Adsorption of ketoprofen and 2- nitrophenol on activated carbon prepared from winery wastes: A combined experimental and theoretical study

Adsorption of two organic pollutants (2-nitrophenol: 2-NRP and ketoprofen: KTP) on activated carbon produced from wastes deriving from a winery industry is investigated in the paper. Experimental data retrieved at T = 298–328 K indicate that, in the investigated equilibrium concentrations, a saturation phenomenon is reached for ketoprofen, while for 2-nitrophenol steeper curves are observed. For both the adsorbates, an increase in temperature determines a reduction of adsorption capacity. A modelling analysis via statistic physics models demonstrates that a double layer model is perfectly suitable to describe the adsorption mechanisms of both the investigated adsorbates. In light of the number of bonded molecules per adsorption site, the inclination of both the molecules upon adsorption is described. The obtained results suggest that they are adsorbed via both parallel and non parallel orientations, depending on the systems and temperature. Adsorption capacity variation is controlled by the number of bonded molecules per adsorption site and the density of receptor sites. Adsorption energy results show that physical interactions are responsible of the adsorption of both the pollutants. Finally, the results demonstrate that our adsorbent has an outstanding adsorption capacity which makes it promising for water depollution.