Electrochemical oxidation of bio-treated landfill leachate using a novel dynamic reactive electrochemical membrane (DREM)

Abstract

Bio-treated landfill leachate contains complex refractory organics, which lead to short membrane life for subsequent membrane processes. In this work, a blue TiO2 nanotubes (TiO2-BNTs) reactive electrochemical membrane combined with dynamic SnO2-Sb magnetic composite particles (MCPs), i.e., dynamic reactive electrochemical membrane (DREM) technology, was developed to enhance contaminant removal and improve antifouling performance under harsh water quality. A 98% removal of ammonia as well as 67% and 78% reduction in nitrate and total nitrogen were achieved, respectively. An increase of nearly 45% and 20% COD removal in a 2.0 g MCP-loaded DREM was found upon a 0 g MCP-loaded DREM and static TiO2-BNTs/SnO2-Sb membrane electrode (SREM), respectively. The synergetic mechanism revealed the inner dynamic MCP layer (adjacent to TiO2-BNTs surface) played a key role in organic degradation, and the outer layer (adjacent to bulk solution) acted as a protective layer to diminish fouling. Additionally, DREM provided a more optimized distribution and effective usage for reactive oxygen species (ROS). A high and stable COD removal of > 75% was confirmed in repeated experiments. A > 24% lower energy consumption was found with the DREM compared with other electrochemical technologies, which proved the DREM is a viable method for practical applications.