The effect of Schiff base network on the separation performance of thin film nanocomposite forward osmosis membranes

Abstract

In this study, Schiff base network-1 (SNW-1) nanoparticles, which are covalent organic frameworks (COFs), were used as fillers in the polyamide (PA) active layer to elevate the performance of thin-film nanocomposite (TFN) forward osmosis (FO) membranes. The TFN membranes were prepared by interfacial polymerization (IP) of m-phenylenediamine (MPD) and trimesoyl chloride (TMC), and the SNW-1 nanoparticles were dispersed in the MPD aqueous solution at various concentrations. The secondary amine groups of SNW-1 nanoparticles reacted with the acyl chloride groups of TMC during the IP reaction to form strong covalent/amide bonds, which facilitated better interface integration of SNW-1 nanoparticles in the PA layer. Additionally, the incorporation of amine-rich SNW-1 nanoparticles into the TFN membranes improved their surface hydrophilicity, and the porous structure of SNW-1 nanoparticles offered additional channels for transport of water molecules. The TFN0.005 membrane with a SNW-1 nanoparticle loading of 0.005 wt.% demonstrated a higher water flux than that of pristine TFC membrane in both AL-FS (12.0 vs. 9.3 Lm -2 h -1 ) and AL-DS (25.2 vs. 19.4 Lm -2 h -1 ) orientations when they were tested with deionized water and 0.5 M NaCl as feed and draw solution, respectively.

Enhancing Chlorine Resistance and Water Permeability during Forward Osmosis Separation Using Superhydrophilic Materials with Conjugated Systems

“…These ASMs remarkably improve both the chlorine resistance and water permeability of membrane in FO separation processes (Figure ). The ASM-3 modified membrane exhibits the best water recovery efficiency and chlorine resistance among the membranes explored in this study, and surpasses other recently proposed PA membranes in separation performance. ,,,− The large conjugated system and ionizable groups in the ASM-3 are key to eliminate the adverse effects of free chlorine and optimize FO water treatment.…”

Influence of graphene oxide lateral size on the properties and performances of forward osmosis membrane

“…The porous PSf substrates were prepared using the phase inversion technique as described elsewhere [36]. Briefly, a homogenous polymer solution was prepared by dissolving 12 wt.…”

Recent advances in nanomaterial-modified polyamide thin-film composite membranes for forward osmosis processes

“…In recent years, porous coordination polymer (PCP), a new kind of nanomaterial, has been used to develop nanocomposite membranes for various applications like gas separation, liquid separation and catalysis [138][139][140][141][142][143][144]. Metal-organic frameworks (MOFs) and covalentorganic frameworks (COFs) are two or three-dimensional PCPs, which have been used to improve the structure and performance of FO nanocomposite membranes [85,86,88,145,146]. MOFs are porous inorganic/organic hybrid nanostructure material comprising of metal ions coordinated to organic ligands as linkers [147,148]; whereas, COFs are organic nanoporous solids with extended structures of light elements comprising functional groups that are linked by strong covalent bonds [149].…”

“…The first study that investigated the effect of COF nanofillers, Schiff base network-1 (SNW-1), on the performance of PA TFN membrane for FO process was conducted by Akther et al [88]. The hydrophilic SNW-1 nanoparticles reacted with the acyl chloride groups of TMC during the IP reaction to form strong tertiary amide bonds, which aided the stability of SNW-1 nanoparticles in the PA layer.…”