Rejection of pharmaceutically active compounds by forward osmosis: Role of solution pH and membrane orientation
Rejection of pharmaceutically active compounds by forward osmosis: Role of solution pH and membrane orientation
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DOI：
10.1016/j.seppur.2012.03.030
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发表时间：
2012-06
影响因子：
8.6
通讯作者：
Ming Xie;W. Price;L. Nghiem
中科院分区：
文献类型：
--
作者：
Ming Xie;W. Price;L. Nghiem
采用实验室规模的正渗透系统，研究了料液pH值和膜取向对水通量和卡马西平、磺胺甲恶唑截留率的影响。水通量的pH值依赖于两个膜的方向。此外，水通量增加，而特定的反向盐通量和氢离子通量下降，随着料液pH值的增加。水通量较低，在正常FO模式相比，在压力延迟渗透（PRO）模式，因为渗透压差降低，由于内部浓度极化（ICP）现象。中性卡马西平的排斥反应在两种膜取向上一般都不依赖于pH。在PRO模式下，由于ICP在多孔支撑层中的浓度梯度较大，对卡马西平的截留率低于FO模式。空间位阻可能是FO分离中性卡马西平的主要机理。另一方面，磺胺甲恶唑的排斥率显着影响的进料溶液的pH值在两个膜取向。磺胺甲恶唑截留率的变化可归因于带负电荷的FO膜表面与磺胺甲恶唑分子的不同有效电荷之间的静电排斥。
The effects of feed solution pH and membrane orientation on water flux and the rejection of carbamazepine and sulfamethoxazole were investigated using a bench scale forward osmosis (FO) system. Water flux was pH-dependent in both membrane orientations. In addition, water flux increased while the specific reverse salt flux and hydrogen ion flux decreased with increasing feed solution pH. Water flux was lower in the normal FO mode compared to that in the pressure retarded osmosis (PRO) mode because osmotic pressure differential was reduced due to the internal concentration polarisation (ICP) phenomenon. The rejection of neutral carbamazepine was generally pH independent in both membrane orientations. The rejection of carbamazepine in the PRO mode was lower than that in the FO mode due to the higher concentration gradient caused by concentrative ICP in porous supporting layer. Steric hindrance was probably the main separation mechanism for the neutral carbamazepine in the FO process. On the other hand, the rejection of sulfamethoxazole was significantly affected by the feed solution pH in both membrane orientations. Variation in the rejection sulfamethoxazole could be attributed to the electrostatic repulsion between the negatively charged FO membrane surface and varying effective charge of the sulfamethoxazole molecule.