**7. Adsorption of other organic pollutants**

Other organic pollutants were found as a pollutants in water and wastewater, this include pharmaceutical effluents, surfactants, organic solvents, phthalates, hydrocarbons, esters, al‐ cohols,volatile, semi-volatile and non-volatile chlorinated organic pollutants. Activated car‐ bons, calys and clay minerals are used widely for the removal of organic pollutants.

#### **7.1. Adsorption on activated carbon**

Adsorption on activated carbon is currently the most frequently used technology for remov‐ ing organic pollutants from aqueous industrial sludge, surface waters and drinking water. Methyl tert-butyl ether (MTBE) is an organic pollutants used mainly as a fuel component in fuel if gasoline engine and also as a solvent. The adsorption of methyl tert-butyl ether (MTBE) by granular activated carbon was investigated, the maximum adsorption capacity of MTBE on granular activated carbon was 204.1 mg/g. Results illustrate that granular activat‐ ed carbon is an effective adsorbent for methyl tert-butyl ether and also provide specific guidance into adsorption of methyl tert-butyl ether on granular activated carbon in contami‐ nated groundwater [82].

A novel triolein-embedded activated carbon composite adsorbent was developed. Results suggested that the novel composite adsorbent was composed of the supporting activated carbon and the surrounding triolein-embedded cellulose acetate membrane. The adsorbent was stable in water, for no triolein leakage was detected after soaking the adsorbent for five weeks. The adsorbent had good adsorption capability to dieldrin, which was indicated by a residual dieldrin concentration of 0.204 μgL−1. The removal efficiency of the composite ad‐ sorbent was higher than the traditional activated carbon adsorbent [83]. Essa et al. [84] stud‐ ied the potential of chemical activated date pits as an adsorbent. The date pits were impregnated with 70% phosphoric acid followed by thermal treatment between 300 to 700°C. The effects of activation temperature and acid concentration on pore surface area de‐ velopment were studied. Samples prepared at 500°C showed a specific area of 1319 m<sup>2</sup> /g and total pore volume of 0.785 cm3 /g. Aqueous phenol adsorption trends using the local ac‐ tivated carbon sample were compared to a commercial sample (Filtrasorb-400).

initial concentration increased from 25 to 250 mg L−1. Therefore, the adsorption of 2,4-D and bentazon by BSAC has strong dependence on the initial concentration of the pesticides. Maximum adsorption capacity (qe) for 2,4-dichlorophenoxyacetic acid (2,4-D) were 168.03

In the other study for using activated carbon as adsorbent, magnetic and graphitic carbon nanostructures was used for the removal of a pesticide (2,4-dichlorophenoxyacetic acid) from aqueous solution.The magnetic and graphitic carbon nanostructures as adsorbents were prepared from two different biomasses, cotton and filter paper. The resultant adsorb‐ ents were characterized with TEM and N2 adsorption–desorption methods. The adsorption capacities for the prepared adsorbents from filter paper and cotton are about 77 and 33

Chemically and thermally treated watermelon peels (TWMP) have been utilized for the re‐ moval of methyl parathion (MP) pesticide from water. The effect of process variables such as pH of solution, shaking speed, shaking time, adsorbent dose, concentration of solution and temperature have been optimized. Maximum adsorption (99±1%) was achieved for (0.38– 3.80)×10−4 mol dm−3 of MP solution, using 0.1 g of adsorbent in 20 ml of solution for 60 min agitation time at pH 6. The developed adsorption method has been employed to surface wa‐

Other organic pollutants were found as a pollutants in water and wastewater, this include pharmaceutical effluents, surfactants, organic solvents, phthalates, hydrocarbons, esters, al‐ cohols,volatile, semi-volatile and non-volatile chlorinated organic pollutants. Activated car‐

