Greener carbon capture using microwave heating for the development of cellulose-based adsorbents

In this work, CO2-activated carbons were produced from microcrystalline cellulose using microwave heating during activation. Activations were thus completed at 400 degrees C to burn-offs of 10, 20 and 30 wt%. The activated carbons' CO2 adsorption capacity was tested over 10 cycles of adsorption (25 degrees C) and desorption (100 degrees C). CO2 adsorption capacity was found to increase with increasing activation burn-off, whilst larger average dynamic adsorption capacities were achieved with activated carbons of 20 wt% (1.64 mmol/g) and 30 wt% (1.73 mmol/ g) burn-off compared to commercial activated carbon Norit R2030CO2 (1.58 mmol/g). These microwaveprepared activated carbons were also compared with similar activated carbons produced using conventional heating in our previous work. The microwave-prepared activated carbons were found to possess 9.5-25.6 % larger CO2 adsorption capacities at equivalent burn-offs, despite being produced at 200 degrees C lower temperature, 83-94 % shorter activation times and 39-68 % lower heating energy consumption. These results represent the establishing of a more efficient means of producing microcrystalline cellulose-based activated carbons for a greener, sustainable carbon capture that contributes to the circular economy.