PAMAM-halloysite Dunino hybrid as an effective adsorbent of ibuprofen and naproxen from aqueous solutions

Abstract The eco-friendly halloysite from Polish mine Dunino was grafted with polyamidoamine dendrimer to obtain the hybrid material for removal of two model drug pollutants – ibuprofen and naproxen – from aqueous solutions. The hybrid was characterized using several physicochemical methods – Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and nitrogen sorptometry. The optimal adsorption conditions were achieved for pH 6 and 50 mg of the adsorbent dose. The adsorption capacities of ibuprofen and naproxen were 68.34 mg g−1 and 5.96 mg g−1 respectively. The adsorption of model drugs increased with increasing initial drug concentration and temperature. The mathematical models indicated the compatibility of the adsorption with pseudo-second-order kinetics and Langmuir isotherm. The calculated thermodynamic parameters – negative Gibbs free energy change and positive enthalpy and entropy change – showed spontaneous and endothermic nature of the process. Additionally, the hybrid studied was obtained using inexpensive and available raw material of significant natural resources, which should increase the possibility of its use for purification of aqueous solutions from pharmaceutical impurities.