Sticky rice lime mortar-inspired in situ sustainable design of novel calcium-rich activated carbon monoliths for efficient SO2 capture

Abstract

Abstract In the present study, a facile and eco-friendly strategy is developed for in situ conversion of waste lime mud and sawdust to valuable calcium-rich activated carbon monoliths (Ca-ACM) in the presence of sticky rice. The obtained “green hybrid bodies” can exhibit superior compressive strength of 18 MPa, water resistance for more than 60 days, and SO2 removal efficiency up to 93.6%. The SO2 adsorption capacity of Ca-ACM was evaluated to be 57.1 mg/g in a fixed bed reactor. The remarkable performance of Ca-ACM could be a result of synergetic desulfurization behaviors derived from the integrated activated carbons and Ca-based components, as well as the compact microstructure that is similar to the biomimetic mineralization system of sticky rice lime mortar. The newly developed Ca-ACM is a promising cost-effective (∼CNY 4.88/kg) alternative to comparable commercial activated carbons that can be used as a clean and ecologically compatible adsorbent for SO2 capture. The route for direct massive utilization of lime mud as an indispensable component for making functional adsorbent reported herein is very beneficial to lime mud waste recycling, SO2 pollution control, and sustainable growth of papermaking industry.