A comparison of two methods for producing CO2 capture adsorbents

Abstract

High capacity CO2 adsorbents were prepared from a biomass residue, almond shells. Two different methods for producing these adsorbents were compared: activation with carbon dioxide and heat treatment with ammonia gas (amination and ammoxidation). The prepared carbons were physically and chemically characterised. Amination and ammoxidation introduced nitrogen into the carbon structure, up to a 5 wt.%, turning the carbon surface more basic, without the need of carrying out a preoxidation treatment. On the other hand, activation with carbon dioxide led to a significantly higher development of the texture of the samples. The CO2 adsorption capacity of the adsorbents was meassured in a thermogravimetric analyser. Amination and activation showed to be suitable methods for the production of CO2 adsorbents. The prepared adsorbents presented a high CO2 capture capacity, comparable to that of commercial activated carbons, and showed fully reversible adsorption.