Metal sulfide nanoparticles have recently been discovered in natural environments subject to fluctuating redox conditions such as wetlands and river floodplains, which are often very rich in natural organic matter (NOM). Strong binding of chalcophile metals like copper by NOM is expected to interfere with sulfide precipitation and is likely to affect the growth of these nanoparticles. We therefore conducted experiments on the formation of copper sulfide nanoparticles (Cu_xS NPs) in anoxic solutions with varying Cu (50, 500 μmol L⁻¹) and sulfide (100, 1000 μmol L⁻¹) concentrations in the absence and presence of Suwannee River fulvic acid (SRFA, 0, 5, 50 mg C L⁻¹). The size development of the Cu_xS nanoparticles and their stability were tracked over 4 weeks using transmission electron microscopy (TEM) and size-exclusion chromatography coupled to ICP-MS (SEC-ICP-MS). Additional dissolution experiments were performed in closed containers in the absence and presence of O₂ and fulvic acid over several months providing insights into the oxidative dissolution behavior of Cu_xS. Our results highlight the high colloidal stability of Cu_xS nanoparticles in anoxic environments irrespective of the NOM concentration. Median particle diameters ranged between a few and a few tens of nanometers with larger particles forming in more concentrated suspensions. At low Cu and S concentrations, fulvic acid restricted particle growth by up to 25% compared to SRFA-free suspensions and metal sulfide clusters even smaller than 1 nm were detected. The Cu_xS nanoparticles exhibited a remarkable chemical stability against oxidative dissolution and were only dissolved when both fulvic acid and O₂ were present.

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NOM对硫化铜纳米颗粒生长，稳定性和氧化溶解的影响

最近在自然环境中发现了金属硫化物纳米粒子，这些自然环境受波动氧化还原条件的影响，例如湿地和​​河漫滩，它们通常富含天然有机物（NOM）。预计NOM对嗜铜金属如铜的牢固结合会干扰硫化物的沉淀，并可能影响这些纳米粒子的生长。因此，我们进行了在不存在和存在以下条件下，在具有不同Cu（50，500μmolL ^-1）和硫化物（100，1000μmolL ^-1）浓度的缺氧溶液中形成硫化铜纳米颗粒（Cu _x S NPs）的实验。 Suwannee河黄腐酸（SRFA，0、5、50 mg CL ^-1）。Cu _x的尺寸发展使用透射电子显微镜（TEM）和结合ICP-MS的尺寸排阻色谱法（SEC-ICP-MS）在4周内追踪了S纳米颗粒及其稳定性。附加溶出试验是在密闭容器中在不存在和的O-存在下进行₂和富里酸几个月提供见解Cu的氧化溶解行为_X S.我们的结果突出Cu的高胶体稳定性_X缺氧环境中的S纳米颗粒，与NOM浓度无关。中值粒径在几纳米和几十纳米之间，较大的颗粒在更浓缩的悬浮液中形成。与不含SRFA的悬浮液和甚至小于1 nm的金属硫化物簇相比，在低的Cu和S浓度下，富里酸抑制的颗粒​​生长高达25％。Cu _x S纳米粒子对氧化溶解表现出显着的化学稳定性，仅当同时存在富里酸和O ₂时才溶解。