An MIL-88A(Fe) rod-like metal–organic framework decorated with tungstophosphate polyoxoanions and nickel ferrite nanoparticles for the removal of antibiotics from water

Abstract

In this work, a magnetic H₃PW₁₂O₄₀(POT)/NiFe₂O₄/MIL-88A(Fe) nanocomposite was fabricated by the hydrothermal method and utilized as a stable and effective ternary adsorbent for the removal of ciprofloxacin (CIP) and tetracycline (TC) from aqueous solution. Characterization of the magnetic nanocomposite was performed by Fourier transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), field emission scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), vibrating-sample magnetometer (VSM) measurement, Brunauer–Emmett–Teller (BET) specific surface area measurement, Raman spectroscopy and zeta potential analysis. Factors influencing the adsorption capacity of POT/NiFe₂O₄/MIL-88A(Fe) including primary dye concentration, pH, temperature, and adsorbent dose were analyzed. The maximum adsorption capacities of POT/NiFe₂O₄/MIL-88A(Fe) for TC and CIP were 200.93 mg g⁻¹ and 181.12 mg g⁻¹ at 25 °C, respectively. Moreover, the POT/NiFe₂O₄/MIL-88A(Fe) adsorbent had good regeneration capacity and reusability after three cycles of use. The adsorption process fit well with the Freundlich isotherm model and pseudo-second-order adsorption kinetics model, demonstrating a multilayer adsorption and chemical adsorption behavior. The adsorption mechanism was mainly ascribed to the electrostatic attraction and π–π interactions. According to these results, POT/NiFe₂O₄/MIL-88A(Fe) can act as an effective reusable adsorbent for the fast elimination of TC and CIP antibiotic drugs from aqueous solution.