CO2 activation of biochar for carbon capture

“One of the most extensively used physical treatments for the formation of tailored biochar is the activation of biochar using CO2. CO2 activation improves the micropores of biochar, which promotes CO2 adsorption, according to several studies (Guo et al., 2009). The CO2 adsorption capacity of CO2-modified biochar was significantly higher than that of pristine biochar (Mahmoud et al., 2015). During the CO2 activation procession, CO2 undergoes dissociative chemisorption on the biochar surface, forming surface oxides and CO. The surface oxides are subsequently desorbed from the surface and further develop the pore. González et al. (González and Manyà, 2020). used olive mill wastes as biochar precursor, which were carbonized at 350 °C, followed by activation under CO2 at 900 °C for 1 hour. The modified biochar exhibited a higher CO2 uptake capacity of 129.61 mg/g than unactivated biochar. The improved CO2 uptake capacity was due to the improved BET surface area after CO2 activation (1135m2/g), compared with that of unactivated biochar. Furthermore, gas purging speeds up the thermal breakdown of carbonaceous materials and improves the aromaticity. (Igalavithana et al., 2018). And the synthesized carbon materials produced synthetically should be of purity after CO2 activation, so there is no need for a washing stage after the activation process (Rashidi and Yusup, 2016).”

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