Modification of the Textural Properties of Chitosan to Obtain Biochars for CO2-Capture Processes

Three chitosans with different morphologies have been used (commercial chitosan powder, chitosan in film form and chitosan in globular form synthesized by the freeze-dried method) for the synthesis of biochars. The pyrolytic treatment has revealed that the biochar synthesized from the chitosan formed by the freeze-dried method reaches the highest CO2-adsorption capacity (4.11 mmol/g at 0 degrees C and a pressure of 1 bar) due to this adsorbent is highly microporous. Moreover, this biochar is more resistant to the pyrolytic treatment in comparison to the biochars obtained from the commercial chitosan and chitosan in the form of film. CO2-adsorption studies at different temperatures have also shown that the adsorption capacity diminishes as the adsorption temperature increases, thus suggesting that the adsorption takes place by a physical process.

Automated summary

This study used different morphologies of chitosan to synthesize biochars and found that the biochar synthesized from chitosan formed by the freeze-dried method showed the highest CO2-adsorption capacity and higher resistance to pyrolytic treatment. CO2-adsorption capacity decreases with increasing temperature, indicating a physical process of adsorption.