**1. Introduction**

With the growth of human; society, science, technology the world is reaching to new high horizons but the cost which will pay in near future is going to be too high. The bad result of this rapid growth is big environmental pollution problem. One of the biggest risks is the water pollution. The major environmental concern worldwide is water pollution associated with release of many different pollutants [1]. Pollutants released into the environment in wastewater effluent, contaminate freshwater resources and are harmful to humans and the environment. These pollutants were released from many different chemical industries such as textile, dyestuffs, metal plating, paper, mining, fertilizer, battery manufacturing metallurgical, pesticides, fossil fuel, tannery, mining, various plastics. Micropollutants, which are mostly found in wastewater, can be pharmaceuticals, industrial chemicals, pesticides and so on. The textile industries micropollutants released in wastewater and sludge can be dyes, phosphorus, sulfamethazine and heavy metals [2]. The release of these contaminants has been increased because of recent rapid industrialization.

Many industries such as textile, dyestuffs, paper and plastics which are used dyes, use substantial volumes of water in process and also, they generate a considerable amount of colored wastewater [3]. Dye is found a lot amount of pollutant in wastewater. More than 10,000 commercially available dyes are existed and over 7 × 105 of dyes are produced annually throughout the world [4].

Wastewater which is rich by dyestuffs must be treated by many different techniques to eliminate dyes before they are discharged to the ecosystem because of large content of organic pollutants (polycyclic aromatic hydrocarbons, nonphenols, phatales, so on.). The results of many researches showed that about 2% of dyes produced form textile industries are directly discharged in wastewater. Many of these dyes are hazardous and a big threat to aquatic life due to their toxicity and carcinogenicity [3].

Dyes are typically classified in two ways: chemical composition and application class or end use. Based on the application method, dyes can be divided into acid, azoic, basic, direct, disperse, mordant, reactive, sulfur, and vat dyes. According to chemical compositions, dyes can be divided into azo, nitro, nitroso, diarylmethane, triarylmethane, xanthene, anthraquinoid, acridine, cyanine, quinone-imine, pthalocyanine, and thiazole dyes. The azo and anthraquinone dyes are two major classes of reactive dyes, which is released to wastewater as 90% of all organic pollutants. Due to their interaction with hydroxyl ions in the solution, these dyes are always wasted in the dyeing process, remained in the effluents and are hardly eliminated under aerobic conditions. Also, the azo dyes have stability against microbial attack. Reduction of azo bond frequently releases aromatic amines, which resist further degradation under anaerobic condition. The acute toxicity of azo dyes to humans are rather low according to the European Union criteria. The toxicity is generally not because of the dye itself, but because of its degradation products. Azo dyes can be caused contact dermatitis in the local lymph node assays. However azo dyes can be very toxic to several aquatic organisms including algae, fish. Because of presence of azo dyes in water; viability, reproduction rate, filtration feeding and O2 consumption of the fishes reduced in the freshwater. Azo dyes also inhibit several biological processes, such as they can inhibit algal photosynthesis by reducing the penetration of light, they inhibit chemical oxygen demand (COD) reduction and respiratory activities of microbial populations. Which are ecologically very important. This may result in inhibition of microbial processes like wastewater treatment systems and natural biogeochemical cycles [2, 5, 6].

Over the last years, different physical, chemical and biological techniques have been developed to remove toxic dyes from wastewater and water reservoirs. All kinds of wastewater containing dyes cannot be treated with one technology. The methods for clean up wastewater are adsorption, electrolysis, ozonation, coagulation/flocculation, physical membrane separation, advanced oxidation processes and biological degradation process. Each technology has some merits and demerits. The demerits of many of these techniques are high cost and the formation of hazardous by products. The problems of some techniques can be listed; the quantification of different dyes related to complicated sample preparation procedures, long analysis times, and the use of large quantities of solvents [7]. Coagulation/ flocculation usually generates large amounts of toxic sludge difficult to deal with. Physical membrane separation employing nanofiltration (NF) membrane is easy to bring pollution and lead to decreasing removal efficiency Advanced oxidation processes including chemical oxidation, catalytic degradation and electro chemical treatment consume high energy and are still quite costly for practical application [8]. Biological degradation with activated sludge cannot clean up wastewater due to the biodegradable difficulty of many synthetic dyes. The problem of anionic dyes is highly water soluble and difficult to remove by conventional methods. The nonionic

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*Wastewater Treatment Using Imprinted Polymeric Adsorbents*

reusable adsorbent for clean up wastewater [10].

