Sulfate radicals generation and refractory pollutants removal on defective facet-tailored TiO2 with reduced matrix effects

Abstract Sulfate radical (SO 4 − ) based oxidation is an efficient and selective strategy for environmental decontamination. Herein, we confirmed, for the first time, that the fine modulation on semiconducting TiO 2 was able to improve the redox-cycling capability for heterogeneous peroxydisulfate (PDS, S 2 O 8 2− ) activation and radicals generation. PDS activation by defective TiO 2− x exposed by high-energy {0 0 1} polar facets was a superior Fenton-like catalytic system for rhodamine B (RhB) and bisphenol A (BPA) degradation, with good activity and selectivity under neutral pH. By radical inhibiting tests with two different scavengers, fluorescence measurements with terephthalic acid and electron paramagnetic resonance (EPR) technique, only the SO 4 − was identified to be the main reactive species from PDS activation on defective TiO 2− x for pollutants degradation. Compared to the reported TiO 2− x /H 2 O 2 system, the proposed TiO 2− x /PDS system exhibited much lower water matrix effects in the presence of four typical anions, natural organic matters and real surface water for target pollutants degradation. The selective SO 4 − -mediated TiO 2− x /PDS catalytic system in natural water matrix and the no toxicity of catalytic material were of considerable interest for practical environmental applications with highly complex chemistry. Our findings elucidated a new strategy for efficient and selective PDS activation based on the defect-related chemistry, which can degrade environmental contaminants and remedy contaminated soil based on sulfate components with much reduced matrix effects.