An investigation of carbon dioxide capture by chitin acetate/DMSO binary system

Chitin is considered to be the second most abundant naturally-occurring polysaccharide. Also, dimethyl sulfoxide (DMSO) is the second highest dielectric constant polar solvent after water. Despite the low solubility of chitin in common organic solvents, and due to its high nitrogen content, it may serve as a potential scrubbing agent “wet scrubbing” for carbon dioxide (CO₂) capturing as an alternative to monoethanolamine “renewables for renewables approach”. Briefly, a detailed investigation for the utilization of low molecular weight, chitin-acetate (CA) in DMSO for the capturing of CO₂ is reported. As carbonation process takes place, the formation of ionic alkylcarbonate was confirmed throughout spectroscopic and computational studies. Supramolecular chemisorption was proven throughout ¹H Nuclear Magnetic Resonance (¹H NMR) together with the absence of sorption of CO₂ by the monomeric repeating unit, glucosamine hydrochloride. Further, Density Functional Theory (DFT) calculations supported the formation of the CA/CO₂ adduct through a newly formed supramolecular ionic interaction and hydrogen bonding along the oligosaccharide backbone between the neighboring ammonium ion and hydroxyl functional groups. The sorption capacity was measured volumetrically within an in situ Attenuated Total Reflectance-Fourier Transform Infrared coupled (in situ ATR-FTIR) autoclave at 25.0 °C, and 4.0 bar CO₂, with a maximum sorption capacity of [Formula presented] at 10.0% (w/v).