**2. Molecularly imprinted polymers (MIPs)**

interactions, e.g. ionic, hydrophobic and hydrogen bonding [12].

MIPs have been successfully used as an alternative adsorbent in several analytical fields such as separation of enantiomers in liquid chromatography (LC) or capillary

dyes (disperse dyes) do not ionize in an aqueous solution and their fused aromatic ring structure makes them highly resistant to degradation. However, a few cationic dyes like methyl blue can be easily removed by adsorption and advanced oxidation processes [4]. With the realization that a single technique cannot give universal solution, the recent trend in dye wastewater treatment is focused around integra-

Adsorption is a low-cost and effective method for expurgate of dye wastewater. The adsorption process is the best choice for the decolorization of dyes and gives the best results for removal of various types of dissolved coloring materials and also removes the entire dye molecule, leaving no fragments in the effluent. The adsorption has a high treatment efficiency and adsorbents can be regenerated for multiple reuses. The initial dye concentration, solution pH, temperature, contact time and adsorbent dosage are usually the main factors that govern the performance. Generally, removal of dyes from water and wastewater is carried out by adsorption using activated carbon. The disadvantage of activated carbon are expensive regeneration process and the decrease of adsorption capacity after regeneration. The other adsorption material can be nanoparticle adsorbents, low cost waste-based adsorbents and polymeric adsorbents. Polymeric adsorbents have the advantages of high flexibility in design, physical stability, porosity, uniform pore size distribution, high surface area, and chemical stability towards acids and bases, feasible regeneration and thermal durability but they are generally expensive materials [4]. The interesting and urgent research needs for a high-efficiency, low cost, attractive and

Molecularly imprinted polymers (MIPs) are interesting materials that can be applied in environmental research for sample preparation, to clean up and for the quantification of contaminants present in wastewater. The advantages of MIPs are related to their small size, high surface area, and specific selectivity towards target molecules. Molecular imprinting can be prepared with nanoscale surface recognition sites for target molecules, providing high binding capacities and fast mass transfer rates. MIPs have resistance under extreme conditions of pH, temperature, and complex environment. The preparation route of molecular imprinting is in which functional and crosslinking monomers are co-polymerized in the presence of the target analyte (the imprint molecule). Initially, the functional monomer forms a complex (monomer-target analyte) via covalent or noncovalent interactions and, after polymerization, their functional groups are held by the highly crosslinking polymeric structure. Upon leaching of the imprint molecule from the polymer matrix, a polymer with binding sites complementary in size and shape to the imprint molecule is created. This polymer is now capable of selectively rebinding the imprint molecule [6, 9–11]. In covalent approach; the imprinted molecule is covalently coupled to a polymerizable molecule. The binding of template with monomers are relies on reversible covalent bonds. After copolymerization with crosslinker, the imprint molecule is chemically cleaved from the highly crosslinked polymer with harsh conditions. In non-covalent approach which is usually used for preparing MIP is composed of self-assembly between the template and monomer, followed by a crosslinked co-polymerization. The template molecules interact with monomers (during imprinting procedure and the rebinding) via non-covalent

*DOI: http://dx.doi.org/10.5772/intechopen.92386*

tion of multiple techniques [7, 9].

*Wastewater Treatment Using Imprinted Polymeric Adsorbents DOI: http://dx.doi.org/10.5772/intechopen.92386*

*Waste in Textile and Leather Sectors*

carcinogenicity [3].

dyes are produced annually throughout the world [4].

systems and natural biogeochemical cycles [2, 5, 6].

