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It is agreed that reducing CO2 emissions is a necessary step for a sustainable world; therefore, a great deal of research attention has been given to designing materials to capture CO2. Postcombustion capture methods, which separate CO2 from flue gas after energy generation, are considered the most “marketable technology”. The main challenges of this method are in the separation of gas, high flow rate, and low partial pressure. A porous carbon framework, called biochar, has received attention for its ability to remove contaminants, sequester carbon in soils, and concurrently improve soil quality. Biochar does not require activation, can be produced from waste biomass, is 10x cheaper than AC , and is environmentally friendly.The surface properties of biochar give it excellent potential for CO2 capture because not only do they tend to be polar and hydrophilic, but the extensive micropores allow biochar to achieve comparatively high surface area-to-weight ratios.
The overarching objective of this work was to determine biochar’s potential as a low-cost CO2 capture material. Two commonly used feedstock materials were converted into the biochars through slow pyrolysis at 300, 450, 600˙C and the chars were assessed for their adsorption of CO2. This study shows that biochar is a promising framework for adsorption of CO2. The sugarcane bagasse feedstock produced at 600˙C showed the most adsorption, with over 1.4mmol CO2/g biochar; however, even when the feedstock was exposed to only 300˙C pyrolysis, it was still able to adsorb .8mmol CO2/g char. Although CO2 weakly sorbs to the surface of the char, the large surface area allows it to be among the highest of physical adsorbents. In future study, metal oxides, amines and other materials can be added to biochar to enhance bonding and functional group attraction. |