Adsorption on activated carbon is currently the most frequently used technology for remov‐ ing organic pollutants from aqueous industrial sludge, surface waters and drinking water. Methyl tert-butyl ether (MTBE) is an organic pollutants used mainly as a fuel component in fuel if gasoline engine and also as a solvent. The adsorption of methyl tert-butyl ether (MTBE) by granular activated carbon was investigated, the maximum adsorption capacity of MTBE on granular activated carbon was 204.1 mg/g. Results illustrate that granular activat‐ ed carbon is an effective adsorbent for methyl tert-butyl ether and also provide specific guidance into adsorption of methyl tert-butyl ether on granular activated carbon in contami‐

A novel triolein-embedded activated carbon composite adsorbent was developed. Results suggested that the novel composite adsorbent was composed of the supporting activated carbon and the surrounding triolein-embedded cellulose acetate membrane. The adsorbent was stable in water, for no triolein leakage was detected after soaking the adsorbent for five

bons, calys and clay minerals are used widely for the removal of organic pollutants.

mg g−1, and for bentazon 100.95 mg g−1 [79]

178 Organic Pollutants - Monitoring, Risk and Treatment

ter samples with percent removal 99%±1 [81].

**7.1. Adsorption on activated carbon**

nated groundwater [82].

**7. Adsorption of other organic pollutants**

mg/g, respectively [80].

Five commercially available types of activated carbon (GAC 1240, GCN 1240, RB 1, pK 1-3, ROW 0.8 SUPRA )are prepared and used to remove organic chlorinated compounds from wastewater of a chemical plant. The various types of activated carbon were tested on the ba‐ sis of Freundlich adsorption isotherms for 14 pure organic chlorinated compounds, of mo‐ lecular weight ranging from that of dichloromethane (MW ¼ 84.93 g mol-1) to hexachlorobenzene (MW ¼ 284.78 g mol-1). The best adsorbent (GAC 1240 granulated acti‐ vated carbon ) was selected and used in a laboratory fixed bed column to assess its removal efficiency with respect to the tested organic chlorinated compounds. Removal efficiency was always higher than 90% (Table 3) [85]


**Table 3.** Removal efficiency (%) of chlorinated compounds from wastewater by five commercially available types of activated carbon, from Pavonia et al [85]

Antibiotic considered as one of the pharmacological organic pollutants. Choi et al. [86] investi‐ gated the treatment of seven tetracycline classes of antibiotic (TAs) from raw waters (synthetic and river) using coagulation and granular activated carbon (GAC) filtration. Their results ended to that both coagulation and GAC filtration were effective for the removal of TAs, and the removal efficiency depended on the type of TAs. GAC filtration was relatively more effective for removal of tetracycline (TC), doxycycline-hyclate (DXC), and chlortetracycline-HCl (CTC), which were difficult to be removed by coagulation. Putra et al. [87] investigated the removal of Amoxicillin (antibiotic) from pharmaceutical effluents using bentonite and activated carbon as adsorbents. The study was carried out at several pH values. Langmuir and Freundlich models were then employed to correlate the equilibria data on which both models fitted the data equal‐ ly well. While chemisorption is the dominant adsorption mechanism on the bentonite, both physisorption and chemisorption played an important role for adsorption onto activated car‐ bon. Ruiz et al. [88] studied the removal of paracetamol (anti analgesic drug) from aqueous sol‐ utions using chemically modified activated carbons. The effect of the chemical nature of the activated carbon material such as carbon surface chemistry and composition on the removal of paracetamol was studied. The surface heterogeneity of the carbon affected the rate of paraceta‐ mol removal. They found that after oxidation the wettability of the carbon was enhanced, which favored the transfer of paracetamol molecules to the carbon pores. At the same time the overall adsorption rate and removal efficiency are reduced in the oxidized carbon due to the competi‐ tive effect of water molecules. Tris (2-chloroethyl) phosphate (TCEP), iopromide, naproxen, carbamazepine, and caffeine drugs were quite frequently observed in both surface waters and effluents from waste water treatment plants. The elimination of these chemicals during drink‐ ing water and wastewater treatment processes at full- and pilot-scale also was investigated. Conventional drinking water treatment methods such as flocculation and filtration were rela‐ tively inefficient for contaminant removal, while efficient removal (99%) was achieved by gran‐ ular activated carbon (GAC).