Many industries such as textile, dyestuffs, paper and plastics which are used dyes, use substantial volumes of water in process and also, they generate a considerable amount of colored wastewater [3]. Dye is found a lot amount of pollutant in wastewater. More than 10,000 commercially available dyes are existed and over 7 × 105

Wastewater which is rich by dyestuffs must be treated by many different techniques to eliminate dyes before they are discharged to the ecosystem because of large content of organic pollutants (polycyclic aromatic hydrocarbons, nonphenols, phatales, so on.). The results of many researches showed that about 2% of dyes produced form textile industries are directly discharged in wastewater. Many of these dyes are hazardous and a big threat to aquatic life due to their toxicity and

Dyes are typically classified in two ways: chemical composition and application class or end use. Based on the application method, dyes can be divided into acid, azoic, basic, direct, disperse, mordant, reactive, sulfur, and vat dyes. According to chemical compositions, dyes can be divided into azo, nitro, nitroso, diarylmethane, triarylmethane, xanthene, anthraquinoid, acridine, cyanine, quinone-imine, pthalocyanine, and thiazole dyes. The azo and anthraquinone dyes are two major classes of reactive dyes, which is released to wastewater as 90% of all organic pollutants. Due to their interaction with hydroxyl ions in the solution, these dyes are always wasted in the dyeing process, remained in the effluents and are hardly eliminated under aerobic conditions. Also, the azo dyes have stability against microbial attack. Reduction of azo bond frequently releases aromatic amines, which resist further degradation under anaerobic condition. The acute toxicity of azo dyes to humans are rather low according to the European Union criteria. The toxicity is generally not because of the dye itself, but because of its degradation products. Azo dyes can be caused contact dermatitis in the local lymph node assays. However azo dyes can be very toxic to several aquatic organisms including algae, fish. Because of presence of azo dyes in water; viability, reproduction rate, filtration feeding and O2 consumption of the fishes reduced in the freshwater. Azo dyes also inhibit several biological processes, such as they can inhibit algal photosynthesis by reducing the penetration of light, they inhibit chemical oxygen demand (COD) reduction and respiratory activities of microbial populations. Which are ecologically very important. This may result in inhibition of microbial processes like wastewater treatment

Over the last years, different physical, chemical and biological techniques have been developed to remove toxic dyes from wastewater and water reservoirs. All kinds of wastewater containing dyes cannot be treated with one technology. The methods for clean up wastewater are adsorption, electrolysis, ozonation, coagulation/flocculation, physical membrane separation, advanced oxidation processes and biological degradation process. Each technology has some merits and demerits. The demerits of many of these techniques are high cost and the formation of hazardous by products. The problems of some techniques can be listed; the quantification of different dyes related to complicated sample preparation procedures, long analysis times, and the use of large quantities of solvents [7]. Coagulation/ flocculation usually generates large amounts of toxic sludge difficult to deal with. Physical membrane separation employing nanofiltration (NF) membrane is easy to bring pollution and lead to decreasing removal efficiency Advanced oxidation processes including chemical oxidation, catalytic degradation and electro chemical treatment consume high energy and are still quite costly for practical application [8]. Biological degradation with activated sludge cannot clean up wastewater due to the biodegradable difficulty of many synthetic dyes. The problem of anionic dyes is highly water soluble and difficult to remove by conventional methods. The nonionic

of

**174**

dyes (disperse dyes) do not ionize in an aqueous solution and their fused aromatic ring structure makes them highly resistant to degradation. However, a few cationic dyes like methyl blue can be easily removed by adsorption and advanced oxidation processes [4]. With the realization that a single technique cannot give universal solution, the recent trend in dye wastewater treatment is focused around integration of multiple techniques [7, 9].

Adsorption is a low-cost and effective method for expurgate of dye wastewater. The adsorption process is the best choice for the decolorization of dyes and gives the best results for removal of various types of dissolved coloring materials and also removes the entire dye molecule, leaving no fragments in the effluent. The adsorption has a high treatment efficiency and adsorbents can be regenerated for multiple reuses. The initial dye concentration, solution pH, temperature, contact time and adsorbent dosage are usually the main factors that govern the performance. Generally, removal of dyes from water and wastewater is carried out by adsorption using activated carbon. The disadvantage of activated carbon are expensive regeneration process and the decrease of adsorption capacity after regeneration. The other adsorption material can be nanoparticle adsorbents, low cost waste-based adsorbents and polymeric adsorbents. Polymeric adsorbents have the advantages of high flexibility in design, physical stability, porosity, uniform pore size distribution, high surface area, and chemical stability towards acids and bases, feasible regeneration and thermal durability but they are generally expensive materials [4]. The interesting and urgent research needs for a high-efficiency, low cost, attractive and reusable adsorbent for clean up wastewater [10].
