聚乙烯醇修饰准对称无机膜的正向渗透效能

Polyvinyl alcohol modified quasi-symmetric thin film inorganic membrane for enhanced forward osmosis performance

摘要:

为进一步提高准对称结构无机薄膜(QSTFI膜)的正向渗透（forward osmosis,FO）效能,利用聚乙烯醇（PVA）对其进行亲水性修饰,研究了不同PVA质量分数对膜的水通量及比盐通量的影响.膜表征结果表明：经过PVA修饰的膜表面负电荷增多,有利于膜对Na+的截留；此外修饰膜表面的亲水性提高有利于获得更高的水通量.通过FO实验确定PVA最佳质量分数为0.5 %.当提取液(DS)为2.0 molL-1 NaCl、原液（FS）为去离子水时,修饰膜水通量为67.08 Lm-2h-1,比同条件下QSTFI膜水通量高12%；而比盐通量为0.15 gL-1,比QSTFI膜低16.7%.

Abstract:

To further promote the FO performance of QSTFI membrane, polyvinyl alcohol (PVA) modified QSTFI membrane (PVA-QSTFI) has been developed. The characterization results indicated that the incorporation of a small amount of PVA onto the QSTFI membrane has significant influence on the surface hydrophilicity, pore structure, surface charge and thus FO performance. An optimum PVA loading rate of 0.5% was chosen based on the water flux and specific salt flux experiments. Using the 2.0 molL-1 NaCl as DS, deionized water as FS, the modified membrane offered a 67.08 Lm-2h-1 water flux at 25 ℃, was 12% higher than that of QSTFI membrane. Meanwhile, a specific salt flux of 0.15 gL-1 was obtained, which is 16.7% lower than QSTFI membrane.