苯酚在活性炭复合材料结构化固定床上的吸附动力学

Adsorption dynamics of phenol in a fixed bed packed with activated carbon and stainless steel fiber-reinforced activated carbon paper

以不锈钢微纤、粉状活性炭和粘合剂为原料,采用湿法造纸和烧结工艺制备出纸状微纤包覆活性炭复合材料;在固定床进出口端分别装填颗粒活性炭(13 cm)和微纤包覆活性炭复合材料(2 cm)形成结构化固定床,测定苯酚在颗粒活性炭固定床和结构化固定床上的吸附透过曲线;考察不同实验条件下苯酚在结构化固定床上的吸附动力学,并采用Yoon模型和无效层厚度理论进行理论分析。结果表明,相对于颗粒活性炭固定床,苯酚在结构化固定床上的吸附透过曲线斜率明显增加,苯酚在结构化固定床上的吸附透过曲线斜率随着进口初始浓度的提高或流体流量的增大而增大;根据无效层厚度理论和Yoon模型分别分析计算,苯酚在结构化固定床上的无效层厚度相对于颗粒活性炭固定床的减少了14%,Yoon模型中的吸附速率常数k值明显增加。因此,采用基于微纤包覆活性炭复合材料的结构化固定床,可以强化床层上的吸附传质过程,并提高吸附床层利用率。

Stainless steel fiber-reinforced activated carbon paper was prepared by a wet papermaking method, followed by a high temperature treatment, using stainless steel fibers as the reinforcement and coniferous wood pulp cellulose as the binder. A fixed bed for phenol adsorption was made by first packing granular activated carbon to a depth of 13 cm followed by 2 cm of the as-made pa- per near the outlet. The adsorption dynamics of phenol in the bed were investigated under different experimental conditions. Results show that the breakthrough curve of phenol in the bed is steeper than that in a bed packed only with activated carbon with the same bed height. The breakthrough time of phenol in the bed decreases and the breakthrough curves become sharper with increasing flow rate and inlet concentration. The length of the unused bed decreases by 14% compared with the bed packed with activated carbon on- ly, indicating that mass transfer in the bed and its utilization ratio are improved by the paper packing.