CuCoFe2O4@MC/AC as a new hybrid magnetic nanocomposite for metronidazole removal from wastewater: Bioassay and toxicity of effluent

CuCoFe2O4@MC/AC was synthesized as a highly powerful, magnetically separable nano-adsorbent using a novel microwave-assisted technique using copper, iron, and cobalt salts on methylcellulose (MC) in the presence of activated carbon (AC) in an alkali medium. FESEM, EDS, Mapping & Linescan, BET, FTIR, XRD, TGA, and VSM were all used to characterize the nanomagnetic adsorbent. At the initial concentration of 5 mg/L, pH 7, contact duration of 30 min, nanocomposite dosage of 2.5 g/L, and temperature of 25 °C were observed as the maximum percentage of pollutant adsorption (83.4%). For simple separation by external magnetic fields, the Ms value was 42.62 emu/g. The adsorption rate dropped as the temperature rose, indicating that the adsorption reaction was exothermic. The metronidazole (MNZ) adsorption process via the synthesized magnetic nanocomposite was compatible with the Freundlich isotherm model, according to data derived from Langmuir (R2 = 0.961) and Freundlich (R2 = 0.984) equilibrium isotherms. Furthermore, the results of the reaction kinetic calculations revealed that the adsorption of MNZ by the adsorbent followed a pseudo-second-order model. It was found that the adsorption process was exothermic based on the findings of thermodynamic studies that included entropy changes (ΔS = 57.182 j/mol. k), enthalpy changes (ΔH = -13.106 kJ/mol), and the Gibbs negative free energy (ΔG = -30.146 kJ/mol). Finally, the reusability of the magnetic nano-adsorbent produced was investigated in the removal of MNZ. The results showed that after four adsorption–desorption cycles, the nano-adsorbents effectiveness in the removal process decreased somewhat. The effluent obtained after the adsorption process was evaluated for toxicity and bioassay using Artemia, Daphnia and tomato, lettuce, radish, and cress seeds. According to the findings of this research, the magnetic nanocomposite CuCoFe2O4@MC/AC might be a promising novel adsorbent for antibiotic adsorption from aqueous solutions.