Disposal of phenol waste water by CoFe₂O₄&AA activated peroxydisulfate

The pathological changes caused by phenolic wastewater discharged from various industries has attracted extensive attention in recent years. In this study, a novel sulfate-radical-based advanced oxidation process (SR-AOP) was used to dispose the target pollutant - phenols. Firstly, a solid-phase active catalyst - cobalt ferrite (CoFe₂O₄) was prepared from a sol-gel process with the innovative addition of ascorbic acid (AA). Then the original AOP was modified by using a novel CoFe₂O₄/AA/PDS combined system (PDS: peroxydisulfate).CoFe₂O₄ was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and H-M magnetic hysteresis loops. The influence factors on degradation in the new system were determined. It was found the activated PDS ($$) generated a strong oxidizer sulfate radical (SO₄·) and the phenol removal process basically obeyed the pseudo-first-order kinetics. The phenol degradation rate maximized to 98.00% under the following optimal conditions: CoFe₂O₄ preparation temperature at 500°C, initial phenol concentration at 50.00 mg/L, PDS dosage of 4.20 mM, CoFe₂O₄ dosage of 1.00 gL^-1, and AA dosage of 0.42 mM. The new system had a high phenol degradation performance in a wide range of pH 3-7.The easy oxidization of metal ion solutions in a homogeneous system and the application limitation of pH range were well solved. The synergistic effect of the novel CoFe₂O₄/AA/PDS combined system on activated PDS was verified. The separation and reuse of CoFe₂O₄ were improved owing to its magnetism. These findings will underlie the practical application of CoFe₂O₄ into disposal of phenol waste water.