Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China.
Chinese Research Academy of Environmental Sciences, Beijing 100012, People's Republic of China.
Ecotoxicol Environ Saf. 2019 Jun 15;174:363-369. doi: 10.1016/j.ecoenv.2019.01.128. Epub 2019 Mar 5.
The immobilization of organic contaminants in sediment-water systems is of growing concern. Using biochar as sorbent amendment to reduce the mobility of pollutants in the sediment-water interface is becoming increasingly popular as a low-cost and environmentally friendly option. In this study, we mixed sediment from the Weishan Lake with biochar (0%, 2%, and 5% (w/w)) derived from corn straw to investigate the adsorption of perfluorooctane sulfonate (PFOS) and 17α-ethinyl estradiol (EE2). Biochar addition significantly improved the adsorption rates and capacities of EE2 and PFOS on sediments by the factors 1.7-3.5; the organic carbon concentration in the sediment was the main factor influencing this process. The sorption of EE2 and PFOS to sediment was near-linear (Freundlich exponent 1/n of 0.799-0.805), but non-linear for biochar (0.430-0.476) and sediment+biochar (0.370-0.421). The mobility of PFOS in the water-sediment system after biochar addition was significantly reduced, with a considerable increase (about three times) in the sediment-water distribution coefficient K. Compared to EE2, PFOS is anionic compound and contains hydrophobic C-F chains and hydrophilic S-O groups, making it more susceptible pH influences and resulting in interactions with-OH, -C=O, Si-O-Si, -O-Si, and -Al-O-Al groups via hydrogen bonding, ligand exchange, and surface complexation. We suggest that biochar amendment at ～5% is a viable approach to immobilize EE2 and PFOS at the sediment-water interface.
在水-沉积物系统中，有机污染物的固定化越来越受到关注。使用生物炭作为吸附剂改良剂来降低污染物在水-沉积物界面的迁移性，作为一种低成本和环境友好的选择，正变得越来越流行。在这项研究中，我们将微山湖沉积物与玉米秸秆生物炭（0%、2%和 5%（w/w））混合，研究了全氟辛烷磺酸（PFOS）和 17α-乙炔基雌二醇（EE2）在沉积物中的吸附。生物炭的添加显著提高了 EE2 和 PFOS 在沉积物上的吸附速率和吸附容量，提高了 1.7-3.5 倍；沉积物中的有机碳浓度是影响这一过程的主要因素。EE2 和 PFOS 对沉积物的吸附接近线性（Freundlich 指数 1/n 为 0.799-0.805），但生物炭为非线性（0.430-0.476），沉积物+生物炭为非线性（0.370-0.421）。添加生物炭后，PFOS 在水-沉积物系统中的迁移性显著降低，沉积物-水分配系数 K 增加了近三倍。与 EE2 相比，PFOS 是一种阴离子化合物，含有疏水的 C-F 链和亲水的 S-O 基团，更容易受到 pH 的影响，并通过氢键、配体交换和表面络合作用与-OH、-C=O、Si-O-Si、-O-Si 和 -Al-O-Al 基团相互作用。我们认为，在水-沉积物界面处，生物炭的添加量为 ～5%是一种可行的固定 EE2 和 PFOS 的方法。
