Facile Preparation of Porous Carbon Derived from Industrial Biomass Waste as an Efficient CO2 Adsorbent

A porous carbon CO2 adsorbent based on soybean cake (industrial biomass waste) has been successfully prepared by direct carbonation, following KOH activation. The prepared porous carbon adsorbent exhibits efficient CO2 capture performance with the highest adsorption capacity of 4.19 and 6.61 mmol/g at 298 and 273 K under atmospheric pressure, respectively. Moreover, the porous carbon adsorbent also shows good static CO2 adsorption capacity at a low pressure (0.15 bar) with an uptake of 1.26 mmol/g and an equally ideal dynamic CO2 capture capability with an uptake of 1.28 mmol/g (15% CO2) at 298 K. Additionally, the ideal adsorbed solution theory (LAST) model has been used to measure the selectivity of the porous carbon, and the LAST factors of CO2/N-2 (15/85, fuel gas), CO2/CH4 (40/60, biogas), and CH4/N-2 (50/50, coalbed gas) are about 27, 6, and 6, respectively. The dynamic breakthrough test reveals the strong interaction between the porous carbon and CO2, which also verifies the considerable selective capture ability of this material for CO2. Furthermore, the soybean cake-based CO2 adsorbent also presents prominent cyclic regeneration capacity (a five-time cyclic test) with lower isosteric heats (34-18 kJ/mmol) of CO2 adsorption.