Electrochemical Oxidation of Reverse Osmosis Concentrates from Landfill Leachate Treatment Using Ti4O7-Nanotube Reactive Electrochemical Membrane

Abstract

With the growing demand for high-quality discharge, reverse osmosis (RO) technology has been widely applied in landfill leachate treatment; however, the problem of reverse osmosis concentrates (ROCs) has worsened. In this work, a Ti4O7-nanotube reactive electrochemical membrane (Ti4O7-NT-REM) was employed to treat ROCs from landfill leachate treatment. The effects of current density, flow rate and pH on COD removal were evaluated, and the appropriate conditions were a current density of 20 mA cm−2, a flow rate of 10 mL s−1 and a pH of 7. Under these conditions, COD, TOC, NH4+-N and NO3−-N were removed by 82%, 68%, 100% and 73%, respectively. In addition, the 3D-EEM fluorescence spectra and GC–MS results revealed that the organics significantly decreased after 120 min of treatment, and aliphatic compounds were the major organic compounds. The stable performance of the REM was illustrated by cyclic treatment (20 cycles) with the assistance of cathodic polarization. In addition, a long service lifetime of 267.3 h and a low energy consumption of 7.6 kWh·kg COD−1 were obtained by related testing and evaluation. The excellent and stable performance confirmed that the Ti4O7-NT-REM has broad application prospects in the treatment of ROCs.