The effects of a co-solvent on fabrication of cellulose acetate membranes from solutions in 1-ethyl-3-methylimidazolium acetate

Abstract

Ionic liquids have been considered green solvents for membrane fabrication. However, the high viscosity of their polymer solutions hinders the formation of membranes with strong mechanical properties. In this study, acetone was explored as a co-solvent with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) to dissolve cellulose acetate. The effects of acetone on the thermodynamic and kinetic aspects of the polymer solutions were studied and the physicochemical properties and separation capability of their resultant membranes were analyzed. The Hansen solubility parameters of [EMIM]OAc were measured by the software HSPiP and these data demonstrated that acetone was a suitable co-solvent to increase the solubility of cellulose acetate. The Gibbs free energy of mixing ΔG m was estimated to determine the proper composition of the polymer solution with better solubility. The study of the kinetics of phase separation showed that the demixing rate of the CA polymer solution in acetone and [EMIM]OAc was higher than that for solutions in [EMIM]OAc only. The membranes prepared from the former solution had higher water permeance and better mechanical stability than those prepared from the later solution. Adding acetone as a co-solvent opened the opportunity of fabricating membranes with higher polymer concentrations for higher separation capability and better mechanical properties.

How Do Polyethylene Glycol and Poly(sulfobetaine) Hydrogel Layers on Ultrafiltration Membranes Minimize Fouling and Stay Stable in Cleaning Chemicals?

“…Poly(ethylene glycol) and poly(ethylene oxide) with different molecular weights were used for solute rejection tests. Detailed calculations for molecular weight cut-off (MWCO) and pore size can be found elsewhere 51 . Figure 3.…”

Two‐stage phase separation of cellulose acetate membranes modified with plasma‐treated natural zeolite: Response surface modeling

“…Any membrane sample was tested for at least three times, and the average values were reported. Water flux (L·m −2 ·h −1 ) was calculated using Equation 3:…”

“…Since the first introduction of cellulose acetate (CA) membranes for seawater desalination, 1,2 CA-derived materials have been widely utilized for membrane-based applications because of their high biocompatibility, high fouling resistance, excellent hydrophilicity, long life time, and low cost. 3 Nowadays, CA-based microfiltration (MF) membranes have been attracted attentions for different applications such as fat and microbial removal in the dairy industry, food and beverage and plant extracts, biomedical processes, and wastewater treatment. [4][5][6] CA membranes are commonly prepared by a phaseinversion process, in which the precipitation of the membrane forming polymer from a layer of the casting solution is occurred by controlling the process condition.…”

Polyethersulfone flat sheet and hollow fiber membranes from solutions in ionic liquids

“…The use of ionic liquids for membrane manufacture is still relatively restricted. Examples are: 1ethyl-3-methylimidazolium acetate [EMIM]OAc for polybenzimidazole [17], cellulose acetate (CA) [18], cellulose [19], and polyacrylonitrile [20]; 1-ethyl (or butyl)-3methylimidazolium thiocyanate ( [EMIM]SCN and [BMIM]SCN) for CA [21,22]. Recently we reported the fabrication of PES flat-sheet membranes using 1-ethyl-3-methylimidazolium diethylphosphate ( [EMIM]DEP) [23].…”