Abstract：
This study examined the distinct effects of algae polysaccharides (AP), namely sodium alginate (SA), fucoidan (FU), and laminarin (LA), on the aggregation of nanoplastics (NP) in seawater, as well as their subsequent transport in seawater-saturated sea sand. The pristine 50 nm NP tended to form large aggregates, with an average size of approximately 934.5 ± 11 nm. Recovery of NP from the effluent (Meff) was low, at only 18.2 %, and a ripening effect was observed in the breakthrough curve (BTC). Upon the addition of SA, which contains carboxyl groups, the zeta (ζ)-potential of the NP increased by 2.8 mV. This modest enhancement of electrostatic interaction with NP colloids led to a reduction in the aggregation size of NP to 598.0 ± 27 nm and effectively mitigated the ripening effect observed in the BTC. Furthermore, SA\'s adherence to the sand surface and the resulting increase in electrostatic repulsion, caused a rise in Meff to 27.5 %. In contrast, the introduction of FU, which contains sulfate ester groups, resulted in a surge in ζ-potential of the NP to -27.7 ± 0.76 mV. The intensified electrostatic repulsion between NP and between NP and sand greatly increased Meff to 45.6 %. Unlike the effects of SA and FU, the addition of LA, a neutral compound, caused a near disappearance of ζ-potential of NP (-3.25 ± 0.68 mV). This change enhanced the steric hindrance effect, resulting in complete stabilization of particles and a blocking effect in the BTC of NP. Quantum chemical simulations supported the significant changes in the electrostatic potential of NP colloids induced by SA, FU and LA. In summary, the presence of AP can induce variability in the mobility of NP in seawater-saturated porous media, depending on the nature of the weak, strong, or non-electrostatic interactions between colloids, which are influenced by the structure and functionalization of the polysaccharides themselves. These findings provide valuable insights into the complex and variable behavior of NP transport in the marine environment.
摘要：
这项研究检查了藻类多糖（AP）的不同作用，即海藻酸钠(SA)，fucoidan(FU),和laminarin（LA），关于纳米塑料（NP）在海水中的聚集，以及它们随后在海水饱和的海砂中的运输。原始的50nmNP倾向于形成大的聚集体，平均尺寸约为934.5±11nm。从废水中回收的NP（Meff）很低，只有18.2%，并且在穿透曲线(BTC)中观察到成熟效应。加入SA后，含有羧基，NP的ζ(ζ)电位增加2.8mV。与NP胶体的静电相互作用的适度增强导致NP的聚集尺寸减小至598.0±27nm，并有效地减轻了BTC中观察到的成熟效应。此外，SA对砂面的粘附和由此产生的静电斥力的增加，导致Meff上升至27.5%。相比之下,FU的介绍，含有硫酸酯基团，导致NP的ζ电位激增至-27.7±0.76mV。NP之间以及NP与沙子之间的静电斥力增强，使Meff大大增加至45.6％。与SA和FU的影响不同，洛杉矶的加入，一种中性化合物,导致NP的ζ电位几乎消失（-3.25±0.68mV）。这种变化增强了空间位阻效应，导致颗粒的完全稳定和NP的BTC中的阻断作用。量子化学模拟支持SA诱导的NP胶体的静电势的显着变化，FU和LA。总之,AP的存在可以诱导NP在海水饱和多孔介质中的迁移率变化，根据弱者的性质，坚强,或者胶体之间的非静电相互作用，其受到多糖本身的结构和官能化的影响。这些发现为海洋环境中NP运输的复杂多变的行为提供了有价值的见解。
