Optimization of Disperse Blue 3 mineralization by UV-LED/FeTiO3 activated persulfate using response surface methodology

Abstract

Response surface methodology based on Box-Behnken design (BBD) was successfully applied for the optimization of the UV-LED/FeTiO3 activated persulfate (PS) process. Disperse Blue 3 (DB3) azo dye oxidation was carried out in a quartz jacketed stirred batch reactor using 405 nm UV at 10 W/m−2 as radiation source. The effects of temperature, catalyst concentration and persulfate dose upon the total organic carbon (TOC) removal were investigated. Optimum operating conditions were found to be: ilmenite: 320 mg/L−1, PS: 1.56 g/L−1 and 67°C. Under these conditions, 96% mineralization was achieved. Ecotoxicity of the final effluent was evaluated using Aliivibrio fischeri bacteria, finding a negligible toxicity.Comunidad Autónoma de Madrid and MINECO have supported this work through projects S2013/MAE-2716 and CTM2016-76454-R, respectively. Jefferson E. Silveira and Wendel S. Paz gratefully acknowledge the support from CAPES: Science Without Borders Program, Ministry of Education Brazil, under grants BEX-1046/13-6 and BEX-9476/13-0 respectively