Said Noresah, Khoo Ying Siew, Lau Woei Jye, Gürsoy Mehmet, Karaman Mustafa, Ting Teo Ming, Abouzari-Lotf Ebrahim, Ismail Ahmad Fauzi
Advanced Membrane Technology Research Centre (AMTEC), School of Chemical and Energy Engineering, Universiti Teknologi Malaysia, Skudai 81310, Malaysia.
Department of Chemical Engineering, Konya Technical University, Konya 42075, Turkey.
Membranes (Basel). 2020 Dec 7;10(12):401. doi: 10.3390/membranes10120401.
In this work, several ultrafiltration (UF) membranes with enhanced antifouling properties were fabricated using a rapid and green surface modification method that was based on the plasma-enhanced chemical vapor deposition (PECVD). Two types of hydrophilic monomers-acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) were, respectively, deposited on the surface of a commercial UF membrane and the effects of plasma deposition time (i.e., 15 s, 30 s, 60 s, and 90 s) on the surface properties of the membrane were investigated. The modified membranes were then subjected to filtration using 2000 mg/L pepsin and bovine serum albumin (BSA) solutions as feed. Microscopic and spectroscopic analyses confirmed the successful deposition of AA and HEMA on the membrane surface and the decrease in water contact angle with increasing plasma deposition time strongly indicated the increase in surface hydrophilicity due to the considerable enrichment of the hydrophilic segment of AA and HEMA on the membrane surface. However, a prolonged plasma deposition time (>15 s) should be avoided as it led to the formation of a thicker coating layer that significantly reduced the membrane pure water flux with no significant change in the solute rejection rate. Upon 15-s plasma deposition, the AA-modified membrane recorded the pepsin and BSA rejections of 83.9% and 97.5%, respectively, while the HEMA-modified membrane rejected at least 98.5% for both pepsin and BSA. Compared to the control membrane, the AA-modified and HEMA-modified membranes also showed a lower degree of flux decline and better flux recovery rate (>90%), suggesting that the membrane antifouling properties were improved and most of the fouling was reversible and could be removed via simple water cleaning process. We demonstrated in this work that the PECVD technique is a promising surface modification method that could be employed to rapidly improve membrane surface hydrophilicity (15 s) for the enhanced protein purification process without using any organic solvent during the plasma modification process.
在这项工作中，采用基于等离子体增强化学气相沉积（PECVD）的快速绿色表面改性方法制备了几种具有增强抗污染性能的超滤（UF）膜。分别将两种亲水性单体——丙烯酸（AA）和甲基丙烯酸2-羟乙酯（HEMA）沉积在商用超滤膜表面，并研究了等离子体沉积时间（即15 s、30 s、60 s和90 s）对膜表面性能的影响。然后使用2000 mg/L胃蛋白酶和牛血清白蛋白（BSA）溶液作为进料对改性膜进行过滤。显微镜和光谱分析证实了AA和HEMA成功沉积在膜表面，并且随着等离子体沉积时间的增加水接触角减小，这有力地表明由于AA和HEMA的亲水性链段在膜表面大量富集，表面亲水性增加。然而，应避免等离子体沉积时间过长（>15 s），因为这会导致形成更厚的涂层，显著降低膜的纯水通量，而溶质截留率没有显著变化。在15 s的等离子体沉积后，AA改性膜对胃蛋白酶和BSA的截留率分别为83.9%和97.5%，而HEMA改性膜对胃蛋白酶和BSA的截留率均至少为98.5%。与对照膜相比，AA改性膜和HEMA改性膜的通量下降程度也较低，通量恢复率更高（>90%），这表明膜的抗污染性能得到了改善，并且大部分污染是可逆的，可以通过简单的水洗过程去除。我们在这项工作中证明，PECVD技术是一种很有前景的表面改性方法，可用于在等离子体改性过程中不使用任何有机溶剂的情况下快速提高膜表面亲水性（15 s），以增强蛋白质纯化过程。
