Enhancement of flux and solvent stability of Matrimid^® thin‐film composite membranes for organic solvent nanofiltration

Abstract

The development of high flux and solvent-stable thin-film composite (TFC) organic solvent nanofiltration (OSN) membranes was reported. A novel cross-linked polyimide substrate, consisting of a thin skin layer with minimum solvent transport resistance and a sponge-like sublayer structure that could withstand membrane compaction under highpressure was first fabricated. Then the solvent flux was significantly enhanced without compromising the solute rejection by the coupling effects of (1) the addition of triethylamine/camphorsulfonic acid into the monomer solution, and (2) the combined post-treatments of glycerol/sodium dodecyl sulphate immersion and dimethyl sulfoxide (DMSO) filtration. Finally, the long-term stability of the TFC membrane in aprotic solvents such as DMSO was improved by post-crosslink thermal annealing. The novel TFC OSN membrane developed was found to have superior rejection to tetracycline (MW: 444 g/mol) but was very permeable to alcohols such as methanol (5.12 lm 22 h 21 bar 21 ) and aprotic solvents such as dimethylformamide (3.92 lm 22 h 21 bar 21 ) and DMSO (3.34 lm 22 h 21 bar 21 ).Solutes dissolved in various organic solvents were subjected to NF experiments in stainless steel permeation cells at 10 bar and rapid stirring (700 rpm). Solvent flux was obtained from the following equationFigure 11. Effects of post-crosslink thermal annealing time on long-term separation performance and membrane stability in (a) methanol and (b) DMSO solutions.

Precise Molecular Sieving Architectures with Janus Pathways for Both Polar and Nonpolar Molecules

“…As presented in Figure S4 (Supporting Information), the CD/TMC nanofilms were in situ fabricated on the crosslinked Matrimid substrate by interfacial polymerization. Figure S5 (Supporting Information) depicts the XPS spectra of the Matrimid substrate, crosslinked Matrimid substrate, freestanding β‐CD/TMC nanofilm, and CD/TMC/Matrimid nanofilm composite membranes, while Table S2 (Supporting Information) summarizes the atomic composition calculated from XPS spectra.…”

Recovery of acetone from aqueous solution by ZIF-7/PDMS mixed matrix membranes

“…PV process has been widely used in the dehydration process of organic solvent-water mixtures 4,5 , the removal/recovery of organics from aqueous solution 6,7 and the separation of organic mixtures 8,9 . Based on solution-diffusion mechanism 3 , the PV membrane technology was developed, where the functional membrane is the key for a certain purpose of separation 10,11 . Thus, great efforts are being made in the development of such membranes with excellent performance.…”

Porous polymeric membranes with thermal and solvent resistance

“…This can be achieved by tuning the polymer solubility by polymer modification [22] or by crosslinking [23,24]. Crosslinked polyimide [25], polyetherketone [22] and polybenzimidazole [23,26] are some of the polymers used for solvent resistant membranes, and the use of hollow fibers was reported by Chung and coworkers [25]. Mix-matrix membranes for OSN have also been reported [27].…”