Lignin-derived biochar to support CoFe2O4: Effective activation of peracetic acid for sulfamethoxazole degradation

The conversion of biomass wastes to highly efficient biochar-based catalysts has attracted more and more attention because it meets the environmental protection concept of waste recycling. In this work, a novel magnetic catalyst (CoFe2O4@BC) was developed by using alkaline lignin, the dominant by-products of paper-making industry, as feedstock for biochar. More importantly, PAA (CH3C(=O) OOH) was successfully activated by CoFe2O4@BC nanoparticles for sulfamethoxazole (SMX) elimination. The catalytic activity of CoFe2O4@BC on PAA activation was systematically studied. When PAA was 825 mu M and CoFe2O4@BC was 100 mg/L, 10 mg/L SMX could be completely degraded. The cycle of Co-3(+)/Co2+ of CoFe2O4 @BC prompted the generation of acetyl (per)oxyl groups (CH3C(O)O center dot and CH3C(O)OO center dot), which were believed to be the dominant reactive substances for SMX degradation. The degradation of SMX was promoted under near-neutral pH conditions, and was inhibited when humic acid and HCO3- were added, while the Cl- showed a negligible influence. According to the analysis of oxidation products, three main transformation pathways of SMX were illustrated. The remarkable stability and magnetic separability of CoFe2O4@BC make it have a wider application prospect in the treatment of various wastewater.

Automated summary

A novel magnetic catalyst, CoFe2O4@BC, was developed using alkaline lignin as feedstock for biochar, and successfully activated PAA for sulfamethoxazole (SMX) elimination. The catalyst showed a wider application prospect in treating various wastewater due to its remarkable stability and magnetic separability.