Cellulose multilayer membranes manufacture with ionic liquid

Abstract

Membrane processes are considered energy-efficient for water desalination and treatment. However most membranes are based on polymers prepared from fossil petrochemical sources. The development of multilayer membranes for nanofiltration and ultrafiltration, with thin selective layers of naturally available cellulose has been hampered by the availability of non-aggressive solvents. We propose the manufacture of cellulose membranes based on two approaches: (i) silylation, coating from solutions in tetrahydrofuran, followed by solvent evaporation and cellulose regeneration by acid treatment; (ii) casting from solution in 1-ethyl-3-methylimidazolum acetate ([C2mim]OAc), an ionic liquid, followed by phase inversion in water. By these methods porous supports could be easily coated with semi-crystalline cellulose. The membranes were hydrophilic with contact angles as low as 22.0°, molecular weight cut-off as low as 3000 g mol-1 with corresponding water permeance of 13.8 Lm . Self-standing cellulose membranes were also manufactured without porous substrate, using only ionic liquid as green solvent. This membrane was insoluble in water, tetrahydrofuran, hexane, N,N-dimethylformamide, 1-methyl-2-pyrrolidinone and N,N-dimethylacetamide.

Sustainable Process for the Preparation of High‐Performance Thin‐Film Composite Membranes using Ionic Liquids as the Reaction Medium

“…Owing to their unique characteristics, the potential applications of ionic liquids (ILs) are investigated extensively, for example, in (bio)catalysis, polymer formation, gas separations, and energy‐related applications . In the field of membrane preparation, ILs have already been used as casting solvents for the preparation of membranes through phase inversion and as low‐concentration additives in interfacial polymerization …”

Effective Interfacially Polymerized Polyester Solvent Resistant Nanofiltration Membrane from Bioderived Materials

“…The cellulose support membrane was prepared by a modified non-solvent induced phase separation (NIPS) method reported in the literature [52,54] . A dope solution of 12.…”

Herstellung von Ultrafiltrations‐Membranen aus Lösungen von Cellulose in ionischen Flüssigkeiten

“…B. aus Polyethylenterephthalat, aufgetragen werden. Andere Gruppen haben bereits UF‐Membranen durch direkte Verarbeitung von Cellulose aus ionischen Flüssigkeiten hergestellt, jedoch handelte es sich hierbei entweder um integral‐anisotrope Membranen oder Dünnschicht‐Kompositmembranen auf einem Träger aus einem synthetischen Polymer .…”