To assess the potential vector effects of degradable MPs (microplastics) on the coexisting pollutant, the adsorption-desorption behaviors of tetracycline (TC) and ciprofloxacin (CIP) by the original and aged polylactic acid (PLA) was investigated. Compared with PVC, the physicochemical properties of PLA changed more observably during the UV ageing. The original smooth surface of PLA appeared holes and cracks, and the S_BET of PLA increased a 2.66-fold after the aging experiments. During the ageing processes, the hydrophily of aged MPs was also enhanced due to the increase of oxygen-containing functional groups. And the zeta potential of PLA decreased from -7.79 to -13.51 mV and PVC from -4.96 to -8.34 mV, respectively. In adsorption experiment, both the original and aged PLA showed better vector effects for antibiotics than PVC. The ageing factor increased the adsorption capacity of antibiotics on PLA 1.18–2.19 times. The desorption experiments showed that the desorption amount of antibiotics on MPs in simulated intestinal fluid was greater than that in Milli-Q water. On this basis, the desorption capacity of antibiotics with PLA was better than that of PVC, which proved that the potential negative impact of PLA on the aquatic environment and organisms might be more serious.

为了评估可降解MP（微塑料）对共存污染物的潜在载体作用，研究了原始和老化的聚乳酸（PLA）对四环素（TC）和环丙沙星（CIP）的吸附-解吸行为。与PVC相比，PLA的物理化学性质在UV老化过程中更明显。PLA的原始光滑表面出现孔洞和裂纹，S _BET老化实验后，PLA的含量增加了2.66倍。在老化过程中，由于含氧官能团的增加，老化的MP的亲水性也得到增强。PLA的Zeta电位分别从-7.79降低至-13.51 mV和PVC从-4.96降低至-8.34 mV。在吸附实验中，原始和老化的PLA对抗生素的载体作用均优于PVC。老化因子增加了抗生素在PLA上的吸附能力1.18–2.19倍。解吸实验表明，模拟肠液中MPs上抗生素的解吸量大于Milli-Q水。在此基础上，PLA对抗生素的解吸能力优于PVC。