Porous wood ceramics for CO₂ adsorption: adsorption capacity, kinetics, isotherms and CO₂/N₂ selectivity

The objective of this study was to produce hydrophobic porous wood ceramics as adsorbents for CO₂ through the resin treatment of pine. The prepared samples underwent analysis using various methods to determine their structure and properties. An orthogonal experimental approach was employed to obtain adsorbents with optimal preparation process. The highest adsorption capacity was determined to be 1.36 mmol/g at a temperature of 30 ℃ and a CO₂ concentration of 15 vol%. The effect of temperature on the microstructure of wood ceramics was studied by characterization. Increasing temperatures adversely affected the adsorption capacity. Nevertheless, the hydrophobic nature of wood ceramics resulted in little impact of humidity on CO₂ absorption. The CO₂ adsorption kinetics of wood ceramics were analyzed using kinetic studies, which demonstrated that the kinetics can be accurately fitted by both the pseudo-first-order and Avrami models. The findings of the adsorption isotherm analysis showed that the Langmuir model fit was optimal. Following 30 cycles of adsorption-desorption in the presence of simulated gas, the CO₂ sorption capacity of the wood ceramics was maintained at over 90%. In terms of CO₂/N₂ selectivity, the wood ceramics showed a clear preference for CO₂, especially at 30 °C, where the CO₂/N₂ selectivity ratio reached 24.50.