Root-like polyamide membranes with fast water transport for high-performance nanofiltration

Abstract

The synthetic membranes universally exhibit a pernicious trade-off effect, on which there exists an upper bound between permeability and selectivity. Tremendous efforts are made to design crumpled membranes to further...

Alginate Hydrogel Assisted Controllable Interfacial Polymerization for High-Performance Nanofiltration Membranes

“…The separation performance for different types of mono/divalent salts is basically in line with the characteristics of nanofiltration (Figure 6c), which exhibits a rejection order: Na 2 SO 4 (97.2%) > MgSO 4 (82.7%) > CaCl 2 (15.8%) ≈ NaCl (15.2%). It also has certain advantages in breaking the trade-off effect compared with other high-performance nanofiltration membranes recently reported in the literature [14,19,24,27,28,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. The collected water permeance and water/Na 2 SO 4 permselectivity A/B are shown in Figure 6d and Table 2.…”

“…Although the Cd(OH) 2 nanostrands layer can be removed by hydrochloric acid after interfacial polymerization, it is still uneconomic and not environmentally friendly for water purification [22]. After that, inorganic nanomaterials [23][24][25], metal-organic framework nanoparticles [26,27], and cellulose nanocrystals [28] were demonstrated to construct an interlayer to further modify the porous substrate and suppress the diffusion of anime monomers. However, it is still a big challenge to evenly distribute or coat the nanowires or nanoparticles on a porous substrate with a large area or in a consecutive way.…”

Ultrathin Membranes for Separations: A New Era Driven by Advanced Nanotechnology

“…On the one hand, some additives are introduced into the aqueous phase of an IP system to subtly manipulate the amine diffusion rate from the solution toward the reaction zone at the interface. [117][118][119][120] Excitingly, by virtue of their chemical or physical interaction at a suitable density with amine monomers or incorporation into PA layer, reduced thickness and interesting micro-structures may be achieved simultaneously. Ultrathin Turing structure was discovered by Tan et al after adding polyvinyl alcohol (PVA) into the aqueous solution, which was believed to regulate the polymerization process (Figure 6a) and water permeance of ≈25 L m −2 h −1 bar −1 was reached at the Na 2 SO 4 rejection of 99.6%.…”

“…On the one hand, some additives are introduced into the aqueous phase of an IP system to subtly manipulate the amine diffusion rate from the solution toward the reaction zone at the interface. [ 117–120 ] Excitingly, by virtue of their chemical or physical interaction at a suitable density with amine monomers or incorporation into PA layer, reduced thickness and interesting micro‐structures may be achieved simultaneously. Ultrathin Turing structure was discovered by Tan et al.…”

“…[ 4,42,43,46,77,92,124,131,174,247–249 ]; b) NaCl rejection versus water permeance of state‐of‐the‐art commercial RO membranes; c) a plot of Na 2 SO 4 rejection versus water permeance of state‐of‐the‐art sub‐50 nm NF membranes; data a–w are taken from refs. [ 29,40,45,49,65,104,105,118–123,126–129,133,137,174,213,250–254 ]; d) MgSO 4 rejection versus water permeance of state‐of‐the‐art commercial NF membranes.…”