CO2 adsorption on Miscanthus × giganteus (MG) chars prepared in different atmospheres

Low-cost solid sorbents with enhanced capacity and selectivity towards CO2 are crucial in the design of an efficient carbon capture process. The suitability of chars prepared by the slow pyrolysis of Miscanthus × giganteus (MG) in different atmospheres as CO2 adsorbents was explored. The adsorption performance of the MG chars was evaluated using a thermogravimetric analyser. The results showed that the CO2 uptakes at 30 °C were between 1.528 to 1.811 mmol g−1 for chars prepared in N2, between 0.208 to 1.746 mmol g−1 for chars prepared in CO2, and between 1.483 to 1.774 mmol g−1 for chars prepared in He, respectively. These values were in line with those from the literature on biomass-derived carbon-based materials. The cyclic adsorption/desorption regeneration experiments showed that 180 °C was the best temperature for CO2 desorption from the MG chars. The char prepared at 800 °C in nitrogen exhibited the best regeneration performance, i.e. losing 13.86 % of its adsorption capacity after seven adsorption/desorption cycles. These results suggested that the biomass waste used in this work could be successfully valorised as efficient CO2 adsorbents with excellent cyclic performance.