Unraveling anisotropic hydration behaviors and mechanisms of fine molybdenite in alkaline conditions: A combined experimental and computational study

IF 5.4 2区化学 Q2 CHEMISTRY, PHYSICAL

Colloids and Surfaces A: Physicochemical and Engineering Aspects Pub Date : 2025-10-10 DOI:10.1016/j.colsurfa.2025.138645

Shulei Li , Wenfeng Pan , Lihui Gao , Yangge Zhu , Yijun Cao , Yande Chao , Lingjian Kong

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Abstract

It is well known that poor recovery has been suffered always for molybdenum ore flotation in alkaline conditions. To elucidate this phenomenon, we systematically investigated the anisotropic hydration behavior and mechanisms of molybdenite surface through integrated computational and experimental approaches. Density functional theory (DFT) calculations revealed that NaOH exhibits preferential edge adsorption on molybdenite, with adsorption energies on (001) surfaces (−228.67 to −92.42 kcal/mol) being significantly less than those on (110) surfaces. Simulations demonstrated that NaOH chemisorption enhances water molecule stabilization, whereas Na⁺ shows negligible influence on H₂O adsorption. Notably, OH⁻ forms stable [OH(H₂O)₅]⁻ hydration clusters and induces a triple-layered hydration film (peak positions at 9.37 Å, 12.30 Å, and 14.98 Å) upon edge adsorption. Comparative analysis indicated 6.54 % and 8.07 % enhancement in hydration layer strength for basal and edge surfaces of molybdenite, respectively, in alkaline conditions versus neutral pH. The fundamental mechanism was identified as OH⁻-mediated formation of hydrated anions that reinforce interfacial hydrogen-bond networks. These findings, validated by XPS, zeta potential, and Visual MINTEQ analyses, provide critical insights into the hydration stabilization process and establish a theoretical framework for optimizing alkaline molybdenite flotation.

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细粒辉钼矿在碱性条件下的各向异性水化行为和机理：实验与计算相结合的研究

钼矿在碱性条件下浮选一直存在回收率差的问题。为了阐明这一现象，我们采用计算和实验相结合的方法系统地研究了辉钼矿表面的各向异性水化行为和机理。密度泛函数理论（DFT）计算表明，NaOH在辉钼矿表面表现出优先的边缘吸附，在（001）表面的吸附能（−228.67 ~−92.42 kcal/mol）明显小于（110）表面的吸附能。模拟表明，NaOH的化学吸附增强了水分子的稳定性，而Na⁺对H2O吸附的影响可以忽略不计。值得注意的是，氢氧毒发展形成稳定的[OH(H2O)5]毒发展团簇，并通过边缘吸附形成三层水化膜（峰值位置为9.37 Å， 12.30 Å和14.98 Å）。对比分析表明，与中性ph相比，碱性条件下辉钼矿基底和边缘表面的水合层强度分别提高了6.54 %和8.07 %。其基本机制被确定为OH -毒化阴离子的形成，强化了界面氢键网络。通过XPS、zeta电位和visualminteq分析验证了这些发现，为水化稳定过程提供了重要见解，并为优化碱性辉钼矿浮选建立了理论框架。

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来源期刊

Colloids and Surfaces A: Physicochemical and Engineering Aspects 化学-物理化学

CiteScore

8.70

自引率

9.60%

发文量

2421

审稿时长

56 days

期刊介绍： Colloids and Surfaces A: Physicochemical and Engineering Aspects is an international journal devoted to the science underlying applications of colloids and interfacial phenomena. The journal aims at publishing high quality research papers featuring new materials or new insights into the role of colloid and interface science in (for example) food, energy, minerals processing, pharmaceuticals or the environment.