Novel chitosan-zeolite X composite beads prepared by phase-inversion method for CO₂ adsorptive capture

The urgent need to mitigate carbon emissions from industrial heat production has led to the exploration of novel carbon-based materials for carbon capture. Chitosan, a versatile framework, has been widely utilized for embedding many materials such as grafted graphene oxide, zeolite, and activated carbon to enhance the carbon capture capacity of diverse carbon-based materials. Remarkably, the combination of chitosan and zeolite overcomes the inherent drawbacks of powdery zeolite, resulting in improved stability and efficiency in carbon capture applications. In this study, zeolite X-chitosan composite was successfully synthesized using phase inversion method followed by solvent exchange and air drying. The synthesis procedure described in this study presents a notable advantage in terms of simplicity and ease of fabrication. The combination of SEM and XRD analyses provided evidence that the composite exhibited a uniform arrangement of zeolite within the chitosan framework and maintained the original properties of the powdered zeolite. The adsorption capacity of the composite was first investigated by varying mass ratio of zeolite per chitosan. The composite with mass ratio that gave the best adsorption capacity were then tested under various temperatures (-20 °C, 0 °C, 30 °C, and 50 °C) and pressures (1 kPa, 3 kPa, 5 kPa, and 30 kPa). The application of different adsorption models was also employed to simulate the breakthrough curves. Furthermore, the material also underwent multiple continuous adsorption-desorption cycles showing its potential for repeated rechargeability. In contrast, the synthesis and characterization of copper ion-exchanged composite yielded significant drop in adsorption capacity, likely due to the formation of ligands or the inherent reactivity of Cu²⁺ ions towards hydroxide.