behaviour (in term of resolution possibilities) of pollutants in
various chromatographic systems. The third group consists of the
works in which physical and chemical properties of pollutants, i.e.
their mobility, bioaccumulation, biotransformation etc. are
examined.
4.1. High Performance Liquid Chromatography High Performance
Liquid Chromatography (HPLC) is a form of column liquid
chromatography. In this technique the mobile phase is pumped
through the
-
15
packed column at high pressure and therefore HPLC is also called
High Pressure Liquid Chromatography. Columns are made of stainless
steel tubes 10-, 20 cm long and internal diameters (I.D.) of a few
millimetres. Depending on the type of interaction between
stationary phase, mobile phase and a sample, following separation
mechanisms can take place: adsorption, partition, ion exchange,
ion- pair and size exclusion.
In adsorption liquid chromatography mainly silica and (rarely)
aluminium oxide, cellulose and polyamide are used as stationary
phases. The separated molecules are reversibly bonded to the solid
surface by dipole-dipole interactions. Because the strength of
interaction is different for different molecules, residence time at
the stationary phase varies for different compounds; thus,
separation can be achieved. This technique is used mainly for
resolution of polar, non-ionic substances; in environmental
analyses it is used occasionally.
In the case of liquid- liquid partition chromatography
stationary phases (liquids) can coat a support or can be chemically
bonded to that support. Distribution mechanism is called
partitioning because separation is based on the use of relative
solubility differences of the sample in the two phases (in fact the
separation is also achieved through the adsorption by non-protected
silanol groups). In the normal phase (NP) liquid-liquid partition
chromatography, the stationary phase is more polar than the mobile
phase, in the reversed phase (RP) liquid-liquid partition
chromatography, the mobile phase is more polar than stationary
phase. The NP liquid-liquid partition chromatography is used for
separation of very polar organic substances, while the RP
chromatography (nowadays more popular technique) is used for the
non-polar or weakly polar compounds.
An example of using the liquid-liquid partition chromatography
for the environmental analyses can be the above mentioned work of
FalcSn et al. [14]. They used a HPLC-fluorescent detection method
for the determination of benzo[a]pyrene in the enriched extract of
the smoked food products. It should be stressed that the
determination of polycyclic aromatic hydrocarbons (PAHs) by HPLC
requires separation columns of high selectivity and efficiency.
Reupert and co-workers [20] proposed a method for the separation of
PAHs by the application of PAH 16-Plus column under optimal
operating conditions. A very good separation of 16 PAHs was
obtained (Figure 3).
Liquid-liquid partition chromatography is often employed in the
analysis of pesticides. The analysis of pesticide residues in the
environment is of great current interest due to the possible risks
that may arise from the exposure of humans and animals to such
agents. From among the latest papers concerning that problem the
special issue of Journal of Chromatography "Chromatography and
Electrophoresis in Environmental Analysis: Pesticide Residues" is
worthy to notice [21]. A good example of taking advantage of
liquid-liquid partition HPLC can be the paper by Somsen and
co-workers [22]. Precolumn packed with Cls (Polygosil) material for
the enrichment of herbicides was combined on-line with the column
liquid chromatography and Fourier-transform infrared
spectrometry.
-
17
100 -
80 -
60-
40
20
O-
9
11
11213
I I I I
0 10 20 30 40
Time, min
Figure 3. HPLC chromatogram of 10 ~tl PAHs standard (EPA) in
CH3CN; concentration of individual substances 90 pg/~tl. Emission
signals. Column- Bakerbond PAH 16-Plus; mobile phase H20 - CH3CN
(gradient elution). 1-naphthalene, 2-acenaphthene, 3-fluorene,
4-phenanthrene, 5-anthracene, 6-fluoranthene, 7-pyrene, 8-benzo [a]
anthracene, 9-chrysene, 10-benzo[e]pyrene, 11-benzo[b]fluoranthene,
12-benzo[k]fluoranthene, 13-benzo[a]pyrene,
14-dibenzo[a,h]anthracene, 15-benzo[g,h,i] perylene, 16-indeno[
1,2,3oc,d]pyrene. Reprinted from [20].
The isocratic separation was carried out on a 200x2.1 mm I.D.
C18 column (Rosil) using acetonitrile-phosphate buffer (40:60) as
eluent. The method was based on post-column on-line liquid-liquid
extraction and solvent elimination, followed by Fourier-transform
infrared spectroscopy. The feasibility of the complete system was
demonstrated by analysing river water spiked with triazines and
phenylureas at the ~g/1 level. Identifiable spectra were obtained
for all analytes. The authors showed that on-line trace enrichment
in combination with column liquid chromatography and
Fourier-transform infrared detector offers a selective method for
the characterisation of moderately polar analytes such as
phenylureas and triazines in water samples.
