Study On Heterogeneous Fenton Degradation Of Butyl Xanthate Using Iron-loaded Sludge Catalyst Fe-SS

In recent years,with the continuous increase of mining development in China,the amount of mining wastewater discharged in the process of mineral processing is also increasing year by year,which has caused serious damage to the water ecological environment.As one of the most commonly used sulfhydryl collectors in the flotation process of non-ferrous sulfide ore,butyl xanthate exists in a large number of mineral processing wastewater.Butyl xanthate not only poisons aquatic organisms and pollutes nearby waters,but also accumulates in human liver through bioaccumulation,which is harmful to health.Nowadays,the pace of promoting the construction of socialist ecological civilization in China is accelerating quickly,which attaching great importance to ecological problems.The efficient treatment of butyl xanthate in mineral processing wastewater is of great significance to realize the sustainable and high quality development of mining industry.A heterogeneous Fenton catalyst was prepared from surplus sludge,which is collected from wastewater treatment plant to catalyze Fenton to degrade the butyl xanthate.The catalyst was characterized and analyzed by various modern analytical methods and the degradation efficiency of butyl xanthate were investigated,which obtaining the optimized reaction conditions,and the degradation mechanism of butyl xanthate was discussed.This research provides theoretical reference and practical guidance for the advanced treatment of butyl xanthate in mineral processing wastewater.The heterogeneous Fenton catalyst Fe-SS was prepared by repeated impregnation and pyrolysis.The characterization of Fe-SS by SEM,BET,FT-IR,XRD,XPS and VSM techniques shows that Fe-SS is mesoporous materials with a specific surface area of 30.027m~2/g an average pore size of 2.125 nm,The surface contains a large number of oxygen-containing functional groups and supported iron oxides exist inα-Fe₂O₃ crystals,catalyst surface Fe（II）is relatively high,is the main catalytic active species.The Fe-SS contains a lot of SiO₂ crystals and Si-OH functional groups,which playing a synergistic catalytic role in the Fenton reaction.The adsorption experiment,single factor experiment and repeated regeneration experiment were carried out to investigate the efficiency of Fe-SS catalytic Fenton to degrade butyl xanthate.The adsorption of butyl xanthate by Fe-SS conforms to the quasi-first-order kinetic model and Langmuir isothermal adsorption model,wich belongs to monolayer physical adsorption.The maximum adsorption capacity of Fe-SS is 103.41 mg/g.According to the single factor experiment,the optimum reaction conditions were as follows:catalyst dosage was 1.0 g/L,pH was 5.0,H₂O₂ concentration was 8.0 mmol/L,after 80 min processing,the removal rate of butyl xanthate was 99.85%,and the removal rate of its TOC is 59.14%,which is equal to the effect of Fe²⁺catalytic homogeneous Fenton degradation of butyl xanthate.Fe-SS leaves without high catalytic activity when Reusing to the fifth time,and the catalytic performance of the Fe-SS was restored to the original level after the regeneration experiment,indicating that Fe-SS has good catalytic performance and regeneration performance.The mechanism of Fe-SS catalytic Fenton degradation of butyl xanthate was discussed from the point of view of reaction process,which considering the decomposition of H₂O₂,the production of free radicals and the reaction kinetics.The degradation of butyl xanthate is divided into two stages:decomposition and mineralization.The decomposition stage result in the relatively rapid reaction rate due to the formation of adsorption-degradation promotion mechanism.·OH play a major role in the degradation of butyl xanthates and OOH/·O₂^-play an auxiliary role.The decomposition and mineralization of butyl xanthate were in accordance with the pseudo-second-order reaction kinetics.