Novel Magnetic MnFe₂O₄-Decorated Graphite-Like Porous Biochar as a Heterogeneous Catalyst for Activation of Peroxydisulfate Toward Degradation of Rhodamine B

Abstract

A magnetic MnFe 2 O 4 -modified graphite-like porous biochar composite (MnFe 2 O 4 /KFS800) was synthesized by the hydrothermal method, and its catalytic activity was evaluated in the activation of peroxydisulfate toward degradation of Rhodamine B. After characterization by SEM, XRD, and the BET method, the specific surface area and total pore volume of the MnFe 2 O 4 /KFS800 catalyst reached 121 m 2 /g and 0.263 m 3 /g, and exhibited plate-like morphology with good crystallinity. The degradation rate of Rhodamine B by the obtained composite was more than 91.1% when the initial concentration of RhB was 10 mg/L, the dosage of MnFe 2 O 4 /KFS800 was 0.2 g/L, and the initial pH was 6.7. Then the anti-interference ability of the obtained composite was studied, and it was found that there was a little effect on the degradation of Rhodamine B with the presence of humic acid. Finally, quenching test, EPR research, and XPS analysis were conducted to reveal the catalytic mechanism, and possible mechanism was a synergistic behavior of free radicals (SO 4•− , •OH, O 2 •− ) and nonfree radicals ( 1 O 2 ), and trace amounts of uncarbonized bagasse was also involved in the formation of free radicals.