铁镍双金属复合材料的制备及对BDE209的降解

Preparation of Fe/Ni bimetallic composites for degradation of BDE209

以多巴胺(PDA)改性硅藻土为载体,采用液相还原法制备铁镍双金属复合材料(硅藻土@PDA@Fe/Ni)并进行了表征,研究了不同制备条件下复合材料对BDE209的去除效果,获得最佳制备条件,分析了不同用量、污染物初始浓度和pH条件下复合材料对BDE209的去除效果,通过分析不同反应时间后的降解产物,明确降解途径.结果表明,Fe/Ni双金属复合材料的最佳制备条件为硅藻土-PDA比例为1:1.1,负载体和纳米Fe的质量比为1:2,Ni的比例为5%.复合材料用量为12 g·L^(−1)、初始浓度5 mg·L^(−1)、溶液pH为5时,BDE209的去除率较高,为99.23%.降解初期高溴联苯醚产生,降解后期低溴联苯醚出现,同时体系中Br^(−)的产生量与BDE209的降解同步,表明Fe/Ni双金属复合材料降解BDE209的途径是逐步脱溴.降解结束后,溶液中Fe^(2+)、Fe3+和Ni^(2+)浓度低于污水综合排放标准限值,有效避免了二次污染问题.

Fe/Ni bimetallic composites(diatomite@PDA@Fe/Ni)were prepared by liquid phase reduction method with dopamine(PDA)modified diatomite as a carrier and characterized.The removal effects of composite materials on BDE209 under different conditions of preparation were analyzes,and the optimum preparation conditions were obtained.Under different conditions of dosage,initial concentration of pollutants and pH,the removal effects were also analyzed.Through the analysis of the degradation products of different reaction time,the degradation pathway was clarified.The results showed that the optimum preparation conditions of Fe/Ni bimetallic composites were as follows:1:1.1 of the ratio of diatomite to PDA,1:2 of the mass ratio of the carrier to nanoiron,and 5%of the proportion of Ni in the composites.When the dosage of composite material was 12 g·L^(−1),the initial concentration was 5 mg·L^(−1),and the pH of solution was 5,the removal rate of BDE209 was high(99.23%).Highly brominated polybrominated diphenyl ethers were produced in the initial stage of degradation and low brominated polybrominated diphenyl ethers appeared in the later stage.At the same time,the production of Br^(−)in the system was synchronized with the degradation of BDE209,indicating that the degradation of BDE209 by Fe/Ni bimetallic composites was gradual debromination.After the degradation,the concentrations of Fe^(2+),Fe3+and Ni^(2+)in the solution were lower than the limits of the integrated wastewater discharge standard,which effectively avoided the secondary pollution.