Selmani Atiđa, Siboulet Bertrand, Špadina Mario, Foucaud Yann, Dražić Goran, Radatović Borna, Korade Karla, Nemet Ivan, Kovačević Davor, Dufrêche Jean-François, Bohinc Klemen
Pharmaceutical Technology & Biopharmacy, Institute of Pharmaceutical Sciences, University of Graz, A-8010, Graz, Austria.
Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia.
ACS Appl Nano Mater. 2023 Jul 11;6(14):12711-12725. doi: 10.1021/acsanm.3c00916. eCollection 2023 Jul 28.
TiO nanotubes constitute very promising nanomaterials for water decontamination by the removal of cations. We combined a range of experimental techniques from structural analyses to measurements of the properties of aqueous suspensions of nanotubes, with (i) continuous solvent modeling and (ii) quantum DFT-based simulations to assess the adsorption of Cs on TiO nanotubes and to predict the separation of metal ions. The methodology is set to be operable under realistic conditions, which, in this case, include the presence of CO that needs to be treated as a substantial contaminant, both in experiments and in models. The mesoscopic model, based on the Poisson-Boltzmann equation and surface adsorption equilibrium, predicts that H ions are the charge-determining species, while Cs ions are in the diffuse layer of the outer surface with a significant contribution only at high concentrations and high pH. The effect of the size of nanotubes in terms of the polydispersity and the distribution of the inner and outer radii is shown to be a third-order effect that is very small when the nanotube layer is not very thick (ranging from 1 to 2 nm). Besides, DFT-based molecular dynamics simulations demonstrate that, for protonation, the one-site and successive association assumption is correct, while, for Cs adsorption, the size of the cation is important and the adsorption sites should be carefully defined.
二氧化钛纳米管是通过去除阳离子来净化水的非常有前景的纳米材料。我们结合了一系列实验技术，从结构分析到纳米管水悬浮液性质的测量，并采用（i）连续溶剂建模和（ii）基于量子密度泛函理论（DFT）的模拟，以评估铯在二氧化钛纳米管上的吸附情况，并预测金属离子的分离。该方法设定为在实际条件下可操作，在这种情况下，实际条件包括在实验和模型中都需要将一氧化碳视为大量污染物。基于泊松 - 玻尔兹曼方程和表面吸附平衡的介观模型预测，氢离子是决定电荷的物种，而铯离子在外表面的扩散层中，仅在高浓度和高pH值时才有显著贡献。纳米管尺寸在多分散性以及内半径和外半径分布方面的影响显示为三阶效应，当纳米管层不太厚（范围为1至2纳米）时，这种效应非常小。此外，基于DFT的分子动力学模拟表明，对于质子化，单位点和连续缔合假设是正确的，而对于铯的吸附，阳离子的大小很重要，并且吸附位点应仔细定义。
