Chitosan-based zwitterionic membrane as well as preparation method and application thereof

Abstract

The invention discloses a chitosan-based zwitterionic membrane as well as a preparation method and application thereof. The film has an interpenetrating network structure composed of a zwitterionic chitosan derivative chemical cross-linked network and a polyvinyl alcohol physical cross-linked network. The zwitterionic chitosan derivative is prepared by carrying out gradient quaternization on a chitosan main chain, carrying out selective oxidation to introduce carboxyl and carrying out secondary quaternization to introduce additional cationic groups. The preparation method comprises the following steps: preparing a chitosan quaternary ammonium salt precursor, respectively carrying out oxidation and secondary quaternization modification, mixing the two modified products, carrying out chemical crosslinking, and carrying out physical crosslinking with polyvinyl alcohol to form the membrane. The film has high ionic conductivity (the room-temperature OH <-> conductivity is 20-150 mS cm <-1 >), high mechanical strength (the elongation at break gt, 120%) and good chemical stability, is low in raw material cost and simple in process, and has wide application prospects in the fields of carbon dioxide electrocatalytic reduction, flow batteries and the like.

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