Zhang Mengjia, Huang Mengjie, Rui Linping, Huan Xinyu, Li Yuanyi, Huang Yao, Wei Wei
School of Environment, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Jiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response Technology, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China.
School of Environment, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Jiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response Technology, Nanjing Normal University, Nanjing 210023, China.
J Hazard Mater. 2024 Nov 5;479:135680. doi: 10.1016/j.jhazmat.2024.135680. Epub 2024 Aug 28.
The potential of microplastics (MPs) to act as carriers for contaminants or engineered nanomaterials is of rising concern. However, directly determining the vector effect of polystyrene (PS) MPs towards nano-hydroxyapatite (nHAP) particles, a typical nano phosphorus fertilizer and soil remediation material, has been rarely studied. In this study, the interaction of differentially surface functionalized PS MPs with nHAP were investigated through batch experiments under different solution chemistry conditions. The results demonstrated that nHAP had the highest attachment/adsorption affinity onto carboxyl-functionalized PS, followed by bare PS and amino-functionalized PS under near-neutral pH conditions. Adsorption of nHAP exhibited a strong pH-dependent behavior with PS MPs, increasing under acidic-neutral pH (3-7) and decreasing at higher pH values. The presence of humic acid and NaCl hindered the adsorption of nHAP onto MPs. Scanning electron microscopy observations revealed a rod-like morphology for adsorbed nHAP, which was randomly distributed on MPs surface. Surface complexation and cation-π interaction were mainly responsible for the adsorption of nHAP as revealed by multiple spectroscopic analyses. These results provide mechanistic insights into nHAP-PS interactions and expound the effect of surface functionalization of PS on binding mechanisms, and thus bring important clues for better understanding the vector effects of MPs towards nanoparticles.
微塑料（MPs）作为污染物或工程纳米材料载体的可能性日益受到关注。然而，直接确定聚苯乙烯（PS）微塑料对纳米羟基磷灰石（nHAP）颗粒（一种典型的纳米磷肥和土壤修复材料）的载体效应的研究却很少。在本研究中，通过在不同溶液化学条件下的批次实验，研究了不同表面功能化的PS微塑料与nHAP之间的相互作用。结果表明，在近中性pH条件下，nHAP对羧基功能化PS的附着/吸附亲和力最高，其次是裸PS和氨基功能化PS。nHAP在PS微塑料上的吸附表现出强烈的pH依赖性，在酸性至中性pH（3-7）下增加，在较高pH值下降低。腐殖酸和NaCl的存在阻碍了nHAP在微塑料上的吸附。扫描电子显微镜观察显示，吸附的nHAP呈棒状形态，随机分布在微塑料表面。多种光谱分析表明，表面络合和阳离子-π相互作用是nHAP吸附的主要原因。这些结果为nHAP与PS的相互作用提供了机理见解，阐述了PS表面功能化对结合机制的影响，从而为更好地理解微塑料对纳米颗粒的载体效应带来了重要线索。
