Significant role of counterion for lead(Ⅱ) ion adsorption on carbon pore surface
Significant role of counterion for lead(Ⅱ) ion adsorption on carbon pore surface
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抗衡离子对铅(Ⅱ)离子在碳孔表面吸附的重要作用
DOI：
10.1016/j.carbon.2022.05.031
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发表时间：
2022
期刊：
影响因子：
10.9
通讯作者：
Yoshida Ken
中科院分区：
文献类型：
--
作者：
Horikawa Toshihide;Okamoto Miku;Kuroki-Matsumoto Ayaka;Yoshida Ken
我们提出了一种描述活性炭 (AC) 上 Pb2+ 吸附的预测工具。基于我们之前的研究（Kuroki et al., 2019）中获得的G/D比与Pb2+吸附量之间的相关性，我们通过仔细分析本研究中不同AC样品上铅离子的吸附结果，进一步验证了预测工具。我们的结果表明，该方法可以预测Pb2+吸附量在10%以内，这证实了我们之前基于硬酸和软酸碱理论的解释。通过分子动力学模拟来解析抗衡阴离子的作用及其如何影响AC非极性石墨表面上Pb2+离子的构型和吸附量。模拟结果表明，当反离子为NO3−时，铅离子与吸附的NO3−的静电相互作用增强了Pb2+的吸附，因为NO3−被强烈吸引到石墨表面。使用 Cl− 作为抗衡阴离子证实了吸附 NO3− 的这一独特特征，由于氯离子没有被石墨表面强烈吸引，因此没有显示出任何显着的铅离子吸附。该机制首次在文献中提出，它可以为探索和理解水相中离子在活性炭上的复杂现象铺平道路。
We have presented a predictive tool for describing Pb2+adsorption on activated carbon (AC). Based on the correlation between the G/D ratio and the adsorbed amount of Pb2+obtained in our previous study (Kuroki et al., 2019), we have further validated the predictive tool by carefully analyzing the results of lead ion adsorption on different AC samples in the present study. Our results show that the method can predict the amount of Pb2+adsorption within 10%, which corroborates our previous interpretation based on the hard and soft acids and bases theory. Molecular dynamic simulations were carried out to resolve the role of the counter anion and how it affects the configuration and the amount adsorbed of Pb2+ions on the non-polar graphite surface of AC. The simulation results showed that when the counterion is NO3−, the adsorption of Pb2+is enhanced by the electrostatic interactions of lead ions with adsorbed NO3−because NO3−is attracted strongly to the surface of graphite. This unique feature of adsorbed NO3−is substantiated with the use of Cl−as the counter anion, which did not show any significant adsorption of lead ions because chlorine ions are not strongly attracted to the surface of graphite. This mechanism is presented for the first time in the literature, and it can pave the path to exploring and understanding the complex phenomena of ions in the aqueous phase onto activated carbon.