Copper oxide nanoparticles (CuO NPs) are one of the most widely used materials owing to their excellent properties such as thermal and photochemical stability, superconductivity, and high electrochemical activity. Once they enter the environment, Cu²⁺ may be released in water, which alters the behavior and toxicity of CuO NPs. The present study thus investigated the dissolution of CuO NPs (40 nm) in the presence of tannic acid (TA), a model chemical of dissolved organic matter. The adsorption of TA decreased the hydrodynamic diameter of CuO NPs and increased the zeta potential of the suspension. Although the adsorption of TA on particle surface improved the dispersion of CuO NPs, their dissolution extents were all reduced at TA concentration up to 55.4 mg C L⁻¹. At pH 5, the contributions of TA complexed Cu to the overall dissolution increased up to 37.8% as a function of TA concentrations. All the findings shown above approved that the strong adsorption of TA played a dominant role in preventing the dissolution of CuO NPs.

Graphical abstract

中文翻译：

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单宁酸的络合、分散和吸附对氧化铜纳米颗粒溶解的相对贡献

氧化铜纳米颗粒（CuO NPs）由于其优异的性能，如热和光化学稳定性、超导性和高电化学活性，是应用最广泛的材料之一。一旦它们进入环境，Cu ²⁺可能会释放到水中，这会改变 CuO NPs 的行为和毒性。因此，本研究调查了在单宁酸 (TA)（一种溶解有机物质的模型化学物质）存在下 CuO NPs（40 nm）的溶解情况。TA 的吸附降低了 CuO NPs 的流体动力学直径并增加了悬浮液的 zeta 电位。尽管 TA 在颗粒表面的吸附改善了 CuO NPs 的分散，但在 TA 浓度高达 55.4 mg CL ^{-1 时}它们的溶解程度都降低了. 在 pH 值为 5 时，作为 TA 浓度的函数，TA 络合的 Cu 对整体溶解的贡献增加至 37.8%。上面显示的所有发现都证实了 TA 的强吸附在防止 CuO NPs 溶解方面起主导作用。

图形概要