Chitosan Based Membranes for Separation, Pervaporation and Fuel Cell Applications: Recent Developments

Water state in chemically and physically crosslinked chitosan membranes

“…26 The absorption bands at 1635 and 1535 cm 21 in the spectrum of Ch=SA and the bands at 1641 and 1538 cm 21 in the spectrum of Ch=GA=SA derive mainly from the asymmetric and symmetric N-H deformation vibrations in protonated amines, but the initial amide-I, amide-II, and imine bands are possibly overlapped by these vibrations. The new band observed at 617 cm 21 in FTIR spectra of Ch=SA and Ch=GA=SA can be attributed to S-O bending vibration in SO 4 22 ions. 26 The spectral changes observed in the FTIR spectra of chitosan membrane treated with glutaraldehyde and=or sulfuric acid confirm the presence of GA and SA in modified chitosan membrane and indicate the formation of covalent and ionic crosslinks between chitosan and crosslinking agents, as shown in Figure 3.…”

“…To improve mechanical and chemical resistance and water permselectivity of chitosan membranes, they are modified by different methods, including blending, multilayer casting, the addition of inorganic reinforcements, and bulk and surface crosslinking. 4,5 In our previous study, we have reported the synthesis of the doubly crosslinked membranes comprising of chitosan (Ch) chemically crosslinked with glutaraldehyde (GA) and physically crosslinked with different ionic crosslinking agents, such as sodium citrate, sodium tripolyphosphate, and sulfuric acid (SA) and data on their equilibrium swelling in buffer solutions of different pH. 6 In this article, we focus on the swelling of Ch=GA=SA membranes in water and the state of water in chitosan membranes with different water content.…”

“…Chitosan is one of the most promising polymers for the preparation of membranes for various uses: for instance for pervaporation, ultrafiltration, reverse osmosis, gas separation, purification processes, or drug delivery due to its high hydrophilicity, favorable permselectivity of water, excellent chemical-resistant properties, and good film-forming character. 4,5 However, chitosan membranes highly swell in water (especially in acidic solutions) and the swollen membranes usually lose their permselectivity and mechanical stability. To improve mechanical and chemical resistance and water permselectivity of chitosan membranes, they are modified by different methods, including blending, multilayer casting, the addition of inorganic reinforcements, and bulk and surface crosslinking.…”

Recent advances in application of chitosan in fuel cells

“…The removal of proteins in chitin by heat treatment causes its deacetylation simultaneously. Free amine and hydroxyl functional groups on the chitosan's backbone enable various chemical modification of chitosan to tailor it for specific applications such as polymer electrolyte membrane for the separation of metal ions, amino acids and protein by adsorption, ultrafiltration, electro-ultrafiltration, fuel cell application and pervaporation [83]. Utilization of a chitosan biopolymer for fuel cell technologies is novel and challenging where biological products are usually considered as waste, non-hazardous, low cost and environmentally benign [84].…”

“…Chitosan-based membrane electrolyte is being studied as alternative candidate for polymer electrolyte membrane application to possibly produce economical fuel cells [5]. To achieve high efficiency, membrane must possess as mentioned before some desirable properties [83]. Modification of chitosan such as sulfonation, phosphorylation, quaternization, chemical cross-linking makes it cost-effective polymer electrolyte membrane with low methanol permeability and suitable ion conductivity especially at high temperature [3].…”