Abstract：
Fate and transport of nanoplastics in aquatic environments are affected by their heteroaggregation with minerals in the presence of macromolecules. This study investigated the heteroaggregation of polystyrene nanoplastics (PSNPs) with goethite nanoparticles (GNPs) under the influence of macromolecules [humic acid (HA), bovine serum albumin (BSA), and DNA] and electrolytes. Under 1 mg C/L macromolecule, raising electrolyte concentration promoted heteroaggregation via charge screening, except that calcium bridging with HA also enhanced heteroaggregation at CaCl2 concentration above 5 mM. At all NaCl concentrations and CaCl2 concentration below 5 mM, 1 mg C/L macromolecules strongly retarded heteroaggregation, ranking BSA > DNA > HA. Raising macromolecule concentration strengthened such stabilization effect of all macromolecules in NaCl solution and that of DNA and BSA in CaCl2 solution by enhancing steric hindrance. However, 0.1 mg C/L BSA slightly promoted heteroaggregation in CaCl2 solution due to stronger electrostatic attraction than steric hindrance. In CaCl2 solution, raising HA concentration strengthened its destabilization effect via calcium bridging. Macromolecules having more compact globular structure and higher molecular weight may exert greater steric hindrance to inhibit heteroaggregation more effectively. This study provides new insights on the effects of macromolecules and electrolytes on heteroaggregation between nanoplastics and iron minerals in aquatic environments.
摘要：
纳米塑料在水生环境中的命运和运输受到大分子存在下它们与矿物质的杂聚集的影响。这项研究研究了聚苯乙烯纳米塑料（PSNPs）与针铁矿纳米颗粒（GNPs）在大分子[腐殖酸（HA）的影响下的杂聚，牛血清白蛋白(BSA),和DNA]和电解质。在1mgC/L大分子下，通过电荷筛选提高电解质浓度促进杂化聚集，除了在高于5mM的CaCl2浓度下，与HA的钙桥连也增强了杂聚集。在所有NaCl浓度和CaCl2浓度低于5mM时，1mgC/L大分子强烈阻碍了杂化聚集，排名BSA>DNA>HA。提高大分子浓度通过增强空间位阻增强了NaCl溶液中所有大分子的稳定作用以及CaCl2溶液中DNA和BSA的稳定作用。然而,0.1mgC/LBSA由于静电引力强于空间位阻而略微促进了CaCl2溶液中的杂聚集。在CaCl2溶液中，提高HA浓度通过钙桥联增强了其去稳定作用。具有更致密的球状结构和更高的分子量的大分子可以发挥更大的空间位阻,以更有效地抑制异质聚集。这项研究为大分子和电解质对水生环境中纳米塑料和铁矿物之间的杂化聚集的影响提供了新的见解。
