Sisal fiber-based solid amine adsorbent and its kinetic adsorption behaviors for CO2

Abstract

A solid amine adsorbent based on sisal fiber was prepared by grafting copolymerization, in which amine was covalently bound onto sisal fiber. In the absence of moisture, the adsorption capacity of the triethylenetetramine-aminated solid amine fiber (SF-AM-TETA) for CO₂ could be 0.75 mmol g⁻¹ through physical adsorption of pores inherited from the bio-texture of sisal fibers. The adsorption capacity of SF-AM-TETA was greatly promoted by the presence of moisture, which could reach 4.20 mmol g⁻¹ at room temperature. After 7 adsorption–desorption cycles, the regenerated fiber showed a adsorption capacity of 3.92 mmol g⁻¹, 93% regeneration efficiency, which confirmed that SF-AM-TETA was capable of keeping its stability and CO₂ adsorption capacity even after numbers of regeneration cycles. Furthermore, in order to better interpret the adsorption behavior and adsorption kinetics of the solid amine fiber SF-AM-TETA, two models were applied to fit CO₂ adsorption experimental data at different temperatures. The results indicated that the solid amine fiber tended to absorb CO₂ by a physical process in the absence of moisture while the chemical absorption was the main process occurring in the presence of moisture.