基于吸附理论分析活性炭对卷烟烟气的吸附

为了解活性炭孔隙结构及被吸附化合物的性质对吸附效率的影响,测定了纯丙酮气体在活性炭上的吸附特性及不同结构活性炭对烟气羰基物的吸附效率。分别用Langmuir模型和D-R模型对活性炭上丙酮气体的吸附数据进行拟合,从模型拟合精度及吸附热预测角度对Langmuir模型及D-R模型进行了比较。进一步分析了吸附效率与模型参数间的关系以及模型参数与活性炭结构和被吸附化合物性质间的关系。结果表明:①与Langmuir模型相比,D-R模型对活性炭上纯丙酮气体吸附数据的拟合相关系数更高,平均相对标准偏差更低,拟合结果更好。②由10-4-3型势函数计算得到活性炭上纯丙酮气体的理论吸附热为17.9 kJ/mol,吸附热较小,说明此吸附以物理吸附为主。D-R模型吸附热预测值为15.8 kJ/mol,与理论计算值较为接近;Langmuir模型吸附热预测值为40.7 kJ/mol,比理论计算值偏大较多。③实现活性炭对不同化合物吸附效率预测的关键是对化合物吸附热的预测。吸附效率主要与吸附温度,活性炭的用量、孔容,化合物的分子量,碰撞直径和能量参数有关。通过分析吸附能可以推断孔径对吸附效率及吸附选择性的影响。

Analysis of Cigarette Smoke Adsorbed on Activated Carbon Based on Adsorption Theories

In order to understand the effects of activated carbon pore structure and adsorbed compound property on adsorption efficiency,the adsorption characters of pure acetone gas on activated carbon and the adsorption efficiencies of activated carbons of different structure to carbonyls in smoke were determined.Langmuir model and D-R model were respectively used to fit the data of gaseous acetone adsorption on activated carbon,and these two models were compared in terms of fitting precision and adsorption heat prediction.The relationships of model parameters with adsorption efficiency,with activated carbon structure and adsorbed compound property were further analyzed.The results showed that: 1) Comparing with Langmuir model,D-R model gave higher correlation coefficient,lower average relative standard deviation and better fitting results for the data of pure acetone gas adsorption on activated carbon.2) The theoretical adsorption heat of pure acetone gas on activated carbon calculated by 10-4-3 potential function was 17.9 kJ/mol,the smaller adsorption heat indicated that it was mainly caused by physical adsorption.The adsorption heat predicted by D-R model was 15.8 kJ/mol,which was more close to the theoretical calculated value.The adsorption heat predicted by Langmuir model was 40.7 kJ/mol,which was much higher than the theoretical calculated value.3) The key to predicting the adsorption efficiency of activated carbon to a compound lay in the prediction of adsorption heat of that compound.The factors affecting adsorption efficiency were mainly adsorption temperature,carbon amount used,pore volume,molecular weight of compound,collision diameter and energy parameters.The analysis of adsorption heat was helpful in investigating the effects of pore size on adsorption efficiency and adsorption selectivity.