Cellulose acetate (CA) embedded with triolein (CA-triolein), was prepared as adsorbent for the removal of persistent organic pollutants (POPs) from micro-polluted aqueous solution. The comparison of CA-triolein, CA and granular activated carbon (GAC) for dieldrin re‐ moval was investigated. Results showed that CA-triolein absorbent gave a lowest residual concentration after 24 h although GAC had high removal rate in the first 4 h adsorption. Then the removal efficiency of mixed POPs (e.g. aldrin, dieldrin, endrin and heptachlor ep‐ oxide), absorption isotherm, absorbent regeneration and initial column experiments of CAtriolein were studied in detail. The linear absorption isotherm and the independent absorption in binary isotherm indicated that the selected POPs are mainly absorbed onto CA-triolein absorbent by a partition mechanism. Thermodynamic calculations showed that the absorption was spontaneous, with a high affinity and the absorption was an endother‐ mic reaction. Rinsing with hexane the CA-triolein absorbent can be regenerated after ab‐ sorption of POPs. No significant decrease in the dieldrin removal efficiency was observed even when the absorption–regeneration process was repeated for five times. The results of initial column experiments showed that the CA-triolein absorbent did not reach the break‐ through point at a breakthrough empty-bed volume (BV) of 3200 when the influent concen‐

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181

tration was 1–1.5 l g/L and the empty-bed contact time (EBCT) was 20 min [90]

removed after 6 h of agitation at 40o

concentrations [92].

be a chemical adsorption rather than a physical one [91].

**7.2. Adsorption on clays and clay minerals adsorbents**

Activated coke (AC) was studied to adsorb organic pollutants from coking wastewater. The study initially focused on the sorption kinetics and equilibrium sorption isotherms of AC for the removal of chemical oxygen demand (COD) from coking wastewater. The results showed that when the dose of AC was 200 g L−1, 91.6% of COD and 90% of color could be

water onto AC was fit to the pseudo-second order model. The adsorption of COD onto AC was enhanced with an increase of temperature, indicating that the adsorption process would

Bottom ash, a kind of waste material generated from thermal coal-fired power plants, is gen‐ erally used in road bases and building materials. Bottom ash was used to remove the organ‐ ic pollutants in coking wastewater and papermaking wastewater. Particular attention was paid on the effect of bottom ash particle size and dosage on the removal of chemical oxygen demand (COD). The results show that the COD removal efficiencies increase with decreas‐ ing particle sizes of bottom ash, and the COD removal efficiency for coking wastewater is much higher than that for papermaking wastewater due to its high percentage of particle organic carbon (POC). Different trends of COD removal efficiency with bottom ash dosage are also observed for coking and papermaking wastewaters because of their various POC

Several adsorbents were used for the removal of these pollutants. One of an effective and low cost adsorbents is calys and clay minerals. Natural clay minerals due to their high sur‐ face area and molecular sieve structure are very effective sorbents for organic contaminants of cationic or polar in character.Natural and modified clay minerals and zeolites are good

C. The kinetics of adsorption of COD from coking waste‐

Liu et al. [89] studied the removal effects of organic pollutants in drinking water (42 species organic pollutants in 11 categories ) by activated carbon, haydite and quartz sand with the method of solid-phase extraction (SPE). The removal rates of total peak area of organic pol‐ lutants by activated carbon, haydite and quartz were 70.35%, 29.68% and 37.36%. Among all, activated carbon showed the best removal effect to most organic pollutants contents, and quartz sand to species. So if activated carbon - quartz sand combined processes were adopt‐ ed, organic pollutants species and total peak area could be reduced simultaneously. The re‐ moval rates for phthalates, hydrocarbons, esters and alcohols were 62.62%, 75.83%, 72.52% and 62.99%, respectively. The adsorption capability of activated carbon for dimethyl phtha‐ late and di-n-butyl phthalate, two priority pollutants in water, were preferable. The removal rates reached 93.27% and 57.02%. For haydite, there were 26 kinds of organic pollutants in 10 categories in corresponding treated water. The total peak area was removed by 29.68%. The removal effects for amines, alkanes and phenols were satisfactory and the removal rates were 68.71%, 49.97% and 41.19%, respectively. But in the case of phthalates, esters and alde‐ hydes the effects were not obviously, the same as dimethyl phthalate and di-nbutyl phtha‐ late. The species of organic pollutants were reduced from 36 to 20 by quartz sand. Most notably, xylene, dimethyl phthalate and di-n-butyl phthalate in raw water were removed ef‐ ficiently. Xylene and di-n-butyl phthalate in tap water were removed absolutely, and di‐ methyl phthalate was removed by 59.59%.

