Application of graphene oxide nanoplatelets for adsorption of Ibuprofen from aqueous solutions: Evaluation of process kinetics and thermodynamics

• GONPs proved to be efficient, inexpensive and non-toxic adsorbent of Ibuprofen.
• Adsorption best fitted Langmuir Isotherm.
• Adsorption process was guided by pseudo 2nd order kinetics.
• Adsorption was spontaneous, endothermic and physisorption in nature.
• GONP was highly effective in reduced time (60 min) and low dose (1 g/L).

Ubiquitous occurrence of several pharmaceuticals in discharged sewage effluents has lead to considerable deterioration of life and quality of receiving water bodies. Ibuprofen, an acidic nonsteroid drug, is one such pharmaceutical being widely used for its analgesic, antipyretic and anti-inflammatory properties. The present work investigated the efficiency of graphene oxide nanoplatelets (GONPs) in adsorption of Ibuprofen from its aqueous solutions. The GONPs were characterized by electron microscopy and X-ray diffraction to analyze changes in structure and morphology occurring due to adsorption (if any). The impact of various process parameters on percentage removal (%) of Ibuprofen was determined by batch adsorption experiments. The data obtained were subjected to isotherm and kinetic analysis in order to describe the distribution of ibuprofen between the liquid and solid phases in the batch studies. The results obtained best fitted the Langmuir isotherm model and were determined to be guided by pseudo second-order kinetics. Thermodynamic parameters such as Gibb's free energy, Enthalpy and Entropy were also evaluated and the results revealed the endothermic and spontaneous nature of the process of adsorption of ibuprofen onto graphene oxide. Hence, graphene oxide may be considered as a suitable adsorbent for large scale efficient treatment of water contaminated with ibuprofen and similar other anti-inflammatory drugs.