Advanced Oxidation Processes (AOP)—Effective Innovative Treatment Methods to Degrade Textile Dye Effluent

Abstract

Textile industry is the second largest consumer and polluter of water for processing fibres, yarns, fabrics and garments. There are wide range of dyestuffs and chemicals used in the treatment of textile materials to enhance several properties. In early days, the dye wastewater effluent was discharged to the nearby freshwater bodies or land. Due to the increase in awareness and necessity for sustainable processes, there are many treatment methods to treat the textile effluent. The processes include physico-chemical treatment, and secondary and tertiary treatment methods are adopted widely which basically work on coagulation and sedimentation, adsorption, biological degradation of dyes. In these processes, the residual sludge is a great problem, and the textile effluent treatment process results in piled up sludge which consists of majority of dyes and other salts. The degradation of the dyes in the sludge takes several years, and to speed up the degradation of dyes, advanced oxidation processes are currently under research, and few technologies are used in effluent treatment plants. The generation of hydroxyl radical species and exposure of textile effluent to these radicals decolourize and degrade the organic compounds. There are several processes to generate the hydroxyl radicals like ozonation, UV treatment, photocatalytic treatment, electrochemical oxidation process, Fenton process, etc. The biodegradability of the by-products after AOPs increases 6–8 times. This chapter will discuss in detail about the above-said treatment methods, their efficacy in treatment of dye decolourization and reduction of pollution load. Each process has its own advantages and disadvantages in terms of decolourization, operational cost, sludge generation and so on. The adaptation of suitable technology will also be discussed briefly.

Appendix: Application of Sustainable and Low-Cost Sludge-Based Adsorbents for Textile Dye Degradation

This appendix enumerates a short description of the articles (Journals/Books/chapters/ standards) referred for relevant data in preparing this book chapter including tables.

S.No.	Journal title	Volume/Issue article title	Year of publication	Page no.	Content referred in the current book chapter
1	Water Science and Technology	30	1994	255–263	Table 1: Various treatment process for cotton textile process effluents with their merits and demerits
2	Dyes Pigments	47	2000	207–218
3	Ozone Science Engineering	17	1995	149–161
4	Soil and Sediment Contamination	10(6)	2001	577–591
5	Water Research	31	1997	868–876
6	Desalination	116	1998	65–80
7	Desalination	70	1988	157–167
8	Separation Science and Technology	34	1999	2501–2519
9	Chemical Engineering and Processing	41	2002	601–609
10	Desalination	143	2002	11–20
11	Separation Science and Technology	26	1991	1295–1313
12	Water Science and Technology	40	1999	37–144
13	Water Research	35	2001	567–572
14	Catalysis Today	53(1)	1999	51–59
15	Modern Applied Science	3	2009	146–160	Table 2: Characteristics of the wastewater and dye bath effluent of various treatment units
16	Water	11(2)	2019	205	Table 3: Comparison of oxidation potential
17	Journal of the Mexican Chemical Society [online]	58(3)	2014	256–275	Table 4: Oxygen evolution potential of different anodes
18	Applied Catalysis B Environmental	198	2016	347–377	Table 5: Energy band gap of different semiconductors