Nano‐Modification of the Polyvinyl Alcohol/Organic Acid‐Modified Polyvinylidene Fluoride Thin‐Film Composite Membrane and Its Application in the Nanofiltration Process

Abstract

In this study, a novel thin‐film nanocomposite (TFN) membrane is developed consisting of a cross‐linked nano‐modified polyvinyl alcohol (PVA) selective layer on an organic acid‐modified polyvinylidene fluoride (PVDF) membrane. The nano‐modification of the PVA layer is performed via incorporating different amounts of the amine‐functionalized multiwalled carbon nanotubes (MWCNTs‐NH2) into the PVA matrix. The effect of citric acid on the chemical structure and morphology of the PVDF support is also investigated. The performance of the resultant membranes in the nanofiltration (NF) of MgSO4 and acid yellow‐17 aqueous solutions is also studied. The results indicate that the modification of the support with 0.5 wt% of citric acid increased the water permeance from 1.59 L m−2 h−1 bar−1 (LMH/bar) for PVA/PVDF to 4.49 LMH/bar for the PVA/modified PVDF membrane. Furthermore, the optimum value of MWCNT‐NH2 (0.6 wt%) increases the permeance of the resultant TFN membrane to 4.94 LMH/bar while maintaining a high rejection. Interestingly, the incorporation of MWCNT‐NH2 into the PVA layer and citric acid into the PVDF solution results in a membrane with the highest permeance of 6 LMH/bar.

Incorporation of amino‐functionalized ZnO nanoparticles into polycarbonate/polyvinyl alcohol thin‐film membrane for enhanced water treatment

“…[ 7 ] Some studies showed that the dip‐coating technique is a useful and practical method, which can provide higher chemical and chlorine stability compared to interfacial polymerization method. [ 8–10 ]…”

“…The results showed that the PVA/TiO 2 coated PVDF membrane had lower irreversible fouling parameters compared to neat PVDF membrane. Eskandary et al [ 8 ] prepared PVA/amine‐functionalized multi‐walled carbon nanotubes (MWCNT‐NH2) as a top layer for PVDF support membranes for dye removal. At the MWCNT‐NH2 optimum value (0.6 wt%) the TFN membrane permeation increased while high rejection was maintained.…”

“…[7] Some studies showed that the dip-coating technique is a useful and practical method, which can provide higher chemical and chlorine stability compared to interfacial polymerization method. [8][9][10] Due to the intrinsic hydrophilicity of polyvinyl alcohol (PVA) as well as its mechanical, thermal, and chemical stability, PVA is a good candidate for the top layer in the preparation of TFC membranes. [11,12] Nanoparticles can be incorporated into PVA top layers for thinfilm nanocomposite (TFN) membranes.…”