11 CHAPTER 2 LITERATURE REVIEW 2.1 INTRODUCTION In this chapter the literature available within the purview of the objectives of the present study is reviewed. The need for the proposed work is also discussed. 2.2 REMOVAL OF CONTAMINANTS USING ORGANIC ADSORBENTS Shokoohi et al (2009) have studied the influence of various experimental parameters such as initial iron concentration, dosage of biomass and contact time in removing iron from the aqueous solution by using dried biomass of activated sludge. From the study it was inferred that when the concentration was 2 mg/L the removal efficiency was 70% and subsequently it decreased to 56% when the concentration of the solution was increased. Shokoohi et al (2009) have concluded that the above influence is due to the driving force of the concentration gradient, and increase in initial iron concentration. Rakhi Gopalan (2007) has investigated the adsorption of hexavalent Chromium from the chrome plating industry effluent using tapioca peel carbon. Both batch and column experiments were conducted and the optimum pH and dosage were found to be 3 and 400 mg respectively. The removal efficiency was found to be 82% based on the experiments. They have
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11
CHAPTER 2
LITERATURE REVIEW
2.1 INTRODUCTION
In this chapter the literature available within the purview of the
objectives of the present study is reviewed. The need for the proposed work is
also discussed.
2.2 REMOVAL OF CONTAMINANTS USING ORGANIC
ADSORBENTS
Shokoohi et al (2009) have studied the influence of various
experimental parameters such as initial iron concentration, dosage of biomass
and contact time in removing iron from the aqueous solution by using dried
biomass of activated sludge. From the study it was inferred that when the
concentration was 2 mg/L the removal efficiency was 70% and subsequently
it decreased to 56% when the concentration of the solution was increased.
Shokoohi et al (2009) have concluded that the above influence is due to the
driving force of the concentration gradient, and increase in initial iron
concentration.
Rakhi Gopalan (2007) has investigated the adsorption of hexavalent
Chromium from the chrome plating industry effluent using tapioca peel
carbon. Both batch and column experiments were conducted and the optimum
pH and dosage were found to be 3 and 400 mg respectively. The removal
efficiency was found to be 82% based on the experiments. They have
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concluded that tapioca peel carbon is more effective in removing Chromium
from wastewater.
Tiwari et al (1995) have investigated the removal of Mercury (II)
from the aqueous solution using the rice husk ash. Both batch and column
experiments were conducted and in the column experiment a circular column
was used and the flow rate was varied from 20-45 mL/min and the pH of the
solution was maintained at 5.5. The study revealed that the adsorption
efficiency decreases with increase in particle size.
Mansour et al (2011) have investigated the removal of Cu (II) ion
from wastewater by adsorption onto polyaniline coated on sawdust. The
concentration of the metal solution was ranged from 5 mg/L to 40 mg/L. The
pH range was 2-8. The adsorption capacity was found to be strongly
dependent on the initial pH of the solution. The adsorption of Cu (II) ions was
significant with the slight increase in pH. The optimum pH was found to be 6
and optimum contact time was 20 minutes. It is found that the sorption
capacity is strongly dependent on the initial concentration and initial pH of
the solution.
Tarek Abdel et al (2000) have carried out a research work on
Fluoride removal from drinking water using activated carbon prepared from
naturally occurring zeolites and molecular sieves. Aqueous solution was
prepared from sodium solution. The initial fluoride concentration was 10mg/l
and the dosage of the adsorbent was 4g/l. It was found that the equilibrium
condition was reached within 48 hours for all combination of adsorbent. It
was found that char fines and bentonite exhibit a removal capacity of 38%
and 40% respectively.
Hameed et al (2009) have studied the effect of pH on the adsorbing
capacity of dye using agricultural waste. pH was varied from 2 to 10 and it
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was found that the adsorbing capacity increased from 13.29 mg/g to
104.50 mg/g when the pH varied between 2 and 10 .The authors used
pineapple stem for removing cationic dye and studied the potentiality of its
usage. The surface texture of the adsorbent was studied using Scanning
Electron Microscope before and after adsorption and Fourier Transform Infra
Red analysis was applied and the spectra was recorded. From the study, the
results indicate that pineapple stem was very effective in its adsorbent
property.
