Chakraborty Swaroop, Drexel Roland, Bhadane Prathmesh, Langford Nathan, Dhumal Pankti, Meier Florian, Lynch Iseult
School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, B15 2TT, UK.
Postnova Analytics GmbH, Landsberg am Lech, Germany.
Nanoscale. 2025 Apr 10;17(15):9122-9136. doi: 10.1039/d5nr00353a.
Micro- and nanoscale plastics (MnPs), arising from the environmental degradation of plastic waste, pose significant environmental and health risks as carriers for potentially toxic element (PTE) metals. This study employs asymmetrical flow field-flow fractionation (AF4) coupled with multi-angle light scattering (MALS) and inductively coupled plasma mass spectrometry (ICP-MS) to provide a size-resolved assessment of chromium (Cr), arsenic (As), and selenium (Se) adsorption onto carboxylated polystyrene nanoparticles (COOH-PSNPs) of 100 nm, 500 nm, and 1000 nm. Cr exhibited the highest adsorption, with adsorption per particle surface area increasing from 9.45 × 10 μg nm for 100 nm particles to 6.87 × 10 μg nm for 1000 nm particles, driven by chemisorptive interactions with carboxyl groups. In contrast, As and Se exhibited slower adsorption rates and significantly weaker interactions, attributed to outer-sphere complexation and electrostatic repulsion. Smaller particles exhibited enhanced adsorption efficiency per unit mass due to their larger surface area-to-volume ratios and higher carboxyl group density (18.5 μEq g for 100 nm compared to 7.9 μEq g for 1000 nm particles). Se adsorption remained negligible across all sizes, near detection limits, highlighting its low affinity for carboxylated surfaces. Our study demonstrates the superior resolution of AF4-MALS-ICP-MS compared to that of bulk ICP-MS, which lacks the ability to discern particle-specific adsorption trends. Unlike bulk ICP-MS, which provides average adsorption values, AF4-MALS-ICP-MS reveals the size-dependent mechanisms influencing metal binding, offering critical insights into the role of MnPs as PTE vectors. The findings highlight the environmental implications of MnPs in facilitating PTE transport and highlights the need for size-specific mitigation strategies. This work sets a foundation for developing more precise risk assessment frameworks and advanced remediation approaches for MnP-contaminated environments.
微纳尺度塑料（MnPs）源自塑料垃圾的环境降解，作为潜在有毒元素（PTE）金属的载体，带来了重大的环境和健康风险。本研究采用不对称流场流分馏（AF4）结合多角度光散射（MALS）和电感耦合等离子体质谱（ICP-MS），对铬（Cr）、砷（As）和硒（Se）在100纳米、500纳米和1000纳米的羧基化聚苯乙烯纳米颗粒（COOH-PSNPs）上的吸附进行尺寸分辨评估。Cr表现出最高的吸附量，每颗粒表面积的吸附量从100纳米颗粒的9.45×10微克/纳米增加到1000纳米颗粒的6.87×10微克/纳米，这是由与羧基的化学吸附相互作用驱动的。相比之下，As和Se的吸附速率较慢且相互作用明显较弱，这归因于外层络合和静电排斥。较小的颗粒由于其较大的表面积与体积比和较高的羧基密度（100纳米颗粒为18.5微当量/克，而1000纳米颗粒为7.9微当量/克），表现出单位质量更高的吸附效率。在所有尺寸下，Se的吸附量都可以忽略不计，接近检测限，这突出了其对羧基化表面的低亲和力。我们的研究表明，与整体ICP-MS相比，AF4-MALS-ICP-MS具有更高的分辨率，整体ICP-MS无法辨别颗粒特异性吸附趋势。与提供平均吸附值的整体ICP-MS不同，AF4-MALS-ICP-MS揭示了影响金属结合的尺寸依赖性机制，为MnPs作为PTE载体的作用提供了关键见解。研究结果突出了MnPs在促进PTE迁移方面的环境影响，并强调了制定针对特定尺寸的缓解策略的必要性。这项工作为开发更精确的风险评估框架和针对MnP污染环境的先进修复方法奠定了基础。