Cellulose acetate (CA) embedded with triolein (CA-triolein), was prepared as adsorbent for the removal of persistent organic pollutants (POPs) from micro-polluted aqueous solution. The comparison of CA-triolein, CA and granular activated carbon (GAC) for dieldrin re‐ moval was investigated. Results showed that CA-triolein absorbent gave a lowest residual concentration after 24 h although GAC had high removal rate in the first 4 h adsorption. Then the removal efficiency of mixed POPs (e.g. aldrin, dieldrin, endrin and heptachlor ep‐ oxide), absorption isotherm, absorbent regeneration and initial column experiments of CAtriolein were studied in detail. The linear absorption isotherm and the independent absorption in binary isotherm indicated that the selected POPs are mainly absorbed onto CA-triolein absorbent by a partition mechanism. Thermodynamic calculations showed that the absorption was spontaneous, with a high affinity and the absorption was an endother‐ mic reaction. Rinsing with hexane the CA-triolein absorbent can be regenerated after ab‐ sorption of POPs. No significant decrease in the dieldrin removal efficiency was observed even when the absorption–regeneration process was repeated for five times. The results of initial column experiments showed that the CA-triolein absorbent did not reach the break‐ through point at a breakthrough empty-bed volume (BV) of 3200 when the influent concen‐ tration was 1–1.5 l g/L and the empty-bed contact time (EBCT) was 20 min [90]

removal efficiency depended on the type of TAs. GAC filtration was relatively more effective for removal of tetracycline (TC), doxycycline-hyclate (DXC), and chlortetracycline-HCl (CTC), which were difficult to be removed by coagulation. Putra et al. [87] investigated the removal of Amoxicillin (antibiotic) from pharmaceutical effluents using bentonite and activated carbon as adsorbents. The study was carried out at several pH values. Langmuir and Freundlich models were then employed to correlate the equilibria data on which both models fitted the data equal‐ ly well. While chemisorption is the dominant adsorption mechanism on the bentonite, both physisorption and chemisorption played an important role for adsorption onto activated car‐ bon. Ruiz et al. [88] studied the removal of paracetamol (anti analgesic drug) from aqueous sol‐ utions using chemically modified activated carbons. The effect of the chemical nature of the activated carbon material such as carbon surface chemistry and composition on the removal of paracetamol was studied. The surface heterogeneity of the carbon affected the rate of paraceta‐ mol removal. They found that after oxidation the wettability of the carbon was enhanced, which favored the transfer of paracetamol molecules to the carbon pores. At the same time the overall adsorption rate and removal efficiency are reduced in the oxidized carbon due to the competi‐ tive effect of water molecules. Tris (2-chloroethyl) phosphate (TCEP), iopromide, naproxen, carbamazepine, and caffeine drugs were quite frequently observed in both surface waters and effluents from waste water treatment plants. The elimination of these chemicals during drink‐ ing water and wastewater treatment processes at full- and pilot-scale also was investigated. Conventional drinking water treatment methods such as flocculation and filtration were rela‐ tively inefficient for contaminant removal, while efficient removal (99%) was achieved by gran‐

