Decolorization of textile azo dyes by ultrasonication and microbial removal

The textile industry involves several processes that generate large quantities of wastewaters. Remediation by a combination of various physical, chemical, and biological techniques of these effluents is required due to their complexity and bioresistance. Ultrasonication is an advanced oxidation process used to degrade organic compounds. It has the potential for use in environmental remediation due to the formation of highly concentrated oxidizing species. In this study, the decolorization of Reactive Red 2 (RR2), Reactive Blue 4 (RB4), and Basic Yellow 2 (BY2) was studied first by continuous ultrasonic irradiation at 20 kHz and second microbially (Rhodotorula mucilaginosa). After the ultrasonic/microbial step by step applications, the highest decolorization yield was 93% in the sample with RR2 at 50 mg/L initial dye and 6 g/L cell concentrations. The lowest dye removal yield was 25% for about 100 mg/L initial BY2 and 4 g/L cell concentrations.