Das Rontu, Kundu Debashis
Department of Chemical Engineering, Institute of Chemical Technology Marathwada Campus, Jalna, Maharashtra, 431203, India.
Environ Sci Pollut Res Int. 2025 Mar 26. doi: 10.1007/s11356-025-36309-3.
Methylene blue, a widely used dye in various industries, poses significant environmental and health risks when released into water bodies. The experimental methods, while effective for studying the adsorption of dye on a macroscopic level, lack the atomic-level insights necessary to fully understand the process which can be studied using molecular dynamics simulations. This study investigates the adsorption mechanism of methylene blue on thiol-norbornene crosslinked polyvinyl alcohol (PVA) hydrogel surfaces using MD simulations for the first time. This adsorption behavior is characterized by analyzing hydrogen bonding, radial distribution function (RDF), mean square displacements, and dye removal efficiency. The hydrogen bonding analysis shows consistent stability of the hydrogel network across different pH conditions. The RDF analysis indicates dissociation of the methylene blue molecule, with the cationic part adsorbing onto PVA's hydroxyl groups and the chloride ion exhibits preferential association with the ions in the pH medium. The mean square displacement result suggests a lower diffusion of methylene blue in pH 12.0 which can enhance the rate of adsorption. These findings provide crucial insights into the molecular-level interactions governing dye adsorption on crosslinked PVA hydrogels.
亚甲蓝是一种在各个行业广泛使用的染料，当它被排放到水体中时会对环境和健康造成重大风险。实验方法虽然在宏观层面上对研究染料的吸附有效，但缺乏全面理解该过程所需的原子层面的见解，而这可以通过分子动力学模拟来研究。本研究首次使用分子动力学模拟研究了亚甲蓝在硫醇 - 降冰片烯交联聚乙烯醇（PVA）水凝胶表面的吸附机制。通过分析氢键、径向分布函数（RDF）、均方位移和染料去除效率来表征这种吸附行为。氢键分析表明在不同pH条件下水凝胶网络具有一致的稳定性。RDF分析表明亚甲蓝分子发生解离，阳离子部分吸附到PVA的羟基上，而氯离子在pH介质中与离子表现出优先缔合。均方位移结果表明在pH 12.0中亚甲蓝的扩散较低，这可以提高吸附速率。这些发现为控制交联PVA水凝胶上染料吸附的分子水平相互作用提供了关键见解。