In the analysis of pesticides the degradation products also have
to be determined because these products will often possess such
activities as the parent pesticides. One ought to emphasise that
the analysis of pesticide degradation in environmental samples is
often difficult to perform due to the different polarities and
lower concentrations of the degradation products relative to the
parent compounds. Taking into account these difficulties Rollang,
Beck-Westermeyer and Hage [23] applied the RP liquid-liquid
partition chromatography and the high performance immunoaffinity
chromatography for determining the degradation products of the
herbicide atrazine in water. A high performance
-
18
immunoaffinity chromatography column containing anti-triazine
antibodies was first used to extract the degradation products of
interest from samples, followed by the on-line separation of the
retained components on C18 analytical column. The limits of
detection for hydroxyatriazine, deethylatriazine and
deisopropylatriazine were 20-30 ng/1. Usefulness of this method was
demonstrated in the analysis of both river water and groundwater
samples.
Rapid methods for the isolation and determination of
alkylphenols from crude oils with the use of partitioning
chromatography were described by Bennett et al. [24].
Determinations were performed by RP liquid-liquid partition HPLC.
The authors have proved that the method affords rapid and accurate
quantitation of phenol, cresols, dimethylphenols and is suitable
for screening large number of samples. They illustrated the methods
with two petroleum geochemical examples: determination of the
partition coefficients of alkylphenols in oil/brine systems under
high pressure and temperature conditions.
Leira, Botana and Cela [25] applied an effect of differences in
the retention capacity and selectivity of C18 and graphitized
carbon column to resolve complex mixtures of non-flavonoid
polyphenols (Table 1). Separation of mixture components was
accomplished in a single switching operation by using mobile phase
of the same composition but a different eluting strength in both
separation steps. The elution conditions used in both columns were
simplified by means of simulation software in order to obtain
multiple fractions. The potential of this technique was realised by
resolving a mixture of 38 very similar species (Figure 4).
AU
2.5
2 .0 - -
1 .5 - -
1.0 - -
0.5
0.0
@
II Ii. I TM , ]
I jl !1 iI A I I I-- - - - l i fl it t ,A ,ll ,,!i, | i I I I I
I 1 Pl if i I I I Iii I I II I I I I II i I I i [I II li I
V 7 VI
Q v i i I I I I
i I I I I I
!AN_ ' ' I I ~.~_ ~. I I I I
0 5 10 15 20
Minutes
Figure 4. Chromatogram of 38 non-flavonoid polyphenols.
Reprinted from [25].
-
19
Table 1 Listing of the non-flavonoid species studied; key
numbers match the spectrum labels in the figures, and heart-cut
groups the labels in Figure 4
Key Compound Heart-cut number Group
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
29 30 31 32 33 34 35 36 37 38
3-Hydroxybenzoic acid III 4-Hydroxybenzoic acid II 2,4
Dihydroxybenzoic acid (~-resorcylic acid) II 2,5 Dihydroxibenzoic
acid (gentisic acid) II 2,6 Dihydroxybenzoic acid (7-resorcylic
acid) I 3,4 Dihydroxybenzenzoic acid (protocatechuic acid) I 3,3
Dihydroxybenzoic acid (a-resorcylic acid) I 3,4,5-Trihydroxybenzoic
acid (gallic acid) 4-Hydroxy-3-methoxybenzoic acid (vanillic acid)
III 3-Hydroxy-4-methoxybenzoic acid (isovanillic acid) III
4-Hydroxy-3,5-dimethoxybenzoic acid (syringic acid IV 2,4
Dimethoxybenzoic acid 2,6 Dimethoxybenzoic acid IV
3,4-Dimethoxybenzoic acid V 3,5- Dimethoxybenzoic acid VII
2-Hydroxycinnamic acid (o-coumaric acid) VI 3-Hydroxycinnamic acid
(o-coumaric acid) V 4-Hydroxycinnamic acid (p-coumaric acid)
3,4-Dihydroxycinnamic acid (caffeic acid) III
4-Hydroxy-3-methoxycinnamic acid (ferulic acid) V
3,5-Dimethoxy-4-hydroxycinnamic acid (sinapic acid) V
3,4,5-Trimethoxycinnamic acid VII 2-Hydroxybenzaldehyde (salicyl
aldehyde) V 3- Hydroxybenzaldehyde III 4-Hydroxybenzaldehyde III
2,5-Dihydroxybenzaldehyde III
3,4-Dihydroxybenzaldehyde(protocatechialdehyde) III
3,5-Dimethoxy-4-hydroxybenzaldehyde 2-Hydroxy-3-methoxybenzaldehyde
(o-vanillin) V 4-Hydroxy-3-methoxybenzaldehyde (vanillin) IV
3-Hydroxy-4-methoxybenzaldehyde (isovanillin) IV
2,4-Dimethoxybenzaldehyde 3,4-Dimethoxybenzaldehyde
(veratraldehyde) V 3,5-Dimethoxybenzaldehyde VII
3-Methoxybenzaldehyde (m.-anisaldehyde) VI 4- Methoxybenzaldehyde
(p-anisaldehyde) VI 3,4,5-Trimethoxybenzaldehyde VI Chlorogenic
acid II
Reprinted from [25].
