Institute of Animal Science and Veterinary Medicine Shandong Academy of Agricultural Sciences, Key Laboratory of Livestock Disease Control and Breeding, Jinan, Jinan 250100, China; Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai 264003, China.
Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, School of Environmental and Resource Sciences, Zhejiang A & F University, Hangzhou 311300, China.
Sci Total Environ. 2020 Apr 20;714:136628. doi: 10.1016/j.scitotenv.2020.136628. Epub 2020 Jan 15.
Particulate organic matter (POM) is a fraction of organic matter with dissimilar properties in different soils. POM isolated from soils and sediments (wetland, oil waste field, farmlands and aquaculture pond sediment) was used to study its sorption behavior on the antibiotic oxytetracycline (OTC). Impacts of solution pH, ionic strength and temperature on the OTC sorption were studied. The sorption rates of OTC in POM from wetland (POM-w) and farmland (POM-f1, POM-f2) were rapid during the first 3 h and gradually decreased with reaction time until reaching the equilibrium. Linear sorption occurred from 3 to 12 h in POM from oil waste field land (POM-o) and aquaculture pond sediment (POM-a). The organic carbon normalized partition coefficient (k) varied from 215.0 to 4493.6 L kg, and it was nearly 10× higher for the POM-w, POM-f1 and POM-f2 than in the POM-o and POM-a. Sorption of OTC by POM exhibited strong pH dependence. Ionic factors affected OTC sorption in POM-f1, POM-f2 and POM-a. The sorption capacity declined >50% in a solution with Ca compared to other ions with similar ionic strength. Sorption thermodynamics showed an entropy increasing and endothermic progress during the OTC sorption in POM, implying a spontaneous sorption process. Several mechanisms were involved in OTC sorption in POM, including hydrogen bonding, cation exchange, hydrophobic partitioning and surface complexation.
颗粒物有机质（POM）是性质不同的有机物质的一个组成部分，存在于不同的土壤中。从土壤和沉积物（湿地、油田、农田和水产养殖池塘沉积物）中分离出的 POM 被用于研究其对抗生素土霉素（OTC）的吸附行为。研究了溶液 pH 值、离子强度和温度对 OTC 吸附的影响。在最初的 3 小时内，湿地 POM（POM-w）和农田 POM（POM-f1、POM-f2）中 OTC 的吸附速率很快，随着反应时间的延长，吸附速率逐渐降低，直到达到平衡。在油田 POM（POM-o）和水产养殖池塘沉积物 POM（POM-a）中，从 3 小时到 12 小时线性吸附发生。有机碳归一化分配系数（k）在 215.0 到 4493.6 L kg 之间变化，POM-w、POM-f1 和 POM-f2 的 k 值比 POM-o 和 POM-a 高近 10 倍。OTC 在 POM 中的吸附表现出强烈的 pH 依赖性。离子因素影响了 POM-f1、POM-f2 和 POM-a 中 OTC 的吸附。与具有相似离子强度的其他离子相比，在含有 Ca 的溶液中，吸附能力下降了>50%。吸附热力学表明，在 POM 中 OTC 吸附是一个熵增加和吸热的过程，这意味着这是一个自发的吸附过程。OTC 在 POM 中的吸附涉及几种机制，包括氢键、阳离子交换、疏水性分配和表面络合。
