文献类型：期刊文献

英文题名：Molecular simulation of diffusion behavior of counterions within polyelectrolyte membranes used in electrodialysis

作者：Sun, Shu-Ying[1];Nie, Xiao-Yao[1];Huang, Jun[2];Yu, Jian-Guo[1,3]

机构：[1]East China Univ Sci & Technol, Natl Engn Res Ctr Integrated Utilizat Salt Lake R, Shanghai 200237, Peoples R China;[2]Univ Sydney, Sch Chem & Biomol Engn, Sydney, NSW 2006, Australia;[3]East China Univ Sci & Technol, Minist Educ, Engn Res Ctr Resources Proc Engn, Shanghai, Peoples R China

年份：2020

卷号：595

外文期刊名：JOURNAL OF MEMBRANE SCIENCE

收录：;EI(收录号：20194407596502);WOS:【SCI-EXPANDED(收录号:WOS:000501804600060)】；

基金：The research was supported by National Natural Science Foundation of China (U1707601, U1407120).

语种：英文

外文关键词：Polyelectrolyte membrane; Molecular dynamics simulation; Lithium recovery; Electrodialysis

摘要：A molecular dynamics simulation was performed to explore the diffusion behavior of counter-ions within polyelectrolyte membranes via Materials Studio software, which could provide a theoretical basis for the screening and performance prediction of selective ion-exchange membranes (IEMs). The mean square displacements of Li+/Mg2+ in sulfonic and phosphatic polyelectrolyte systems were calculated, and the sulfonic group was determined as a higher preference fixed charge group. The conformational variation of the polyelectrolyte chain with the concentration of counter-ion was assessed via the radius of gyration and, in combination with the pair correlations function. The interaction of counter-ions with sulfonic groups in cation exchange membranes (CEMs) was also determined. The results showed that Mg2+ ions were easily adsorbed on sulfonic groups in CEMs, shielding the negative charge of the polyelectrolyte, which resulted in the coiling of the molecular chain; hence, the radius of gyration decreased. By replacing the adsorbed Li+ ions, more Mg2+ ions were preferentially bound on the sulfonic groups with the increase in Mg2+ ions in the aqueous solution, which is consistent with the ion-exchange isotherms of the Selemion CSO membrane. By calculating the interaction energy of the counter-ions toward the polyelectrolyte and via a permeation experiment involving various cations, we found the difference in interaction energy between monovalent and divalent ions was remarkable, indicating that the interaction of counter-ions toward fixed charge groups in polyelectrolyte mainly determined the ionic diffusion performance. Raising the energy barrier on the interface was determined as an efficient method for the modification of selective IEMs.