Danica Barlokova et al (2009) have made studies on the removal
of Iron and Manganese from small water sources by passing the raw water
containing Iron and Manganese through the filtration materials namely
Klinopur-Mn, (activated zeolite), Birm (granulated filter medium) and green
sand. From the study it was found that Kilnopur - Mn was effective in
removing both Iron and Manganese, but the other materials showed lower
efficiency in Manganese removal and found to be effective in Iron removal.
Manjeet Bansal et al (2008) studied the removal of Cr (IV) from
aqueous solution using rice husk. He used two forms of rice husk namely
boiled rice husk and formaldehyde treated rice husk. He conducted batch
studies by varying the parameters such as pH, dosage and agitation speed. The
initial concentration of the solution was taken as 100mg/L, the contact time
was fixed as 180 min, pH of the solution was maintained as 2. The removal
efficiency for boiled rice husk was found to increase from 33.2% to 71% with
increase in dosage from 2 g/L to 4 g/L. Similarly for formaldehyde treated
rice husk the removal efficiency increased from 38% to 78.5% with the
increase in dosage from 5 g/L to 4 g/L. The results indicate that the metal
removal was found to be maximum at pH 2. It is also found that there is no
much difference in adsorption capacity of boiled rice husk and formaldehyde
treated rice husk.
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Veeraputhiran and Alagumuthu (2011) have investigated the
efficiency of activated carbon prepared from Phyllanthus emblica (Indian
Gooseberry) for fluoride removal from groundwater. It was concluded that the
rate of adsorption of fluoride was increased with increase in contact time.
Also the adsorption capacity decreases with increase in concentration. The
removal efficiency at 2 mg/L concentration was found to be 87.95% and at
10 mg/L it was found to decrease to 47.22%. It was concluded that the
removal efficiency is highly dependent upon contact time, adsorption dose
and concentration and fluoride could be successfully removed from
groundwater using Phyllanthus emblica based activated carbon.
Bhargava et al (2008) have studied the removal of fluoride by
adsorption using fish bone charcoal. The concentration of the solution was
maintained as 6.5 mg/L and pH of the solution was varied from 6 - 9 and the
agitation speed was maintained at 100 rpm to perform batch studies. It was
found that fluoride removal was efficient for pH values less than 9. With
respect to contact time it was found that the fluoride removal increases with
increase in time and it has reached its equilibrium condition in about
540 minutes.
Veeraputhiran and Alagumuthu et al (2011) have studied the
fluoride adsorption capacity using Cynodon dactylon (Bermuda grass) based
activated carbon. The concentration of fluoride solution was varied from
2 mg/L to 10 mg/L with dosage of adsorbent as 1.25 g and the contact time
was maintained at 105 minutes. The adsorption of fluoride decreased from
84% to 51% with increase in fluoride concentration from 2 mg/L to 10 mg/L.
Along with the batch study the effect of coexisting anions such as sulfate,
nitrate, chloride and bicarbonate on fluoride adsorption was studied using
Cynodon dactylon adsorbent. It was found that chloride and nitrate ions did
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not interfere with fluoride removal upto the concentration of 500 mg/L, while
the sulphate ion showed some adverse effects in the removal process.
Lalhruaitluanga et al (2011) have carried out a research to study the
feasibility of chemically activated raw charcoals of Melacanna baccifera
(bamboo) for the removal of Ni (II) and Zn (II) from aqueous solution. Batch
adsorption studies were conducted by varying the adsorbent quantity from 0.1
g to 0.5 g. The concentration was kept constant at 50 mg/L and 30 mg/L. It
was found that beyond 0.4g, the adsorption capacity decreases which is due to
the overlapping and aggregation of adsorption sites resulting in the decrease
of the surface area available for the metal ions. Lalhruaitluanga et al (2011)
have concluded that chemically activated charcoal of Melacanna baccifera has
higher adsorption capacity than the raw charcoal.
Anjali Gupta et al (2010) have evaluated the effect of novel space
granular chitosin impregnated with molybdate for the removal of arsenite and
arsenate from contaminated water by conducting column studies. Fixed bed
column reactor was employed with a flow rate of 10ml/min. Batch adsorption
experiments were carried out by varying the pH from 4 to 10.The maximum
adsorption was obtained for a pH of 7 for both AS (III) and AS (V). It is
proved that chitosin impregnated with molybdate has been very effective in
both AS (III) and AS (V) in complete removal.
