Usability of brass and stainless steel electrodes in electrochemical treatment of 4-nitrophenol

Abstract

4-Nitrophenol (4NP), which is used in many industries, is among the priority pollutants due to its carcinogenic, teratogenic, and mutagenic effects. In this study, the treatment of an aqueous solution containing 4NP was carried out by electrochemical method. A stainless steel electrode (Ss) allowing both electro-oxidation and electrocoagulation to occur together was used at the anode, while a brass (Bs) electrode with high conductivity was used at the cathode. By performing 4NP and total organic carbon (TOC) analyses on the samples taken from the reactor at certain times, the removal efficiencies and mineralization current efficiency (MCE) were determined. Based on the results, the optimum values of the operating parameters affecting the treatment efficiency were determined, the specific energy consumption (SEC) was calculated and the parameter-based statistical analysis of the data was performed. Under optimum conditions (pH: 5.5; Electrolyte: 3 g/L NaCl (5950 µs/cm); Current: 3.0 A (78 mA/cm2); Time: 20 min.; Distance: 0.5 cm), 97.44% 4NP and 33.09% TOC removal efficiencies were obtained. The energy consumption required to treat 1 m3 of wastewater electrochemically under these conditions was calculated as 28.37 kWh/m3. As a result of the statistical analysis, the most effective parameters in electrochemical treatment were determined as current, and time, respectively.