炭基材料吸附VOCs及电致热脱附性能研究

发布时间：2018-06-10 13:38

  本文选题：VOCs + 活性炭纤维　； 参考：《浙江工业大学》2015年硕士论文

【摘要】：挥发性有机化合物(VOCs)是已经成为继SO2和NOX后最受关注的大气污染物,它与NOX、烟尘一起作用可形成光化学污染,是造成城市“雾霾”等复合型大气污染物的主要原因。目前工业上往往采用高效、节能、操作简单的吸附技术作为主要手段对其进行治理。而活性炭作为工业应用较多的吸附剂存在着疏水性差、易燃易爆、脱附困难等问题。活性炭纤维作为新型的炭基吸附材料以其高比表面积、大孔容、丰富的微孔以及导电性在VOCs治理中得到了越来越多的应用。首先本文选用三种活性炭纤维ACF1、ACF2、ACF3,系统考察了VOCs种类(甲苯、乙酸乙酯、丙酮、异丙醇)及甲苯浓度、床层温度、不同湿度对三种活性炭纤维吸附VOCs性能的影响。结果表明,具有高比表面、大孔容的ACF2活性炭纤维其吸附容量最佳,甲苯饱和吸附容量可达到318.3mg/g。甲苯浓度对吸附推动力影响较大,在浓度为12000mg/m3下,可使吸附容量达到434.8mg/g。活性炭纤维吸附甲苯受温度影响较小,在60℃下仍然具有288.6mg/g的吸附容量。其次,动态吸附实验测定303K、318K、333K温度下,甲苯在活性炭纤维和活性炭二种吸附剂上的吸附平衡等温线,通过模型拟合吸附等温线,并计算吸附热。实验结果表明:①在低压区二种吸附剂的吸附量都快速上升,这与其富含微孔有关,同时在低温(303K)高压区,活性炭纤维表现出更好的吸附效果;②利用Clansius-Clapeyron方程计算得到等量吸附热数据,活性炭纤维的等量吸附热要低于活性炭的吸附热,可有效防止吸附床层飞温,更具安全性;③在不同温度、不同浓度条件下,Yoon-Nelson模型对活性炭和活性炭纤维床层动态吸附穿透曲线均能很好拟合,模型参数能较好描述动态吸附过程,通过模型参数也能很好预测穿透曲线。基于水蒸汽再生活性炭纤维存在热传递速率慢,脱附时间长等问题,利用活性炭纤维自身的电阻,通过电流产生焦耳热,从而使活性炭纤维升温进行再生,论文考察了不同电压下电致热再生活性炭纤维的性能。结果表明,电压越大,活性炭纤维升温速率越快,脱附效率越高,而且经过100min即可完全脱附。同时经过4次循环,活性炭纤维仍然有较好的吸附效果,饱和吸附量依然能达到原有吸附量的80%以上。
[Abstract]:Volatile organic compounds (VOCs) have become the most concerned atmospheric pollutants after SO2 and NOX. They interact with NOX and soot to form photochemical pollution, which is the main cause of urban "smog" and other complex atmospheric pollutants. At present, the adsorption technology of high efficiency, energy saving and simple operation is used as the main means to treat it. However, activated carbon is widely used as an adsorbent with poor hydrophobicity, flammable and explosive properties, difficult desorption and so on. As a new carbon based adsorption material, activated carbon fiber (ACF) has been used more and more in VOCs treatment with its high specific surface area, large pore volume, rich micropore and electrical conductivity. The effects of VOCs (toluene, ethyl acetate, acetone, isopropanol), toluene concentration, bed temperature and humidity on the adsorption properties of three kinds of activated carbon fibers (ACF1 / ACF2 / ACF3) were investigated. The results show that the adsorption capacity of ACF2 activated carbon fiber with high specific surface and large pore volume is the best, and the saturated adsorption capacity of toluene can reach 318.3 mg / g. The concentration of toluene has a great influence on the driving force of adsorption. When the concentration of toluene is 12000mg/m3, the adsorption capacity can reach 434.8 mg / g. The adsorption of toluene by activated carbon fiber is less affected by temperature, and still has the adsorption capacity of 288.6mg/g at 60 鈩，

本文编号：2003406