Rosales-Segovia Kevin, Companys Encarna, Puy Jaume, Galceran Josep
Departament of Chemistry, Physics, Environmental and Soil Sciences and AGROTECNIO-CERCA, Rovira Roure 191, 25198 Lleida, Catalonia, Spain.
Departament of Chemistry, Physics, Environmental and Soil Sciences and AGROTECNIO-CERCA, Rovira Roure 191, 25198 Lleida, Catalonia, Spain.
Sci Total Environ. 2024 May 20;926:171784. doi: 10.1016/j.scitotenv.2024.171784. Epub 2024 Mar 18.
Indium oxide (InO) nanoparticles (NPs) are used in electronic devices, from which indium (as its nanoparticulate form or as other generated chemical species) can be released to natural waters. To assess for the impacts of such releases (e.g. toxic effects), information on the kinetics and thermodynamics of the InO dissolution processes is key. In this work, the evolution with time of the dissolution process was followed with the technique AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) by measuring the free indium concentration ([In]). AGNES can determine the free ion concentration in the presence of nanoparticles without a prior separation step, as shown in the case of ZnO nanoparticles, a procedure that is more accurate than the typical sequence of centrifugation+filtration+elemental analysis. Excess of indium oxide NPs were dispersed in 0.1 mol L KNO at various pH values ranging from 2 to 8. Additional dispersions with bulk InO at pH 3 or NPs in synthetic seawater at pH 8 were also prepared. The temperature was carefully fixed at 25 °C. The dispersions were continuously stirred and samples were taken from time to time to measure free indium concentration with AGNES. 180-day contact of InO to solutions at pH 2 and 3 was not enough to reach equilibrium. The dissolution of the NPs at pH 3 was faster than that of the bulk (i.e. non nanoparticulate) material. Equilibrium of the NPs with the solution was reached at pH 4 and 5 in KNO and at pH 8 in seawater, in shorter times for higher pH values, with free indium concentrations decreasing by a factor of 1000 for each increase in one pH unit. The solubility products of In(OH) and InO were compared. Equilibration of NPs with synthetic seawater took <18 days, with an average free [In] (up to 196 days) of 1.03 amol L.
氧化铟（InO）纳米颗粒（NPs）用于电子设备，铟（以其纳米颗粒形式或作为其他生成的化学物质）可从这些设备中释放到天然水体中。为评估此类释放的影响（如毒性效应），了解InO溶解过程的动力学和热力学信息至关重要。在这项工作中，通过测量游离铟浓度（[In]），采用AGNES（无梯度和能斯特平衡溶出）技术跟踪溶解过程随时间的变化。AGNES可在无需预先分离步骤的情况下测定纳米颗粒存在时的游离离子浓度，如氧化锌纳米颗粒的情况所示，该程序比典型的离心+过滤+元素分析序列更准确。将过量的氧化铟纳米颗粒分散在pH值范围为2至8的0.1 mol/L KNO中。还制备了pH为3时的块状InO或pH为8时合成海水中纳米颗粒的额外分散体。温度小心地固定在25°C。将分散体持续搅拌，并不时取样用AGNES测量游离铟浓度。InO在pH为2和3的溶液中接触180天不足以达到平衡。纳米颗粒在pH为3时的溶解速度比块状（即非纳米颗粒）材料快。在KNO中，纳米颗粒与溶液在pH为4和5时达到平衡，在海水中在pH为8时达到平衡，pH值越高达到平衡所需时间越短，每增加一个pH单位，游离铟浓度降低1000倍。比较了In(OH)和InO的溶度积。纳米颗粒与合成海水的平衡在不到18天内达到，平均游离[In]（长达196天）为1.03 amol/L。
