Construction of adsorption-oxidation bifunction-oriented carbon by single boron doping for non-radical antibiotic degradation via persulfate activation

Abstract

Enhanced adsorption and persulfate-driven oxidation of pollutant were simultaneously achieved on single boron-doped carbon, originating from a facile pyrolysis of glucose and boric acid. Boron with vacant p orbital can act as Lewis acid site to increase the adsorption capacity. High catalytic activity toward persulfate was attributed to the generation of carbon-based structural defects, and BC3/BC2O functionalities induced by B doping. The adsorptive and catalytic behaviors were significantly affected by B doping amount. With 0.82 % B (CB-0.9), the best performance of 96.1 % removal efficiency and 79.7 % mineralization rate was obtained within 90 min by degrading sulfamethoxazole (SMX). Correspondingly, the rate constant (kobs) was up to 0.0340 min−1 and the adsorption capacity was 56.20 mg g−1. Furthermore, our findings suggested that adsorption positively promoted the subsequent oxidation. The effects of inorganic anions, pH, humic acid, and real water matrices were investigated. Combined with LC-MS analysis and frontier molecular orbital theoretical calculation, six possible degradation pathways were proposed. The toxicity effects of intermediates and parent SMX were monitored by the growth inhibition of Chlorella. Radical and non-radical pathways jointly resulted in the catalytic degradation of SMX, in which 1O2 dominated the oxidation, SO4−/OH/direct electron transfer process played the secondary role, and O2− served as the precursor for 1O2 production. This study developed a plausible approach for rational synthesis of adsorption-oxidation bifunction-oriented carbons for antibiotic removal in AOPs.