酸碱盐改性对活性炭吸附油气特征的影响

采用酸碱盐溶液浸渍方法对活性炭进行改性，探究了其吸附油气的特征，考察了改性后的活性炭对油气吸附量和穿透时间的影响，采用BET、SEM、XRD及FT-IR等方法对活性炭进行了表征。结果表明：改性后的活性炭孔结构和表面化学性质发生了明显的变化，2^#样品(醋酸改性)比表面积最大为1 264.33 m²·g⁻¹，碱改性活性炭对油气的吸附性能优于其他改性方法，3^#样品(氨水改性)吸附容量最高为0.279 g·g⁻¹，拟合动力学速率常数k′值是0.096 3，5^#样品(氢氧化钾改性)穿透时间最长为130 min；改性处理后，增加了活性炭表面的—OH与C=C含量，正丁烷主要以—CH₂基团吸附在吸附剂表面。在综合酸碱盐溶液改性的基础上，利用Yoon-Nelson动力学方程对吸附曲线进行拟合，评价改性活性炭对油气的吸附性能。以上研究结果可为活性炭吸附油气的工业应用提供参考。

Effect of acid,alkali and salt modification on adsorption characteristics of oil vapour by activated carbon

Activated carbon (AC) was modified with acid, alkali and salt solution impregnation method, and the oil vapour adsorption characteristics by this modified AC were evaluated in a fixed-bed reactor, as well as the effects of modified AC on oil vapour adsorption amount and penetration time. The activated carbon was characterized by specific surface area and pore size analyzer (BET), scanning electron microscopy (SEM), X-ray diffraction(XRD) and Fourier transform infrared spectroscopy (FT-IR). The results showed that the significant changes in the pore structure and surface chemical properties of the modified AC occurred, 2# samples (acetic acid modification) had the maximum surface area of 1 264.33 m2·g−1. The performance of alkali modification AC had better performance on oil vapour adsorption than other AC samples. The highest adsorption capacity of 3# sample (ammonia modification) was up to 0.279 g·g−1 and the fitted kinetic rate constant (k′) was 0.096 3, the longest penetration time of 5# samples (potassium hydroxide modification) was 130 min. After modification, the content of —OH and C=C on AC surface increased, and n-butane adsorption on the AC surface was mainly through the group of —CH2. Based on the acid, alkali and salt solution modification of AC, the adsorption curves were fitted by Yoon-Nelson kinetics equation. So this study provides the reference for the industrial application of AC to adsorb oil vapour.