Single and Hybrid Applications of Ultrasound for Decolorization and Degradation of Textile Dye Residuals in Water - Green Chemistry for Dyes Removal from Wastewater - page 261

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Single and Hybrid Applications of
Ultrasound for Decolorization and
Degradation of Textile Dye
Residuals in Water
Nilsun H. Ince* and Asu Ziylan
Institute of Environmental Sciences, Boğaziçi University, Istanbul, Turkey
Abstract
The discharge of textile dyeing wastewater into sewage treatment facilities is of
major concern due to the complexity and intense color of the effluent, the strict
regulations on color, the low biodegradability of synthetic dyes and the politi-
cal dimensions of the problem. As such, it has been a common practice in most
parts of the world to pretreat dyeing process effluent before discharging it into
sewage treatment works. Emerging public interest on environmentally friendly
methodologies for treating industrial effluents has lately led to the search and
development of “green processes” that are recognized with low or no chemical and
energy consumption, and with no hazardous sludge generation. Ultrasound has
lately emerged as a suitable option for serving this objective via the unique means
of generating reactive oxidizing and reducing species that are highly capable of
destroying the color components in dyeing mill process effluents. The aim of this
chapter is to give an overview of the nature of textile dyeing mill wastewater and
its treatability by ultrasonic irradiation and/or a variety of hybrid processes that
utilize ultrasound, focusing particularly on the degradation and mineralization of
reactive azo dyes, which are vastly consumed throughout the globe, although they
exert toxic effects in water via their ability to transform into carcinogenic amines
under anaerobic conditions.
Keywords: Reactive azo dyes, ultrasound, bulk solution, bubble-liquid interface,
hybrid processes, sonocatalysis, advanced oxidation