Degradation of Acid Orange II by sludge-derived biochar supported Cu/Fe bimetallic particles activating persulfate

CuFe2O4 and biochar composite (CuFe/BC) was successfully prepared by a simple hydrothermal synthesis method. As an excellent catalyst, it was utilized toward the activation of persulfate (PS) for Acid Orange II (AOII) degradation. The surface morphology and structure characterizations of CuFe/BC measured by X-ray diffraction, scanning electron microscopy-energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller. The CuFe/BC exhibited high catalytic activity and reusability. The AOII degradation rate could reach 0.106 min(-1) and AOII degradation efficiency was 95.89%. After 4 reuse cycle, CuFe/BC exhibited good reactivity in CuFe/BC/PS system and AOII degradation efficiency still kept 73.58%. During the AOII degradation process in CuFe/BC/PS system, the main active radicals (SO4 center dot- center dot OH, and O-1(2)) were identified by the radical scavenging experiment and electron spin resonance analysis. Moreover, the mechanism of the CuFe/BC/PS system for AOII degradation was further proposed. The acute toxicity of the reaction solution to Photobacterium phosphoreum T3 spp. in the CuFe/BC/PS process increased during the first 20 min and then decreased, which illustrated that CuFe/BC/PS was an effective and safe method for the removal of AOII.