Xu Yanghui, Ou Qin, He Qiang, Wu Zhengsong, Ma Jun, Huangfu Xiaoliu
Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University 400044, China; Section of Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, the Netherlands.
Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University 400044, China.
Water Res. 2021 May 15;196:117054. doi: 10.1016/j.watres.2021.117054. Epub 2021 Mar 15.
Dissolved black carbon (DBC), widely found in soil and water environments is likely to affect the transport of nanoplastics in aquatic environments. The aggregation and deposition behaviors of fresh and aged polystyrene nanoplastics (PSs) with and without DBC in NaCl solution were investigated by time-resolved dynamic light scattering (DLS) and quartz crystal microbalance with dissipation monitoring equipment (QCM-D) techniques. The results suggest that DBC can screen the surface charges of PSs by interacting with PSs through hydrogen bonding, hydrophobic interactions and π-π interactions, although they were negatively charged. DBC promoted the aggregation of PSs under relatively low ionic strengths, and it minimally affected the stability of PSs under high ionic strength. Deposition experiments showed that both DBC in salt solution and DBC adsorption on silica surface facilitated the deposition of fresh PSs while HA inhibited both deposition processes. After aging, PSs were more stable, and the effects of DBC and HA were weakened. This study investigated the influence mechanism of DBC on the aggregation and deposition behaviors, which provides new insights into the stability and transport of PSs in complex aquatic environments.
溶解态黑碳（DBC）广泛存在于土壤和水环境中，可能会影响纳米塑料在水生环境中的迁移。采用时间分辨动态光散射（DLS）和带耗散监测设备的石英晶体微天平（QCM-D）技术，研究了有无DBC存在时，新鲜和老化的聚苯乙烯纳米塑料（PSs）在NaCl溶液中的聚集和沉积行为。结果表明，尽管PSs带负电荷，但DBC可通过氢键、疏水相互作用和π-π相互作用与PSs相互作用，从而屏蔽PSs的表面电荷。在相对较低的离子强度下，DBC促进了PSs的聚集，而在高离子强度下，DBC对PSs稳定性的影响最小。沉积实验表明，盐溶液中的DBC和DBC在二氧化硅表面的吸附均促进了新鲜PSs的沉积，而腐殖酸（HA）则抑制了这两个沉积过程。老化后，PSs更稳定，DBC和HA的影响减弱。本研究探讨了DBC对聚集和沉积行为的影响机制，为PSs在复杂水生环境中的稳定性和迁移提供了新的见解。
