Lignin derived absorbent for efficient and sustainable CO_(2) capture

摘要

High and cost-efficient capture of CO_(2) is a prerequisite and an inevitable path of carbon emission reduction. To address the challenges(high cost, low efficiency, less sustainability, etc.) of existing petroleum-based CO_(2) absorbents, herein, a class of efficient and sustainable lignin-based absorbents were resoundingly prepared by grafting the active amine group on a lignin derived compound vanillin and alkali lignin. The results demonstrated that vanillin modified by acrylamide achieved the excellent absorption capacity among the three absorbents, whose ability was 0.114 g CO_(2) per gram of absorbent under 25 ℃ and 100 kPa. In addition, the absorbent retained stable absorbability of CO_(2) after 6 cycles.The absorbing capacity of the absorbent formed by the coupling of vanillin and acrylamide to CO_(2) was much greater than their own(i.e. 0 g CO_(2) ·g^(-1)vanillin, 0.01 g CO_(2) ·g^(-1) acrylamide, respectively).Detailed information revealed the multi-site synergistic absorption mechanism, in which CO_(2) has C and O double interactions with the amide group of the absorbent, and single interaction with the hydroxyl oxygen on the benzene ring of the absorbent. The absorption capacity of modified lignin for CO_(2) is as high as 0.12 g CO_(2) per gram of absorbent, which is comparable with that of model compound vanillin.This work not only provides a new idea for the design of bio-absorbents for CO_(2) capture, but explores the application potential of lignin-based materials.