Evaluation of TiO2/UV; O3/UV, and PDS/Vis for improving chlorfenvinphos removal from real municipal treated wastewater effluent

This article investigates the advanced oxidation processes (TiO2/UV; O-3/UV, and PDS/Vis) for final treatment of real municipal treated wastewater containing chlorfenvinphos at a concentration of 1 mg/l. During the advanced oxidation processes, the mineralization tests and kinetics described by pseudo-first-order model were performed. An approach using specific energy consumption and electric energy per order indicators was used to estimate the minimum energy requirement to degrade the chlorfenvinphos. MICROTOX (R) was used for the assessment of toxicity. Within 20 min, chlorfenvinphos concentration in the three studied advanced oxidation processes was reduced by between 51 and 81%, but the most effective process was PDS/Vis. The Total Organic Carbon mineralization index indicated that chlorfenvinphos is not fully degraded. The maximum Total Organic Carbon removal percentage of 81% was obtained for the PDS/Vis process, as well as the reduction in toxicity was the highest for this process. The solutions subjected to the TiO2/UV and PDS/Vis showed less toxicity than the chlorfenvinphos contaminated wastewater. The conducted study showed that the visible-light-driven activation of sodium persulfate is the most effective for: (1) lowering the final concentration of chlorfenvinphos, (2) the mineralization degree and (3) toxicity of the solution. PDS/Vis was also the most effective process from the economic point of view. Experimental research showed that the PDS/Vis process can be a valuable alternative to TiO2/UV and O-3/UV processes.