Abstract

Abstract This study aimed to evaluate the efficiency of integrating photo-oxidation process based on UV-persulfate and adsorption on arsenic (As) removal from aqueous environments. The effects of different parameters were studied on a laboratory scale by means of a cylindrical reactor containing a UV-C lamp (15 W). After passing the oxidized samples from the adsorption column, the oxidation and arsenic removal rates were measured using UV–visible spectrophotometer and inductively coupled plasma (ICP), respectively. Response surface methodology (RSM) based on Box Behnken design was applied to evaluate the effect of independent variables on the arsenic oxidation efficiency. The highest As removal efficiency (96%) was obtained in the oxidation phase under optimum pH 3, initial As concentration of 0.5 mg L−1, and persulfate concentration of 14 mM L−1. Moreover, in the adsorption phase, the optimal conditions were occurred for pH 6.5 and the equilibrium time of 75 min. The Langmuir isotherm was the best fitted model with an value of 0.97 compared to Freundlich and Temkin isotherms. Oxidation of As (V) was determined through RSM based on Box Behnken design ( >0.934). Use of UV-activated persulfates can greatly increase the As oxidation efficiency. This process has two advantages: transformation of toxic and dangerous form of arsenic into its low-risk one and better removal of As(V) than the conventional filtration methods.