Preparation and characterization of polymeric Schiff's base for carbon dioxide adsorption

The increasing concentration of carbon dioxide in the atmosphere poses significant challenges for its capture. Carbon dioxide emissions contribute substantially to the greenhouse effect, leading to detrimental effects on ecosystems and drastic climate change. In this study, we synthesized two polymeric Schiff's bases, by condensing partially oxidized polyvinyl alcohol (OPVA) with 1,2-ethylene diamine and 1,6-hexamethylene diamine. The formed Schiff's bases are abbreviated OPVA-ED and OPVA-HMD, respectively. OPVA was initially prepared through oxidation of polyvinyl alcohol using potassium permanganate. We investigated the potential of these Schiff's bases for CO2 adsorption. Structural elucidation of the Schiff's bases was conducted using Fourier transform infrared (FTIR), H-1 nuclear magnetic resonance (NMR), and X-ray diffraction (XRD) techniques. Thermogravimetric analysis (TGA) and gas adsorption experiments were employed to determine their physical properties. The capture and release of CO2 were evaluated at a temperature of 25 degrees C using these Schiff's bases as adsorbents. The findings indicate that OPVA-ED exhibits superior CO2 adsorption capacity compared to OPVA-HMD, with adsorption capacities of 0.22 mmol/g and 0.18 mmol/g at 15 bars for OPVA-ED and OPVA-HMD, respectively.