Degradation Of Chlorophenols By Persulfate Activated With Iron–carbon–manganese Composites

Manganese dioxide（MnO₂）as a persulfate activator has the advantages of low ion leaching rate,strong persistence and low toxicity.However,MnO₂ is difficult to recycle due to its lack of magnetism.In addition,MnO₂ has a weak adsorption effect on organic pollutants,which affects the degradation effect of pollutants.Therefore,in this research,a kind of iron–carbon-manganese composites（MnO₂-Fe₂O₃/C）was prepared,and the degradation of Chlorophenols（CPs）by activated persulfate of MnO₂-Fe₂O₃/C was systematically studied by a series of experiments.Firstly,in this study,sucrose,manganese sulfate,ferrous sulfate and potassium permanganate were used as precursors,and MnO₂-Fe₂O₃/C was obtained by ultrasonic spray combined with the hydrothermal method.Then,MnO₂-Fe₂O₃/C was characterized by SEM,TEM,BET,XRD,TGA and other methods to determine the internal structure,external morphology,element proportion and other key information.Secondly,MnO₂-Fe₂O₃/C was used to construct a persulfate activation system to degrade p-chlorophenol,and the optimal persulfate type,dosage and the optimal dosage of MnO₂-Fe₂O₃/C were determined.Under the optimum conditions,p-chlorophenol could be completely removed after 150 min treatment.After that,the excellent performance of MnO₂-Fe₂O₃/C activated persulfate was verified by control experiments.Compared with MnO₂,MnO₂-Fe₂O₃/C has better activation,adsorption and cycling properties.Subsequently,in this study,active substances in the reaction system were identified by the active substance quenching experiment and electron paramagnetic resonance（EPR）.Meanwhile,intermediate products in the process of p-chlorophenol were detected by LC-MS,and the reaction mechanism was deduced.Finally,the influence of initial p H value and common background substances in water on the degradation effect was investigated,and the reaction system was applied to other pollutants to investigate the practical application prospect of the reaction system.