Zhu Si-Fu, Liu Jian-Chao, Lu Guang-Hua
Key Laboratory for Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Huan Jing Ke Xue. 2024 Aug 8;45(8):4946-4955. doi: 10.13227/j.hjkx.202309168.
Microplastics （MPs） coexist with plasticizers in the aqueous environment to form composite pollution, but the adsorption and desorption behaviors of MPs and plasticizers under natural conditions are unknown. Polyvinyl chloride （PVC） and rubber were used as the target MPs to characterize the changes in their morphological features after aging for one anniversary in atmospheric exposure and lake sedimentary burial environments and to investigate the adsorption and desorption behavior of the MPs to the coexisting phthalate esters （PAEs） plasticizer before and after aging. The results showed that the surface of MPs was rougher after exposure to the atmospheric environment and burial in a depositional environment, showing the characteristics of porous polymers. The carbonyl index （CI） of PVC and rubber increased by 62.2% and 321.2%, respectively, in the atmospheric environment and increased by 51.1% and 223.1%, respectively, in the depositional environment. The atmospheric exposure was capable of accelerating the aging process of MPs. PAEs were adsorbed on the surface of MPs through hydrophobic interaction, and the amount of adsorption was significantly and positively correlated with their hydrophobic properties. The adsorption capacity and adsorption rate of PVC on PAEs were inhibited after aging. Aging promoted the adsorption of rubber on strongly hydrophobic PAEs plasticizers and inhibited the adsorption of weakly hydrophobic PAEs. The environmental aging process reduced the desorption of strongly hydrophobic PAEs from rubber, enhanced the reversibility of rubber adsorption of weakly hydrophobic PAEs, and increased the desorption rate of PAEs from PVC.
微塑料（MPs）与增塑剂在水环境中共存形成复合污染，但在自然条件下微塑料和增塑剂的吸附与解吸行为尚不清楚。以聚氯乙烯（PVC）和橡胶作为目标微塑料，表征其在大气暴露和湖泊沉积埋藏环境中老化一周年后形态特征的变化，并研究老化前后微塑料对共存邻苯二甲酸酯（PAEs）增塑剂的吸附和解吸行为。结果表明，微塑料在大气环境暴露和沉积环境埋藏后表面更粗糙，呈现多孔聚合物特征。PVC和橡胶的羰基指数（CI）在大气环境中分别增加了62.2%和321.2%，在沉积环境中分别增加了51.1%和223.1%。大气暴露能够加速微塑料的老化过程。PAEs通过疏水作用吸附在微塑料表面，吸附量与其疏水性能呈显著正相关。老化后PVC对PAEs的吸附容量和吸附速率受到抑制。老化促进了橡胶对强疏水性PAEs增塑剂的吸附，抑制了对弱疏水性PAEs的吸附。环境老化过程降低了强疏水性PAEs从橡胶上的解吸，增强了橡胶对弱疏水性PAEs吸附的可逆性，增加了PAEs从PVC上的解吸速率。
