Aqueous-phase adsorption of glycerol and propylene glycol onto activated carbon

Adsorption of reactant and product species can have a major effect on local pore concentrations in activated carbon-supported metal catalysts. Individual and combined adsorption of glycerol (GO) and propylene glycol (PG) onto activated carbon in aqueous solution is reported here at concentration ranges of 0.05-2.0 M and temperatures from 25 degrees C to 160 degrees C. Langmuir and Freundlich isotherms are used to model the single component data, with the Langinuir model best describing results below 0.75 M. The extended Langmuir model has been used to model the competitive adsorption system - model parameters determined from single component experiments accurately predict two component adsorption data over the temperature and concentration ranges studied. Propylene glycol adsorbs more strongly than GO onto the activated cat-bon supports studied, and also adsorbs to a somewhat greater extent compared to GO. This is attributed to the greater organic character of PG, which favors its selective adsorption onto the support material. (c) 2006 Elsevier Ltd. All rights reserved.