-
20
Ion-exchange chromatography is a separation procedure in which
ions of similar charges are separated by elution from a column
packed with a finely divided resin. The stationary phase consists
of acidic or basic functional groups bonded to the surface of the
polymer matrix. Charged species present in the mobile phase are
attracted to appropriate functional groups in the ion exchanger and
separated. Mixtures of bases and acids can be separated by this
technique. The stationary phases used in ion-pair chromatography
are the same as in RP chromatography. Ionic organic compounds (e.g.
C7H15803- - heptane sulfonic ion for bases or Bu2N - tetrabutyl
ammonium ion for acids), which form the ion-pair with the analysed
sample component of opposite charge, are added to the mobile phase.
This ion-pair is a salt, which behaves chromatographically like a
non-ionic organic molecule that can be separated by RP
chromatography. These methods found only limited application in
environmental analysis. D. Krochmal and A. Kalina [26] proved that
coupling the ion-exchange chromatography with active or passive
sampling of air pollutants gives the possibility of simultaneous
determination of sulphur dioxide and nitrogen dioxide. Both gases
can be quantitatively absorbed in aqueous solution of
triethanolamine and subsequently determined with ion chromatography
as sulphates and nitrates. Absorbing solutions were analysed with a
single column ion chromatograph equipped with a packed column.
Size-exclusion chromatography is a powerful technique applicable
for separation of high-molecular-weight pollutants. Packing
material for size- exclusion chromatography consists of a small
silica or polymer particles containing network of uniform pores
into which solute and solvent molecules can diffuse. In the
chromatographic process molecules are effectively trapped in pores
and removed by the flowing mobile phase. The compounds with higher
molecular weight cannot penetrate into the pores and are retained
to a less extend than smaller ones. Some of size-exclusion packing
materials are hydrophilic and are used with aqueous mobile phase
(gel filtration); others are hydrophobic and are used with
non-polar, organic solvents (gel permeation). In environmental
analyses size-exclusion chromatography is used for sample clean-up
and fractionation. For example, gel permeation chromatography is a
standard technique for the isolation of herbicides and fungicides
from samples that contain high-molecular-weight interferences, such
as solid waste extract, oil or fats [16].
In the case of environmental analyses information about
pollutants may be obtained not only from environmental matrix.
Kabzifiski [27] proposed a new analytical method for the
quantitative determination of metallothioneins protein in human
body fluids and tissues, in order to determine the level of
environmental and industrial exposition to heavy metals. For
metallothioneins isolation covalent affinity chromatography with
thiol-disulfide interchange was applied, which is a modern
technique of separation of high affinity, good repeatibly and
reproducibility, allowing specific isolation of the thiolproteins
and metallothiolproteins. Fundamentals of indirect determination of
the contents of metallothioneins protein were worked out throughout
estimation of the
-
21
quantities of metals bound with metallothionein protein and
adsorbed on covalent affinity chromatography gel as on the
solid-phase extraction support during a separating process.
4.2. Gas chromatography The term gas chromatography (GC) is used
to denote the chromatographic
techniques in which the mobile phase is a gas (the carrier gas,
mostly N2, H2, Ar or He). The stationary phase is placed in the
column; it may be a porous solid (GSC-gas solid chromatography,
adsorption chromatography) or viscous liquid (GLC-gas liquid
chromatography, partition chromatography). In both cases the
transport of components of analysed mixtures (adsorbates, analytes)
is realised exclusively in the gas phase, separation - exclusively
in the stationary phase. The time of passing of particular analytes
through the stationary phase and the frequency of interactions of
analytes with this phase are the decisive factors in the separation
process. In case of GSC separation occurs because of differences in
the adsorption equlibria between the gaseous components of the
sample and the solid surface of the stationary phase. In case of
GLC, in contrast to HPLC, there is no interaction between the
mobile phase and the analyte.
