CO2 adsorption in hydrochar produced from waste biomass

Sugar and ethanol plants produce a large amount of sugarcane bagasse. Such biomass can be the raw material for the production of an adsorbent to uptake CO 2 . Thus, this work aimed to evaluate the hydrocarbonization of sugarcane bagasse and to study its use as a CO 2 adsorbent from a simulated flue gas. The temperature of the hydrothermal carbonization (HC) was set at 220 °C, while the operating time ranged from 12 to 48 h. Through the SEM–EDS analysis, the 48-h sample (HC48) was selected for chemical activation with KOH, resulting in activated hydrochar (AHC). The CO 2 and N 2 simple adsorption isotherms were obtained at 50, 70 and 80 °C. The results have shown a higher adsorption at a temperature of 50 °C for both gases. Activated hydrochar clearly preferred CO 2 instead of N 2 at 100 kPa as the maximum adsorption was 1.99 and 0.207 mmol g −1 , respectively. The highest selectivity of CO 2 /N 2 was 12–50 °C, according to the “Ideal adsorbed solution theory” model. Therefore, AHC is clearly an eco-friendly adsorbent that can be used to minimize the resulting release of climate-damaging CO 2 from flue gas to atmosphere.