Data from: Enrichment of lithum from salt lake brine by forward osmosis

Forward osmosis(FO) is a concentration on the nature phenomena of osmosis. It is nowadays considered a breakthrough technology that can be potentially used for concentrating solutions and suspensions. The diluted nature of brine restricts the treatment technologies that can be applied. Then, brine concentration by FO could represent a habilitating technology enabling the application of a wider range of treatment alternatives. The performance of concentrated brine depended upon FO membranes was investigated at normal temperature and pressure in this research. Cellulose triacetate on radio-frequency-weldable nonwoven support (CTA-NW) and a thin-film composite with embeded polyester screen support (TFC-ES) were compared; and their orientations were consisdered. The brine was from Chaerhan saltlake after extracting potassium as feed solution, NaCl solution or MgCl2 solution as draw solution. The results indicated that CTA-NW exhibited better concentrate performance than TFC-ES; while the water fluxes of the two membrane was exactly opposite. In case of CTA-NW in AL-FS(active layer facing feed solution) orientation with MgCl2 as draw solution, the concentration factors of Li+ was nearly 3.0. Quantitative structure-activity relationship (QSAR) of FO membranes and concentration characteristics was correlated, based on results of SEM, FT-IR, and contact angles studies. The concentration performance could be mainly attributed to the porosity and the thickness of FO membranes; while the water flux was depended on hydrophily of FO membrane surface.

正渗透（Forward osmosis, FO）是一类基于渗透自然现象的浓缩工艺。如今，它被视作一项具有突破性的前沿技术，具备用于溶液与悬浮液浓缩的应用潜力。卤水的低浓度属性限制了可选用的处理技术，而通过正渗透实现卤水浓缩，则可作为一项赋能技术，为更多元的处理方案提供应用可能。本研究在常温常压条件下，探究了正渗透膜对浓卤水的浓缩性能。对比了射频可焊接非织造布支撑的三醋酸纤维素膜（Cellulose triacetate on radio-frequency-weldable nonwoven support, CTA-NW）与嵌入聚酯网支撑的薄膜复合膜（thin-film composite with embedded polyester screen support, TFC-ES），并考察了两种膜的运行取向。实验所用进料液为察尔汗盐湖提钾后产出的卤水，汲取液分别采用氯化钠溶液与氯化镁溶液。实验结果表明，CTA-NW膜的浓缩性能优于TFC-ES膜，但二者的水通量表现恰好相反。当采用活性层朝向进料液（Active layer facing feed solution, AL-FS）取向的CTA-NW膜，并以氯化镁作为汲取液时，锂离子的浓缩因子接近3.0。基于扫描电子显微镜（Scanning Electron Microscope, SEM）、傅里叶变换红外光谱（Fourier Transform Infrared Spectroscopy, FT-IR）以及接触角测试的结果，本研究建立了正渗透膜的定量构效关系（Quantitative Structure-Activity Relationship, QSAR）与浓缩特性的关联模型。研究发现，正渗透膜的浓缩性能主要取决于膜的孔隙率与厚度；而水通量则与膜表面的亲水性紧密相关。