Abstract:

The 13X/activated carbon composite was treated by 0.2 g·ml^-1 glucose solution for carbon deposition. The effect of deposition times on the pore structure, surface properties and separation performance of CH₄/N₂ were studied. The crystalline, pore structure and surface properties of the samples were investigated by X-ray diffraction (XRD), N₂ adsorption-desorption isotherms at 77 K, scanning electron microscopy (SEM), CO₂-TPD and Fourier transform infrared spectrum (FT-IR). The adsorption isotherms of CH₄ and N₂ were tested at 298 K and 100 kPa,and compared with the adsorption separation properties of carbon materials and 13X zeolite reported in the literatures. The experimental results showed that the relative content of X zeolite, the micropore surface area and the micropore volume of AC/X-G were gradually decreased with the increase of deposition times. The surface of samples was covered by carbon membrane, which led to decrease of the alkaline functional groups but increase of containing C-O groups. The adsorption capacities of CH₄ and N₂ decreased, while the adsorption separation coefficient was improved. After third deposition, the adsorption separation coefficient of CH₄/N₂ reached 3.0. The oxygen-containing functional groups on the surface of AC/X-G were beneficial to improve the separation performance of CH₄/N₂.

Key words: adsorbent, glucose, carbon deposition, adsorption, separation

摘要：

采用浓度为0.2g·ml^-1的葡萄糖溶液对13X沸石/活性炭复合材料(AC/X)进行碳沉积,研究沉积次数对复合吸附剂(AC/X-G)孔结构、表面性质和CH₄/N₂吸附分离性能的影响。通过X射线衍射,77K下的N₂吸附/脱附,扫描电镜,CO₂-TPD以及红外光谱表征样品的晶型、孔结构和表面性质,在298K、100kPa下对其CH₄和N₂吸附等温线进行测定,并将吸附结果与文献中碳材料和13X沸石的吸附性能进行比较。结果表明:随着沉积次数的增加,AC/X-G吸附剂中X型沸石的相对含量降低,微孔比表面积和微孔体积减少。AC/X-G的表面被碳膜覆盖,碱量降低,但出现强碱位和含氧基团C-O键。AC/X-G的CH₄和N₂吸附量下降,但吸附分离系数提高,沉积3次的样品AC/X-G-3的CH₄/N₂吸附分离系数达到3.0,表面的含氧基团有利于提高复合材料的CH₄/N₂吸附分离性能。

关键词: 吸附剂, 葡萄糖, 碳沉积, 吸附, 分离