Application of imidazole modified clinochlore for adsorption of ibuprofen residues from polluted water: preparation, characterization, kinetic and thermodynamic studies

The contamination of water resources with various pharmaceutical residues confirms the importance of developing their removal methods by introducing new efficient adsorbents. In this study, the potential of imidazole modified clinochlore (Im@clin) as a new adsorbent for removal of Ibuprofen (IBP) from polluted water was assessed. The characterization studies of synthesized Im@clin by using X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM), SEM-mapping, Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) confirms that the Im@clin is convenient for adsorption. Then, the adsorption capacity of synthesized Im@clin was assessed with regard to removing ibuprofen under different conditions such as varying pH levels of IBP solutions (2–11), initial IBP concentrations (5–200 mg L−1), contact time (5–60 min), and the amount of Im@clin as adsorbent (1.7–33.3 g L−1). The results demonstrate that maximum adsorption capacity of Im@clin for removal of IBP in aqueous solutions is 5.8 mg g−1. The pseudo-second-order and the Langmuir model successfully represented the adsorption kinetic and isotherm of procedure. The thermodynamic parameters such as ΔG0 (the Gibbs free-energy difference), ΔH0 (Enthalpy change difference), and ΔS° (Entropy change difference) are calculated. The endothermic nature (ΔH0 16.19 kJ mol−1) and spontaneous nature (Gibbs free energy change, ΔG0 − 2.03 kJ mol−1) of the IBP adsorption process by Im@clin were confirmed and this process is entropy derived (ΔS0 0.06 kJ mol−1).The authors are grateful to Institute for Advanced Studies in Basic Sciences (IASBS) Research Council, Zanjan University and Iran National Science Foundation (INSF-Grant number of 4000252) for support of this work. We also gratefully acknowledge financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) (projects CTQ2013-43446-P and CTQ2014-51912-REDC), the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, EU) (projects CTQ2016-76782-P and CTQ2016-81797-REDC), the Generalitat Valenciana (PROMETEOII/2014/017) and the University of Alicante