Comparison between activated carbon, carbon xerogel and carbon nanotubes for the adsorption of the antibiotic ciprofloxacin

A comparison was made for the adsorption capacity of ciprofloxacin (CPX) on three types of carbon-based materials: activated carbon, carbon nanotubes and carbon xerogel. The obtained samples were characterised by adsorption of N-2 at -196 degrees C, determination of the point of zero charge and by temperature programmed desorption. The Langmuir and Freundlich models were used to describe the equilibrium isotherms obtained. Adsorption capacities ranging from approximately 112 to 231 mg(CPX) gC(-1) were obtained (for carbon xerogel and activated carbon, respectively). The influence of the textural and surface properties of the carbon materials on the CPX adsorption was discussed and it was shown that the carbon nanotubes sample presents the best performance per unit surface area. (C) 2011 Elsevier B. V. All rights reserved.