Chlorine Resistant Glutaraldehyde Crosslinked Polyelectrolyte Multilayer Membranes for Desalination

Abstract

Crosslinked polyelectrolyte multilayer membranes are synthesized with salt rejection values approaching those of commercial desalination membranes, but with increased chlorine resistance. The membranes are fabricated directly onto porous commercial substrates. Subsequent crosslinking of the polycation layers with glutaraldehyde leads to NaCl rejections of up to 97%, while the incorporation of a highly sulfonated polysulfone polyanion leads to high chlorine resistance.

Ultrathin Alginate Coatings as Selective Layers for Nanofiltration Membranes with High Performance

“…It is widely acceptedt hat cross-linkinga lways results in low membrane swelling and high ion rejection. [37,38] In this study, prolonged chemical cross-linking time led to an increasei ns alt rejection but ad ecrease in water permeation flux in the first 4h because the long cross-linking time resultsi nahigh degree of cross-linking( Figure 4b). The nanofiltrationp erformance changes only slightly with longer cross-linking time, as the reaction was mostly completed in 4h.T herefore, the optimized fabrication conditions were determined to be contra-diffusion for 5min followed by cross-linking for 4h.…”

“…It is widely accepted that cross‐linking always results in low membrane swelling and high ion rejection . In this study, prolonged chemical cross‐linking time led to an increase in salt rejection but a decrease in water permeation flux in the first 4 h because the long cross‐linking time results in a high degree of cross‐linking (Figure b).…”

Nanofiltration membranes with dually charged composite layer exhibiting super-high multivalent-salt rejection

“…Most of the commercial NF membranes synthesized via interfacial polymerization (IP) are negatively charged during normal aqueous processes. According to the Donnan exclusion, the negatively charged NF membranes tend to exhibit excellent rejection to multivalent anions (e.g., Cr 2 O 7 2 À , SO 4 2 À ) and relatively low rejection to multivalent cations (e.g., Mg 2 þ , Ca 2 þ ) [15,16]. For example, Hilal et al studied the rejection of heavy metal ions using NF270 membrane and the results showed that with all metals examined (except As (III)), when the feed pH is below the isoelectric point at pH around 4, the rejection increased.…”

Modification of poly(amide-urethane-imide) (PAUI) thin film composite reverse osmosis membrane with nano-silver particles

“…6,14 However, oxidation and fouling are currently two major obstacles for the aromatic polyamide RO membranes, which limit further application of RO membrane technology. [15][16][17][18][19][20] To address these two problems, various approaches have been performed including pretreatment of the RO feed solution, development of new membrane materials, surface modication of commercial RO membranes, [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] optimization of process conditions, and periodic cleaning. [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] Even aer long periods of such developments, however, biofouling is still the major reason for performance deterioration of conventional PA membranes including water ux decline and salt rejection reduction.…”