Senthil Kumar et al (2010) have made an attempt to study the
feasibility of Bengal gram husk (BGH) for the removal of ion Fe(III) . The pH
of the aqueous solution was varied from 0.5 to 3 and it was observed that the
removal efficiency increases with increased pH. The dosage of the adsorbent
was varied from 5 to 30 mg/L and significant increase in uptake was observed
when the dosage was increased and the maximum removal of 77.35% was
observed at adsorbent dosage of 20 g/L. The increased contact time raised the
iron adsorption and it remains constant after equilibrium in 30 minutes. From
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the above results it can be concluded that Bengal gram husk powder has high
potential in removing iron from aqueous solution.
Mohd Rafatullah et al (2010) reviewed the adsorption of methylene
blue on low cost adsorbents such as agricultural wastes, industrial solid
wastes, biomass, clay minerals and Zeolites. Among the various adsorbents
used for removal of methylene blue dye, the fly ash was found to be an
effective adsorbent. The adsorption capacity of fly ash was found to be 6.46
mg/g. The authors have concluded that a number of inexpensive, locally
available materials can be employed in place of commercial activated carbon
in removing the contaminants.
Kailash Daga and Pallav (2009) have made an attempt on the
adsorption of Zinc (II) onto polyvinyl alcohol coated datura stramonium and
by varying the dose from 3-6 g/L. The adsorption capacity was found to be
17.24 mg/g for a pH of 8 for a removal efficiency of 74.3%. Kailash Daga and
Pallav (2009) concluded that polyvinyl alcohol coated with datura
stramonium available cheaply and widely in Thar Desert can be used for
preparation of adsorbent with high adsorption capacity.
Karthikeyan et al (2005) used chitin for iron (III) removal by
adsorption study. The initial concentration of the iron (III) solution was
maintained at 10 mg/L. The dosage was varied from 10 – 30 mg. Maximum
adsorption occurs at the 8th minute after which the adsorption remains
uniform. The time variation curve was smooth with the formation of
monolayer coverage on the outer interface of the absorbent. It was found that
sorption of iron increased at higher concentrations and dosages.
Munavallin et al (2010) have made comparitive studies of
defluoridation techniques. Various adsorbents such as activated alumina,
activated carbon, brick powder of used tea powder were used as absorbents.
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For all the absorbents it was found that the removal of fluoride increased with
increase in dose of adsorbent till equilibrium is reached. It is also observed
that the adsorption of fluoride increased with time and there is no significant
change beyond a contact time of 60 minutes. The minimum contact time
required for adsorption is independent of initial concentration of fluoride.
Tonni Agustiono Kurniawan et al (2006) compared the effects of
low cost adsorbents for treating waste waters laden with heavy metals, it was
found that low cost adsorbents prepared from agricultural waste have
demonstrated outstanding removal capacity for Cr (VI). The adsorption
capacity was 170 mg/g of hazelnut shell activated carbon, for Ni (II), it was
158mg/g of orange peel, for Cu (II), it was 154.9mg/g of chemically modified
soybean hull, for Cu (II), it was 52.08 mg/g of jackfruit.
Emine Malkoc et al (2006) conducted batch and column studies to
find the adsorption capacity of Chromium (VI) on pomale an olive oil indenty
waste. The effect of pH on the Cr (VI) was investigated by varying the pH
value as 2, 3, 4 and 5 by fixing the contact time as 180 min. The adsorption
capacity of Cr (Vl) at pH 2 was 8.4mg/g which reduced to 2.7 mg/g at pH 5.
In the column study influent flow rate were varied from 5 mL/min to
20 mL/min with bed depth as 10 cm. It was found that breakthrough curve
becomes steeper when the flow rate was increased.
Adeniyi Ogunlaja et al (2010) conducted activity tests using Co-Mo
catalysts prepared from egg shell based activated carbon using silicon dioxide
as supporting element for the hydrogenation of methyl orange. The catalysts
were prepared from leached and unleached carbon. It was found that Co is
more efficient in hydrogenating methyl orange than Mo.
Subramanyan Vasudevan et al (2009) have carried out a research
on the removal of iron from drinking water by electro coagulation. The
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parameters such as pH, temperature and current density were considered.
