Microwave Pyrolysis Combined with CO<sub>2</sub> and Steam as Potential Approach for Waste Valorization

Microwave pyrolysis combined with CO 2 and steam environment is investigated for its feasibility as an alternative method for waste disposal. The combined use of CO 2 and steam under microwave radiation created a synergistic effect in enhancing the thermal cracking of waste material during pyrolysis. The motivation of using CO 2 is to replace N 2 as carrier gas during pyrolysis as an effort to reduce the production of potent greenhouse gas. In this study, different types of microwave pyrolysis are performed including conventional, CO 2 and CO 2 +steam on waste particleboard. It was found that the utilization of steam and CO 2 affect the final pyrolytic products yield and composition. Incorporating CO 2 and steam in microwave pyrolysis decreased the yield of char by 33% but increased the yield of bio-oil by 108%. Biochar obtained under CO 2 showed well-developed and cleaner pore structure compared to biochar produced under N 2 . Our results demonstrate that the utilization of CO 2 and steam in microwave pyrolysis shows great potential to convert wastes into value-added char and bio-oil with desirable properties.