Zaidi Syed Javaid, Fadhillah Farid, Saleem Haleema, Hawari Alaa, Benamor Abdelbaki
Center for Advanced Materials, Qatar University, P.O. Box 2713 Doha, Qatar.
Chemical Engineering Department, Al Imam Mohammad Ibn Saud Islamic University, P.O. Box 5701 Riyadh, Saudi Arabia.
Materials (Basel). 2019 Nov 19;12(22):3803. doi: 10.3390/ma12223803.
This study validates, for the first time, the effectiveness of two nanoclays, that is, cloisite (CS)-15A and montmorillonite (MNT) at the polyamide (PA) active layer in the reverse osmosis (RO) membrane. Cloisite-15A is natural montmorillonite modified with dimethyl dihydrogenated tallow quaternary ammonium salt. Thin-film composite (TFC) membranes were fabricated by the interfacial polymerization (IP) process between the trimesoylchloride (TMC)-n-hexane solution and m-phenylenediamine (MPD)-aqueous solution; the IP process took place on a polysulfone support sheet. The two types of nanoparticles were added in various weight ratios (0.005 wt.%-0.04 wt.%) in the n-hexane solution of TMC. Different characterizations like X-ray diffraction (XRD), contact angle, transmission electron microscopy (TEM), and membrane performance tests were performed to analyse the membrane properties. Both XRD and TEM studies proved that the two nanoclays are successfully anchored at the different sites of the PA layer. CS-15A could accelerate the water flux from 15 to 18.65 L/m·h with NaCl rejection enhancement from 72% to 80%, relative to the control membrane. Conversely, MNT also enhanced the flux from 15 to 40 L/m·h, but NaCl rejection reduced from 70% to 23%. The mechanism of water uptake in nanoclays was also discussed. The results pave the way for a complete future study, in which these phenomena should be studied in great detail.
本研究首次验证了两种纳米黏土，即 Cloisite（CS）-15A 和蒙脱石（MNT）在反渗透（RO）膜聚酰胺（PA）活性层中的有效性。Cloisite-15A 是用二甲基二氢化牛脂季铵盐改性的天然蒙脱石。通过均苯三甲酰氯（TMC）-正己烷溶液与间苯二胺（MPD）-水溶液之间的界面聚合（IP）工艺制备了复合薄膜（TFC）膜；IP 工艺在聚砜支撑片上进行。将这两种类型的纳米颗粒以不同的重量比（0.005 wt.% - 0.04 wt.%）添加到 TMC 的正己烷溶液中。进行了不同的表征，如 X 射线衍射（XRD）、接触角、透射电子显微镜（TEM）以及膜性能测试，以分析膜的性能。XRD 和 TEM 研究均证明这两种纳米黏土成功地锚定在 PA 层的不同位置。相对于对照膜，CS-15A 可使水通量从 15 升/平方米·小时提高到 18.65 升/平方米·小时，同时 NaCl 截留率从 72%提高到 80%。相反，MNT 也将通量从 15 升/平方米·小时提高到 40 升/平方米·小时，但 NaCl 截留率从 70%降至 23%。还讨论了纳米黏土的吸水机制。这些结果为未来全面的研究铺平了道路，在该研究中应详细研究这些现象。