Glass, metal (copper, aluminium, stainless steel) or Teflon
tubes long 2-3 m and I.D. 2-4 mm are used for making the packed
columns to GC. Open tubular columns (capillary columns) are of two
basic types: wall coated open tubular (WCOT) and support coated
open tubular (SCOT). WCOT is the traditional capillary column made
of glass or stainless steel. The liquid phase is applied as a
continuous thin film on the inside walls of the tube. The newest
WCOT are fused silica open tubular columns (FSOT). This is a very
small outer diameter thin wall column that is inherently a straight
tube but is flexible enough to be coiled to diameters c.a. 20 cm.
FSOT are drawn from specially purified silica that contains minimal
amounts of metal oxides. Compared to packed column these
capillaries show inert surfaces and higher reproducibility with at
last equal separation efficiencies. PLOT (porous layer open
tubular) column is similar to a SCOT except for the fact, that the
support material is responsible for the separation through the
adsorption process. In a PLOT columns there is no coating liquid
phases.
There are two basic types of packing materials employed in GC.
The first type is porous materials used in GSC. The second type are
the support materials which are covered with a layer of liquid
phase used in GLC. The adsorption properties and selectivity of
adsorbents applied in GSC depend first of all on the chemical
composition and geometrical structure of their surface. There are
several kinds of attractive adsorbate-adsorbent interactions
occurring during the separation of mixturecomponents. The most
important interactions are: dispersion or London forces,
electrostatic forces, induction forces and specific interaction
(mainly charge-transfer, which occur between one component with n-
bonding electrons and showing small ionisation energy and the
second component showing high electron affinity). Among dozens of
different solids which have been
-
22
used in adsorption chromatography only few adsorbent types have
wide application today. Non-organic adsorbents such as silica,
aluminium oxide or Florisil and polymeric adsorbents type of Tenax,
Chromosorb or Porapak belong to the porous packings (which do not
need to be coated with stationary phases). They can directly be
used for adsorption chromatography. The carbonaceous adsorbents are
today used in gas adsorption chromatography rather
occasionally.
In case of GLC the stationary phase is a liquid (often
rubber-like), it is immobilised on the surface of a solid support
by adsorption or by chemical bonding. Liquid stationary phases are
applied both in packed and capillary columns. Packed columns are
completely filled with a packing, liquid stationary phases coating
an inert support such as diatomite (Kieselguhr), rarely Teflon or
glass spheres. Capillary columns do not require a support because
their inert walls are coated with the stationary phases. The most
important feature of liquid stationary phase is its polarity. The
very popular non-polar phases are Squalane (hexamethyltetracosane)
and Apolane-87 (24,14-diethyl-19,29-dioctadecylhapta-
tetracontane). Squalane is used as reference for determination of
polarity of other liquid phases in packed column.
Apolane-87 is high temperature standard phase used in capillary
chromatography. In environmental analyses semipolar phases are used
most often. That group of phases is mainly represented by
Silicones. Depending on the kind of substituent in oxosilanes chain
(dimethyl-, phenyl-, trifluoropropyl-, cyano- etc.), the weak-,
medium- and strong polar phases can be prepared. Polygethylenelycol
is an example of strong-polar phase. Among specific liquid phases a
family of polysiloxane stationary phases (Chirasil), developed for
the separation of optical enantiomers, has a great practical
importance. Chemicaly bonded phases used in GLC are identical as
twere used in HPLC.
Barrefors et al. [28] showed that furan and alkylfurans might be
selectively analysed on PLOT (aluminium oxide) columns, since other
oxygen-containing compounds are normally not eluted. Furan,
2-methylfuran, 3-methylfuran, 2,5-dimethylfuran and the five
isomeric C6 alkylfurans, two C7 and three C6-C7 alkenylfurans were
determined by adsorbent sampling and GC/MS technique. Separation on
PLOT column is presented on Figure 5. Furan elutes after isoprene
and cyclopentadiene in the same region as minor pentadienes and
branched hexanes. Several minor C6 and C7 furans appear.in the
chromatographic range before and after methylbenzene. The purpose
of this study was to characterise volatile furans in birdwood smoke
which may be of interest with respect to human exposure and as
indoor and outdoor wood-smoke tracers in studies of air
pollutants.
