Efficient removal of organic pollutants by activation of peroxydisulfate with the magnetic CoFe 2 O 4 /carbon nanotube composite

A magnetic composite of CoFe 2 O 4 and carbon nanotube (CNT) was prepared using the solvothermal approach and then employed for the activation of peroxydisulfate (PDS) to degrade reactive black 5 (RB5) and other organic pollutants. Characterization results of the composite catalyst revealed the successful loading of spherical CoFe 2 O 4 particles on CNTs, possessing abundant porosity as well as magnetic separation capability. Under the degradation conditions of 0.2 g/L CoFe 2 O 4 -CNT dosage and 4 mM PDS dosage, the removal efficiencies of 10 mg/L RB5 and other pollutants were in the range of 94.5 to ~ 100%. The effects of pH, co-existing ions/humic acid, and water matrices as well as the reusability of the catalyst were also investigated in detail. Furthermore, the degradation mechanism and pathway were proposed based on quenching experiments, LC–MS analysis, and density functional theory (DFT) calculations, and the toxicity of the degradation products was evaluated in the quantitative structure–activity relationship approach.