Single, binary, and mixture adsorption of nine. organic contaminants onto a microporous and a microporous/mesoporous activated carbon cloth

The adsorption kinetics of nine contaminants (ibuprofen, carbamazepine, ofloxacin, bisphenol-A, diclofenac, mecoprop, pentachlorophenol, benzotriazol and caffeine) on a microporous and a microporous/mesoporous activated carbon cloth were studied in single, two-component and complete mixture at pH 7.5. Adsorption capacities at equilibrium were highest for the highly microporous carbon material, showing that pollutant adsorption mainly takes place in the micropores. This effect was more pronounced for small size adsorbates. Adsorption kinetics were increased for small size adsorbates thanks to their easy diffusion in the narrow porosity. Same behaviors were observed in the complex mixture containing the nine pollutants. Competition and sieving effects were observed in two-component mixtures, while considering two adsorbates having different molecular volumes, as for example caffeine and diclofenac. Moreover, the desorption of the co-adsorbates having the highest Gibbs energy value of adsorption determined from adsorption isotherms at 298 K (caffeine, mecoprop and benzotriazol) was observed for the kinetics of the complex mixture of the nine contaminants and of the two component mixture. This desorption was provoked by the competition with the contaminants having lower Gibbs energy variation in single adsorption and thus strongly attracted at the adsorbent surface. (C) 2016 Elsevier Inc. All rights reserved.