改性粉煤灰对空气中甲醛的吸附研究

摘要

以粉煤灰为主要材料,使用3种方法分别对粉煤灰进行改性,研究不同条件下改性粉煤灰对空气中甲醛的吸附特性和去除效果,并探讨粉煤灰对甲醛的吸附和脱附机理.研究结果表明3种改性粉煤灰对甲醛的吸附能力由高到低为:ZnCl2改性粉煤灰,热处理粉煤灰,水洗粉煤灰；在甲醛初始质量浓度为0.41 mg/m3,改性粉煤灰用量为1.0 g,温度为25℃的情况下,ZnCl2改性粉煤灰对甲醛最大去除率达70.48％,去除效果与煤基活性炭的相当(最大去除率为68.96％),远超过了未改性的粉煤灰的最大去除率(30.71％); ZnCl2改性的粉煤灰重新活化后,可重复使用,5次再生实验后的吸附率仍达60.02％.%Using fly ash as a carrier, three kinds of methods were used to modify the nature of fly ash in order to study adsorption characteristics and the removal of formaldehyde in air under different experimental conditions. The mechanism of fly ash to adsorption and desorption of formaldehyde was also discussed. The results show that the adsorptive capacities of formaldehyde by modified fly ash from strong to weak are as follows: ZnCl2-modified fly ash, heat-treatment fly ash, water-treatment fly ash. When dosage of ZnCl2-modified fly ash is 1.0 g, the original concentration of formaldehyde is 0.41 mg/m3 and the temperature is 25℃, the maximum removal rate can reach 70.48%, which is much higher than that of non-modified fly ash (30.71%), and as much as that of coal-based activated carbon (68.96%). ZnCl2-modtfied fly ash can be effectually reused after reactivated, and the removal rate of formaldehyde remains up to 60.02% after five regenerations.