船闸式LiAlFe-LDHs/PVDF复合膜系统高效选择性提取锂离子

doi:10.11949/0438-1157.20250876

摘要/Abstract

摘要：

针对我国盐湖卤水中镁锂比高、品味低导致的锂提取难题，本研究开发了一种高效、选择性强的船闸式离子选择性渗透（SL-ISP）系统，实现了锂资源的高效开采。以锂铝铁层状双金属氢氧化物（LiAlFe-LDHs）作为活性物质，聚偏二氟乙烯（PVDF）为粘结剂，通过流延成型法制备了LiAlFe-LDHs/PVDF复合膜，并用于SL-ISP系统实现了Li⁺的选择性定向提取。该复合膜制备方法简单高效，SL-ISP系统操作简单、能耗低且易于工业化生产。结果表明，在等摩尔浓度（C_Mg = C_Li = 0.05 mol·L^-1）下，LiAlFe-LDHs/PVDF复合膜的Li⁺通量为0.039 mol·m^-2·h^-1，Li⁺/Mg²⁺分离因子达到了13.44。此外，在模拟卤水中进行了Li⁺的选择性渗透实验，其Li⁺渗透通量为0.036 mol·m^-2·h^-1，Li⁺/Mg²⁺、Li⁺/K⁺、Li⁺/Na⁺和Li⁺/Ca²⁺分离因子分别达到了164.28、98.49、120.09和47.52。因此，将LiAlFe-LDHs/PVDF复合膜应用于SL-ISP系统具有良好的工业应用前景。

关键词: 船闸式离子选择渗透, Li⁺提取, Li/Mg分离, LiAlFe-LDHs/PVDF复合膜

Abstract:

To address the challenge of lithium extraction from Chinese salt lake brines characterized by high Mg²⁺/Li⁺ ratios and low lithium grades, this study developed an efficient and highly selective ship lock-type ion selective permeation (SL-ISP) system for effective lithium extraction. Employing Lithium Aluminum Iron Layered Double Hydroxides (LiAlFe-LDHs) as the active component and polyvinylidene fluoride (PVDF) as the binder, a LiAlFe-LDHs/PVDF composite membrane was prepared via the casting method and successfully applied in a SL-ISP system to achieve selective and directional extraction of Li⁺ ions. The composite membrane fabrication method demonstrates simple yet efficient processing characteristics, while the SL-ISP system offers straightforward operation with low energy consumption, showing excellent potential for industrial scale-up. The membrane displayed a Li⁺ flux of 0.039 mol·m^-2·h^-1 and a separation factor of 13.44 at equimolar concentrations (C_Mg = C_Li = 0.05 mol·L^-1). In simulated brine, it achieved a Li⁺ permeation flux of 0.036 mol·m^-2·h^-1, with notable separation factors of 164.28 for Li⁺/Mg²⁺, 98.49 for Li⁺/K⁺, 120.09 for Li⁺/Na⁺, and 47.52 for Li⁺/Ca²⁺, confirming its utility in the SL-ISP system for extracting Li⁺ from saline lake brine.

Key words: ship lock-type ion selective permeation, Li⁺ extraction, Li/Mg separation, LiAlFe-LDHs/PVDF composite membrane

中图分类号:

TQ 150.5

邓雨晨, 王熠, 高凤凤, 郝晓刚, 仙运昌, 赵瑞. 船闸式LiAlFe-LDHs/PVDF复合膜系统高效选择性提取锂离子[J]. 化工学报, DOI: 10.11949/0438-1157.20250876.

Yuchen DENG, Yi WANG, Fengfeng GAO, Xiaogang HAO, Yunchang XIAN, Rui ZHAO. Efficient and selective Li⁺ etraction by ship-lock LiAlFe-LDHs/PVDF membrane system[J]. CIESC Journal, DOI: 10.11949/0438-1157.20250876.

图/表 10

图1 锂离子阱LiAlFe-LDHs/PVDF复合膜的制备流程图

Fig. 1 Schematic illustration of the fabrication of the Li+-trap LiAlFe-LDHs/PVDF composite membrane

图2 （a）LiAlFe-LDHs、（b）PVDF粉末、（c）LiAlFe-LDHs/PVDF-T、（d）锂离子阱LiAlFe-LDHs/PVDF-T、（e）锂离子阱LiAlFe-LDHs/PVDF-B和（f）锂离子阱LiAlFe-LDHs/PVDF复合膜的横截面的SEM图

