The effect of water inorganic matrix in ibuprofen adsorption onto activated carbon for water and wastewater treatment

Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

In this thesis the ibuprofen adsorption onto activated carbon F400 was studied. Some of the chemical and physical properties of the carbon were studied, with two different particle sizes and one functionalized carbon. Through model solutions of natural and wastewaters, the influence of the pH and ionic strength was studied, varying also the ratio of monovalent and divalent ions. The integrated analyses of the chemical and the textural characterization of the carbons as well as the kinetic and isotherm studies performed, using non-linear models for the parameters calculation and respective fittings of the experimental data allowed the following conclusions: i) the carbon particle size has a significant influence on the adsorption, being the limiting step the external mass transfer for the smaller granulometry, while for the larger granulometry the process was governed by the internal diffusion; ii) increasing the basicity of the carbon surface (functionalized carbon) it was possible to obtain better removal ratios, so the chemical surface is relevant in this process; iii) adsorption at acid pH is primarily governed by hydrophobic forces and the compound removal is favored; iv) when electrostatic forces govern the reaction (pH 6-8) the adsorption greatly depends on the ionic strength, being favored when the adsorbent/adsorbate interactions are repulsive and disfavored when the interactions are attactive; v) for saline waters with high pH it proved disadvantageous the use of carbon with higher basicity, possibly because the two effects cancel each other out the functionalization has only proven effective when the pH and the ionic strength varied inversely; vi) the ibuprofen adsorption did not varied when the only parameter changed was the type of ion, the ions used were the calcium (which confers hardness) and the potassium (conferring salinity). Therefore, only the ionic strength seems to influence the compound adsorption and not the nature of the ions.