低浓度甲苯和对二甲苯在微纤包覆活性炭结构化固定床上的竞争吸附

通过湿法造纸技术制备了微纤包覆活性炭复合材料，研究了甲苯和对二甲苯在基于微纤复合材料结构化固定床上的吸附透过行为. 结果表明，颗粒活性炭被很好地包覆在烧结锁定的三维网络中，活性炭包覆前后的比表面积分别为976和955 m2/g，微孔体积分别为0.261和0.247 cm3/g；甲苯和对二甲苯在单一颗粒碳固定床和结构化固定床上的吸附均展示出竞争吸附特性，在两床层中均是甲苯先透过. 在5%透过浓度下，甲苯和对二甲苯在结构化固定床上的透过时间较在颗粒碳固定床上分别延长了20和30 min，甲苯和对二甲苯分离时间增加了10 min. 采用Yoon-Nelson模型对透过曲线进行拟合，相关系数R2>0.98，甲苯和对二甲苯在结构化固定床上的吸附速率常数分别为颗粒碳固定床的3和1.6倍.

Competitive Adsorption of Toluene and P-xylene at Low Concentration on Microfibrous Entrapped Activated Carbon Composite in a Structured Fixed Bed

Microfibrous entrapped activated carbon composite was prepared by wet layer paper-making technique. The adsorption breakthrough behaviors of volatile organic compounds (toluene and p-xylene) on microfibrous composites in a structured fixed bed were studied. The results showed that the activated carbon particles were well entrapped into the locked three-dimensional porous networks. The specific surface areas of the activated carbon before and after entrapment were 976 and 955 m2/g, and the mircopore volumes 0.261 and 0.247 cm3/g, respectively. The adsorption of toluene and p-xylene in both individual GAC bed and structured fixed bed showed significant competitive effect. The breakthrough time for toluene was earlier than that for p-xylene in both beds. The breakthrough time of toluene and p-xylene in the structured fixed bed with microfibrous composite increased about 20 and 30 min respectively, compared with those in the individual GAC bed at 5% breakthrough concentration, and the separation time between toluene and p-xylene increased 10 min. The breakthrough curves fitted to Yoon-Nelson model. The results fitted well to Yoon-Nelson model with the correlation coefficients R2>0.98 and k' value of the structured fixed bed was 3 and 1.6 times larger, compared with that of individual GAC bed for toluene and p-xylene adsorption, respectively.