Effect of Impregnation Temperature on Monoethanolamine-Kenaf Biosorbent for CO2 Adsorption from Gas Mixture

Abstract

Capturing carbon dioxide (CO2) from industrial resources to mitigate the global increase in carbon emissions is a challenging and expensive process, especially when utilizing Carbon Capture and Storage (CCS) technologies. The energy cost of CO2 capture in post-combustion CCS, employing the absorption method with monoethanolamine (MEA) as the commonly used liquid amine. This study focusing on the adsorption method, which is more energy saving and less corrosive for CO2 captured, by using modified kenaf biosorbent. Its low density, highly porous and permeability is well matched to be used as adsorbent. This study specifically investigated the influence of impregnation temperature of kenaf modified with a constant concentration of MEA towards the CO2 adsorption capability at different gas flowrates and pressure bed. From the surface morphology of modified kenaf sorbent, MEA-kenaf impregnated at 55 °C exhibited large pore openings and more structured walls compared to the other temperatures. The kenaf samples were then utilized in IsoSORP gas analyzer for CO2 adsorption with a mixture of CO2 - Nitrogen (N2) at two different flow rates and various pressure beds. The highest CO2 adsorption was achieved by the modified kenaf at impregnation temperature of 55 °C (gas flowrate 150 cm3/min) and 65 °C (gas flowrate 250 cm3/min). Apart from that, the adsorption ability shows a proportional increment when the gas pressure flow increased from 10 up to 30 bar. The research findings indicated that increasing the impregnation temperature enhanced the sorbent's pore size and nitrogen content impregnated on the kenaf surface (increase basicity), resulting in a significant improvement in CO2 adsorption capacity.