Ti/IrO₂/SnO₂ anode for electrochemical degradation of chlorpyrifos in water: optimization and degradation performances

Chlorpyrifos, a widely used organophosphate pesticide which can be found in surface water bodies, is harmful for human body. Thus, treating water contaminated with chlorpyrifos is important. In our previous studies, novel Ti/IrO₂–SnO₂ anode was successfully developed for electrochemical degradation of chlorpyrifos in chloride free water. In this study, optimization of previously developed Ti/IrO₂–SnO₂ anode for mineralization of chlorpyrifos was successfully performed through response surface methodology. During the optimization study, two-level factorial design was used to determine the optimal coating solutions concentration for developing the Ti/IrO₂–SnO₂ anode. Cyclic voltammetry and open circuit potential were performed to investigate the electrochemically active surface area and stability of these anodes. The response surface and contour plots show that 0.3 M of [Ir] and 7.5 mM of [Sn] coated electrode has both highest anodic charge and stability. Scanning Electron Microscopic (SEM) images show the evidence of having both compact and porous regions in the surface of the thin film, resulting larger surface area. Within 6 h, the best result for mineralization (55.56%) of chlorpyrifos was obtained with 0.3 M of [Ir] and 7.5 mM of [Sn] coated anode using Total organic Carbon (TOC) analyzer. Therefore, the optimum coating concentration was found as 0.3 M of [Ir] and 7.5 mM of [Sn]. It would require an energy consumption of 6 kWhm^-3.