Optimization of a novel hybrid photo-ozonation peroxymonosulfate process for degradation of Acid Black ATT dye in aqueous environment

Abstract

The current research aimed to simultaneously generate sulfate and hydroxyl radicals to break down Acid Black ATT dye. It was observed that using UV radiation and ozonation separately is insufficient for the complete decomposition of this dye compound. Based on the results, the UV/O₃/PMS process is able to completely remove all dye concentrations under the optimum conditions (pH=10, O₃=20 mg/min, PMS=0.4 mM L^-1, and AB-ATT=20 mg/L) in 10 minutes, with significant removal of TOC and COD. For every 0.1 mM increase in PMS concentration, dye removal increased by 14 %. Hydroxyl and sulfate radicals were identified as the primary active species responsible for the degradation. The degradation followed first kinetic order, and hydroxylation and decarboxylation pathways were found to contribute significantly to the process. Therefore, the combined UV/O₃/PMS process can be used as an environmentally friendly hybrid technology of advanced sulfate-based oxidation to remove recalcitrant contaminants from aqueous solutions.