Removal Of Refractory Organic Pollutants By Peroxymonosulfate Activated With Magnetic Cu/Fe Based Materials

With the development of modern industry,especially the development of printing and dyeing,medicine,chemical,pesticide,textile and other industries,resulting in high organic content of industrial sewage discharge is increasing,most of the organic pollutants are difficult to degrade,toxicity,poor biodegradability and other problems.At present,advanced oxidation processes based on persulfate（AOPs）has become an effective technology to degrade organic pollutants in wastewater due to its high stability,wide pH range and low cost.As a catalyst,the high efficiency and recycling ability of transition metals in the process of activating persulfate have attracted wide attention.Catalytic materials based on Cu/Fe composite have shown excellent stability and reusing ability.And the catalyst particles can be effectively separated from solution through magnets.Therefore,the system including a Cu/Fe composite catalytic material activated peroxymonosulfate was constructed in this paper to investigate its performance and mechanism of degradation of organic pollutants in water.The main contents are as follows:（1）The magnetic nano-Cu/Fe composites were successfully synthesized and used as the activator of peroxymonosulfate（PMS）for the degradation of oxytetracycline（OTC）.Among them,The obtained catalysts with different ratios showed excellent degradation effects,especially the Cu/Fe-1 catalysts.The removal efficiency of OTC（93%）was achieved with0.2 g/L PMS and 0.1 g/L catalyst in 60 min.To explore the mechanism for OTC degradation,radical scavenging and electron spin resonance（EPR）experiments were carried out,and non-radical ¹O₂was identified to be the main radical.TEM and XRD results showed the presence of CuFe₂O₄composites in Cu/Fe-1,which can promote the production of ¹O₂and thus improve the OTC degradation efficiency.The results of this work provided an efficient,stable,and inexpensive catalyst for the degradation of oxytetracycline.（2）Cu-Fe bimetallic modified orange peel biochar（CuFe/OPB）was prepared for the removal of bisphenol A（BPA）by peroxymonosulfate（PMS）activation.At the optimum reaction conditions of 0.3 g/L catalyst dosage,0.1 g/L PMS dosage,pH=5.2 to 9.0 and 30℃,the removal efficiency of 20 mg/L BPA in 90 min was about 90.0%,and the mineralization rate was about 69.5%.The presence of HCO₃^-further improved the degradation efficiency of BPA.The results of quenching experiment and EPR showed that both radical and non-radical pathways existed in the removal of BPA,and the main reactive oxygen species（ROS）were¹O₂.The formation of SO₄^·-and·OH on CuFe/OPB-1 heterogeneous surface also contributed to the degradation of BPA.Fe,Cu nanoparticles and electron-rich ketone functional groups on OPB were active sites for PMS activation.nine intermediates and three possible degradation pathways were concluded based on the results of LC-MS.This study revealed the application prospect of Cu-Fe bimetallic orange peel biochar in the treatment of phenolic wastewater.