Novel Dimensionally Controlled Nanopore Forming Template in Forward Osmosis Membranes

Abstract

To lower the unfavorable internal concentration polarization effect in forward osmosis (FO) membranes, support layers of highly porous interconnected structures with specifically large surface-to-volume ratios are indispensable. Herein, zinc oxide (ZnO) has been introduced as a new template to manipulate the porous structure of poly(ether sulfone) (PES) support layer. The ZnO can be readily synthesized as desired in different dimensionally controlled nanostructures. The performance of the FO membrane was initially ameliorated in terms of permeability and selectivity through simple incorporation of ZnO nanostructures in the PES support layer. The PES support layer was blended with appropriate amounts of ZnO nanostructures, casted on a glass plate, and subsequently acid washed to leach out the embedded ZnO nanostructures. Different nanoporous structures were achieved when ZnO of different nanostructures was used to modify the PES support layer. The experimental results indicated that the permeability of FO membranes could be simply improved by incorporation of ZnO nanostructures in PES support layer. Higher hydrophilicity and formation of suitable internal pores were mainly responsible for such observation. Although surface hydrophilicity of the support layers was reduced after being acid washed, water permeation through the membrane was intensified due to the formation of interconnected porous structure.

Ultrathin water-stable metal-organic framework membranes for ion separation

“…The system temperature was maintained at 25° ± 0.5°C throughout the experiment. The water flux (J w ; mol m −2 h −1 ) and salt ion permeation rate (J s ; mol m −2 hour −1 ) of Al-MOF membranes were calculated as follows (29)…”

Nanocomposite Membranes for Liquid and Gas Separations from the Perspective of Nanostructure Dimensions

“…Lu et al compared the templated porous structure of forward osmosis (FO) polysulfone (PSf) substrate formed upon the washing of 0D LDH spherule and 3D LDH flower from the nanocomposite membrane [ 137 ]. Similarly, Rastgar et al introduced 0D ZnO nanoparticle and 2D ZnO nanorods within PES FO substrate to create secondary pores as shown in Figure 4 b upon the washing-off of these nanostructures [ 134 ]. 0D spherical nanotemplate with particle size <100 nm cannot effectively interconnect the isolated pore space.…”

“… ( a ) Schematic illustration of solvent molecule transport pathway in small-flake graphene oxide (GO) and large-flake GO with different lateral [ 133 ], cross-sectional images of polyethersulfone (PES) support layers templated with ( b ) ZnO nanoparticles and ( c ) ZnO nanorods [ 134 ]. …”

Durability and Recoverability of Soft Lithographically Patterned Hydrogel Molds for the Formation of Phase Separation Membranes

“…The average pore size of each membrane was calculated based on water filtration velocity method [14]…”

“…As permeation characteristics of membranes improved, the rejection capability is reduced [10]. To improve membrane performance and lower the membrane fouling, chemical treatments [11,12] or physical modifications [13,14] have commonly been attempted by either coating the membrane surface with hydrophilic/hydrophobic layers or modifying the membrane matrix by blending with additives (such as nanofillers, surfactants, and polymeric additives). However, these approaches suffer from many disadvantages which restrict their extended applications in practice.…”