Research On Degradation Of TBBPA By Waste-derived NZVI/CuO@BC Activated Peroxodisulfate System

Sulfate radical(SO4^·-) based advanced oxidation technology is an emerging environmental treatment technology.It generates strong oxidizing SO4^·-through the activation of persulfate,which can efficiently degrade refractory organic pollutants in wastewater.Among persulfate activation methods,transition metals-based activation is favored because it does not require additional input energy.Materials for persulfate activation are the key factors that determine the performance of transition metal-activated persulfate advanced oxidation systems.Therefore,it is necessary to develop high-activity,green,and low-cost persulfate-activated materials.Iron-based composite materials have become a research hotspot in the field of activator development due to their high activity,low toxicity,and low cost.In this paper,a biochar-loaded nanometer zero-valent iron?nZVI?and copper oxide?CuO?nanocomposite material?nZVI/CuO@BC?was fitted to activate persulfate to degrade tetrabromobisphenol A?TBBPA?in aqueous solution.In the preparation of materials,this study further attempts to apply wastes as the raw materials to synthesize nZVI/CuO@BC.In this research,nZVI/CuO@BC was successfully prepared using waste iron scraps,waste copper leachate,and corn stalks as raw materials.In this paper,with TBBPA as the target pollutant,an nZVI/CuO@BC activated PDS system was constructed to evaluate the activation and degradation performance of the system and explore the activation mechanism of PDS.The main results obtained are as follows:?1?The biochar-supported CuO composite?CuO/BC?was synthesized by pyrolyzing the corn stalk powder which being impregnated with a copper-containing solution.The nZVI/CuO@BC nanocomposite was prepared by loading nZVI onto CuO/BC by liquid phase reduction.The surface morphology and structural characteristics of nZVI/CuO@BC were characterized by XRD,BET,FTIR,SEM,TEM and other methods.The study found that nZVI/CuO@BC has a large specific surface area;nZVI/CuO@BC surface is rich in oxygen-containing functional groups;nZVI and CuO particles are evenly loaded on BC,and the particle sizes are both nanometers.?2?To evaluate the activation performance of nZVI/CuO@BC and the degradation performance of TBBPA of nZVI/CuO@BC-PDS system through the activation efficiency of PDS and the degradation performance of TBBPA under different reaction systems.The results show that the activation efficiency of nZVI/CuO@BC for PDS is as high as 86.32%,and nZVI/CuO@BC has excellent activation performance for PDS;under the condition of:the dosage of nZVI/CuO@BC is 100 mg/L,the concentration of PDS is 0.2 m M,the initial p H value is 8.0 and the reaction temperature is 25°C,98.46%of TBBPA was degraded after 45minutes in nZVI/CuO@BC-PDS system.?3?Investigated the degradation of nZVI/CuO@BC-PDS system by nZVI/CuO@BC dosage,PDS concentration,initial p H value,reaction temperature,and four common inorganic anions and humic acid?HA?in natural water The impact of TBBPA.The results show that within a certain range,the dosage of nZVI/CuO@BC and the concentration of PDS increase,and the degradation efficiency of TBBPA increases.The excessive dosage of nZVI/CuO@BC and the concentration of PDS are not conducive to the degradation of TBBPA;in the alkaline range,Increase the initial p H value,the degradation efficiency of TBBPA decreases;the reaction temperature has a significant impact on the degradation of TBBPA,increase the reaction temperature,the degradation efficiency of TBBPA is greatly increased;when inorganic anions and HA are added to the reaction system,the degradation of TBBPA is inhibited to varying degrees,The inhibition intensity is HCO₃^->HA>SO₄^2->Cl^->NO₃^-in order from large to small.?4?Explored the debromination and mineralization effects of nZVI/CuO@BC-PDS system on TBBPA and the stability of the system's performance in different water bodies.The results are as follows:when the PDS concentration is 2 m M,the debromination efficiency and mineralization efficiency of TBBPA are 79.12%and 79.36%respectively;the degradation efficiency of TBBPA in ultrapure water,tap water and surface water are 98.46%,94.36%and84.61%,respectively.The results show that the nZVI/CuO@BC-PDS system has a good debromination and mineralization effect on TBBPA,the nZVI/CuO@BC-PDS system has a relatively stable performance,and has great application potential in actual environmental remediation.?5?The activation mechanism of PDS in nZVI/CuO@BC-PDS system was explored through EPR test,free radical quenching experiment,iron substance change analysis and XPS analysis.The analysis found that two radicals,sulfate radical(SO4^?-)and hydroxyl radical??OH?,exist simultaneously in the PDS system activated by nZVI/CuO@BC.SO4?-and?OH jointly dominate the degradation process of TBBPA;Ferrous ion(Fe²⁺)indirectly activates PDS through the electron transfer mechanism and is the main active species for activating PDS;nZVI and CuO have a synergistic effect and jointly activate PDS.