Anchoring Cu-N active sites on functionalized polyacrylonitrile fibers for highly selective H2S/CO2 separation

• Published in: Journal of hazardous materials 2023-05, Vol.450, p.131084-131084, Article 131084
• Main Authors: Liu, Zhihao, Sun, Gang, Chen, Zhijie, Ma, Yue, Qiu, Kui, Li, Min, Ni, Bing-Jie
• Format: Article
• Language: English
• Subjects: Coordination; Cu-N; Desulfurization; H2S/CO2 separation; Polyacrylonitrile fibers
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.131084

As an essential part of clean energy, natural gas is often mixed with varying degrees of H2S and CO2, which poses a serious environmental hazard and reduces the fuel's calorific value. However, technology for selective H2S removal from CO2-containing gas streams is still not fully established. Herein, we synthesized functional polyacrylonitrile fibers with Cu-N coordination structure (PANFEDA-Cu) by an amination-ligand reaction. The results showed that PANFEDA-Cu exhibited a remarkable adsorption capacity (143 mg/g) for H2S at ambient temperature, even in the presence of water vapor, and showed a good separation of H2S/CO2. X-ray absorption spectroscopy results confirmed the Cu-N active sites in as-prepared PANFEDA-Cu and the formed S-Cu-N coordination structures after H2S adsorption. The active Cu-N sites on the fiber surface and the strong interaction between highly reactive Cu atoms and S are the main reasons for the selective removal of H2S. Additionally, a possible mechanism for the selective adsorption/removal of H2S is proposed based on experimental and characterization results. This work will pave the way for the design of highly efficient and low-cost materials for gas separation. [Display omitted] •Grafting Cu-N ligand structures on polyacrylonitrile fibers can enhance Cu reactivity.•The maximum adsorption capacity of PANFEDA-Cu for H2S is 143 mg/g.•H2S forms a six-coordinated unitary structure on the adsorbent based on the original Cu-N tetra-coordination.•H2S-anchored adsorption by the Cu-N ligand structureleads to the selective adsorption of H2S.