Liu et al. [89] studied the removal effects of organic pollutants in drinking water (42 species organic pollutants in 11 categories ) by activated carbon, haydite and quartz sand with the method of solid-phase extraction (SPE). The removal rates of total peak area of organic pol‐ lutants by activated carbon, haydite and quartz were 70.35%, 29.68% and 37.36%. Among all, activated carbon showed the best removal effect to most organic pollutants contents, and quartz sand to species. So if activated carbon - quartz sand combined processes were adopt‐ ed, organic pollutants species and total peak area could be reduced simultaneously. The re‐ moval rates for phthalates, hydrocarbons, esters and alcohols were 62.62%, 75.83%, 72.52% and 62.99%, respectively. The adsorption capability of activated carbon for dimethyl phtha‐ late and di-n-butyl phthalate, two priority pollutants in water, were preferable. The removal rates reached 93.27% and 57.02%. For haydite, there were 26 kinds of organic pollutants in 10 categories in corresponding treated water. The total peak area was removed by 29.68%. The removal effects for amines, alkanes and phenols were satisfactory and the removal rates were 68.71%, 49.97% and 41.19%, respectively. But in the case of phthalates, esters and alde‐ hydes the effects were not obviously, the same as dimethyl phthalate and di-nbutyl phtha‐ late. The species of organic pollutants were reduced from 36 to 20 by quartz sand. Most notably, xylene, dimethyl phthalate and di-n-butyl phthalate in raw water were removed ef‐ ficiently. Xylene and di-n-butyl phthalate in tap water were removed absolutely, and di‐

ular activated carbon (GAC).

180 Organic Pollutants - Monitoring, Risk and Treatment

methyl phthalate was removed by 59.59%.

Activated coke (AC) was studied to adsorb organic pollutants from coking wastewater. The study initially focused on the sorption kinetics and equilibrium sorption isotherms of AC for the removal of chemical oxygen demand (COD) from coking wastewater. The results showed that when the dose of AC was 200 g L−1, 91.6% of COD and 90% of color could be removed after 6 h of agitation at 40o C. The kinetics of adsorption of COD from coking waste‐ water onto AC was fit to the pseudo-second order model. The adsorption of COD onto AC was enhanced with an increase of temperature, indicating that the adsorption process would be a chemical adsorption rather than a physical one [91].

Bottom ash, a kind of waste material generated from thermal coal-fired power plants, is gen‐ erally used in road bases and building materials. Bottom ash was used to remove the organ‐ ic pollutants in coking wastewater and papermaking wastewater. Particular attention was paid on the effect of bottom ash particle size and dosage on the removal of chemical oxygen demand (COD). The results show that the COD removal efficiencies increase with decreas‐ ing particle sizes of bottom ash, and the COD removal efficiency for coking wastewater is much higher than that for papermaking wastewater due to its high percentage of particle organic carbon (POC). Different trends of COD removal efficiency with bottom ash dosage are also observed for coking and papermaking wastewaters because of their various POC concentrations [92].

#### **7.2. Adsorption on clays and clay minerals adsorbents**

Several adsorbents were used for the removal of these pollutants. One of an effective and low cost adsorbents is calys and clay minerals. Natural clay minerals due to their high sur‐ face area and molecular sieve structure are very effective sorbents for organic contaminants of cationic or polar in character.Natural and modified clay minerals and zeolites are good candidates for improving activated carbon(AC) performance, because they have large sur‐ face areas for retention of pollutants [93].

exhibit efficient removal of organic pollutants (e.g., aniline, pchloroaniline,o-aminophenol, and p-nitroaniline) of up to 90% within a short period (in the order of minutes). In terms of prox‐ imity adsorption, the functional acid sites and the condensed and rigid monoliths with tunable periodic scaffolds of the cubic mesocages are useful in providing easy-to-use removal assays for organic compounds and reusable adsorbents without any mesostructural damage, even under

**DDAB Conc.(Mm) Pollutants**

Atrazine

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183

Alachlor

Imazaquin

Sulfentrazone

3 5

Adsorption Technique for the Removal of Organic Pollutants from Water and Wastewater

3 6

3 6

3 6

chemical treatment for a number of repeated cycles [100].

