Simultaneous conventional and microwave heating for the synthesis of adsorbents for CO2 capture: Comparative study to pristine technologies.

[Display omitted] • Hybrid heating in preparation of activated carbons was investigated. • High CO 2 adsorption was achieved with low KOH impregnation ratio. • Synergic effects observed by using modest microwave intensity and temperature. • Linear correlation between CO 2 uptake and microporosity. • Langmuir model describes the adsorption mechanism in hybrid AC. Microwave has become an attractive technology in the valorisation of renewable biomass and in the mitigation of challenges of climate change. In this work, the synergic effects of coupling microwave and mild conventional heating conditions has been investigated in preparing engineered ultra-micropore carbons from lignocellulosic biomass. The processing conditions were systematically investigated and correlated to the physicochemical properties of activated carbons produced and their performance in post-combustion CO 2 capture. The highest CO 2 uptake (225 mg g−1) was achieved for the hybrid carbon produced at low temperature (600 °C) and modest microwave intensity. The synergic effect of hybrid heating was confirmed by the significant CO 2 uptake increase up to 80 and 60 % for the activated carbons prepared by microwave and conventional heating, respectively. The enhanced adsorption was confirmed by cyclic regeneration up to 99 % after 16 adsorption–desorption cycles, showing a linear correlation between the surface area, micropore volume and CO 2 uptake. The Pseudo-first order model accurately describes the adsorption phenomena, indicating that physisorption is the primary mechanism governing the process. The results acquired from this study highlight the process intensification in the synthesis of porous materials with comparable properties that are typically attained in conventional heating using energy intensive conditions. Additionally, this approach reveals the benefits of conventional treatment for increasing the material's microwave susceptibility and as consequence to reduce the processing time by microwave heating. The synergic effects confirms the potential of hybrid heating for applications where fast and selective heating is paramount. [ABSTRACT FROM AUTHOR]