Abstract:

A series of glucose-based porous carbons (C-GLCs-800) were developed by simple carbonization and KOH activation, and characterized by scanning emission microscopy (SEM), nitrogen sorption, Fourier transformed infrared (FI-TR) and thermogravimetric analysis (TGA). Pure component adsorption isotherms of CO₂ and CH₄ were measured separately at 288, 298, and 308 K. The ideal adsorbed solution theory (IAST) model was used to estimate adsorption selectivity of the samples for CO₂/CH₄ binary mixtures. Results showed that the specific surface area and total pore volume of C-GLCs-800 increased at first and then decreased with the ratio of KOH/C at which the samples were activated. The BET surface area and total pore volume of C-GLC-800-4 reached as high as 3153 m²·g^-1 of 2.056 cm³·g^-1, respectively. The narrow micropores voulme of C-GLC-800-2 reached as high as 0.3538 cm³·g^-1. The C-GLC-800-2 exhibited an extraordinary CO₂ adsorption capacity of 3.96 mmol·g^-1 at 298 K under 10⁵ Pa, which was comparable to many traditional adsorbents and MOFs. The isosteric heats of CO₂ adsorption on C-GLC-800-2 was higher than that of CH₄. The IAST-predicted CO₂/CH₄ selectivity was about 8.35.

Key words: glucose, hydrothermal carbonization, porous carbons, carbon dioxide, methane, adsorption, selectivity

摘要：

以淀粉糖（主要成分为葡萄糖）为碳前体，制备了一系列多孔碳材料（C-GLCs-800），对其进行孔隙结构分析，并应用FT-IR、SEM、TGA对其进行了表征，测定了材料在288、298和308 K下的CO₂和CH₄吸附等温线，根据IAST理论预测了材料对CO₂/CH₄二元体系的吸附选择性。实验结果显示，活化条件对材料的孔隙结构有明显影响，随着KOH/C质量比的增加，所制备的C-GLCs-800比表面积和总孔容先增加后降低。其中C-GLC-800-4的BET比表面积高达3153 m²·g^-1，总孔容为2.056 cm³·g^-1。C-GLC-800-2的窄微孔（V_d<1 nm，孔容0.3538 cm³·g^-1）含量最高，为30.63%。C-GLC-800-2在298 K和10⁵ Pa下对CO₂吸附量高达3.96 mmol·g^-1，明显高于许多传统吸附材料和MOFs材料在相同条件下对CO₂的吸附容量。应用Clausiuse-Clapeyron方程计算了CO₂和CH₄在材料上的吸附热，应用IAST理论计算了CO₂/CH₄的吸附选择性，结果显示C-GLC-800-2对CO₂/CH₄的吸附选择性为8.35。

关键词: 葡萄糖, 水热碳化, 多孔碳, 二氧化碳, 甲烷, 吸附, 选择性