Tseng Ru-Ling, Tseng Szu-Kung
Graduate Institute of Environmental Engineering, National Taiwan University, Taiwan.
J Colloid Interface Sci. 2005 Jul 15;287(2):428-37. doi: 10.1016/j.jcis.2005.02.033.
Carbonaceous adsorbents with controllable surface area were chemically activated with KOH at 780 degrees C from chars that were carbonized from corncobs at 450 degrees C. The pore properties, including BET surface area, pore volume, pore size distribution, and mean pore diameter of these activated carbons, were characterized by the t-plot method based on N(2) adsorption isotherms. Two groups are classified according to the types of adsorption/desorption isotherms. Group I corncob-derived activated carbons, with KOH/char ratios from 0.5 to 2, exhibited BET surface area ranging from 841 to 1221 m(2)/g. Group II corncob-derived activated carbons, with KOH/char rations from 3 to 6, showed high BET surface areas, from 1976 to 2595 m(2)/g. From scanning electron microscopic (SEM) results, the surface morphology of honeycombed holes on corncob-derived activated carbons was significantly influenced by the KOH/char ratios. The adsorption kinetics of methylene blue, basic brown 1, acid blue 74, 2,4-dichlorophenol, 4-chlorophenol, and phenol from water at 30 degrees C were studied on the two groups of activated carbons, which were suitably described by two simplified kinetic models, pseudo-first-order and pseudo-second-order equations. The effective particle diffusivities of phenols and dyes at the corncob-derived activated carbons of group II are higher than those of ordinary activated carbons. The high-surface-area activated carbons were demonstrated to be promising adsorbents for pollution control and for other applications.
在780℃下，用KOH对由450℃碳化的玉米芯制得的具有可控表面积的含碳吸附剂进行化学活化。基于N₂吸附等温线，采用t-图法对这些活性炭的孔隙特性进行了表征，包括BET表面积、孔体积、孔径分布和平均孔径。根据吸附/解吸等温线的类型将其分为两组。第一组玉米芯衍生的活性炭，KOH/炭比为0.5至2，BET表面积为841至1221 m²/g。第二组玉米芯衍生的活性炭，KOH/炭比为3至6，BET表面积较高，为1976至2595 m²/g。扫描电子显微镜（SEM）结果表明，KOH/炭比对玉米芯衍生活性炭上蜂窝状孔的表面形态有显著影响。研究了两组活性炭在30℃下对水中亚甲基蓝、碱性棕1、酸性蓝74、2,4-二氯苯酚、4-氯苯酚和苯酚的吸附动力学，这两组吸附动力学可以用两个简化的动力学模型，即拟一级和拟二级方程进行适当描述。第二组玉米芯衍生活性炭上酚类和染料的有效颗粒扩散率高于普通活性炭。高表面积活性炭被证明是用于污染控制和其他应用的有前景的吸附剂。
