Hydrogen-based sono-hybrid catalytic degradation and mitigation of industrially-originated dye-based pollutants

Hazardous pollutants in water bodies have increased global concern due to their consid-erable toxicity and threat to the environmental matrices. Conventional remediation ap-proaches are futile for eliminating various toxic dyes and other related pollutants. Regulations compliances for wastewater expulsion have forced scientists to either intro-duce new methods or upgrade present technologies to attain operative deprivation and mineralization of pollutants. Advanced oxidation processes (AOPs) relying on the genera-tion of highly reactive oxidizing radicals, like center dot O, and center dot OH are considered efficient to attain high mineralization of a large number of dye pollutants and many other organic con-taminants. Compared to conventional AOPs, including photocatalysis, Fenton, photo-ferrioxalate, ozone/UV, ozonation, H2O2/UV, etc., sonolysis is a comparatively newer AOP that implicates the use of ultrasound irradiation for generating oxidizing radicals, leading to the degradation of recalcitrant dyes. Due to no chemical catalyst requirement and being executed at ambient pressure and temperature, ultrasound-assisted AOPs have become robust hybrid AOPs to degrade environmental contaminants. Ultrasound treatments to mitigate pollutants are important because of the cavitation phenomenon. This review focuses on the degradation of dyes through ultrasound-based advanced oxidation pro-cesses. Firstly, we have described the ecotoxicity and health hazards of dye pollutants, then different sono-based methods such as sono-hybrid Fenton (US + Fe+2/H2O2), Fenton like (Fe+3/H2O2) process, sono-hybrid photo-Fenton process (US + Fe2+/H2O2/UV system, sono-hybrid hydrogen peroxide (US + H2O2), sono-hybrid catalytic (photo/electro) pro-cesses have been examined in details for their efficacy for degradation of dyes in waste-water. Future perspectives of ultrasound-assisted AOPs for dyes removal have also been discussed.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.