**(mg/L)**

8 8

10 10

10 10

10 10

**Table 4.** Removal of organic pollutants from water by DDAB-Clay complex adsorbent a,b (From Undabeytiaa et al. [98])

Modified clays were used as adsorbents for the removal of organic pollutants from waste‐ water. Two pillared clays are synthesized by intercalation of solutions of aluminium and zir‐ conium and evaluated as adsorbents for the removal of Orange II and Methylene Blue from aqueous solutions. The contact time to attain equilibrium for maximum adsorption was found to be 300 min. Both clays were found to have the same adsorption capacity when Or‐ ange II was used as adsorbent, whereas the adsorption capacity of Zr-PILC was higher (27 mg/g) than that of Al-PILC (21 mg/g)for Methylene Blue. The adsorption kinetics of dyes has been studied in terms of pseudo-first- and -second-order kinetics, and the Freundlich, Langmuir and Sips isotherm models have also been applied to the equilibrium adsorption data. The addition of NaCl has been found to increase the adsorption capacities of the two

**% removal Initial herbicide conc.**

37.3±0.3 (57.4± 0.7) 56.6±1.0 (59.8±0.1) [59.0]

94.9±0.8 (85.6±1.0) 95.5±0.1 (87.2±0.2) [92.7]

73.6±0.4 (92.0±0.3) 75.52±0.3 (92.3±1.0) [95.8]

98.0±1.0 (99.7±0.1) 99.7±0.1 (99.7±0.1) [99.9]

Adsorbent prepared from organoclays and activated carbon were shown to remove a varie‐ ty of organic contaminants [94-95]. Montmorillonite was applied as adsorbent for the re‐ moval of cationic surfactants, while the hydrophilic surface of montmorillonite was modified and used as adsorbent [96]. Calcined hydrocalcites was prepared and used to re‐ move organic anionic pesticides [97] from polluted water. Vesicle–clay complexes in which positively charged vesicles composed of didodecyldimethy- lammonium bromide (DDAB) were adsorbed on montmorillonite and removed efficiently anionic (sulfentrazone, imaza‐ quin) and neutral (alachlor, atrazine) pollutants from water. These complexes (0.5% w:w) re‐ moved 92–100% of sulfentrazone, imazaquin and alachlor,and 60% of atrazine from a solution containing 10 mg/L. A synergistic effect on the adsorption of atrazine was observed when all pollutants were present simultaneously (30 mg/L each), its percentage of removal being 85.5. Column filters (18 cm) filled with a mixture of quartz sand and vesicle–clay (100:1, w:w) were tested. For the passage of 1 L (25 pore volumes) of a solution including all the pollutants at 10 mg/L each, removal was complete for sulfentrazone and imazaquin, 94% for alachlor and 53.1% for atrazine, whereas removal was significantly less efficient when using activated carbon. A similar advantage of the vesicle–clay filter was observed for the capacities of removal. Table (4 ) show the removal efficiencies of organic pollutants from water by DDAB-Clay complex adsorbent [98]

Data in parentheses correspond to the procedure when dried complex was added to the sol‐ ution, whereas the other case correspond to the removal after incubation with DDAB fol‐ lowed by clay addition.

Data in brackets are the predicted removal by Langmuir equation (binding coeffients)

Zhao et al. [99] prepared mesoporous silica materials and used it for adsorption of organic pollutants in water. Mesoporous silica materials is performed using self-assembling micellar aggregates of two surfactants: cetylpyridinium bromide (CPB) and cetyltrimethylammoni‐ um bromide (CTAB). The retention properties have been studied of these two kinds meso‐ porous silicas towards environmental pollutants (mono-, di-, tri-chloroacetic acid, toluene, naphthalene and methyl orange). The effect of the composition (presence and absence of surfactants, different kinds of surfactants) on the sorption performance has been considered. They found that materials show excellent retention performance toward chloroacetic acids, toluene, naphthalene and methyl orange. The materials without surfactants does not show, if any, affinity for ionic and non-ionic analytes.

