Optimization of Ti/SnO2–Sb2O5 anode preparation for electrochemical oxidation of organic contaminants in water and wastewater

Abstract

The preparation of antimony-doped tin oxide anodes on a titanium substrate (Ti/SnO2–Sb2O5 anodes) by dipping in a solution of tin chloride and antimony chloride and annealing at high temperatures was optimized for the potential applications of drinking water disinfection, wastewater effluent disinfection, and industrial waste stream treatment. The effectiveness of Ti/SnO2–Sb2O5 anodes prepared under different conditions was evaluated by using hexanol as a probe molecule to measure the extent of oxidative reactions, and anode performance was monitored by cyclic voltammetry. A large factorial matrix consisting of tin chloride concentration × antimony chloride concentration × annealing temperature was first evaluated, and the optimum conditions were found to be 20% tin chloride and 1% antimony chloride in the dip solution and an annealing temperature of 500°C. Further investigation showed that the rate of withdrawal from the dip solution, the number of coatings of the dip solution, and the addition of oxygen during annealing did not significantly affect anode performance. Under optimum preparation conditions, Ti/SnO2–Sb2O5 anodes showed no loss of performance over 1,280 cycles of cyclic voltammetry, suggesting that their performance can be sustained over long periods of use. The result of this research is a simple preparation method for effective and long-lived Ti/SnO2–Sb2O5 anodes; this method could be easily adopted by a utility for pilot- or full-scale disinfection of water and wastewater and the treatment of industrial waste streams.