Insight Into Removal Of Decabromodiphenyl Ethane By Biochar Supported Zero-Valent-Nano Iron And Mechanism In Soil System

Brominated flame retardants have been widely used due to their properties of resistance flame.Decabromobiphenyl ether(BDE-209)has been listed as persistent organic pollutants(POPs),which increases the demand for decabromodiphenyl ethane(DBDPE)that was used as an alternative of BDE-209.DBDPE can accumulate in organisms and amplify through the food chain and has been widely detected in environmental media such as soil.The harm to ecological environment caused by DBDPE attracts widespread attention.There is little research reporting on the removal of DBDPE in soil.In this paper,bagasse was used to prepare biochar(BC)supported nano-zero-valent iron(nZVI)materials(BC/nZVI).Then the DBDPE removal of kinetic and mechanism by BC/nZVI in soil were explored.This technology may provides scientific basis and technical support to remove DBDPE from soil by carbon-based nZVI.The main conclusions are as follows:(1)SEM and EDS characterization results show that nZVI dispersed on the surface of biochar,increasing the dispersion and reactivity of nZVI.The BET specific surface area of nZVI and BC/nZVI are 8.9280 m2/g and 14.2715 m2/g respectively,which show that BC/nZVI has a larger specific surface area than nZVI.The results of EDS,XRD and XPS confirmed the presence of Fe in BC/nZVI.The result of FT-IR confirmed the presence of Fe-CO and Fe-OH in BC/nZVI indicating that BC and nZVI are combined by chemical bonding.EPR show that PFRs existed in the biochar and interacted with water and oxygen generating OH.(2)Three materials BC,nZVI and BC/nZVI were used to remove DBDPE in the soil respectively.The removal efficiency of BC/nZVI was the highest(the dosage was 0.10 g/g,BC:nZVI was 2:1,the initial concentration of DBDPE was 10 mg/kg),which was 86.90%at 24 h.The process involves simultaneous adsorption and degradation.The reaction fitted the pseudo-first-order kinetic equation.(3)LC-MS-MS was used to identify degradation products and speculate on degradation pathways.ECOSAR program was used to assess the toxicity of DBDPE and products to aquatic organisms.The results of ECOSAR show that BC/nZVI can reduce the ecological toxicity of DBDPE.