Lignin derived absorbent for efficient and sustainable CO2 capture

High and cost-efficient capture of CO2 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 CO2 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 CO2 per gram of absorbent under 25 degrees C and 100 kPa. In addition, the absorbent retained stable absorbability of CO2 after 6 cycles. The absorbing capacity of the absorbent formed by the coupling of vanillin and acrylamide to CO2 was much greater than their own (i.e. 0 g CO2.g(-1) vanillin, 0.01 g CO2.g(-1) acrylamide, respectively). Detailed information revealed the multi-site synergistic absorption mechanism, in which CO2 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 CO2 is as high as 0.12 g CO2 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 CO2 capture, but explores the application potential of lignin-based materials. (C) 2022 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

Efficient and sustainable lignin-based absorbents were prepared by grafting the active amine group on a lignin-derived compound. These absorbents showed low cost, high efficiency, and good sustainability, addressing the challenges of existing petroleum-based CO2 absorbents.