Effect of extracellular polymeric substance components on the sorption behavior of 2,2′,4,4′-tetrabromodiphenyl ether to soils: Kinetics and isotherms

• Published in: The Science of the total environment 2017-12, Vol.609, p.144-152
• Main Authors: Liu, Guangxia, Bian, Yongrong, Jia, Mingyun, Boughner, Lisa A., Gu, Chenggang, Song, Yang, Sheng, Hongjie, Zhao, Wei, Jiang, Xin, Wang, Fang
• Format: Article
• Language: English
• Subjects: Bovine serum albumin; Partition effect; Persistent organic pollutant; Sodium alginate; Surface sorption
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2017.07.089

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. [Display omitted] •Addition of bovine serum albumin increased sorption capacity of BDE-47 to soils.•Partition of highly concentrated BDE-47 to soils was impeded by sodium alginate.•Physical and chemical sorption may coexist throughout the BDE-47 sorption process.•Aromatic CC, H-bonds and OH groups may all be involved in the sorption process.