The applicability of mesoporous aluminosilica monoliths with three-dimensional structures and aluminum contents with 19≤Si/Al≥1 was studied as effective adsorbents of organic mole‐ cules from an aqueous solution. Mesocage cubic Pm3n aluminosilica monoliths were success‐ fully fabricated using a simple, reproducible, and direct synthesis (scheme 2). The acidity of the monoliths significantly increased with increasing amounts of aluminum species in the silica pore framework walls. The batch adsorption of the organic pollutants onto (10 g/L) aluminosili‐ ca monoliths was performed in an aqueous solution at various temperatures. These adsorbents exhibit efficient removal of organic pollutants (e.g., aniline, pchloroaniline,o-aminophenol, and p-nitroaniline) of up to 90% within a short period (in the order of minutes). In terms of prox‐ imity adsorption, the functional acid sites and the condensed and rigid monoliths with tunable periodic scaffolds of the cubic mesocages are useful in providing easy-to-use removal assays for organic compounds and reusable adsorbents without any mesostructural damage, even under chemical treatment for a number of repeated cycles [100].

candidates for improving activated carbon(AC) performance, because they have large sur‐

Adsorbent prepared from organoclays and activated carbon were shown to remove a varie‐ ty of organic contaminants [94-95]. Montmorillonite was applied as adsorbent for the re‐ moval of cationic surfactants, while the hydrophilic surface of montmorillonite was modified and used as adsorbent [96]. Calcined hydrocalcites was prepared and used to re‐ move organic anionic pesticides [97] from polluted water. Vesicle–clay complexes in which positively charged vesicles composed of didodecyldimethy- lammonium bromide (DDAB) were adsorbed on montmorillonite and removed efficiently anionic (sulfentrazone, imaza‐ quin) and neutral (alachlor, atrazine) pollutants from water. These complexes (0.5% w:w) re‐ moved 92–100% of sulfentrazone, imazaquin and alachlor,and 60% of atrazine from a solution containing 10 mg/L. A synergistic effect on the adsorption of atrazine was observed when all pollutants were present simultaneously (30 mg/L each), its percentage of removal being 85.5. Column filters (18 cm) filled with a mixture of quartz sand and vesicle–clay (100:1, w:w) were tested. For the passage of 1 L (25 pore volumes) of a solution including all the pollutants at 10 mg/L each, removal was complete for sulfentrazone and imazaquin, 94% for alachlor and 53.1% for atrazine, whereas removal was significantly less efficient when using activated carbon. A similar advantage of the vesicle–clay filter was observed for the capacities of removal. Table (4 ) show the removal efficiencies of organic pollutants from

Data in parentheses correspond to the procedure when dried complex was added to the sol‐ ution, whereas the other case correspond to the removal after incubation with DDAB fol‐

Zhao et al. [99] prepared mesoporous silica materials and used it for adsorption of organic pollutants in water. Mesoporous silica materials is performed using self-assembling micellar aggregates of two surfactants: cetylpyridinium bromide (CPB) and cetyltrimethylammoni‐ um bromide (CTAB). The retention properties have been studied of these two kinds meso‐ porous silicas towards environmental pollutants (mono-, di-, tri-chloroacetic acid, toluene, naphthalene and methyl orange). The effect of the composition (presence and absence of surfactants, different kinds of surfactants) on the sorption performance has been considered. They found that materials show excellent retention performance toward chloroacetic acids, toluene, naphthalene and methyl orange. The materials without surfactants does not show,

The applicability of mesoporous aluminosilica monoliths with three-dimensional structures and aluminum contents with 19≤Si/Al≥1 was studied as effective adsorbents of organic mole‐ cules from an aqueous solution. Mesocage cubic Pm3n aluminosilica monoliths were success‐ fully fabricated using a simple, reproducible, and direct synthesis (scheme 2). The acidity of the monoliths significantly increased with increasing amounts of aluminum species in the silica pore framework walls. The batch adsorption of the organic pollutants onto (10 g/L) aluminosili‐ ca monoliths was performed in an aqueous solution at various temperatures. These adsorbents

Data in brackets are the predicted removal by Langmuir equation (binding coeffients)

face areas for retention of pollutants [93].

182 Organic Pollutants - Monitoring, Risk and Treatment

water by DDAB-Clay complex adsorbent [98]

if any, affinity for ionic and non-ionic analytes.

lowed by clay addition.


