Separation of alcohol–water mixture by pervaporation through a novel natural polymer blend membrane–chitosan/silk fibroin blend membrane

Abstract

A novel natural polymer blend membrane, namely chitosan/silk fibroin blend membrane, was prepared. The selective solubility and the pervaporation properties of alcohol-water mixture were studied. The results showed that the membrane was water selective and the separation factor of ethanol-water mixture could be improved compared to pure chitosan membrane, when silk fibroin content in blend membrane was no more than 40 wt %. The blend membrane exhibited a best performance, (i.e., the water in permeate was large than 99 wt % when silk content was 20 wt % and the crosslinking agent-glutaraldehyde content was 0.5 mol %). The mechanism of improvement on pervaporation properties was explained by reducing the free volume and freeing hydrophilic groups of chitosan because of the strong intermolecular hydrogen bond forming between chitosan and silk fibroin in blend membrane. In addition, the influence of operation temperature and feed concentration as well as the pervaporation properties of isopropanol-water mixture were also studied.

Protein adsorption and separation with chitosan-based amphoteric membranes

“…The absolute numbers of amino groups in the CS/CMCS blend membranes decreases with the increase in CMCS content, so it seems abnormal for the increase of the ovalbumin adsorption capacity with CMCS content. The same phenomenon was found in the CS/CMC blend membrane [28] and in other cases [46,47], which suggests an increase in the free amino groups. At pH ¼ 5.2, the amino groups in CS are less protonized, so there is still strong hydrogen bonding between the amino groups and the hydroxyl groups within CS.…”

Tuning Chemical and Physical Cross-Links in Silk Electrogels for Morphological Analysis and Mechanical Reinforcement

“…Covalent modification and crosslinking of silk fibroin with glutaraldehyde have been demonstrated previously. 25,26 A 20 % w/w glutaraldehyde solution was added to each of the three silk hydrogels, giving a final crosslinker to silk weight ratio in the range of about 0.2:1. 27 The crosslinking reaction was allowed to proceed at room temperature for 20 minutes.…”

Supported silk fibroin/poly(vinyl alcohol) membrane blends: Structure, properties, and ethanol dehydration by pervaporation

“…Several biopolymers can be used for the development of hydrophilic membranes and silk fibroin has shown to be a viable option, improving the water permeation in a chitosan/fibroin blend . Silk fibroin is a natural protein obtained from the cocoons of the silkworm Bombyx mori and it is widely used as a highly valuable textile fiber.…”

“…The crosslinking occurs mainly through the hydroxyl functional groups, exposing other hydrophilic groups. This explains why fibroin membranes have shown to be water selective, despite the fact that their structure is mostly hydrophobic .…”

“…Studies have been carried out with silk protein sericin for the development of water‐selective membrane blends crosslinked with DMU, which have led to a high water selectivity in the pervaporation process . Silk fibroin has also been employed in hydrophilic membranes through blending with chitosan and cellulose , which present relatively high water selectivity. However, in the literature there is a lack of studies relating the water selectivity of protein‐based membrane blends with the mechanical and morphological properties.…”