Reutilization of biomass pyrolysis waste: Tailoring dual-doped biochar from refining residue of bio-oil through one-step self-assembly

Abstract

The biochar with porous structure and functionalized surface from biomass waste is strongly appealing as a CO2 adsorbent due to its cost-effectiveness and eco-friendliness. In this study, N/S dual-doped porous biochar was fabricated from bio-oil refining residue through one-step carbonization-activation combined with in-situ doping. The CO2 adsorption performance and mechanisms of biochar were investigated in pure CO2 and simulated fuel gas based on its porous architecture and physicochemical properties. Specifically, the biochar derived from refining residue had abundant pores with a high proportion of micropores (above 87%). In addition, the biochar prepared at 800 °C exhibited relatively outstanding CO2 adsorption performance (2.21 mmol/g) due to its ideal pore structure and more abundant surface functional groups (N and S). Although the increase in induced temperature promoted the pore development of biochar to obtain a higher specific surface area (957.44 m2/g), it had no significant positive effect on the subsequent CO2 adsorption. Moreover, biochar demonstrated excellent recyclability through ten consecutive adsorption-desorption. The pathway advocated here for tailoring porous biochar from bio-oil refining residue will open up a new perspective in exploring the large-scale preparation of biochar from waste by-products of biomass pyrolysis-refining system for CO2 capture.