Fig. 2 (a) SEM images of LiAlFe-LDHs, (b) SEM images of PVDF powder, (c) LiAlFe-LDHs/PVDF composite membrane, (d) LiAlFe-LDHs/PVDF-T, (e) Li+-trap LiAlFe-LDHs/PVDF-B, and (f) the cross-section of the Li+-trap LiAlFe-LDHs/PVDF composite membranes

图3 （a）LiAlFe-LDHs/PVDF和锂离子阱LiAlFe-LDHs/PVDF复合膜的XRD图谱；（b）锂离子阱LiAlFe-LDHs/PVDF-T与锂离子阱LiAlFe-LDHs/PVDF-B的接触角图

Fig. 3 (a) XRD patterns of LiAlFe-LDHs/PVDF and Li+-trap LiAlFe-LDHs/PVDF composite membranes, (b) contact angle diagrams of the LiAlFe-LDHs/PVDF-T and Li+-trap LiAlFe-LDHs/PVDF-B

图4 锂离子阱LiAlFe-LDHs/PVDF复合膜在SL-ISP系统中提取Li+的示意图和机理图

Fig. 4 Schematic illustration and mechanism diagram of Li+ extraction by the Li+-trap LiAlFe-LDHs/PVDF composite membrane in the SL-ISP system

图5 LiAlFe-LDHs/PVDF复合膜在不同脱附液浓度下的（a）脱附曲线、（b）脱附速率变化曲线线；不同初始浓度下对Li+的（c）吸附曲线、（d）吸附速率变化曲线（脱附温度：40℃）

Fig. 5 (a) Desorption curves of LiAlFe-LDHs/PVDF composite membrane at different desorption solution concentrations and (b) variation curves of desorption rate; (c) adsorption curves of Li+ by LiAlFe-LDHs/PVDF composite membrane at different initial concentrations and (d) variation curves of adsorption rate (desorption temperature: 40°C)

图6 SL-ISP系统中（a）膜配比、（b）流速和（c）吸附/脱附脉冲宽度对LiAlFe-LDHs/PVDF复合膜分离性能的影响；（d）LiAlFe-LDHs/PVDF复合膜的循环稳定性

Fig. 6 The effect of (a) membrane formulation, (b) flow rate, and (c) adsorption/desorption pulse width on the separation performance of the LiAlFe-LDHs/PVDF composite membrane; (d) the cyclic stability of the LiAlFe-LDHs/PVDF composite membrane in the SL-ISP system

表1 模拟卤水实验中原料液和接收液的阳离子浓度

Table 1 Cation concentrations on the feedstock and receiver solutions in simulated brine

离子种类	原料室溶液		接收室溶液
离子种类	初始浓度 (mg L^-1)	结束浓度 (mg L^-1)	初始浓度 (mg L^-1)	接收浓度 (mg L^-1)
Li⁺	226.61	149.82	0	55.95
Mg²⁺	80982.68	75348.88	0	121.71
K⁺	841.66	810.6	0	2.11
Na⁺	2162.98	2096.44	0	6.52
Ca²⁺	121.62	19.43	0	0.86

图7 LiAlFe-LDHs/PVDF复合膜在模拟卤水中计算所得的Li+/Mg2+、Li+/K+、Li+/Na+和Li+/Ca2+分离因子

Fig. 7 The calculated separation factors of Li+/Mg2+, Li+/K+, Li+/Na+, and Li+/Ca2+ for the LiAlFe-LDHs/PVDF composite membrane in simulated brine

表2 盐湖卤水中主要离子的裸离子和水合离子的离子半径

Table 2 Ionic radii of naked ions and hydrated ions for major ions in salt lake brine

离子种类	裸离子半径 (nm)	水合离子半径 (nm)
Li⁺	0.068	0.38
Mg²⁺	0.065	0.43
Na⁺	0.095	0.36
K⁺	0.133	0.33
Ca²⁺	0.099	0.41

图8 本研究与参考文献对Li+/Mg2+分离性能的对比

Fig. 8 Comparison of the Li+/Mg2+ separation performance in this work with that reported in the literature

