生物炭负载零价纳米铁去除土壤中十溴二苯乙烷

Removal of decabromodiphenyl ethane (DBDPE) by biochar doped with zero-valent-nano iron in a soil system

作为十溴联苯醚的替代品,新型溴代阻燃剂十溴二苯乙烷(DBDPE)已经在国内外大量使用.随着DBDPE在各种环境介质中被普遍检测到,其造成的环境污染正引起广泛关注.本论文首先制备生物炭(BC)负载零价纳米铁(nZVI)材料(BC/nZVI),进而研究了BC/nZVI去除土壤中DBDPE的动力学过程,并探究了作用机制.结果表明:BC加入能促进nZVI均匀分散在生物炭的表面,并改善了其分散程度;BC/nZVI去除效率最高(投加量为0.1 g·g^-1,BC∶nZVI为2∶1,DBDPE初始浓度为10 mg·kg^-1),24 h内达到了89.74%,去除过程涉及到吸附和降解的共同作用,实验数据符合准一级动力学方程;采用LC-MS-MS探究了DBDPE的降解产物和途径;ECOSAR毒性评价数据显示BC/nZVI能够降低DBDPE的生态毒性.

As a substitute for decabromobiphenyl ether, decabromodiphenyl ethane(DBDPE), a novel brominated flame retardant, has been widely used in the world. As DBDPE is generally detected in environmental matrices, the environmental contamination caused by DBDPE attracts widespread attention. In this work, biochar(BC) supported zero-valent-nano iron(nZVI) material(BC/nZVI) was first synthesized. Then the removal kinetics and mechanism of DBDPE by BC/nZVI in soil were explored. The results show that the addition of BC facilitated uniform distribution and dispersion level of nZVI on the surface of biochar. The removal efficiency of DBDPE by BC/nZVI was the highest(the dosage was 0.1 g·g^-1, ratio of BC and nZVI was 2∶1, the initial concentration of DBDPE was 10 mg·kg^-1), which was 89.74% at 24 h. The removal of DBDPE involved simultaneous adsorption and degradation. The data fitted the pseudo-first-order kinetics model well. LC-MS-MS was used to explore the degradation products and pathway of DBDPE. The results of ECOSAR analyses reveal that BC/nZVI could reduce the ecologic toxicity of DBDPE.