Enhanced carbon dioxide adsorption by potassium hydroxide modified peat soil as porous adsorbent

Abstract

Carbon dioxide (CO2) capture is a strategy established to mitigate issues related to CO2 emission through various methods, for instance by adsorption. Soil, a natural resources, depending on its particular type are abundant carbon precursor. However, previous studies have neglected the possibility of soil modification for CO2 adsorption. In this study, a natural soil, peat soil was used to prepare dried, carbonised, and alkaline-modified soils. Through nitrogen adsorption-desorption analysis, the porosity of the alkaline modified soil has higher BET surface area and total pore volume of 72.08 m2/g and 0.11 cm3/g respectively. Furthermore, the functional groups of OH, C=O, and S=O presence in the adsorbents which were determined by FTIR also capable to assist the adsorption of CO2. Hence, the performance of the soil after alkaline modification increased by 85% compared to the non-modified soil where the adsorbent recorded an adsorption capacity of 11.70 mg/g. Moreover, the isotherms and kinetics fitting suggest that the adsorption of CO2 onto the adsorbents was governed by physisorption. In conclusion, modified soils showed better performance for CO2 adsorption. Thus, further investigations such as optimisation of the modification process or amine functionalisation are anticipated in development of soil-based adsorbents.