Decolorization of acid yellow 23 by photo-electro-fenton process using alkaline batteries / Clinton Brinyang Dris

Wastewater, a pressing environmental issue worldwide, is exacerbated by substances like azo dyes, such as acid yellow 23, and increasing volumes of electronic waste, including alkaline battery waste. Alkaline batteries contain pollutants like lead, cadmium, and lithium and the use of novel materials in batteries raises environmental safety concerns. Reusing materials from used batteries for wastewater treatment is gaining interest since this can create a closed-loop system, turning e-waste into useful products and reducing the need for new raw materials. Thus, the objective of this study is to determine the removal efficiency of acid yellow 23 when used alkaline batteries are being used as graphite electrodes in photo-electro fenton (PEF) process and subsequently the optimal conditions that can maximize this efficiency. PEF is a fenton reaction variant that uses light to generate hydroxyl radicals (OH·) rather than relying solely on electrochemical methods. In this process, hydrogen peroxide (H2O2) and a photosensitizer, which absorbs light and initiates chemical reactions, are added to a solution with the target pollutant. The combination of hydrogen peroxide (H2O2), ultraviolet (UV) radiation, and ferrous ion, Fe2+ or ferric ion, Fe3+ (as oxalate ions) produces more OH· than the traditional fenton method. The results indicated that the system achieved the highest removal rate of 88.2% when the optimum conditions were recorded at the initial concentration of acid yellow 23 was 40 mg/L, the catalyst concentration [FeSO4]0 was 6 mM, and the applied voltage was 4.5 V. Under this condition, kinetic study of dye removal fitted more with second-order reaction. Hence, the results obtained demonstrate significant improvement when light is introduced as photo-electro fenton in the system.