Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Sci Total Environ. 2017 Dec 31;609:144-152. doi: 10.1016/j.scitotenv.2017.07.089. Epub 2017 Jul 20.
Microbial extracellular polymeric substances (EPS) and persistent organic pollutants (POPs) commonly exist in the soil environment. Currently, there is a knowledge gap regarding the effect of EPS on the fate of POPs in soil. In the present study, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) was used as a model compound to investigate the effects of bovine serum albumin (BSA) and sodium alginate (SA) - mimicking the main components of EPS - on sorption of POPs to soils, through batch experiments. Irrespective of the concentration of BSA: the addition of BSA did enhance the sorption capacity of BDE-47 to soils, due to generation of more sorption sites. For SA, it increased the sorption capacity of BDE-47 at low BDE-47 concentrations, while the presence of SA negatively affected sorption of BDE-47 at high BDE-47 concentrations. The partition effect dominates the sorption of BDE-47 to soils, but after adding either BSA or SA, the sorption of BDE-47 to soils is dominated by surface sorption. Film diffusion and intra-particle diffusion were also involved in the sorption process with and without BSA or SA, with the latter being the rate-limiting step. The heterogeneous surface and nonlinear sorption behavior of BDE-47 to soils increased in the presence of either BSA or SA. The FTIR spectra indicated that the aromatic CC, H-bonds and OH groups may be involved in the sorption process. Therefore, BSA enhanced the retention of BDE-47 to soil, while SA's influence on BDE-47 sorption to soil depended on the concentration of BDE-47.
微生物胞外聚合物（EPS）和持久性有机污染物（POPs）通常存在于土壤环境中。目前，关于 EPS 对土壤中 POPs 归宿的影响还存在知识空白。本研究以 2,2',4,4'-四溴二苯醚（BDE-47）为模型化合物，通过批量实验，研究了牛血清白蛋白（BSA）和海藻酸钠（SA）（模拟 EPS 的主要成分）对 POPs 与土壤的吸附作用。无论 BSA 的浓度如何：由于生成了更多的吸附点位，添加 BSA 确实增强了 BDE-47 对土壤的吸附能力。对于 SA，它在低 BDE-47 浓度下增加了 BDE-47 的吸附能力，而在高 BDE-47 浓度下，SA 的存在则对 BDE-47 的吸附产生了负面影响。分配效应主导着 BDE-47 对土壤的吸附，但添加 BSA 或 SA 后，BDE-47 对土壤的吸附则由表面吸附主导。膜扩散和内颗粒扩散在有或没有 BSA 或 SA 的情况下都参与了吸附过程，后者是限速步骤。BSA 或 SA 的存在增加了 BDE-47 对土壤的非均相表面和非线性吸附行为。FTIR 光谱表明，芳香族 CC、氢键和 OH 基团可能参与了吸附过程。因此，BSA 增强了 BDE-47 对土壤的保留能力，而 SA 对 BDE-47 与土壤的吸附的影响取决于 BDE-47 的浓度。