Langmuir and Freundlich isotherms were plotted. The results revealed that the
removal efficiency of 98.8% was achieved at pH 6.5.The temperature studies
also showed that the adsorption was endothermic and spontaneous.
Olayinka Kehinde et al (2009) have compared the efficiencies of
two low cost adsorbents in the removal of chromium and nickel from aqueous
solution. Coconut husk and teak tree bark based adsorbents were employed
for the removal of chromium and nickel. The influence of pH, dosage, contact
time and temperature were studied. The coconut husk adsorbents gave better
results the teak tree bark adsorbents at the increased contact time it was also
found that the percentage of adsorption of the adsorbents increased with
increasing adsorbent dosage. From the results it is found that coconut husk
adsorbent was more efficient in removing the metals when compared with
teak tree bark adsorbent.
Kadirvelu and Namasivayam (2001) have made studies on the
removal of Nickel (II) from aqueous solution onto the activated carbon
prepared from coirpith. The batch experiments were conducted and the
concentration of the solution was varied from 10-40 mg/L and the removal
efficiency was found to be 100% for the concentration of 20 mg/L solution.
The results indicate that the removal of metals was strongly dependent on the
pH of the solution. The removal efficiency was increased from 0% to 100%
for a concentration of 20 mg/L and 80% for 40 mg/L with the pH range of
2 to 7. The authors have also made the desorption studies by using HCl, and it
indicated that ion exchange is an important process in the adsorption of metal
ion by carbon.
Vishwanath (1974) has investigated the effect of Lignite in the
removal of Nickel from the aqueous solution and conducted batch
experiments. The effect of the parameters such as sorbent particle size, pH,
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sorbent/sorbent ratio, retention time, temperature and carbonate ion
concentration was varied. The removal efficiency was found to be 98% at the
retention time of 30 minutes and the optimum pH was found to be 12.6.
Ramesh et al (2009) have prepared activated carbon from green pea
peels for treating dyeing industry wastewater. Wastewaters from textile
industry were collected. 100 ml of the sample was collected and agitated with
0.5 g of adsorbent at 120 rpm. The adsorbent dose was varied from 0.5 g to
3.5 g and pH was varied from 3 to 10. The results revealed that the removal
efficiency increases with agitation time and attains equilibrium after
60 minutes and remains constant thereafter.
Belgin Bayat (2002) has studied the properties of turkish fly ashes
and made a comparative study for the adsorption of copper, nickel and zinc
ashes such as Afsin-Elbistan fly ash and Seyitomer fly ash. The pH was
varied from 3 to 6 and it was found that pH had a greater influence in the
removal efficiency. Equilibrium time was maintained as for minutes. The
effect of concentration, pH and contact time was studied and the results
revealed that the adsorption efficiency for copper was found to be more than
that of zinc and nickel.
Kermit Wilson et al (2006) have carried out research on select
metal adsorption by using activated carbon made from peanut shell. The
metals considered were cadmium, copper, lead, nickel and zinc. The activated
carbon was prepared by different methods such as pyrolysis steam activation,
oxidation and ash removal. It was found that carbons with higher titratable
functional groups are better at binding metal ions than those carbons with
fewer amounts of titratable functional groups.
Ramesh et al (2008) have made studies on COD removal using
cement kiln dust based adsorbents. The adsorbent dose of 4 g was mixed with
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100 ml sample and it was stirred at 150 rpm in an orbital shaker. It was found
that the removal efficiency of COD increased gradually from 5 minutes and
attained its optimum level at 90 minutes. In this optimum time removal
efficiency of 82% was achieved. Finally it can be concluded that the
maximum adsorption capacity of cement kiln dust based adsorbent was
19.56 mg/g.
Sreenivasulu et al (2010), have conducted experiments on the
adsorption of chromium on acid treated soapnut tree stem bark carbon. The
concentration of chromium was varied from 1.25 mg/L to 50 mg/L. The
stirring speed was maintained as 120 rpm. Equilibrium time was maintained
at 5 hours. The experiment data show 68.4% removal for chromium ion at
pH 3.7 and adsorbent dose of 6 g/L.
Halil Hazar (2003) has investigated the removal of Nickel (II) from
aqueous solution using activated carbon prepared from almond husk and
found that the removal efficiency at 25 mg/L concentration was 97.8% and at
250 mg/L concentration was 68.6%. The data reveal that activated carbon
prepared from almond husk could be used effectively as a potential adsorbent
for the removal of Nickel ions from aqueous solution.
