Investigation of different activation methods in peroxymonosulfate oxidation for the treatment of chemical industry wastewater

Abstract

The chemical industry produces complex and toxic wastewater that is difficult to treat with traditional methods. In a pioneering effort, this study provides the first systematic comparison of peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) using four distinct activation methods-iron (Fe2+), heat, ultraviolet (UV), and electric current (EC)-for the treatment of this challenging wastewater. The chemical oxygen demand (COD) removal efficiency with a single PMS application was 18.0 %, which increased to 54.2 %, 41.4 %, 51.6 %, and 82.1 % with Fe/PMS, Heat/PMS, UV/PMS, and EC/PMS, respectively. Using the Box-Behnken Design (BBD) to determine optimum conditions, validation experiments yielded COD removal rates of 59.5 % for Fe/PMS, 47.5 % for Heat/PMS, 57 % for UV/PMS, and 91 % for EC/PMS. Additionally, UV254 removal rates were 83.8 %, 78.5 %, 83.0 %, and 94.5 %, respectively. The treatment costs were calculated as 4.66 /kg COD for Fe/PMS, 2.60 /kg COD for Heat/PMS, 2.40 /kg COD for UV/PMS, and 0.43 /kg COD for EC/PMS. Among the methods compared, the EC/PMS system emerged as the most efficient and cost-effective process, achieving a remarkable 91 % COD removal at a minimal cost. These findings confirm that the activator type has a strong impact on the performance of PMS-based AOPs and highlight the utility of BBD in optimizing these processes.