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    磺化石墨烯气凝胶的制备及对醇胺的吸附性能研究

    Preparation of sulfonated graphene aerogel and its adsorption performance for alcoholamine

    • 摘要: 在煤化工行业,醇胺可作为有效萃取煤焦油中酚类化合物的溶剂,但萃取剂的氨基(—NH2)和酚羟基之间易形成氢键,导致部分有机胺残留在酚油中。因此,开发高效、稳定的固体吸附剂,去除酚油中残留的胺类萃取剂是极为必要的。以氧化石墨烯和对氨基苯磺酸重氮盐为原料、乙二胺为交联剂,经过水热反应和冷冻干燥制备了一种可压缩、易回弹的磺化石墨烯气凝胶(SGA),并作为去除酚油中残留有机胺的吸附剂。通过强吸电子效应的磺酸基(—SO3H)将—NH2固相吸附。FT−IR和元素分析结果证实,磺化策略能够在石墨烯表面有效引入—SO3H,且其含量可调控;氮气吸脱附测试结果表明,SGA的平均孔径为12~14 nm,其较大的介孔结构有利于粗酚油的吸附贮存。饱和吸附试验结果表明,SGA对粗酚油的平均吸附量为100 g/g。吸附试验结果表明,当氧化石墨烯和对氨基苯磺酸重氮盐的质量比为1∶3时,在180 ℃下水热反应12 h制备的磺化石墨烯气凝胶(SGA2),对酚油中残留醇胺的吸附效果较好,酚组分质量分数由69.02%提升至76.41%(吸附醇胺后)。对SGA2进行20 min氧等离子体处理后,其在50 ℃时对醇胺吸附效果达到最高,酚组分质量分数进一步提升至79.89%。SGA2展现出较好的醇胺吸附性能,为高效碳基吸附剂的制备提供了理论支撑。

       

      Abstract: In the coal chemical industry, alcoholamine can be used as an effective solvent to extract phenolic compounds from coal tar, while the easy formation of hydrogen bonds between the amino group (—NH2) of the extractant and the phenolic hydroxyl group results in residual alcoholamine in the phenolic oil. Therefore, it is necessary to develop efficient and stable solid adsorbents to remove the residual amine extractant and improve the purity of phenol oil. A compressible and resilient sulfonated graphene aerogel (SGA) was prepared by hydrothermal reaction and lyophilization using graphene oxide and diazonium p-aminobenzenesulfonate as precursors and ethylenediamine as crosslinking agent, which was used as adsorbent to remove residual amines in phenol oil via electrostatic interaction between —SO3H and —NH2. FT−IR and elemental analysis results confirm that sulfonation strategy can effectively graft —SO3H on the graphene surface. The results of nitrogen adsorption and desorption test show that the average pore size of SGA is 12~14 nm, and its large mesoporous structure is conducive to the adsorption and storage of crude phenol oil. The saturation adsorption experiment reveals that the average adsorption capacity of SGA for crude phenol is 100 g/g. The sulfonated graphene aerogel (SGA2) prepared at 180 ℃ for 12 h, where the mass ratio of graphene oxide to diazonium p-aminobenzenesulfonic acid was 1:3, manifests a good adsorption effect on residual alcoholamine in phenol oil. The content of phenolic components increased from 69.02% (concentration of crude phenolic oil) to 76.41% after adsorption process. When the SGA2 was subjected to oxygen plasma treatment for 20 min, the adsorption performance for alcoholamine was further elevated with adsorption temperature of 50 ℃ and the content of phenolic components increased to 79.89%. The SGA2 demonstrates good adsorption performance for alkanolamine, providing design principles for efficient carbon-based adsorbents.

       

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