Organic solvent nanofiltration with a Poly(dimethylsiloxane) membrane: Parameters affecting its sieving properties

Abstract

In this study, retention experiments were performed to characterize the variable sieving properties of a poly(dimethylsiloxane) (PDMS) membrane in relation with operating parameters. The swelling, transmembrane pressure, and temperature are all known to impact the physicochemical properties and morphology of PDMS polymer and were therefore varied for the purposes of our retention experiments which assessed them with the homologous series of polyethylene glycols (PEGs; 200-1500 g mol 21 ). The objectives were twofold-first, to evaluate the capacity to induce a targeted molecular weight cutoff (MWCO) by selecting appropriate filtration conditions and second to better understand the mechanisms involved during solvent-resistant nanofiltration with PDMS. The selected solvents or solvent/solvent mixtures used throughout this study were found to induce swelling ratios of 1.16 (ethanol/ethyl acetate: 25/75), 1.26 (ethyl acetate), 1.33 (ethyl acetate/toluene: 50/50), and 1.41 (toluene), respectively. Linear correlations were obtained between the MWCO and the swelling ratio induced by each solvent and between the MWCO and the transmembrane pressure. Pore size calculations using solvent flux and retention data confirmed the variable sieving properties of the PDMS membrane in relation to the solvent-induced swelling and applied transmembrane pressure. In addition, the study of the solutetransfer rate through several operating conditions showed that both diffusive and convective transports occurred for the PEG solutes and that their respective contributions appeared dependent on the variable pore size of the PDMS membrane.

Effect of polyacid dopants on the performance of polyaniline membranes in organic solvent nanofiltration

“…These results are in good consistence with previous studies that found swelling increased permeance as larger channels were formed in the polymer matrix [66,67]. For PANI-PAMPSA, the MWCO curves in methanol and isopropanol were similar and the MWCO value was found to be around 400 g mol -1 .…”

Crosslinked Polyvinylnorbornene‐Based Membranes as a New Class of Solvent‐Resistant Nanofiltration Membranes

“…Third, norbornenes with many different side chains are readily obtainable, being either commercially available or easily synthesized . One of the major drawbacks of polymer membranes for SRNF applications is that they tend to swell or even dissolve when used in harsh solvents, resulting in a loss of retention . Introducing crosslinks can help suppress this undesirable response …”

“…[18][19][20]23 One of the major drawbacks of polymer membranes for SRNF applications is that they tend to swell or even dissolve when used in harsh solvents, resulting in a loss of retention. 10,24,25 Introducing crosslinks can help suppress this undesirable response. 26,27 Therefore, this article focuses on the synthesis of polyvinylnorbornene (pVNB), via addition polymerization, using a catalyst that preserves the exocyclic vinyl groups [Scheme 1, (1)].…”