3种维度类水滑石纳米改性正渗透复合膜的制备

Preparation of Thin-Film Composite Forward Osmosis Membranes with Three Different Dimensionalities Layered Double Hydroxides Nanoparticles as Modifiers

以零维(小球状)、二维(片状)和三维(花瓣状)的类水滑石(LDH)纳米颗粒与聚砜共混制备多孔支撑层,在多孔支撑层上通过界面聚合的方法得到聚酰胺活性层。通过X-射线衍射、红外、接触角和SEM表征,系统考察了3种维度的LDH纳米颗粒及其维度对聚砜多孔支撑层结构和理化性质的影响,并对所制备的3种维度的LDH正渗透复合膜进行了性能测试。结果表明,LDH的添加提高了聚砜支撑层的亲水性、表面和断面孔径;以1 mol/L的NaCl溶液做驱动液,去离子水做原料液的条件下,三维花瓣状LDH的质量分数3%的LDH-F改性复合膜的水通量(PRO模式)提高了52.7%,并没有降低盐的截留,其特定盐通量Js/Jw为0.22 g/L。

The polyamide(PA) thin-film composite(TFC) membranes on the porous substrates were prepared by interfacial polymerization method for forward osmosis, and the porous substrates were obtained via the different dimensionality layered double hydroxide(LDHs) nanoparticles blended polysulfone(PSf) polymer, e.g. zero-dimensionality(spherical-like), two-dimensionality(plate-like) and three-dimensionality(flower-like). The effects of nano-particles and dimensionality of three LDHs on the structure and physicochemical properties of the substrates were systematically investigated by XRD, ATR-FT TR, contact angle and SEM characterization, and performance of three prepared LDHs FO membranes was tested. The results indicated that the addition of LDHs increased the hydrophilicity and pore diameter of substrates. Consequently, the water flux of LDH-F with mass fraction of 3% modified TFC membrane was improved 52.7% without compromise in salt rejection at PRO mode, when 1 mol/L NaCl as draw solution and DI-water as feed solution, and the specific salt flux Js/Jwwas 0.22 g/L.