Breakthrough curve in CO2 adsorption using palm oil mill residues derived biochar

“The application of biochar obtained from palm kernel shells by the pyrolysis condition at 500 °C and 2 L/min of N₂ flow rate was used for adsorption of CO₂ in the fixed bed reactor. Figure 7 showed the operating line and the breakthrough at the test condition that the concentration of CO₂ was maintained at 1,400 ppm in N₂ gas. The flow rate of the gas mixture was controlled at approximately 2.5 L/min, and 3.0 g of adsorbent was used for this test. The CO₂ concentration in the outlet stream was ultimately zero until 9 min, which indicated a good potential of the biochar as the CO₂ adsorbent. This result agreed with the BET surface area in Table 6, where biochar from the palm kernel shells showed the highest value (389.02 m²/g). The shape of the breakthrough curve clearly illustrated that CO₂ molecules easily penetrated through an absorbents bed having highly porous biochar and allowed a large amount of CO₂ to enter and be absorbed into the porous surface. Furthermore, it was anticipated that CO₂ molecules were adsorbed onto the pore surface of biochar due to a weak intermolecular cohesive force (physisorption) [21]. The CO₂ adsorption test was conducted to indicate the breakthrough time of each sample. Breakthrough time and the adsorption capacity of biomass samples in this study and previous studies are shown in Table 7. ” https://doi.org/10.1016/j.heliyon.2020.e04019

“Figure 7. Operating line and breakthrough curve in CO₂ adsorption system by the biochar adsorbent.”

“Table 7 revealed that the CO₂ adsorption capacity of virgin carbonaceous materials could be improved by a surface modification using chemical treatment. Although those carbonaceous adsorbents have good potential for CO₂ adsorption, the production cost for synthesizing carbonaceous materials into adsorbents and further activation costs are high because of heat treatments at high temperatures. In the future, focusing on innovative research will be required to fill the gap between experimental data and the application use practically to initiate highly cost-effective production and activate processes of carbonaceous material adsorbents.”

https://doi.org/10.1016/j.heliyon.2020.e04019