dsorption sotherms fo r Phenol Onto ctivated arbon awaiah Imam Maarof assim H ameed ax 604-5941013 Email: [email protected]bdul Latif hmad School of ChemicalEngineering Engineering ampus University ien e Malaysia eri Ampangan Nib ong Tebal 14300 eberang Pe ra i Selatan Pulau Pina ng Malaysia Thislaboratorystudy investigatedthe ef fect ivenessoftwotypes ofact iva tedcarbons ACs , NORIT GranularActi vated Carbon NAC 1240 and OR T GranularActivat ed Carbon 01 0 NAC 010 , for the removal of phenol from aqueous solutions. The study was carried ou t under batch mode at dif fer ent in it ia l concentrations 10-60 mg/I and at temperature of 30°C. The adsorption isotherm parameters for the LangmUir an d Freundlich models were determined usin the adsorption data. It was found that both the Langmuir an d the Fr eundli ch isot he rms described we ll the adsorption behavior of phenol on NAC 010 while the Freundlich isotherm described very well the adsorption of phenol on NA C 1240. Keywords Activated carbon AC , adsorption, Langmuir and Freund li ch isotherm models, phenol , and wastewate r treatment. INTRO U TION Phenol a n d phenolic derivatives are the organic chemicals that appear ver y freq ue ntly in wastewater from almost all heavy chemical, petrochemical, an d oil re fi ning indust ri es. Large amounts of wastewater are usually generated during the manufacturing a n d processing stages of organic chemicals. Th e concentration of these organic matters in wastewater usually exceeds the level for safe discharge. Thus the removal of organic compounds from wastewater ha s become a priority in th e management of wastewater treatment syst ems in chemical, petr ochemical, an d oil industries. Various methodshave been proposedforthe removal of phenolic compounds in wastewater. These methods are often based on biochemical oxidation and solvent extraction Streat 1998 . The main limitation of these methods, however, is their low efficiency in the removal of tr ace- level phenols. Among the more established of these methods is the cat aly ticwet air oxidation CWAO which permits detoxification of hazardous substances at relatively mild conditions
7
Embed
Adsorption Isotherms for Phenol Onto Activated Carbon
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
8/13/2019 Adsorption Isotherms for Phenol Onto Activated Carbon
School ofChemical Engineering Engineering ampusUniversity ien e Malaysia eri Ampangan Nibong Tebal
14300 eberang Perai Selatan Pulau Pinang Malaysia
This laboratory study investigated the effectiveness of two types of activated carbons
ACs , NORIT GranularActivated Carbon NAC 1240 and OR TGranular Activated
Carbon 010 NAC 010 , for the removal of phenol from aqueous solutions. The
study was carried out under batch mode at different initial concentrations 10-60
mg/I and at temperature of 30°C. The adsorption isotherm parameters for the
LangmUir and Freundlich models were determined using the adsorption data. Itwas found that both the Langmuir and the Freundlich isotherms described well theadsorpt ion behavior of phenol on NAC 010 while the Freundlich isotherm
described very well the adsorption of phenol on NAC 1240.
Keywords Activated carbon AC , adsorption, Langmuir and Freundlich isotherm models, phenol,and wastewater treatment.
INTRO U TION
Phenol and phenolic derivatives are the
organic chemicals that appear very frequently in
wastewater from almost all heavy chemical,
petrochemical, and oil refining industries.
Large amounts of wastewater are usually
generated dur ing the manufacturing and
processing s tages of organic chemicals. The
concentration of these organic matters in
wastewater usually exceeds the level for safe
discharge. Thus the removal of organic
compounds from wastewater has become a
priority in the management of wastewater
treatment systems in chemical, petrochemical,and oil industries.
Various methods have been proposed for the
removal of phenolic compounds in wastewater.
These methods are often based on biochemical
oxidation and solvent extraction Streat 1998 .
The main limitation of these methods, however,
is their low efficiency in the removal of trace-level
phenols. Among the more established of these
methods is the catalytic wet air oxidation CWAO
which permits detoxification of hazardous
substances at relat ively mild conditions
8/13/2019 Adsorption Isotherms for Phenol Onto Activated Carbon
was found to be at 0.0322. This value confirmsthat the present adsorpt ion sys tem reveal
favorable.·
ON LUSIONS
It is well known that matching the pore size
of adsorbent and the size of adsorbate molecule
should be considered when explaining the
adsorption process. The phenol molecular
diameter is in the range of approximately 0.8
1.0 nm Lange 1985 . The ave rage pore
diameter ofthe ACs are approximately 2-3 times
those of phenol, which means that it is easy for KNOWLEDGMENT
phenol to diffuse into the inner pores ofthe ACs
and adsorb on the internal surfaces. Thus, fne The authors acknowledge the research grant,
range of pore sizes is appropriate for phenol to which resulted in this paper, provided by the
adsorb and is not an important factor in the University Science Malaysia at Penang.
adsorption process.
The adsorption tendency between the ACs NOT TION
used, however, cannot be explained by suchphysical properties as surface area and pore b adsorption energy constantdiameter. Therefore, the adsorption of the Langmuir adsorption
characteristics ofphenol on NAC 1240 and NAC isotherm
010 may be interpreted in terms of their Ce
equilibrium liquid-phase
chemical aspects. concentration
Jt-hadbeen-repmte.d that the a d s e F J i e F l - - B f - - - - G ~ - - - i n i t i a l l i q u i d P h a s ephenol on ACs may imply an electron donor- concentration
acceptor complex or may even involve dispersion KF
Freundlich isotherm constant
forces between 1r -electrons in phenol and 1r - related to the adsorption
electrons in ACs (Coughlin and Ezra 1986). Al- capacity m/g l/mg n
Oegs et al. (2000) also explained that the n Freundlich isotherm constantdifferences in the capacities of adsorbents for related to adsorption intensitythe same adsorbate were caused by former s Q maximum surface coverage
surface properties. (formation of monolayer)
Activated carbon has high-adsorption of sorbent
capacity for reactivity towards a wide range of qe equilibrium solid-phaseorganic pollutants. This reactivity arises from the adsorbate concentration
complexity of its chemical surface groups R correlation coefficient
compared to those of other surfaces. RL
dimensionless separation factor
V volume of solution
W weight of adsorbent
Phenol was found to adsorb strongly on the
surface of both commercial ACs NAC 1240 andNAC 010.
The equilibrium time for the adsorption of
phenol on NAC 010 was achieved in almost 3 h
when up to 96 of phenol had already been
removed from the aqueous solution. In contrast,
the equilibrium for NAC 1240 was attained
in 24 h up to 85 of phenol had been
removed.
Both the Langmuir and Freundlich isotherm
models described well the adsorption behaviorof phenol on NAC 010; while the Freundlich
REFEREN ES
Abdulkrim, M. A., DarWish, N. A., Magdy, Y
M. Owaidar, A. (2002). Adsorption of
phenolic compounds and methylene
blue onto activated carbon prepared
from date fruit pits, Eng Life SeL 6
161-65.
Al-Oegs Y, Khraisheh, M. A. M. Allend, S. J.
and Ahmad, M. N. (2000). Effect of
carbon chemistry on the removal of
reactive dyes from textile effluent, Wat
Ews 34, 3, 927-35.
8/13/2019 Adsorption Isotherms for Phenol Onto Activated Carbon