The influence of physico-chemical properties of VOCs on theactivated carbon adsorption capacity

摘要

In order to systematically investigate how properties of volatile organic chemicals (VOCs) influence activated carbonadsorption capacity, eight compounds (isopropylamine, heptane, dichloromethane, 2-chloro-2-methylpropane, 2-butanone, 1-chloropentane, acetonitrile, benzene) were selected for experimental evaluation. These compounds represent a large variationof physico-chemical properties. The adsorption isotherms of these eight compounds on Norit R1 at 294.5K were obtained bythe headspace method. Using partial least squares analysis (PLS) the adsorption capacity at relative pressures: 0.001, 0.01,0.05, 0.10, 0.15 were correlated with physico-chemical properties, as described by 45 variables. The correlations reveal thatthe property parameters affecting adsorption capacity vary during the different stages of adsorption, thus reflecting differentmechanisms. It was found that electronic properties have a dominating influence on adsorption capacity at low relativepressures, while at higher relative pressure adsorption capacity is essentially affected by molecular size and water solubilityof the adsorbates. It was also found that the energy of HOMO has a significant influence on the activated carbon adsorptioncapacity for VOCs at low relative pressures.