Characteristics of CO₂ adsorption on biochar derived from biomass pyrolysis in molten salt

Abstract

Abstract This work focused on the preparation and characterization of a promising biochar as a novel solid adsorbent towards CO 2. The biochar was prepared by catalytic pyrolysis of waste roasted peanut shell in molten salt; it was characterized by means of SEM‐EDS, BET, FTIR, and TGA, followed by determining the adsorption characteristics, such as adsorption capacity, isosteric heat of adsorption, uptake rate, and selectivity via adsorption temperature and gas pressure. The results indicated that the as‐prepared biochar had a rich microporous structure with a peak pore size in the range of 0.69–1.3 nm, and exhibited a good performance of CO 2 adsorption with a capacity of 3.8 mmol/g at 273 K and 100 kPa. Moreover, the adsorption selectivity of CO 2 over N 2 , O 2 , CO, and CH 4 was found to be above 12, 11, 8, and 7, respectively. In addition, an interesting phenomenon of an initial increase and then a decrease in the selectivity of CO 2 /N 2 adsorption with increasing gas pressure was experimentally revealed.