Degradation of Rhodamine dyes by Advanced Oxidation Processes (AOPs) – Focus on cavitation and photocatalysis - A critical review
Ashish V. Mohod, Malwina Momotko, Noor S. Shah, Mateusz Marchel, Mohammad Imran, Lingshuai Kong, Grzegorz Boczkaj
Abstract
This review evaluates selected advanced oxidation processes (AOPs) - cavitation and photocatalysis - successfully used for wastewater treatment towards degradation of Rhodamine (Rh) dyes. Reactor configuration and impact of process parameters and oxidants addition (hydrogen peroxide, ozone, persulfates) on degradation effectiveness along with degradation mechanisms are discussed. Best technologies provide 100% degradation within 10–30 min. Rhodamine B is effectively degraded in highly acidic conditions (pH 2), while Rhodamine 6G requires basic conditions (pH 10). The most effective oxidants were hydrogen peroxide and ozone. Ecological Structure Activity Relationships (ECOSAR) revealed acute toxicities of the intermediates and by-products of the Rh dye.