3种微塑料与头孢拉定吸附作用的理论研究

A theoretical investigation of the adsorption of three different microplastics and cefradine

微塑料(microplastics,MPs)和抗生素是海洋环境中的两类污染物,微塑料吸附水体中的抗生素后可作为其迁移的载体,对海洋环境及海洋生物产生更大的危害。不同微塑料对抗生素不仅相互吸附作用存在差异,而且吸附能力和机理均尚未取得深入明确的结论。本研究以聚乙烯(polyethylene,PE)、聚丙烯(polypropylene,PP)、聚酰胺(polyamide,PA)、紫外线老化聚酰胺(PA^(UV))以及紫外线和H_(2)O_(2)共同老化聚酰胺(PA^(UV)+H)为对象,通过密度泛函方法(DFT)的计算探究其对头孢拉定(cefradine,CE)的吸附能力和吸附稳定性。结果表明:CE在PE、PP、PA、PA^(UV)和PA^(UV+H)上的吸附属于物理吸附,其中PA、PA^(UV)和PA^(UV+H)的吸附稳定性强于PE和PP。静电作用在这3种PAs与CE之间的吸附机理方面发挥了重要的作用,使得它们对CE的吸附更加稳定。另外,根据热力学性质的计算结果表明,在T=273~311 K、P=1~1000 atm条件下所有MPs对CE的吸附都是一个自发的放热过程。

As two types of pollutants in Marine environment,microplastics can adsorb antibiotics in water and act as carriers for their migration,which can cause greater harm to the marine environment and marine organisms.The interaction of antibiotics with different microplastics not only differs,but the adsorption capacity and mechanism have not been deeply and clearly concluded.In this study,polyethylene(PE),polypropylene(PP),polyamide(PA),ultraviolet aging polyamide(PA^(UV))and ultraviolet and H_(2)O_(2)co-aging polyamide(PA^(UV+H))were chosen as object,and the adsorption capacity and adsorption stability of efradine(CE)were investigated by density functional theory(DFT)calculation.The results show that the adsorption of CE on P,P,PA,PA^(UV)and PA^(UV+H)belongs to hysial adsoption,d he adsoptionstaility of A,PA^(UV)and PA^(UV+H)stonger than that f PE and P.For the adsortion mechanism between these theetypes of PAs and CE,electrostatic interaction plays a more important role,making their adsorption of CE more stable.In addition,the calculation results based on thermodynamic properties indicate that the adsorption of CE by MPs at T=273-311 K and P=1-1000 atm is a spontaneous exothermic process.