Facile Preparation of Polyamide–Graphene Oxide Composite Membranes for Upgrading Pervaporation Desalination Performances of Hypersaline Solutions

Abstract

Polyamide (PA)–graphene oxide (GO) composite membranes were fabricated to enhance pervaporation desalination for hypersaline solutions. Thin- and stripe-structured PA layers were formed on a base GO membrane via interfacial polymerization, which enhanced the hydrophilicity of the membrane surface and provided more active sites for enrichment and permeation of water molecules. The water flux through prepared membranes could reach up to 26.7 kg m–2 h–1 with 99.99% salt rejection for 3.5 wt % NaCl aqueous solution under 70 °C. When the feed salt concentration was increased to 10 wt %, the water flux could keep a high level (ca. 24.0 kg m–2 h–1) with an ideal ion rejection (99.99%). Moreover, satisfactory performance could be preserved in a long-term test for the prepared PA–GO composite membrane. All of the results demonstrate that PA–GO composite membranes prepared in this study have great application prospects in practical pervaporation desalination of hypersaline seawater or aqueous solutions.

Fabrication and characterization of polyamide thin-film composite membrane via interfacial polycondensation for pervaporation separation of salt and arsenic from water

“…99.9% for As( v ) removal, while the permeation flux is 17.2 kg m −2 h −1 and the lower rejection is 98.7% for separating NaCl solution. Compared with the pervaporation desalination membranes of PA-GO, 21 diamines modified graphene oxide nanosheets (Ax-GO), 31 polyvinyl alcohol (PVA), 32,33 MXene, 34 zeolites, 35,36 and polysulfonamide, 37 the PIP-TMC membrane exhibits a reasonable pervaporation performance with adequate permeation flux and good rejection.…”

“…This result is well consistent with previous ndings. 21,29,30 However, the variation of permeation ux is depended on the salt concentration in the feed solution. The increasing rate in the permeation ux for separating lower NaCl concentrations is more signicant than that for rejecting higher ones.…”

“…Moreover, the different operation temperatures could increase the thermal motion of polymer chains, which extends the fractional free volume space in the PA matrix for improving the diffusion of free water molecules through the PA layer. 20,21 The ion concentration in the feed side also exerts a detrimental effect on the permeation ux of the membrane. 4 The growth of ion concentration in the feed solution leads to a decrease in the water vapor pressure and the reduction of the free water molecules and, therefore, decreasing the permeation ux.…”

“…The researchers have focused on fabricating graphene-based membrane and GO-based nanocomposite membranes for desalination. [18][19][20][21] Huang et al reported a novel GO-polyimide hollow ber membrane with a water ux of 15.6 kg m À2 h À1 and a salt rejection of 99.8% for desalination of 3.5 wt% seawater. 20 Zhao et al studied fabricating a polyamide-graphene oxide (PA-GO) composite membrane by vacuum ltration combined with IP to upgrade the pervaporation desalination performance of hypersaline solutions.…”

“…20 Zhao et al studied fabricating a polyamide-graphene oxide (PA-GO) composite membrane by vacuum ltration combined with IP to upgrade the pervaporation desalination performance of hypersaline solutions. 21 It shows that PA plays a role in stabilizing the GO layer, and the GO thickness controls the water ux and selectivity of the membrane. The fabricated membrane exhibited a high water ux of 24-26.7 kg m À2 h À1 and excellent rejection of 99.99% for the desalination of NaCl aqueous solutions (3.5-10 wt%).…”