Removal of p-chloroaniline from polluted waters using a cathodic electrochemical ceramic membrane reactor

Abstract

Degradation of p-chloroaniline (PCA) was investigated using an electrochemical reactor with Ti/SnO2-Sb anode and cathodic electrochemical porous ceramic microfiltration (MF) membrane under galvanostatic control. Results showed that electrochemical degradation of PCA followed pseudo-first-order kinetics. At applied current 0.8 A and membrane flux 80 L m−2 h−1, complete degradation of PCA (initial concentration of 0.6 mM) was achieved after 90-min electrolysis following adding 0.2 mM Fe2+ at pH 3, with 75.1% of mineralization ratio and 46.7% of total nitrogen abatement. The production of OH via either anodic water oxidation or homogeneous and surface Fenton reaction was responsible for PCA degradation. The degradation pathways of PCA involving protonation, OH oxidation, and cathodic reduction were proposed by quantifying generated organic byproducts and inorganic nitrogen ions. Compared to cross-by operation, the cross-through operated EF system exhibited an enhanced oxidation power, leading to more efficient destruction of PCA and its toxic intermediate byproducts and improving electrical energy efficiency. This was ascribed to the increased ROS production and better contact of the contaminants with ROS present in the vicinity of membrane (cathode) surface induced by the enhanced mass transfer under membrane filtration. These results highlight the potential of the cross-through operated EF system to be used for the treatment of PCA-contaminated water and wastewater.