Development of biomass derived highly porous fast adsorbents for post-combustion CO_2 capture

摘要

This study is carried out for a comparative screening of three groups of biomasses, soft or non-woody (peanut shell), intermediate woody (walnut shell), and hard woody (pinewood), for the development of adsorbents/activated carbons for post-combustion CO_2 capture (over N_2 balance). Three different groups of biomass residues are selected to study the role and nature of the material in adsorption and selection of the raw material for CO_2 adsorbent synthesis for future researches because of the hot issue of anthropogenic CO_2 emissions. The adsorption isotherms studied by the thermal gravimetric analyser (TGA) revealed that CO_2 adsorption capabilities are in the range of 2.53-3.92 mmol/g (over N_2 balance) at 25°C. The newly synthesized activated carbons (ACs) exhibited a fast rate of adsorption as 41-94% in the initial 2 min. Porous surface development with catalytic KOH activation is seen clearly through SEM surface morphological analyses and mathematically confirmed from S_(BET) ranges from 146.86 to 944.05 m~2/g. FTIR and XRD peaks verify the generation of basic or inorganic O_2-rich moieties that help in acidic CO_2 capture. It is also observed from adsorption isotherms that the order of higher adsorption groups is peanut shell > pine wood > walnut shell, while the best activation mass ratio (sample/KOH) is 1∶3. The synthesized low-cost ACs with an amount of 1.93 US$ per kg production could help to overcome the environmental hazards and problems caused by CO_2 and biomass waste.