纳米塑料对依诺沙星的吸附及密度泛函理论计算

Adsorption of nanoplastics on ENO and density functional theory calculations

从吸附动力学和热力学两个角度考察了聚苯乙烯纳米微球(PSNPs)和羧基修饰的PSNPs(PSNPs-COOH)对水溶液中抗生素依诺沙星(ENO)的吸附特征,分析了pH、温度、大分子有机物和金属离子等因素对ENO吸附量的影响,探讨了PSNPs和PSNPs-COOH对ENO的吸附机理。实验结果表明:PSNPs和PSNPs-COOH对ENO的吸附特征符合准二级动力学模型和Langmuir等温吸附模型,为自发放热过程;在温度298 K、溶液pH 6.0、PSNPs或PSNPs-COOH质量浓度为2.5 mg/L、ENO质量浓度为10 mg/L的条件下,PSNPs和PSNPs-COOH对ENO的平衡吸附量分别为231 mg/g和257 mg/g;Na^(+)、Cu^(2+)和Zn^(2+)均对PSNPs和PSNPs-COOH吸附ENO的过程有明显的抑制作用;静电相互作用是PSNPs吸附ENO的主要机理;氢键作用和静电相互作用是PSNPs-COOH吸附ENO的主要机理。

The adsorption behavior of polystyrene microspheres(PSNPs)and carboxyl-modified PSNPs(PSNPs−COOH)on antibiotic enoxacin(ENO)in aqueous solution was studied from the perspectives of adsorption kinetics and thermodynamics.The effects of pH,temperature,macromolecular organic matter,and metal ions on the adsorption capacity of ENO were analyzed,and the adsorption mechanism of PSNPs and PSNPs-COOH on ENO was discussed.The experimental results show that the adsorption characteristics of PSNPs and PSNPs-COOH on ENO are consistent with the quasi-second-order kinetics model and Langmuir isothermal adsorption model,which is a spontaneous exothermic process.Under the conditions of temperature of 298 K,pH of 6.0,mass concentration of PSNPs or PSNPs-COOH of 2.5 mg/L,and mass concentration of ENO of 10 mg/L,the adsorption capacities of PSNPs and PSNPs-COOH for ENO were 231 mg/g and 257 mg/g,respectively.The adsorption of ENO by PSNPs and PSNPs-COOH was significantly inhibited by Na^(+),Cu^(2+),and Zn^(2+).Electrostatic interaction is the main mechanism of ENO adsorption by PSNPs.Hydrogen bonding and electrostatic interaction are the main mechanisms of ENO adsorption by PSNPs-COOH.