Jiménez-Robles Ramón, Moreno-Torralbo Beatriz María, Badia Jose David, Martínez-Soria Vicente, Izquierdo Marta
Research Group in Environmental Engineering (GI2AM), Department of Chemical Engineering, School of Engineering, University of Valencia, Avda. Universitat s/n, 46100 Burjassot, Spain.
Research Group in Materials Technology and Sustainability (MATS), Department of Chemical Engineering, School of Engineering, University of Valencia, Avda. Universitat s/n, 46100 Burjassot, Spain.
Membranes (Basel). 2022 Apr 15;12(4):426. doi: 10.3390/membranes12040426.
A three-step surface modification consisting of activation with NaOH, functionalisation with a silica precursor and organofluorosilane mixture (FSiT), and curing was applied to a poly(vinylidene fluoride) (PVDF) membrane for the recovery of dissolved methane (D-CH4) from aqueous streams. Based on the results of a statistical experimental design, the main variables affecting the water contact angle (WCA) were the NaOH concentration and the FSiT ratio and concentration used. The maximum WCA of the modified PVDF (mPVDFmax) was >140° at a NaOH concentration of 5%, an FSiT ratio of 0.55 and an FSiT concentration of 7.2%. The presence of clusters and a lower surface porosity of mPVDF was detected by FESEM analysis. In long-term stability tests with deionised water at 21 L h−1, the WCA of the mPVDF decreased rapidly to around 105°, similar to that of pristine nmPVDF. In contrast, the WCA of the mPVDF was always higher than that of nmPVDF in long-term operation with an anaerobic effluent at 3.5 L h−1 and showed greater mechanical stability, since water breakthrough was detected only with the nmPVDF membrane. D-CH4 degassing tests showed that the increase in hydrophobicity induced by the modification procedure increased the D-CH4 removal efficiency but seemed to promote fouling.
采用三步表面改性方法，包括用氢氧化钠活化、用二氧化硅前驱体和有机氟硅烷混合物（FSiT）进行功能化以及固化，对聚偏氟乙烯（PVDF）膜进行处理，以从水流中回收溶解的甲烷（D-CH4）。基于统计实验设计的结果，影响水接触角（WCA）的主要变量是氢氧化钠浓度以及所使用的FSiT比例和浓度。在氢氧化钠浓度为5%、FSiT比例为0.55且FSiT浓度为7.2%时，改性PVDF（mPVDFmax）的最大WCA>140°。通过场发射扫描电子显微镜（FESEM）分析检测到mPVDF存在团聚体且表面孔隙率较低。在21 L h−1的去离子水长期稳定性测试中，mPVDF的WCA迅速降至约105°，与原始纳米PVDF的WCA相似。相比之下，在3.5 L h−1的厌氧流出物长期运行中，mPVDF的WCA始终高于纳米PVDF，并且表现出更高的机械稳定性，因为仅在纳米PVDF膜上检测到水穿透。D-CH4脱气测试表明，改性过程引起的疏水性增加提高了D-CH4的去除效率，但似乎促进了污垢形成。
