织物增强型正渗透复合膜的制备、表征及性能研究

Preparation,characterization and performance of fabric-reinforced FO composite membrane

以高强度、高开孔率、低厚度聚酯机织物为新型增强基材,首次采用双刮刀共涂布法,结合铸膜液黏度选择,实现了聚砜铸膜液在机织物表面上的超薄、低缺陷涂布,并通过非溶剂致相分离和界面聚合,成功制备了织物增强型薄层复合正渗透膜。该膜具有活性层-织物嵌入式多孔支撑层两层结构,整体厚度约60μm,拉伸强度和杨氏模量分别约为90MPa和370MPa。该膜结构强度满足了正渗透膜规模化生产与使用的要求,具有良好的实际应用价值。此外,由于增强机织物嵌入多孔支撑层内部,所制备的正渗透复合膜内浓差极化现象较轻,结构参数低至303.0μm,以1.0mol/L的NaCl溶液作汲取液,正渗透(FO)模式下膜渗透通量可达21.8LMH。

The polyester woven fabric with high strength,high porosity and low thickness was explored as a new reinforcement material for polymeric membrane.An ultrathin and low-defect coating of polysulfone membrane casting solution with suitable viscosity on the fabric surface was realized via double-blade casting method for the first time.Then,through non-solvent induced phase separation and interfacial polymerization,fabric-reinforced thin film composite membrane was successfully developed for forward osmosis(FO).The as-prepared membrane consisted of polyamide active layer and fabric-embedded polysulfone support layer and had an overall thickness of 60μm.Its tensile strength and Young’s modulus were about 90 MPa and 370 MPa respectively,which was practical for designing commercially available FO membrane.Furthermore,the fabricated FO membrane had low-level internal concentration polarization because the fabric was integrated into the polysulfone matrix instead of being a separate backing layer on the bottom.The optimal FO membrane achieved a structural parameter of as low as 303.0μm and gains an osmotic water flux of 21.8 LMH in FO mode when using 1.0 mol/L NaCl draw solution.