Feasible Preparation of a Thin‐Film Composite Nanofiltration (TFC NF) Membrane with Enhanced Skin–Substrate Adhesion and Compaction Resistance: In Situ Construction of Rigid–Flexible Polymer Composited Microspheres (CPs) in the Casting Solution

Abstract

Novel microspheres (CPs) composited by rigid and flexible polymers are synthesized and embedded in the supporting membranes to enhance both the skin–substrate adhesion and compaction resistance of the thin‐film composite (TFC) nanofiltration membranes. The CPs are in situ formed in the casting solution after the rigid poly(p‐phenylene terephthamide) (PPTA) is produced in the flexible poly(m‐phenylene isophthalamide) (PMIA) solution. Then the PPTA/PMIA in situ blending membranes are prepared by using the NIPs method, and the TFC NF membranes are fabricated via interfacial polymerization on them. The CPs are characterized via polarizing microscopy and TEM. The surface morphology and chemical composition of the blended membranes are characterized by using FESEM, AFM, FTIR, and WCA, respectively. As the results show, the supporting membrane with higher PPTA content exhibits higher permeability, thermal stability, and compaction resistance. Moreover, the adhesion strength between the TFC functional layer and the supporting membrane is improved significantly. It is proposed that this improvement can be attributed to the CPs that are exposed on the top surface of the supporting membrane, which leads to a great enhancement because of the anchoring effect between the functional layer and the CPs.

Polyethyleneimine‐Mediated Polyamide Composite Membrane with High Perm‐Selectivity for Forward Osmosis

“…This could be attributed to the PEI interlayer increasing the surface hydrophilicity, leading to more MPD monomers uniformly distributed on the substrate and decreasing the migration rate of diamine monomer to the organic phase. [ 39,40 ] Consequently, a thin, smooth, and defect‐free PA layer was formed due to the uniform distribution and controllable release of MPD monomer as well as the extra cross‐linking between PEI and TMC. [ 41 ] Such membrane structure will simultaneously contribute to the enhanced separation performance and antifouling capacity.…”

Fabrication and performance of the ammonium molybdophosphate/polysulfone mixed matrix membranes for rubidium adsorption in aqueous solution

“…However, the indisputable fact is that the granular composite adsorbents have the problems of high intraparticle diffusion resistance, and the adsorption efficiency need to be optimized furtherly. [25][26][27] In recent decades, pressure-driven membrane separation technology has been widely used in desalination, 28,29 removal of pollutants in water, 30 and separation or removal of metal ions. [31][32][33][34] For example, to separate cesium and rubidium from other alkaline metal ions in aqueous solutions, Jia et al 35 developed a novel adsorption membrane by in-situ preparation of Prussian blue (PB) nano-layer on porous polyacrylonitrile (PAN) membranes, results indicated that the Cs + maximum adsorption capacity attained 0.714 mmol g À1 , and the selectivity factors of Cs + versus Li + , K + , and Na + were 41.76, 35.50, and 23.67, respectively.…”