Highly effective elimination of tetracycline and ciprofloxacin antibiotics from synthetic wastewater by novel magnetic P2W18O62/MIL-101 (Fe)/NiFe2O4 nanocomposite

Abstract

In this study, a novel magnetic nano sorbent P2W18O62/Fe-MIL-101/NiF2O4 was synthesized in the laboratory setting and was effectively employed for the removal of tetracycline (TC) and Ciprofloxacin (CIP) from water. Several investigations were conducted to substantiate these outcomes such as vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, X-ray diffraction (XRD) and BET analysis. The research established that nanoadsorbent has a surface area of 67.54 m2/g and adsorption capacities of 243.90 mg/g for TC and 596.54 mg/g for CIP. Factors impacting the adsorption process (solution pH, drug concentration, adsorbent dosage, contact time, and temperature) were investigated using the Box-Behnken design (BBD) in response surface methodology (RSM). The optimal values for obtaining the highest removal of the studied drugs were pH of 10, Contact time of 10 min for CIP and 20 min for TC, Drug concentration 75 mg/L, and Nanoadsorbent mass 0.04 g/L. These optimal values resulted in a removal efficiency of 100% for CIP and 90% for TC were achieved. The Langmuir isotherm and pseudo-second-order (PSO) with (R2 = 0.999) and (R2 = 0.999 for TC and 0.998 for CIP) were the best isotherms and kinetic models in the description of the observed data, respectively. The adsorption process demonstrated chemisorption behavior, characterized by adsorption energies of 16.92 kJ/mol for TC and 11.2 kJ/mol for CIP. Thermodynamic assessments revealed an endothermic and spontaneous nature of the adsorption process with elevated temperatures correlating with increased adsorption. The magnetic properties of P2W18O62/Fe-MIL-101/NiFO nanoadsorbent facilitated easy separation post-adsorption. The adsorbent displayed consistent performance over five cycles, maintaining its chemical composition and structural integrity, as validated by XRD, SEM, and VSM analyses before and after reuse. The interaction mechanism between P2W18O62/Fe-MIL-101/NiFO and TC/CIP encompassed electrostatic interactions, p-p interactions, hydrogen bonding, and pore filling. As a result, MOF-based magnetic nanoadsorbent can be used as a suitable adsorbent for TC and CIP removal from aqueous solutions.