聚乙烯醇改性对二维蒙脱石通道薄膜锂镁分离的影响

doi:10.16552/j.cnki.issn1001-1625.2025.0875

摘要/Abstract

摘要：

锂是支撑新能源革命的关键战略资源，我国盐湖锂资源总量占据主导地位。然而我国盐湖普遍存在高镁锂比的问题，使高效分离锂镁面临极大的挑战。本文提出利用聚乙烯醇（PVA）改性蒙脱石纳米片，通过调控PVA的用量梯度调节了蒙脱石纳米片的通道高度，实现了锂镁的高效分离，揭示了PVA调控蒙脱石纳米片通道高度的行为规律及机制。研究发现，PVA可以通过氢键与蒙脱石纳米片连接，并通过插层的方式进入蒙脱石层间，对二维蒙脱石薄膜通道高度进行调控，进而实现对锂镁离子的高效分离。经过改性的薄膜对模拟卤水的锂镁分离因子可达到92.61，相较未改性的薄膜提高了20倍。改性后的薄膜在高盐浓度及多种阳离子共存的卤水环境下均表现出优异的锂镁分离能力，在长周期稳定运行48 h时镁离子截留率稳定在97%左右，通量能够稳定保持在30 L·m^-2·h^-1左右。

关键词: 蒙脱石, 聚乙烯醇, 二维纳米片, 纳米通道膜, 锂镁分离

Abstract:

Lithium is a key strategic resource to support the new energy revolution， and the total amount of China’s salt lake lithium resources holds a dominant position globally. However， Chinese salt lakes commonly suffer from a high magnesium-lithium ratio， which poses a significant challenge for the efficient separation of lithium and magnesium. This study proposed the use of polyvinyl alcohol （PVA）-modified montmorillonite nanosheets. By precisely controlling the gradient amount of PVA， the channel height of montmorillonite nanosheets was regulated， enabling the highly efficient separation of lithium and magnesium. Furthermore， this work elucidated the mechanism by which PVA modulates the channel height of montmorillonite nanosheets. It is found that PVA can be connected to montmorillonite nanosheets through hydrogen bonds， and enters the montmorillonite layers through intercalation， regulating the channel height of two-dimensional montmorillonite membranes， and achieving efficient separation of lithium and magnesium ions. The separation factor of lithium and magnesium in the simulated brine of the modified membrane can reach up to 92.61， which is 20 times higher than that of the unmodified membrane. The modified membrane demonstrates excellent lithium and magnesium separation capability in brine with high salt concentrations and coexisting multiple cations. The magnesium ion rejection rate remains stable at approximately 97%， and the flux is consistently maintained at a level of approximately 30 L·m^-2·h^-1 after 48 h of long-term stable operation.

Key words: montmorillonite, polyvinyl alcohol, two-dimensional nanosheet, nanochannel membrane, lithium-magnesium separation

中图分类号:

V254.3

王介瑞, 赵云良, 王振磊, 张婷婷, 张鑫, 李滢. 聚乙烯醇改性对二维蒙脱石通道薄膜锂镁分离的影响[J]. 硅酸盐通报, 2026, 45(2): 675-683.

WANG Jierui, ZHAO Yunliang, WANG Zhenlei, ZHANG Tingting, ZHANG Xin, LI Ying. Influence of Polyvinyl Alcohol Modification on Lithium-Magnesium Separation of Two-Dimensional Montmorillonite Channel Membrane[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2026, 45(2): 675-683.

图/表 10

图1 不同PVA用量下MMTM及P-MMTM薄膜的XRD谱

Fig.1 XRD patterns of MMTM and P-MMTM films with different PVA amount

图2 MMTM和P-MMTM薄膜的红外光谱

Fig.2 FTIR spectra of MMTM and P-MMTM films

图3 MMTM和P-MMTM薄膜的XPS分析

Fig.3 XPS analysis of MMTM and P-MMTM films

图4 MMTM和P-MMTM薄膜的SEM照片

Fig.4 SEM images of MMTM and P-MMTM films

图5 薄膜粗糙度及亲水性表征

Fig.5 Film roughness and hydrophilicity characterization

图6 锂镁离子在P-MMTM薄膜中的传输速率及传质活化能

Fig.6 Transfer rate and mass transfer activation energy of lithium-magnesium ions in P-MMTM film

图7 不同PVA用量下薄膜锂镁分离性能

Fig.7 Separation performance of lithium-magnesium infilms under different PVA dosages

图8 MMTM和P-MMTM薄膜在不同盐浓度锂镁混合溶液中的Mg2+截留率和Li+透过率

Fig.8 Mg2+ retention rate and Li+ transmittance of MMTM and P-MMTM films in lithium-magnesium mixed solutions with different salt concentrations

图9 MMTM和P-MMTM薄膜在不同共存离子体系下的Mg2+截留率和镁锂分离选择性

Fig.9 Mg2+ retention rates and Mg2+/Li+ separation selective of MMTM and P-MMTM films under different coexisting ion systems

图10 P-MMTM薄膜长周期稳定性

Fig.10 Long-term stability of P-MMTM film

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