Elimination of Micropollutants in Catalytic Ozonation using Aniline-Derived Metal-Carbon Composite

Abstract

This study investigates the efficacy of aniline-derived metal-carbon catalysts (Me-N-C) in catalytic ozonation for the removal of persistent micropollutants from drinking water. Micropollutants, including pharmaceuticals and pesticides, pose significant environmental and public health challenges due to their persistence and resistance to conventional water treatment processes. Catalytic ozonation, leveraging enhanced hydroxyl radical (•OH) production, offers a promising solution to these limitations. Five nitrogen-doped carbon-supported metal catalysts—manganese (Mn), nickel (Ni), copper (Cu), cobalt (Co), and iron (Fe)—were evaluated. Among these, Mn-N-C and Ni-N-C exhibited superior performance in promoting ozone decay, •OH radical generation, and micropollutant degradation. Notably, Mn-N-C achieved a highest removal of para-chlorobenzoic acid (pCBA) via combined •OH-driven reactions and adsorption mechanisms. Comparative analyses revealed that catalytic ozonation improved the removal efficiency of ozone-resistant micropollutants by 35.5% compared to conventional ozonation, achieving an average removal rate of 67.9%. In addition to its high degradation efficiency, Mn-N-C demonstrated a 41.6% reduction in bromate formation, a key carcinogenic byproduct, compared to conventional ozonation. Furthermore, Mn-N-C enhanced dissolved organic carbon (DOC) removal by 45%, indicating its dual capability to mitigate disinfection byproduct formation while improving overall water quality. These results highlight the transformative potential of Mn-N-C catalysts in advancing catalytic ozonation as a sustainable and effective advanced oxidation process for drinking water treatment.