liquids/task-specific ionic liquids provides better opportunities to change the structures in cation and anion to achieve functionalized ionic liquid for specific pollutant
removal. Therefore, recent applications of functionalized ionic liquids for the treatment of metal ions and different dyes are discussed. Later, a case study on the
photodegradation with possible mechanisms of organic dyes, namely, methylene
blue and congo red using a synthesized polymer-supported ionic liquid Fe-porphyrin
complex is presented. Catalyst loadings of 10 mg and 12.5 mg at constant time of
60 min are found to be a better choice for the photodegradation of methylene blue
and congo red dyes, respectively. The highest photodegradations of methylene blue
and congo red are found to be ~78% and ~ 99%, respectively.
Keywords Wastewater treatment · Functionalized ionic liquids · Photodegradation ·
Organic dyes · Polymer supported ionic liquid iron porphyrin
12.1 Introduction
Approximately 7,00,000 tons of dyes are manufactured worldwide annually;
wherein about 60% is azo dye out of which 10–15% of azo dyes is passed in the
water system (Langhals 2004). Azo dyes are classified as acidic, basic, disperse,
reactive, direct, and solvents/food dyes. An azo dye which is derived from benzidine,
C 12 H 12 N 2 is the main segment of carcinogenicity. Textile industries use a huge
amount of freshwater for dyeing and processing, which discharge large amount of
chemical pollutants like organic surfactants, dyes, dispersants, alkalis, acids, solvents, and various salts into the water bodies. The presence of dyes in water creates
acute aesthetic and aquatic problems by disturbing the photosynthetic reaction due to
light penetration. So, it is essential to focus on wastewater treatment technologies for
its reuse and recycle. From the view of an environment, severe problems such as
toxicity to water bodies and foremost to carcinogenic and mutagenic effects on
humans are created by the textile-based industries (Dalvand et al. 2011; Du et al.
2017). The removal/treatment of dyes from polluted wastewater is comparatively
more significant than the other soluble polluted compounds, which also add the
portion of biochemical oxygen demand (Holkar et al. 2016). Many methods exist to
eradicate harmful dyes from wastewater such as coagulation, an electrochemical
process, membrane separation process, chemical oxidation, adsorption, reverse
osmosis, and biodegradation. But most of these processes are not so acceptable
due to additional chemical demand, producing large amount of secondary by
products with their disposal problem and monetary disadvantages. A massive
amount of such dyes in wastewater is nonbiodegradable because of their complex
and stable molecular structures.
The drawback with the conventional biological methods (Shankar et al. 1999) is
the treatment period. Treatment period typically varies from 1 day to 6 days. In
392
D. S. Patle et al.
removal. Therefore, recent applications of functionalized ionic liquids for the treatment of metal ions and different dyes are discussed. Later, a case study on the
photodegradation with possible mechanisms of organic dyes, namely, methylene
blue and congo red using a synthesized polymer-supported ionic liquid Fe-porphyrin
complex is presented. Catalyst loadings of 10 mg and 12.5 mg at constant time of
60 min are found to be a better choice for the photodegradation of methylene blue
and congo red dyes, respectively. The highest photodegradations of methylene blue
and congo red are found to be ~78% and ~ 99%, respectively.
Keywords Wastewater treatment · Functionalized ionic liquids · Photodegradation ·
Organic dyes · Polymer supported ionic liquid iron porphyrin
12.1 Introduction
Approximately 7,00,000 tons of dyes are manufactured worldwide annually;
wherein about 60% is azo dye out of which 10–15% of azo dyes is passed in the
water system (Langhals 2004). Azo dyes are classified as acidic, basic, disperse,
reactive, direct, and solvents/food dyes. An azo dye which is derived from benzidine,
C 12 H 12 N 2 is the main segment of carcinogenicity. Textile industries use a huge
amount of freshwater for dyeing and processing, which discharge large amount of
chemical pollutants like organic surfactants, dyes, dispersants, alkalis, acids, solvents, and various salts into the water bodies. The presence of dyes in water creates
acute aesthetic and aquatic problems by disturbing the photosynthetic reaction due to
light penetration. So, it is essential to focus on wastewater treatment technologies for
its reuse and recycle. From the view of an environment, severe problems such as
toxicity to water bodies and foremost to carcinogenic and mutagenic effects on
humans are created by the textile-based industries (Dalvand et al. 2011; Du et al.
2017). The removal/treatment of dyes from polluted wastewater is comparatively
more significant than the other soluble polluted compounds, which also add the
portion of biochemical oxygen demand (Holkar et al. 2016). Many methods exist to
eradicate harmful dyes from wastewater such as coagulation, an electrochemical
process, membrane separation process, chemical oxidation, adsorption, reverse
osmosis, and biodegradation. But most of these processes are not so acceptable
due to additional chemical demand, producing large amount of secondary by
products with their disposal problem and monetary disadvantages. A massive
amount of such dyes in wastewater is nonbiodegradable because of their complex
and stable molecular structures.
The drawback with the conventional biological methods (Shankar et al. 1999) is
the treatment period. Treatment period typically varies from 1 day to 6 days. In
392
D. S. Patle et al.