An analytical method to determine highly volatile saturated
aldehydes, degradation products of lipid peroxidation, was
developed for the capillary GC [29]. The carbonyl compounds were
derivatized quantitatively with 2-hydrazinobenzothiazole at room
temperature to form their corresponding water-insoluble hydrazones.
The derivatives were extracted and detected with high selectivity
(Figure 6) by high-resolution GC with nitrogen-phosphorous
-
23
m
C
k
9
0 I I~I
5
9
10 20 -1
4~ min 200~ isothermal
m
3O L . | v ,
Figure 5. Gas chromatographic separation on aluminium oxide
column of prominent furans, alkadienes. Reprinted from [28].
34 ISTD,
21
5
6
1 - Methanal 2- Ethanal 3 - Propanal 4- Butanal 5 - Isopentanal
6- Pentanal
7 - Hexanal
I I I I
0 5 l 0 15 Time (min)
Figure 6. Typical gas chromatogram of the
2-hydrazinobenzothiazole-derivative aldehydes. ISTD- internal
standard: 2,4 pentanedione-2-hydrazinobenzothiazole-derivative.
Reprinted from [29].
-
24
detection due to their high nitrogen content. Analyte
concentration, pH and type of extraction technique (LLE and SPE)
were studied to determine optimal recovery conditions. The method
was applied to the analysis of the volatile aldehydes generated
during the thermal oxidation of olive oil at 220~
Begerov and co-workers [30] applied the screen method for the
simultaneous determination of 28 volatile organic compounds in the
indoor and outdoor air at environmental concentrations. Using
passive (sorption-diffusive) samplers, the volatile organic
compounds were adsorbed onto charcoal during a four-week sampling
period and subsequently desorbed with carbon disulphide. The eluate
was split via an Y-connector and led onto two capillary columns of
different polarity switched in parallel. This dual column
configuration provides additional information about the volatile
organic compound components and can be obtained for verification
purpose. Detection was in both cases performed by connecting each
column with a non-destructive electron-capture detector and a flame
ionisation detector switched in series. The procedure has been
successfully applied in the context of a large field study to
measure outdoor air concentration in three areas with different
traffic density (Figure 7). It is applicable to indoor air
measurements in a similar manner.
a) b)
7 0.275]--~
0.345 1 4 11 0.265
0.305 13
0.305 2 5 10 17 0.255
1516 3 1 0.245, , .- 0.285 8 14 / ," - -"""
6 r " 18 . . - ' " 0.265 " "
0.245 , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,
, , , , , 5 10 15 20 25 30 35 40
Time (min)
Figure 7. Typical gas chromatograms of an indoor air sample
obtained by flame ionisation detection. (a) more polar column, (b)
less polar column. Reprinted from [30].
Lobiafiski et al. [31] studied the potential of the
microwave-induced plasma atomic emission detector for capillary GC
(GC/AED) as a tool for the specification of organotin compounds in
environmental samples. The operational variables are optimised for
chromatographic resolution and detection limits. A
comprehensive
-
25
method for the determination of mono-, di-, tri-, and some
tetraalkylated organotin compounds in water and sediments by GC/AED
was developed. Ionic organotin compounds were extracted as diethyl
dithiocarbamates into pentane and, after its evaporation, dissolved
in a small volume of octane and derivatized by pentylmagnesium
bromide to give the solution suitable for gas chromatography.
The phenoxy acids were first introduced as herbicides in the
late 1940s. They have found widespread usage in the post-emergence
control of annual and perennial broad leafed weeds cereals and
grasses. Functioning as synthetic plant growth regulators these
herbicides accumulate in the roots and stems of the plants. A
method for the determination of phenoxy acid herbicides in
vegetation samples is described among other things in the work of
Rimmer and co-workers [32]. Macerated samples were extracted with
acetone. After filtration and acidification they were introduced
into dichloromethane. The herbicides were than cleaned-up using
high-resolution gel permeation chromatography.
Analysis of PCB normally includes extensive sample clean-up and
preconcentration followed by high resolution capillary GC either
with electron capture or mass-selective detection. Although both
techniques provide the high sensitivity required for PCB
investigations, quantitative analysis is complicated by structural
variations of detectors-response factors. The quantitative aspect
of GC with atomic emission detection (GC/AED) used for the analysis
of PCB is presented in work of Bjergaard et al. [33]. Since
Cl-responses were almost independent on the PCB structure,
individual PCBs were quantitated with an acc