黑炭作为大气PM,5的核心组分,可以通过大气的干湿沉降进入到土壤,从而对土壤中有机污染物的迁移转化产生一定的影响.而土壤中普遍存在的矿物会与黑炭发生一定的界面作用.因此,明确这种作用对污染物迁移转化的影响,会为科学合理评价污染物的生态环境风险提供理论依据.本文以针铁矿和蒙脱石为矿物代表,以泰乐菌素(TYL)为有机污染物的代表,系统研究了针铁矿/蒙脱石与黑炭复合物对TYL的吸附特性.吸附动力学、吸附等温线、以及pH和离子强度的实验表明,黑炭与针铁矿/蒙脱石复合后其对TYL的吸附能力明显高于单独的针铁矿和蒙脱石;黑炭与针铁矿复合物(FeOOH-BC)和黑炭与蒙脱石复合物(MT-BC)对TYL的吸附动力学可以用拉格朗日二级动力学模型较好地拟合;吸附等温线用线性模型和Freundlich模型拟合的效果相对较好;pH和离子强度的实验表明,溶液pH和离子强度可以明显地影响FeOOH-BC和MT-BC对TYL的吸附;FeOOH-BC对TYL的吸附主要是氢键作用、范德华力和表面络合作用,而MT-BC对TYL吸附机理则主要是静电作用和离子交换.
Black carbon is the key component of fine particulate matter (PM2.5) that may enter the soil via dry and wet deposition,influencing the migration and transformation of organic pollutants in soil.Generally,the minerals in the soil may interacts with black carbon at the interface.Therefore,investigation of the impact of such interfacial interaction on the migration and transformation behavior will provide a theoretical basis for the scientific evaluation of ecological risks of pollutants.In this paper,we systematically studied the characteristics of sorption behavior of tylosin using black carbon and goethite/montmorillonite composites,wherein goethite and montmorillonite as minerals,tylosin as organic pollutant.Experiments on the sorption kinetic,sorption isotherm,and the pH and ionic strength effects showed that the sorption of tylosin on black carbon and goethite/montmorillonite composites was significantly higher than individual goethite and montmorillonite.The sorption kinetics data of tylosin on FeOOH-BC and MT-BC well fit the pseudo-second-order kinetics model,and the sorption isotherm data well fit Linera model and Freundlich model.Besides,the sorption of tylosin on FeOOH-BC and MT-BC was significant affected by solution pH and ionic strength.The sorption mechanisms of tylosin on FeOOH-BC mainly involed hydrogen bonding,van der Waals forces and surface complexation,while electrostatic interaction and ion exchange played a primal role in the sorption of tylosin on MT-BC.
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