载钼活性炭的制备、表征及其苯吸附性能

doi:10.3969/j.issn.0253-2417.2018.03.004

摘要/Abstract

摘要： 利用（NH₄）₆Mo₇O₂₄·4H₂O溶液对椰壳活性炭掺杂改性，制得对苯蒸气具有较好吸附能力的载钼活性炭（Mo/AC），当钼盐质量分数分别为0.1%、0.3%、0.5%和0.7%时，改性活性炭分别标记为AC-1、AC-2、AC-3和AC-4。采用扫描电镜（SEM）、N₂吸附-脱附等温线、X射线衍射（XRD）和X射线光电子能谱（XPS）对Mo/AC进行表征，以常温动态吸附装置考察浸渍钼盐质量分数对Mo/AC吸附苯蒸气性能的影响，结果表明：钼在活性炭表面主要以MoO₃形式存在；改性后活性炭的比表面积和总孔容均有不同程度提高，AC-2的比表面积和总孔容最大，分别为1 372.12 m²/g和0.74 cm³/g，但平均孔径变化不大，维持在2.16 nm左右；表面醚键和羧基含量明显下降；随着浸渍钼盐溶液质量分数增加，活性炭样品对苯蒸气的平衡吸附量增加，但钼盐质量分数过高（>0.3%）时吸附性能下降，质量分数为0.3%时，制得改性活性炭AC-2的吸附性能最好，平衡吸附量高达332.80 mg/g，较原炭（267.20 mg/g）提高24.55%，理论吸附时间为110.93 min，较原炭提高24.54%。AC-2循环吸附5次后，平衡吸附量仍达306.99 mg/g，理论吸附时间为101.27 min。

关键词: 活性炭, 四水合七钼酸铵, 浸渍, 气相苯, 吸附

Abstract: Mo-loaded activated carbon materials (Mo/AC) with high adsorption performance for gaseous benzene were prepared by modification of coconut shell based activated carbon with ammonium molybdate tetrahydrate aqueous solution. The modified activated carbons were labeled as AC-1, AC-2, AC-3, and AC-4 to represent molybdenum salt solutions with the mass fractions of 0.1%, 0.3%, 0.5%, and 0.7%, respectively. Mo/AC was characterized by means of nitrogen adsorption isotherm, SEM, XRD, and XPS. Dynamic studies of gaseous benzene adsorption at room temperature were carried out. The results showed that element molybdenum existed on the surface of activated carbon in the form of MoO₃. Specific surface area and total pore volume of the modified activated carbon were improved after modification, among them, those of AC-2 were the largest with the values of 1 372.12 m²/g and 0.74 cm³/g respectively, but the average pore size did not change much and remained at about 2.16 nm. Ether and carboxyl groups on the surface of activated carbon decreased obviously. With the increase of impregnation mass fractions of molybdenum salt, the adsorption capacity of gaseous benzene increased, but it showed degradation when the mass fractions exceeded 0.3%. As the mass fractions of (NH₄)₆Mo₇O₂₄·4H₂O was 0.3%, the modified activated carbon AC-2 had the most excellent adsorption capacity with the equilibrium adsorption capacity of 332.80 mg/g, which increased by 24.55% compared to that of the original one (267.20 mg/g), and the theoretical adsorption time was as high as 110.93 min, which was 24.54% higher than that of the original carbon. After 5 cycles of adsorption, the equilibrium adsorption capacity of AC-2 still reached 306.99 mg/g, and the theoretical adsorption time was 101.27 min.

Key words: activated carbon, ammonium molybdate tetrahydrate, impregnation, gaseous benzene, adsorption

中图分类号:

TQ35

佟国宾, 徐州, 李伟, 刘守新. 载钼活性炭的制备、表征及其苯吸附性能[J]. 林产化学与工业, 2018, 38(3): 33-40.

TONG Guobin, XU Zhou, LI Wei, LIU Shouxin. Preparation,Characterization and Gaseous Benzene Adsorption Performance of Mo-loaded Activated Carbon[J]. Chemistry and Industry of Forest Products, 2018, 38(3): 33-40.

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