Demirbas (2002) has made equilibrium studies on the removal of
Nickel (II) from aqueous solution by adsorption onto hazelnut shell activated
carbon by varying the parameters such as pH, contact time, temperature,
agitation speed, concentration and the particle size of the adsorbent and pH
was varied from 3 to 8. The studies were carried out at equilibrium contact
time of 180 minutes. Initial metal ion concentration was varied from
15-200 mg/L. It was found that the adsorption efficiency increased as the pH
of the solution was increased.
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Malathy and Rajkumar (2008) have investigated the use of fly ash
for the removal of colour from the textile factory effluent. The effect of pH,
dosage and concentration of the solution were studied and the maximum
adsorption was found to take place when the pH of the solution was 8. The
retention time was kept for 3 hours. The results showed that fly ash could be
used as an alternative to other adsorbents to reduce the pollution
concentration discharged from dying industries.
Xin Huang et al (2009) have made studies on the adsorption
removal of phosphate in industrial wastewater using metal – loaded skin split
waste taken from the tannery industries. The adsorbent dose taken was 0.1g
and the pH of the solution was adjusted to 7 and the column studies were also
conducted with a constant flow rate of 40 mL/h. Studies revealed that skin
split waste loaded with Fe (III) exhibit good results when compared to skin
split waste loaded with Al (III).
Xiaotian Xu et al (2011) have prepared magnesia loaded fly ash
cenospheres for fluoride removal from aqueous solution. Coal fly ash has
been employed by impregnating it at wet condition with magnesium chloride.
The physiochemical properties were analysed using Scanning Electron
Microscopy and Fourier Transform Infrared Spectrometry. The maximum
adsorption capacity was about 6.0 mg/g with the concentration of the solution
as 100 mg/L with pH 3. It has been concluded that magnesia loaded fly ash is
low cost and found to be more effective in removing fluoride from aqueous
solution.
Raju and Saseetharan (2010) have carried out research on the
removal of lead from metal plating industries using sludge based activated
carbon. The parameters such as pH, contact time and dosage were varied. The
contact time was varied from 0 to 30 minutes with an interval of 5 minutes
and the dosage was varied from 0.25 g to 2g. It was observed that the
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optimum contact time was 20 minutes with the adsorbent dosage of 1g. The
pH of the solution was varied from 2 to 9. It is clearly understood that the
lead removal was 96% at optimum contact time of 20 minutes and optimum
pH of 5.3, and these results show that sugar mill sludge based carbon can be
an effective alternative to commercial activated carbon for lead removal.
Kalpana et al (2010) have determined the efficiency of eggshell
powder in removing cadmium ions from aqueous solution. Batch studies were
performed to optimize the experimental conditions. The parameters such as
concentration, contact time, dosage and partical size were varied. The results
revealed that percentage biosorption of cadmium decreased with increase in
metal ion concentration. Dosage of the adsorbent was varied from 0.1 g to
0.5 g. At pH 6 and at optimum contact time of 90 minutes the adsorption
capacity of the eggshell powder was found to be 34.38 mg/g.
Ajmal et al (2000) employed orange peel for Ni (II) removal from
simulated wastewater. They found out that the maximum metal removal from
simulated wastewater. They also found out that the maximum metal removal
occurred at pH 6.0 and that the adsorption followed Langmuir isotherm,
indicating that Ni (II) uptake might occur on a homogeneous surface by
mono-layer adsorption. A metal adsorption capacity of 158 mg/g was
achieved at 323 K.
Babel and Kurniawan (2004) investigated the applicability of
Coconut Shell Charcoal (CSC) modified with oxidising agents or chitosan for
Cr (VI) removal. They found out that CSC oxidised with nitric acid had
higher Cr adsorption capacities (10.88 mg/g) than that oxidised with sulphuric
acid (4.05 mg/g) or coated with Citosan (3.65 mg/g). The results suggest that
surface modification of CSC with a strong oxidising agent generated more
adsorption sites on its solid surface for metal adsorption.
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Bansode et al (2003) made studies on Cu (II) and Zn (II) removal
from real wastewater using pecan shells activated carbon. Some treated pecan