Preparation of full-bio-based nanofiltration membranes

Abstract

Cellulose acetate (CA) as polymer, glycerol derivatives (namely triacetin, diacetin, monoacetin or glycerolformal) as solvents and 2-methyltetrahydrofuran (2-MeTHF) as co-solvent were selected as bio-based ingredients for the preparation of full-bio-based nanofiltration membranes via non-solvent induced phase separation (NIPS). Membrane performance was investigated using an aqueous rose bengal (1017Da) solution (RB/ H 2 O) as feed. Membrane morphologies were characterized using SEM (scanning electron microscopy). Both kinetic and thermodynamic aspects of the phase inversion process were studied in detail to gain more insight in the membrane formation process. When implementing a 90s evaporation step prior to coagulation, rejection increased with increasing 2-MeTHF concentration in the casting solution in the case of diacetin and triacetin solvents. In the case of monoacetin and glycerol-formal based casting solutions, evaporation had a less significant impact on RB rejection even though the same volatile co-solvent was used. The best membranes were finally obtained using diacetin as a solvent and 2-MeTHF as co-solvent with permeances ranging from 5.5 to 12.8 L/m 2 h bar for membranes with >90% RB rejections.

Assessment on Performance-properties of Asymmetric Nanofiltration Membranes from Polyethersulfone/n-Methyl-2-pyrrolidone/water Blends with Poly(vinyl pyrrolidone) as Additive

“…1. polymeric additives such as PVP [12][13][14][15] and polyethylene glycol (PEG) [16][17][18]; 2. low molecular weight chemicals, including salts such as lithium chloride (LiCl) [19][20][21] and lithium perchlorate (LiClO 4 ) [22], inorganic acids (acetic acid, phosphoric acid) [23] and organic acids (propionic acids [24]; 3. weak non-solvents such as glycerol [25], and strong non-solvent, water, as an additives in a tiny amount [26]. Nevertheless, the roles of different additives vary in different polymer /solvent/non-solvent systems.…”

Green solvents for membrane manufacture: Recent trends and perspectives

“…Figoli's group has been proposing different solvents, like Cyrene TM [19] and isosorbide [20]. Other bio-sourced solvents are methyl lactate [15], γ-valerolactone [17][18], N,N-dimethyl lactamide [21], succindiamide [22], glycerol derivatives [23], 2-methyl tetrahydrofuran (2-MeTHF). [15] Glycerol derivatives such as monoacetin, diacetin, triacetin, glycerol-formal together with 2-MeTHF as a co-solvent can be used for NF membrane fabrication.…”

“…[15] Glycerol derivatives such as monoacetin, diacetin, triacetin, glycerol-formal together with 2-MeTHF as a co-solvent can be used for NF membrane fabrication. Rasool et al [23] analyzed thermodynamic and kinetic aspects, depending on the combination of glycerol derivates and 2-MeTHF and the J o u r n a l P r e -p r o o f 7 concentration of CA, and examined the resultant morphology of membranes.…”

γ-Valerolactone as Bio-Based Solvent for Nanofiltration Membrane Preparation

“…Upon immersion, demixing occurs, resulting in the solidification of the polymer and creation of a porous structure. Controlling the process of demixing in the polymer film allows the desired membrane morphology to be fine-tuned [6][7][8][9][10][11][12][13][14][15][16][17][18]. NF membranes are asymmetric and often prepared via NIPS.…”