Degradation of bisphenol A on SnO2-MWCNT electrode using electrochemical oxidation

Abstract

Bisphenol A (BPA) is an organic pollutant that is widely spread in waterbody with effluents as a result of its extensive use in the plastics industry. It posses to the class of compounds that are endocrine disruptors and has a great negative impact on living organisms. Therefore, the progress in development of green technology for BPA removal from the aquatic media is crucial for environmental protection. This paper presents BPA removal by electrochemical oxidation on SnO2-MWCNT (tin dioxide-multi walled carbon nanotube) nanocomposite anode. The nanocomposite was structural and morphological characterized by X-ray powder diffraction and transmission electron microscopy. Electrochemical properties of the SnO2-MWCNT anode were investigated using cyclic voltammetry, linear sweep voltammetry and electrical impedance spectroscopy. The electrochemical behavior of anodes toward BPA in sodium sulfate solutions has shown that BPA is oxidized by indirectly mechanism via hydroxyl radicals (verified by quenching tests). Electrolysis of BPA has been done in galvanostatic regime at current densities 2.5, 5.0, 10.0, 15.0 and 20.0 mA cm−2 in 0.1 M sodium sulfate supported electrolyte pH 4.0. Complete degradation of BPA was accomplished after 5 h of electrolysis at a current density of 20 mA cm−2. The proposed electrochemical technology using a low-cost SnO2-MWCNT electrode is promising for wastewater BPA removal.