Removal of the antidepressants bupropion and sertraline from aqueous solutions by using graphene oxide: A complete adsorption/desorption evaluation for single-component and binary mixtures

Abstract

Graphene oxide, a material with exceptional adsorption properties, was employed for the removal of two antidepressants, sertraline and bupropion, from aqueous solutions. Batch adsorption experiments were conducted, under various conditions, to determine the optimal parameters for efficient removal. Equilibrium was met at 3 h, at pH 4 for 1 g/L of dosage, while a removal of 86 % and 98 % was achieved for bupropion and sertraline, respectively. According to Langmuir model, adsorption capacities of 147.88 mg/g and 67.35 mg/g were achieved at 25 °C for sertraline and bupropion, respectively. Thermodynamic analyses showed that the adsorption of both drugs was endothermic and spontaneous. The binary adsorption studies were performed in different ratios and revealed a higher affinity for sertraline, where a removal efficiency of > 90 % was maintained. The stability of the adsorbent under varying pH conditions was tested and showed higher stability at neutral conditions. Comprehensive material characterizations, including Fourier-transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction (XRD), and pH at the point of zero charge (pHpzc) were performed. These findings demonstrate the potential of graphene oxide as an efficient adsorbent for the removal of pharmaceuticals from wastewater.