Boosting active sites of protogenetic sludge-based biochar by boron doping for electro-Fenton degradation towards emerging organic contaminants

Abstract

There has been extensive research on biochar materials in the field of adsorption, catalysis, etc. Hereon, we reported a gentle synthesis of electrode by abundant biomass of municipal sludge and cheap precursor of boric acid as carbon source and boron source. Experimental results demonstrated that a small amount of boron doping had a profound impact on the elemental composition and active sites of sludge-based biochar significantly, resulting the improvement of EF activity for sulfamerazine (SMR) removal. Under the optimal reaction conditions, including initial pH, added divalent iron, applied current and air flow, 95.12% of SMR could be removed in 180 min in EF system. It was confirmed that hydroxyl radical (·OH) and superoxide radical (·O2–) were the primary active substances for SMR degradation. The effect experiments of various ions, types of wastewater and pollutants were carried out and the stability experiments were conducted for eight cycles without significant efficiency loss, which proved the exceptional applicability and reusability of the gained boron doped sludge-based biochar electrode BSBC-E. These functions of boron-doped sludge-based biochar cathode could be a promising material for emerging organic contaminants remediation.