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In this study, green bio-membranes were investigated. Alginate membranes were prepared by crosslinking of sodium alginate in calcium chloride aqueous solution. By fabricating membranes simply using three abundant cheap materials i.e. sodium alginate, salt and water, we have demonstrated membranes with acceptable performance for OSN with excellent chemical stability. Membranes prepared on three different polymeric supports (PAN, crosslinked PAN and Cellulose) showed similar performance. The alginate membranes were also spun coated on glass plate and laminated on alumina support. Great chemical stability was observed towards various solvents including dimethylformamide and dimethylsulfoxide. Characterization tests with FTIR, SEM, AFM and contact angle were carried out. Using same support, many parameters were explored such as the alginate concentration and the post treatment such as drying, crosslinking or precipitating in non-solvent. The range of the membranes permeance was 0.08–1.8 L/m2 h bar depending on conditions used. The nanofiltration experiments revealed a molecular weight cut off of about 1200 g/mol when tested with dyes such as Methyl Orange, Brilliant Blue and vitamin B12 in methanol. We initiated the preparation of fully green organic solvent nanofiltration membranes using green routes by preparing alginate selective layer on top of cellulose support. This study demonstrates that alginate membranes can be a promising candidate for green organic solvent nanofiltration. Image 1 • Nanofiltration membranes with selective crosslinked alginate biofilm were prepared on PAN or cellulose supports and tested for OSN. • DMF stable composite membranes were prepared of such crosslinked biofilms on crosslinked PAN supports. • Freestanding biofilms of alginates were prepared and mounted on porous alumina and non-woven polyester and tested for DMSO and DMF. • The membranes were resistant to harsh organic solvents and had a molecular weight cut-off of 1200 g/mol. • The entire fabrication is green, from a biopolymer dissolved at room temperature in water to crosslinking in salt/water solution. • The prepared membranes are marked as a promising beginning of green OSN. [ABSTRACT FROM AUTHOR]

Synthetic membranes with a high selectivity for demanding molecular separations and high permeance have a large potential for the reduction of energy consumption in separation processes. Herein, for the first time, the fabrication of an ultrathin layered macrocycle membrane for molecular separation in organic solvent nanofiltration using per‐6‐amino‐β‐cyclodextrin as a monomer for membrane manufacturing by interfacial polymerization is reported. Compared to a regular nonfunctionalized cyclodextrin, a higher reactivity is observed, enabling a very fast membrane formation under mild conditions. The formed membrane is composed of a layered structure of polymerized cyclodextrin, which shows high stability in different organic solvents. The membrane exhibits excellent separation performance for organic solvent nanofiltration, both with nonpolar and polar solvents. Most importantly, this new membrane type can discriminate between molecules with nearly identical molecular weights but different shapes. The unmatched high permeance and shape selectivity of the membranes can be attributed to the ultralow thickness, controlled microporosity, as well as the layered macrocycle structure, which makes the membranes promising for high‐performance molecular separation in the chemical and biochemistry industry. [ABSTRACT FROM AUTHOR]

Abstract In this work, a novel thin-film composite membrane composed of a polyester film on a cellulose support was successfully synthesised. The polyester film was formed from the interfacial reaction between catechin, a bio-derived poly-phenol, and terephthaloyl chloride (TPC). The cellulose support was prepared by non-solvent induced phase separation from a 12.5 wt% cellulose dope solution in 1-ethyl-3-methylimidazolium acetate ionic liquid. The composite membrane was characterised by Fourier Transform Infrared and X-Ray Photoelectron Spectroscopy to confirm the success of the interfacial reaction. Scanning electron and atomic force microscopy were used to study the surface morphology and roughness of the membranes produced. The performance of the composite membranes in terms of solvent permeance and solute rejection was investigated by studying the rejection of a broad range of different molecular weight dyes in dimethylformamide (DMF) solution. The membranes showed an average DMF permeance of 1.2 L m−2 h−1 bar−1 with a molecular weight cut-off of around 500 g mol−1. The membrane was stable in DMF over 30 days with no significant change in performance. The membrane has potential application in the food and pharmaceutical industries. Highlights • A catechin/cellulose composite nanofiltration membrane has been developed. • The membrane made from bio-derived materials is stable in dimethylformamide. • The cross-linked catechin selective layer exhibits high DMF fluxes. • The membrane rejects molecules with a molecular weight higher 500 g mol−1. [ABSTRACT FROM AUTHOR]