参考文献 39

[1]	Grosjean C, Miranda P H, Perrin M, et al. Assessment of world lithium resources and consequences of their geographic distribution on the expected development of the electric vehicle industry[J]. Renewable and Sustainable Energy Reviews, 2012, 16(3): 1735-1744.
[2]	Benson T R, Jowitt S M, Simon A C. Special issues on the geology and origin of lithium deposits: introduction: lithium deposit types, sizes, and global distribution[J]. Economic Geology, 2025, 120(3): 503-511.
[3]	Ann Munk L, Boutt D, Butler K, et al. Lithium brines: origin, characteristics, and global distribution[J]. Economic Geology, 2025, 120(3): 575-597.
[4]	张正, 何永平, 孙海东, 等. 蛇形流场电控离子交换装置用于选择性提锂[J]. 化工学报, 2023, 74(5): 2022-2033.
	Zhang Z, He Y P, Sun H D, et al. Electrochemically switched ion exchange device with serpentine flow field for selective extraction of lithium[J]. CIESC Journal, 2023, 74(5): 2022-2033.
[5]	陈仰, 李欢, 顾升波, 等. 盐湖锂资源现状及提锂技术研究进展[J]. 工程科学学报, 2024, 46(9): 1659-1670.
	Chen Y, Li H, Gu S B, et al. Present situation of salt-lake lithium resources and research progress of lithium extraction technology[J]. Chinese Journal of Engineering, 2024, 46(9): 1659-1670.
[6]	蒋晨啸, 陈秉伦, 张东钰, 等. 我国盐湖锂资源分离提取进展[J]. 化工学报, 2022, 73(2): 481-503.
	Jiang C X, Chen B L, Zhang D Y, et al. Progress in isolating lithium resources from China salt lake brine[J]. CIESC Journal, 2022, 73(2): 481-503.
[7]	Zhao C L, Zhang Y L, Cao H B, et al. Lithium carbonate recovery from lithium-containing solution by ultrasound assisted precipitation[J]. Ultrasonics Sonochemistry, 2019, 52: 484-492.
[8]	Lv Y W, Xing P, Ma B Z, et al. Efficient extraction of lithium and rubidium from polylithionite via alkaline leaching combined with solvent extraction and precipitation[J]. ACS Sustainable Chemistry & Engineering, 2020, 8(38): 14462-14470.
[9]	Zhang L C, Li J F, Liu R R, et al. Recovery of lithium from salt lake brine with high Na/Li ratio using solvent extraction[J]. Journal of Molecular Liquids, 2022, 362: 119667.
[10]	Kanagasundaram T, Murphy O, Haji M N, et al. The recovery and separation of lithium by using solvent extraction methods[J]. Coordination Chemistry Reviews, 2024, 509: 215727.
[11]	Xu S S, Song J F, Bi Q Y, et al. Extraction of lithium from Chinese salt-lake brines by membranes: Design and practice[J]. Journal of Membrane Science, 2021, 635: 119441.
[12]	Zhang L J, Zhang T T, Lv S K, et al. Adsorbents for lithium extraction from salt lake brine with high magnesium/lithium ratio: From structure-performance relationship to industrial applications[J]. Desalination, 2024, 579: 117480.
[13]	Yu H W, Naidu G, Zhang C Y, et al. Metal-based adsorbents for lithium recovery from aqueous resources[J]. Desalination, 2022, 539: 115951.
[14]	Prestopino G, Pezzilli R, Calavita N J, et al. Layered-double-hydroxide (LDH) pyroelectric nanogenerators[J]. Nano Energy, 2023, 118: 109017.
[15]	Lu C Y, Kim T H, Bendix J, et al. Stability of magnetic LDH composites used for phosphate recovery[J]. Journal of Colloid and Interface Science, 2020, 580: 660-668.
[16]	Veeralingam S, Gunasekaran S S, Badhulika S. Bifunctional NiFe LDH as a piezoelectric nanogenerator and asymmetric pseudo-supercapacitor[J]. Materials Chemistry Frontiers, 2022, 6(16): 2297-2308.
[17]	Wang J, Lv G C, Wang C. A highly efficient and robust hybrid structure of CoNiN@NiFe LDH for overall water splitting by accelerating hydrogen evolution kinetics on NiFe LDH[J]. Applied Surface Science, 2021, 570: 151182.
[18]	高凤凤, 程慧峰, 杨博, 等. 电驱动NiFeMn LDH/CNTs/PVDF膜电极选择性提取钨酸根离子[J]. 化工学报, 2025, 76(7): 3350-3360.
	Gao F F, Cheng H F, Yang B, et al. Electrically driven NiFeMn LDH/CNTs/PVDF film electrode for selective extraction of tungstate ions[J]. CIESC Journal, 2025, 76(7): 3350-3360.
[19]	李彦乐, 刘宜林, 霍俊杰, 等. 层状结构铝系吸附剂在盐湖提锂领域的研究[J]. 化工学报, 2023, 74(12): 4777-4791.
	Li Y L, Liu Y L, Huo J J, et al. Research progress of aluminum adsorbents in lithium extraction from salt lakes[J]. CIESC Journal, 2023, 74(12): 4777-4791.
