Green remediation: Casuarina equisetifolia fruit-based activated carbon for pharmaceutical removal

This work utilized Casuarina equisetifolia fruit-based activated carbon (CEAC) to investigate the simultaneous removal of paracetamol (PA), caffeine (CAF), and acetylsalicylic acid (AS) from aqueous solutions. The efficacy of adsorbent removal was investigated using adsorption factors such as pH, CEAC amount, initial pharmaceutical concentration, and adsorption period. Fourier-transform infrared spectroscopy, scanning electron microscopy, and UV-visible analysis confirmed the simultaneous adsorption of the pharmaceutical mixture onto the CEAC surface. The results showed a slight effect of pH on the simultaneous adsorption efficiencies with a CEAC dose of 110 mg. The ideal initial concentration for the pharmaceutical mixture was determined to be 15 mg L^-1. The perfect contact duration for the simultaneous removal of the three pharmaceuticals was found to be 30 min. Kinetic tests demonstrated that the pharmaceutical mixture adsorbs using a pseudo-second-order process. The Freundlich isotherm model describes the equilibrium data. The maximum adsorption capabilities were PA (84.15.23 mg g^-1), CAF (79.16 mg g^-1), and AS (61.32 mg g^-1). A thermodynamic study reveals that these adsorption processes are endothermic and spontaneous. Finally, regeneration experiments confirm the reusability of CEAC.