Evaluation of plasmon-enhanced catalytic ozonation for the abatement of micropollutants in environmental matrices

Abstract

Advanced oxidation processes (AOPs) have been widely investigated for the treatment of recalcitrant organic pollutants. Here we report the first study on the performance evaluation in different environmental matrices of a newly-developed AOP, plasmon-enhanced catalytic ozonation with silver doped spinel ferrite (0.5wt%Ag/MnFe2O4) as the catalyst, for the degradation of representative micropollutants (e.g. atrazine and atenolol). The real matrices include surface water (SW, pH 6.82), secondary effluent (SE, pH 7.22), and reverse osmosis/RO concentrate (ROC, pH 7.90) generated during water reuse. A kinetic model combining the Rct concept (the ratio of the total •OH-exposure to the total O3-exposure) and expressions of transient steady state hydroxyl radical (•OH) concentrations has been successfully developed to predict the treatment performance, where the effects of major influencing factors (e.g. solution chemistry such as pH and water constituents, and operating conditions) were explicitly quantified. Bulk organic contents, carbonate/bicarbonate, and phosphate were found to be the major chemical species that influenced the target compound removal, through interactions with reactive species (e.g. •OH) and/or the solid catalysts. Lower bromate formation was observed in the plasmon-enhanced catalytic ozonation process, compared with ozonation and catalytic ozonation processes. Low energy consumption (electrical energy per order/EEO 0.011–0.086 kWh/m3 for different matrices) together with low byproduct formation has demonstrated that plasmon-enhanced catalytic ozonation is a novel promising AOP for various water treatment and reuse applications.