[20]	Li J, Luo Q L, Dong M Z, et al. Synthesis of granulated Li/Al-LDHs adsorbent and application for recovery of Li from synthetic and real salt lake brines[J]. Hydrometallurgy, 2022, 209: 105828.
[21]	Ma Y J, Luo Q L, Li J, et al. One-pot synthesis of transition metals-doped LiAl-LDHs to improve lithium adsorption performance and stability[J]. Process Safety and Environmental Protection, 2024, 192: 878-886.
[22]	Li Y Y, Tang N, Zhang L, et al. Fabrication of Fe-doped lithium-aluminum-layered hydroxide chloride with enhanced reusable stability inspired by computational theory and its application in lithium extraction[J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2023, 658: 130641.
[23]	Yu M, Li H P, Du N, et al. Understanding Li-Al-CO₃ layered double hydroxides. (I) Urea-supported hydrothermal synthesis[J]. Journal of Colloid and Interface Science, 2019, 547: 183-189.
[24]	Luo Q L, Dong M Z, Li Q, et al. Improve the durability of lithium adsorbent Li/Al-LDHs by Fe³⁺ substitution and nanocomposite of FeOOH[J]. Minerals Engineering, 2022, 185: 107717.
[25]	Pan Y N, Zhang W C. Enhanced continuous lithium extraction using self-designed porous nanosorbent fibers in a fixed-bed system: Optimization and mechanistic insights[J]. Desalination, 2025, 593: 118223.
[26]	Roberts J, Song Y, Crocker M, et al. A genetic algorithmic approach to determine the structure of Li–Al layered double hydroxides[J]. Journal of Chemical Information and Modeling, 2020, 60(10): 4845-4855.
[27]	Pan Y N, Tao H L, Su H P, et al. High mixing enhancement for continuous uniformity Li/Al-LDHs in lithium extraction from low grade salt lakes[J]. Separation and Purification Technology, 2025, 354: 129282.
[28]	Zhang L J, Zhang T T, Lv S K, et al. Steering interlayer interaction of lithium-aluminum layered double hydroxide beads for stable lithium extraction from sulfate-type brines[J]. Desalination, 2024, 592: 118130.
[29]	Nishad H S, Kotha V, Sarawade P, et al. Exchanging interlayer anions in NiFe-LDHs nanosphere enables superior battery-type storage for high-rate aqueous hybrid supercapacitors[J]. Journal of Materials Chemistry A, 2024, 12(16): 9494-9507.
[30]	Wang Y, Guo H H, Xing X H, et al. Lithium-selective extraction utilizing lithium-trap LiAlFe-LDHs/MWCNTs/QCS composite membrane within the ship lock-type ion selective permeability system[J]. Separation and Purification Technology, 2025, 375: 133730.
[31]	Xu L, Zeng X J, He Q, et al. Stable ionic liquid-based polymer inclusion membranes for lithium and magnesium separation[J]. Separation and Purification Technology, 2022, 288: 120626.
[32]	Lu J, Dai C Y, Li S L, et al. Ultraefficient Li⁺/Mg²⁺ separation with MXene/CNT membranes under electric field assistance[J]. Separation and Purification Technology, 2024, 338: 126508.
[33]	Zeng X J, Xu L, Deng T, et al. Polymer inclusion membranes with P507-TBP carriers for lithium extraction from brines[J]. Membranes, 2022, 12(9): 839.
[34]	Bing S S, Xian W P, Chen S F, et al. Bio-inspired construction of ion conductive pathway in covalent organic framework membranes for efficient lithium extraction[J]. Matter, 2021, 4(6): 2027-2038.
[35]	Zhao Z W, Liu G, Jia H, et al. Sandwiched liquid-membrane electrodialysis: Lithium selective recovery from salt lake brines with high Mg/Li ratio[J]. Journal of Membrane Science, 2020, 596: 117685.
[36]	Saif H M, Huertas R M, Pawlowski S, et al. Development of highly selective composite polymeric membranes for Li⁺/Mg²⁺ separation[J]. Journal of Membrane Science, 2021, 620: 118891.
[37]	Sheng F M, Wu B, Li X Y, et al. Efficient ion sieving in covalent organic framework membranes with sub-2-nanometer channels[J]. Advanced Materials, 2021, 33(44): 2104404.
[38]	Zhou Z Y, Shinde D B, Guo D, et al. Flexible ionic conjugated microporous polymer membranes for fast and selective ion transport[J]. Advanced Functional Materials, 2022, 32(6): 2108672.
[39]	Li B, Peng J J, Li M H, et al. Facile synthesis and exfoliation of micro‐sized LDH to fabricate 2D membranes towards Mg/Li separation[J]. AIChE Journal, 2023, 69(11): e18212.