**Table 4.** Removal of organic pollutants from water by DDAB-Clay complex adsorbent a,b (From Undabeytiaa et al. [98])

Modified clays were used as adsorbents for the removal of organic pollutants from waste‐ water. Two pillared clays are synthesized by intercalation of solutions of aluminium and zir‐ conium and evaluated as adsorbents for the removal of Orange II and Methylene Blue from aqueous solutions. The contact time to attain equilibrium for maximum adsorption was found to be 300 min. Both clays were found to have the same adsorption capacity when Or‐ ange II was used as adsorbent, whereas the adsorption capacity of Zr-PILC was higher (27 mg/g) than that of Al-PILC (21 mg/g)for Methylene Blue. The adsorption kinetics of dyes has been studied in terms of pseudo-first- and -second-order kinetics, and the Freundlich, Langmuir and Sips isotherm models have also been applied to the equilibrium adsorption data. The addition of NaCl has been found to increase the adsorption capacities of the two pillared clays for Orange II Pillared InterLayered Clays (PILCs) are porous materials that can be obtained by the intercalation of soils, thereby creating high value added materials from natural solids [101]. Also, pillared clay adsorbent was used for the removal of ben‐ zo(a)pyrene and chlorophenols [102], chlorinated phenols from aqueous solution by surfac‐ tant-modified pillared clays [103] and herbicide Diuron on pillared clays [104].

**8. Conclusion**

**Abbreviations**

benzofurans

dinitrophenol

ferent kinds of natural and synthetic adsorbents.

AC Activated carbon, PCP Pentachlorophenol

WC Wood charcoal, HCB Hexachlorobenzene

GAC Granular activated carbon, CD Cyclodextrin

TCP 2,4,6-trichlorophenol, MP Methyl parathion

HIC Hemidesmus Indicus carbon, BP Bromopropylate

Organic pollutants in the ecosystem, especially persistent organic pollutants (POPs),are of the most important environmental problems in the world. The literature reviewed revealed that there has been a high increase in production and utilization of organic pollutants in last few decades resulting in a big threat of pollution. Efficient techniques for the removal of highly toxic organic compounds from water and wastewater have drawn significant inter‐ est. Adsorption is recognized as an effective and low cost technique for the removal of or‐ ganic pollutants from water and wastewater, and produce high-quality treated effluent. This chapter highlighted the removal of organic pollutants using adsorption technique with dif‐

Adsorption Technique for the Removal of Organic Pollutants from Water and Wastewater

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185

Many researches have given considerable attention aimed at establishing to the removal effi‐ ciency of organic pollutants by adsorption technique. To decrease treatment costs, attempts have been made to find inexpensive alternative activated carbon (AC), from waste materials of industrial, domestic and agricultural activities. Also, clays and natural clay minerals, due to their high surface area and molecular sieve structure, are very effective adsorbents for or‐ ganic contaminants. The chapter focus, reviews and evaluates literature dedicated on the ad‐ sorption phenomenon, different types of natural and synthetic adsorbents, adsorption of dyes, phenols, pesticides and other organic pollutants. Finally it ended with recent research‐

CAC Commercial Activated carbon, PCDD/Fs polychlorinated dibenzo-p-dioxins and di‐

ACC Activated carbon cloth adsorbent, DNOC 2,4-dinitrophenol (DNP) and 2-methyl-4,6-

es of organic pollutants adsorption on activated carbons, clays and clay minerals.

PAC powdered activated carbons, DDT dichloro-diphenyl-trichloroethane

POPs Persistent organic pollutants, LDHs MgAl layered double hydroxides

BET Buruner, Emmett, and Teller, MTBE Methyl tert-butyl ether

DCP Dichlorophenol, TCEP Tris (2-chloroethyl) phosphate

**Scheme 2.** Aluminosilica monoliths with a disc-like shape (A) and mesocage pores (B) as adsorbents (C) of organic compounds (I–IV) inside the mesocage cavity and onto pore surfaces of 3D cubic Pm3n structures (D). Note that 3D TEM image (B) was recorded with aluminosilica monoliths with a Si/Al ratio of 4 ( From El-Safty et al. [100]).
