中文关键词膨润土十八烷基二甲基甜菜碱四环素诺氟沙星吸附 英文关键词bentoniteoctadecyl dimethyl betainetetracyclinenorfloxacinadsorption

作者	单位	E-mail
王新欣	西北农林科技大学资源环境学院, 杨凌 712100	wxx15735186382@163.com
孟昭福	西北农林科技大学资源环境学院, 杨凌 712100 农业农村部西北植物营养与农业环境重点实验室, 杨凌 712100	zfmeng1996@263.net
刘欣	西北农林科技大学资源环境学院, 杨凌 712100
王腾	西北农林科技大学资源环境学院, 杨凌 712100
胡啸龙	西北农林科技大学资源环境学院, 杨凌 712100
孙秀贤	西北农林科技大学资源环境学院, 杨凌 712100

中文摘要 环境中抗生素污染已经成为当前研究的热点问题.为了探讨长碳链两性修饰膨润土对不同类型抗生素复合吸附的效应及机制，采用两性表面活性剂十八烷基二甲基甜菜碱（BS-18）修饰膨润土，研究了不同修饰比例、温度、pH值及离子强度条件下，BS-18两性修饰膨润土对四环素和诺氟沙星在单一及复合条件下的吸附，并结合两性修饰膨润土的表面特征来探讨其吸附机制.结果表明，与CK相比，经BS-18修饰后的土样CEC和比表面积下降，总碳和总氮含量上升.BS-18两性修饰膨润土对四环素的吸附量顺序为CK > 100BS > 25BS > 50BS，吸附符合Langmuir模型；而对诺氟沙星的吸附量顺序为25BS > 50BS > CK > 100BS，吸附符合Henry模型.四环素和诺氟沙星复合体系中，供试土样对四环素和诺氟沙星的吸附量均高于单一体系.随着温度的升高，两性修饰膨润土对四环素的吸附呈增温正效应，而对诺氟沙星随温度的升高吸附量总体上呈现下降的规律；当离子强度由0.001 mol·L^-1增加到0.5 mol·L^-1时，会抑制各供试土样对四环素和诺氟沙星的吸附；溶液pH会影响抗生素的存在形态，进而影响供试土样对其的吸附.BS-18修饰膨润土吸附四环素主要以电荷引力为主，而对诺氟沙星吸附则以电荷引力和疏水结合共同作用为主，两者辛醇/水分配系数对数值（lgKow）的不同以及结构的差异造成了吸附模式的不同；四环素+诺氟沙星复合体系中，形成了TC+NOR混合物促进了土样的吸附. 英文摘要 Antibiotic pollution in the environment has become a hot topic. The amphoteric surfactant octadecyl dimethyl betaine (BS-18) was adopted to modify bentonite to investigate the effects and mechanisms of the composite adsorption of different types of antibiotics. Under the different modification ratios, temperatures, pH values, and ionic strength conditions, the adsorption of tetracycline (TC) and norfloxacin (NOR) by bentonite was studied under single and compound conditions, and the adsorption mechanism was analyzed and discussed in combination with the surface properties of amphoterically modified bentonite. The results showed that compared with those of CK, the CEC and specific surface area of the soil samples modified by BS-18 decreased, whereas the total carbon and total nitrogen contents increased. The adsorption order of BS-18 amphoterically modified bentonite to TC was CK > 100BS > 25BS > 50BS, which was in accordance with the Langmuir model; the adsorption order of NOR was 25BS > 50BS > CK > 100BS, which was consistent with the Henry model. The adsorption capacity of TC and NOR in the TC and NOR composite system was higher than that in the single system. With the increase in temperature, the adsorption of amphoterically modified bentonite to TC showed a positive warming effect, whereas the adsorption of NOR declined as the temperature increased. When the ionic strength increased from 0.001 mol·L^-1 to 0.500 mol·L^-1, the adsorption of TC and NOR on each soil sample was inhibited. The pH of the solution can affect the existing forms of TC and NOR, and the adsorption capacity showed different trends as the pH increased. The adsorption of TC by BS-18-modified bentonite was mainly caused by electric charge attraction, whereas the adsorption of NOR was mainly caused by the combination of electric charge attraction and the hydrophobic effect. The different values of the octanol/water partition coefficient and the difference in structure resulted in different adsorption modes. In the TC and NOR composite system, a TC+NOR mixture was formed to promote the adsorption of soil samples.

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