分子筛负载型吸附剂对典型VOCs的吸附行为特性

以浸渍法制备的分子筛负载铜锰铈(Cu-Mn-Ce/ZSM)为吸附剂,以甲苯、乙酸乙酯和丙酮作为挥发性有机物(VOCs)的典型代表,考察了单组分和混合组分VOCs在吸附剂固定床上的吸附行为。研究表明,Cu-Mn-Ce/ZSM吸附单组分VOCs时,甲苯的吸附穿透时间与饱和吸附量分别为110 min和32.47 mg/g,乙酸乙酯为150 min和52.29 mg/g,丙酮为210 min和86.40 mg/g,可见Cu-Mn-Ce/ZSM对单组分VOCs的吸附能力大小为:丙酮 > 乙酸乙酯 > 甲苯。Cu-Mn-Ce/ZSM吸附混合组分VOCs时,在甲苯与乙酸乙酯的穿透曲线上出现了明显的"驼峰",吸附穿透过程中存在共吸附和竞争吸附行为,甲苯的吸附穿透时间与饱和吸附量降至50 min、10.42 mg/g,乙酸乙酯为95 min、15.12 mg/g,丙酮为105 min、44.37 mg/g。通过Yoon-Nelson模型对单组分VOCs吸附穿透曲线的拟合,表明吸附模型参数可以准确地预测吸附质在固定床上的穿透行为。速率参数k'值计算表明,不同VOCs在固定床上的吸附速率大小为丙酮 < 乙酸乙酯 < 甲苯。

Adsorption characteristics of typical VOCs on Cu-Mn-Ce/ZSM adsorbent fixed-bed

The adsorption performances of single and mixed volatile organic compounds (VOCs), including toluene, ethyl acetate, and acetone, were investigated using a fixed-bed filled with Cu-Mn-Ce/ZSM adsorbent prepared by the impregnation method. When a single VOC was used as the adsorbate, the breakthrough time and saturated adsorption amount, respectively were 110 min and 32.47 mg/g for toluene, 150 min and 52.29 mg/g for ethyl acetate, and 210 min and 86.40 mg/g for acetone. The results indicate that the adsorption properties of VOCs on Cu-Mn-Ce/ZSM are in the order of acetone > ethyl acetate > toluene. When mixed VOCs were tested for adsorption, there were clear humps in the breakthrough curves for toluene and ethyl acetate, indicating obvious co-adsorption and competitive adsorption. The breakthrough time and saturated adsorption amount, respectively decreased to 50 min and 10.42 mg/g for toluene, 95 min and 15.12 mg/g for ethyl acetate, and 105 min and 44.37 mg/g for acetone. The Yoon-Nelson model was used to fit the breakthrough curve for single VOCs, and the obtained model parameters were useful for predicting the breakthrough process on the fixed-bed. Moreover, the rate parameter k' indicated that the adsorption rates were in the order of acetone < ethyl acetate < toluene.