Application of electrochemical reactor divided by cellulosic membrane for optimized simultaneous removal of phenols, chromium, and ammonia from tannery effluents

Abstract

The post treatment of simulated tannery wastewater was evaluated in an electrochemical oxidation process under galvanostatic conditions. A continuous flow reactor divided by a cellulosic membrane consisted of Ti/SnO2–Sb anodes and iron cathodes was used. Central composite design and response surface methodology (RSM) were applied to investigate the effects of six operational parameters, namely initial concentration of total phenols (TPh), total chromium (TCr), total ammonia nitrogen (TAN), flow rate (Q), current intensity (I), and electrode surface area (A). Effectiveness of the innovative cellulosic membrane was proven by considerable pH variations in the anolyte and catholyte chambers. A faster removal rate was observed for TPh and TAN, followed by TCr. The treatment level was very sensitive to Q and I in the studied ranges. RSM showed the removal efficiencies of 78.14%, 63.42%, and 86.09% for TPh, TCr, and TAN, respectively, are achieved under optimal conditions with consumption of only 9.03 kWh m−3 electrical energy. Chlorinated compounds such as chloroform, 2,4-dichlorophenol, and chlorobenzene were detected as the degradation intermediates. According to the obtained results, electrolysis in the divided cell with cellulosic membrane is a practical, cost-effective method for advanced treatment of tannery effluents.