Study on the adsorption performance and regeneration of lignin-derived graphitic carbon for H2S--颗粒学报PARTICUOLOGY

Li, F., Wang, R., Yang, Y., Zheng, M., Li, Q., Yang, D., & Chen, H. (2024). Study on the adsorption performance and regeneration of lignin-derived graphitic carbon for H2S. Particuology, 94, 197-210. https://doi.org/10.1016/j.partic.2024.08.005

Study on the adsorption performance and regeneration of lignin-derived graphitic carbon for H₂S

Fen Li^*, Ruiying Wang, Ying Yang, Menglong Zheng, Qiushuang Li, Dongdong Yang, Huiyu Chen

Key Laboratory of Green Chemical Engineering and Technology of College of Heilongjiang Province, School of Materials Science and Chemical Engineering, Harbin University of Science and Technology, Harbin, 150080, China

10.1016/j.partic.2024.08.005

Volume 94, November 2024, Pages 197-210

Received 13 May 2024, Revised 5 August 2024, Accepted 7 August 2024, Available online 14 August 2024, Version of Record 24 August 2024.

E-mail: hgxylf@126.com

Highlights

• We prepared lignin carbon by direct pyrolysis for H₂S adsorption.

• KOH modification increased the specific surface area of lignin carbon but decreased its degree of graphitization.

• The modified lignin carbon shows a high specific surface area of 1672.9 m²/g and a sulfur capacity of 67.1 mg/g.

• Heating can regenerate lignin carbon saturated with adsorbed H₂S, allowing two cycles of reuse.

Abstract

In pursuit of effective adsorption materials for malodorous gases such as H₂S and to broaden the utilization avenues of lignin waste, this study employed the direct pyrolysis method to synthesize three types of alkali lignin graphitized carbons, namely C-800, KC-700, and KEC-700. Among them, KEC-700 exhibits a high specific surface area of 1672.9 m²/g, significantly superior H₂S adsorption performance compared to other materials, an adsorption breakthrough time of up to 220 min, and a sulfur capacity of 67.1 mg/g. Structural analysis showed that the more oxygen-containing functional groups of lignin charcoal and the larger specific surface area facilitated the adsorption of H₂S. After reaching adsorption saturation, the degree of graphitization of lignin carbon diminishes. The H₂S adsorption products primarily manifest as elemental sulfur and sulfate within the pores of lignin carbon measuring less than 2 nm. Through thermal regeneration, the charcoal effectively eliminates the elemental sulfur adsorption product. Nevertheless, sulfate removal proved unsatisfactory, as the adsorption efficiency of KEC-700 following two thermal regenerations was approximately 41% of that observed for fresh samples.

Graphical abstract

Keywords

Hydrogen sulfide; Alkali lignin; Lignin carbon; Regeneration

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