Biomass Gasification Char as a Low-Cost Adsorbent for CO2 Capture

This study wants to investigate a possible valorization route for char from biomass gasification taking advantage of its similarities to biomass-derived activated carbon in terms of properties and mechanisms of formation and assess its suitability for CO2 adsorption. Char was collected from a commercial gasifier operating in South Tyrol, Italy, and characterized through elemental analysis, X-ray diffraction technique, physisorption analysis and scanning electron microscopy. The CO2 adsorption/desorption capacity of the char was investigated through thermogravimetric analysis at different adsorption temperatures (Tads = 50 - 100 °C) and CO2 concentrations (CO2:N2 = 1:1 - 0.8:0.2). CO2 adsorption capacity of char decreases with temperature and increases with CO2:N2 ratio. The highest CO2 uptake of 3.4 % resulted for Tads = 50 °C and CO2:N2 = 1:1.