Elimination of Ciprofloxacin from Aqueous Solution by Ultrasonic-Assisted Adsorption Using Chitosan Crosslinked Graphene Oxide Nanoparticles

Abstract

Aquatic life is largely affected by the toxic nature of pharmaceutical waste that is released into the environment and affects nature at every level. To preserve nature, it is very important to remove pharmaceutical waste, such as ciprofloxacin (CIP) and other antibiotics from nature. In this study, chitosan-graphene-based eco-friendly nano-adsorbent (CS-GO-NPs) was synthesized for the removal of CIP from an aqueous medium using ultrasonic-assisted adsorption. A detailed analysis of process conditions including pH, initial concentration, adsorbent dose, and temperature was performed. Results were found to be significant and more than 94% removal efficiency was achieved using an optimum concentration of 200 mg/L, 5 pH, and adsorption time of 20 min. Further, batch adsorption data was used to study the kinetic and thermodynamic behavior and an isotherm study was performed to determine the adsorbate-adsorbent interaction. Experimental results showed a significant agreement with the theoretical values and more than 0.99 regression coefficient (R²) values were obtained for pseudo-second-order and Freundlich isotherm. Further, an adsorption mechanism was also proposed for the CIP-(CS-GO-NPs) system, and found that film diffusion dominates the process, while pore diffusion also plays a vital role in devising an effective eco-friendly adsorbent. The proposed study provides an effective and sustainable route for the management of toxic pharmaceutical wastes using chitosan-graphene-based nano-adsorbent under mild process conditions.