苯基键合高比表面积活性炭的制备及其对挥发性有机化合物的吸附性能研究

摘要

The activated carbon with high specific surface area was prepared by carbonization with walnut shell as raw material and activation by potassium hydroxide.The surface of activated carbon was then modified by phenyltrimethoxysilane to prepare phenyl-bonded high specific surface area activated carbon adsorption material.The specific surface area and pore size distribution of phenyl-bonded activated carbon were measured by nitrogen adsorption method.The organic functional groups of the phenyl-bonded activated carbon, the chemical environment of the surface elements and the crystal structure were characterized by infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray powder diffraction method.The volatile organic compounds (VOCs) in the air were absorbed by a sampling tube filled with the adsorption material prepared here, then desorbed into carbon disulfide solution and detected by gas chromatography.The saturated adsorption capacities of phenyl bonded activated carbon to 7 kinds of VOCs (ethanol, acetone, hexane, ethyl acetate, tetrahydrofuran, 1,2-dichloroethane, benzene) were in the range of 129-216 mg/g.In the range of 0.05-2.50 mg/mL, there was a good linear relationship between the peak height of the 7 components and the concentration, and the detection limits were in the range of 0.92-3.60 mg/m3.%以核桃壳为原料,经过碳化、KOH活化, 制备了高比表面积活性炭,通过三甲基氧基苯基硅烷对活性炭表面进行改性,制得苯基键合高比表面积活性炭吸附材料.通过氮气吸附法测定了苯基键合活性炭的比表面积及孔径分布;采用红外光谱、X射线光电子能谱、X射线粉末衍射技术对苯基键合活性炭的有机官能团、表面元素的化学环境及晶体结构进行了表征.将该吸附材料制成采样管,吸附空气中的挥发性有机物,二硫化碳解吸后使用气相色谱进行分析.考察了苯基键合活性炭对乙醇、丙酮、正己烷、乙酸乙酯、四氢呋喃、1,2-二氯乙烷和苯共7种挥发性有机化合物(VOCs)的吸附性能,饱和吸附量在129~216 mg/g之间;在0.05~ 2.50 mg/mL范围内,7种组分的峰高与浓度呈良好的线性关系,检出限在0.92~3.60 mg/m3之间.