Qiao Liu,Xiaotian Xia,Nong Xu,Qing Wang,Long Fan,Yinhua Wan
Achieving uniform dispersion of nanoparticles within the polymer membrane matrix while simultaneously constructing continuous selective permeation channels has always been key to preparing high-performance mixed matrix membranes. In this study, we employ glycerol (Gol) molecules as “bridges” to harness the hydrogen bonding interactions between Gol, TpHz, and poly(vinyl alcohol) (PVA) molecules. This approach facilitates the nanoscale dispersion of TpHz nanoparticles within the PVA membrane, establishing continuous channels that selectively permit the permeation of water molecules. By incorporating just 0.3 wt % of TpHz nanoparticles, the resultant PVA/Gol/TpHz membrane demonstrates a mechanism that favors the selective adsorption, dissolution, and rapid diffusion of water molecules from the feed, thereby reducing the activation energy required for their permeation through the membrane. The prepared PVA/Gol/TpHz membrane with pure water contact angle of only 19.6° has total flux and separation factor of 134 L m −2 h −1 and 705, which were 3.4 and 3.5 times higher than those of the pure PVA membrane, respectively. It broke the “trade-off” effect of traditional PVA membrane. Moreover, the tensile strength and thermal decomposition temperature of the PVA/Gol/TpHz membrane were increased from 130.31 MPa to 120.90 °C to 442.05 MPa and 246.8 °C, respectively. The membrane structure and separation performances remained stable during the 80-h pervaporation test, which suggests potential for industrial applications.
Qiao Liu,Bingshan Tao,Nong Xu,Qing Wang,Long Fan,Yinhua Wan
Two-dimensional (2D) MXene membranes have attracted significant attention for their high efficiency in molecule separation. In this study, an interlaminar in-situ growth strategy was employed to incorporate TpHz into the adjacent layer space between the Ti 3 C 2 T x nanosheets of the 2D Ti 3 C 2 T x membrane. In the typical synthesis process, due to the hydrophilic nature of Ti 3 C 2 T x , the aqueous phase monomer diffuses through the Ti 3 C 2 T x layers, reacts with the organic phase monomer in the top-surface and generate TpHz in-situ . Gradually, TpHz grows into the interlaminar space of the Ti 3 C 2 T x nanosheets and the interior of the membrane. Owing to the charge transfer interaction existing between the TpHz and Ti 3 C 2 T x nanosheets, the adjacent layer space between the Ti 3 C 2 T x nanosheets is broadened without compromising the structural stability of the composite membranes. Accordingly, the TpHz/Ti 3 C 2 T x composite membrane (TTCM) exhibit highly efficient molecule sieving properties and excellent structural stability, with a high pure water permeance of 986.5 L m −2 h −1 ·bar −1 and a rejection rate of over 95.0 % for anionic organic dyes. Additionally, the TpHz/Ti 3 C 2 T x layer, with the thickness of only 160 nm, in the TTCM could withstand 80 h of water and solution flushing at a flow rate of 40 L min −1 in cross-flow filtration tests, maintaining stable solution permeance of 448 L m −2 h −1 ·bar −1 and rejection rates of 95.3 % demonstrating its high structural stability and potential for expanding industrial application in molecule sieving processes.
Linhan Ni,Ke Chen,Jia Xie,Qin Li,Junwen Qi,Chaohai Wang,Xiuyun Sun,Jiansheng Li
The performance of polyamide-based thin film nanocomposite (TFN) membranes essentially hinges on nanofillers, polyamide (PA) selective layer and the interaction between them. Incorporating synthesized nanofillers into PA layer has attracted significant attention, yet this fabrication route suffers from the unsatisfactory interfacial compatibility between nanofillers and polymer matrix . As pure organic nanofillers, covalent organic frameworks (COFs), however, are constrained by their large pore size and demanding synthesis condition. Herein, COF TpHz was synchronously synthesized with the interfacial polymerization (IP) process of PA layer to fabricate COFs incorporated TFN membranes. The addition of TpHz was optimized by controlling the content of monomers and the resultant TFN membrane achieved enhanced nanofiltration performance thanks to the in-situ synthesized TpHz. At ambient temperature, the prepared membrane showed higher permeance (23.6 L m 2 h −1 bar −1 ) and salt rejection (96.9%) than the pristine thin film composite (TFC) membrane under 4 bar toward 1 g/L Na 2 SO 4 solution, corresponding to an improvement of 44.8% and 3.2% of permeance and rejection, respectively. Meanwhile, the anti-fouling property of the prepared membrane was also improved compared with TFC membrane. This in-situ interfacial polymerization (IIP) strategy proposes a new idea for the preparation of COFs incorporated TFN membranes, revealing its promising prospect in desalination.
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