自锁界面层策略：通过正渗透技术增强盐湖卤水的锂浓缩

《Journal of Membrane Science》：Self-locking interlayer strategy for enhanced lithium concentration from salt lake brines via forward osmosis

　　### IntroductionThe global transition to low-carbon energy systems has increased demand for lithium, making its extraction from salt-lake brines essential [1, 2]. Lithium ion concentration is vital for product purity [3]. Chinese salt lake brines have low Li+ concentrations, requiring effective concentration methods [4]. Forward osmosis (FO) is a promising technology for lithium concentration without external pressure.### Challenges in TFC Membrane FormationThe efficiency of lithium enrichment in FO is determined by thin-film composite (TFC) membranes formed through uncontrolled interfacial reaction-diffusion processes. Conventional substrates often result in poorly cross-linked polyamide (PA) layers with broad pore distributions, leading to insufficient selectivity and permeability [5, 6].### Role of Functional InterlayersIntroducing functional interlayers between the substrate and PA film allows for better control over interfacial polymerization [7, 8]. These interlayers, such as those made from polyvinyl alcohol or metal-organic frameworks (MOFs), can enhance membrane performance by regulating monomer flux and diffusion [9, 10, 11, 12].### Lithium-Selective MembranesRecent advancements include interlayer concepts applied to lithium-selective membranes. Defect-engineered UiO-66-NH2 and other interlayers have improved lithium concentration in FO systems [13, 14, 15]. Similarly, surfactant-assisted interlayers enhance Li+/Mg2+ separation in pressure-driven nanofiltration [16, 17].### Development of ZIF-8/PVP InterlayerThis study introduces a ZIF-8/PVP interlayer to address existing challenges. The interlayer is designed with N-vinyl-2-pyrrolidone (NVP), which promotes monomer adsorption through hydrogen bonding. UV irradiation polymerizes NVP into PVP, creating a dynamic interlayer that initially enriches monomers and later suppresses diffusion [18].### Experimental MethodsThe study includes various characterization techniques, such as XRD to analyze ZIF-8 and its composites. The materials used include NVP, zinc nitrate, and others from specified suppliers.### ConclusionsThe ZIF-8/PVP interlayer effectively enhances lithium enrichment in TFC membranes, producing a thinner and denser PA selective layer. The optimized membrane showed a water flux of 25.6 L m?2 h?1 and a Li+ rejection rate of 92.89 ± 0.14%.### FundingThis research was supported by various funding bodies including the Key R&D Programs and the Shaanxi Provincial Education Department.### ContributionMiaolu He and others contributed in various roles including writing, visualization, and analysis of the research.This structured summary captures the key aspects of the paper while adhering to the guidelines provided.