微塑料对土壤吸附土霉素的影响初探  

Influence of microplastics on sorption behaviors of oxytetracycline onto soils: A preliminary study

作　　者：李嘉 余松国 沈林恩 崔敏 王玉琳 LI Jia;YU Songguo;SHEN Linen;CUI Min;WANG Yulin(School of Environmental Science and Engineering,Yangzhou University,Yangzhou,225127,China)

机构地区：[1]扬州大学环境科学与工程学院,扬州225127

出　　处：《环境化学》2021年第10期3133-3143,共11页Environmental Chemistry

基　　金：国家自然科学基金(42007108);江苏省高等学校自然科学研究面上项目(19KJB610007);山东省海岸带环境过程重点实验室(中国科学院烟台海岸带研究所)开放基金(2019SDHADKFJJ12);中国博士后科学基金(2019M661948)资助。

摘　　要：为揭示微塑料对土壤吸附抗生素的影响,以聚酰胺(PA)、聚乙烯(PE)、聚苯乙烯(PS)等3种微塑料和土霉素(OTC)为研究对象,通过批实验研究了OTC在土壤、添加微塑料的土壤及微塑料中的吸附行为.结果表明,微塑料可通过改变液膜厚度、内部孔道数量和吸附位点数量影响土壤对OTC的吸附动力学行为. Temkin模型能够较好地拟合OTC在土壤和含微塑料土壤上的吸附等温线,而OTC在微塑料上的等温吸附更符合Freundlich模型.向土壤中添加微塑料(质量分数10%)可抑制土壤对OTC的吸附,但不同类型微塑料对土壤吸附OTC的抑制程度不同,含有PE或PS的土壤对OTC的吸附量显著降低(P<0.05),而添加等量PA的土壤对OTC的吸附量未明显减少(P>0.05),这可能与3种微塑料对OTC的亲和力不同有关. 3种微塑料对OTC的吸附能力(K_(f)=0.103—0.152 L·g^(-1))显著(P<0.01)弱于土壤(K_(f)=1.297 L·g^(-1)),因此向土壤中添加微塑料将减少吸附位点,从而导致OTC的吸附量减少;微塑料能改变反应体系的pH值,由此干扰OTC的形态分布,并间接影响OTC的吸附行为;此外,微塑料还可能通过侵占土壤颗粒内部孔道和竞争吸附位点的方式影响土壤对OTC的吸附.In order to reveal the effects of microplastics on sorption behaviors of antibiotics onto soils, polyamide(PA), polyethylene(PE), polystyrene(PS), and oxytetracycline(OTC) were selected as the target, and batch experiments were conducted to investigate sorption of OTC onto the soil, soil containing 10%(mass fraction) of microplastics, and microplastics. Results show that microplastics could influence the sorption rate of OTC by altering the thickness of liquid film, the number of internal channels, and the number of sorption sites. The sorption isotherms of OTC onto the single soil and mixtures of soil and microplastics were in accordance with the Temkin model, while Freundlich model could fit the sorption isotherms of OTC onto microplastics well. Adding microplastics into the soil inhibited sorption of OTC. However, various types of microplastics have different inhibitory effects on OTC sorption. That is, the sorption capacity of soil containing PE or PS microplastics reduced significantly(P<0.05), while the soil containing the same amount of PA microplastics had similar sorption amount of OTC with the soil. This may be related to the different affinity of the three types of microplastics to OTC. Sorption amounts of OTC onto the three types of microplastics(K_(f) =0.103—0.152 L·g^(-1)) were significantly(P<0.01) smaller than that onto the soil(K_(f) =1.297 L·g^(-1)). Therefore, adding microplastics to the soil will reduce the overall sorption sites,which in turn will decrease the sorption capacity of the soil containing microplastics to OTC.Microplastics can alter the pH of the reaction system, which will affect speciation of OTC, thereby sorption of OTC is influenced. Further, the influencing mechanisms of microplastics on OTC sorption may also include competing sorption sites and occupying internal pores of soil particles.

关 键 词：微塑料 土霉素 土壤 吸附 批实验 

分 类 号：X505[环境科学与工程—环境工程]