Insights into the mechanism of peroxydisulfate activated by magnetic spinel CuFe2O4/SBC as a heterogeneous catalyst for bisphenol S degradation

Abstract

• CuFe 2 O 4 /SBC was synthesized via hydrothermal method assisted by PEG-20000. • The CuFe 2 O 4 /SBC/PDS system showed superior stability against metal ions leaching. • CuFe 2 O 4 /SBC could efficiently degrade 84.5% BPS in CuFe 2 O 4 /SBC/PDS system. • The adsorbed BPS on CuFe 2 O 4 /SBC could be further degraded. • The surface-bound radical pathways played a more crucial role. The CuFe 2 O 4 catalyst in advanced oxidation processes had received much attention, while the leaching metal ions and its agglomeration limited its application prospect. The conversion of waste activated sludge (WAS) into sludge-derived biochar (SBC) through pyrolysis could not only be the option of reducing the environmental burden but also converted to be the value-added environmental remediation materials. Hence, the present study prepared as a CuFe 2 O 4 /SBC heterogeneous catalyst to degrade new environmental pollutants (bisphenol S, BPS). To our best knowledge, CuFe 2 O 4 /SBC as a heterogeneous catalyst activating peroxydisulfate to degrade BPS in solution is rarely reported, and the catalytic performances and degradation mechanism of CuFe 2 O 4 /SBC need to be comprehensively investigated. The synergistic effect between CuFe 2 O 4 and SBC enhanced catalytic performances and alleviated agglomeration. The CuFe 2 O 4 /SBC was greatly ameliorated metal ions leaching, but the synthetic strategy could better optimize to further reducing Cu ion leaching. The dominant role of heterogeneous catalysis by CuFe 2 O 4 /SBC also have been elucidated. It was proposed that radical ( OH and SO 4 − ) and non-radical ( 1 O 2 ) oxidation processes worked together for BPS degradation, but surface-bound radical pathways played more crucial roles. Some intermediate products with higher toxicity may be produced due to the non-completely mineralized, thus future attention should be paid to their environmental risks. Hence, the detoxification efficiency of CuFe 2 O 4 /SBC needs to be further strengthened via improving the reaction conditions. Overall, this study provided a new strategy to simultaneously solve the problems of WAS disposal and leaching metal ions of CuFe 2 O 4 .