Treatment of metronidazole in wastewater by nano zero-valent iron/copper slag nanocomposite

In the last two decades, special concern has been focused on certain drugs such as Metronidazole (MNZ) owing to their potential carcinogenic and mutagenic properties. In the current study, nano zero-valent iron (nZVI) combined with Copper Slag was utilized for the adsorption of MNZ from an aqueous environment. The proper distribution of nZVI was confirmed by surface morphology analysis using FESEM. In addition, the incorporation of nZVI into Copper Slag led to an approximate 82% increase in BET surface area and a more than 20% rise in iron content according to the EDX result, which together contributed to a 90% improvement in MNZ removal efficiency from aqueous solutions. The optimum conditions (initial MNZ concentration of 27.9 mg/L, adsorbent quantity of 6.8 g/L, contact time of 35.5 min, and an initial pH of 5.04) were attained, demonstrating excellent adsorbent removal efficiency through running the CCD design. The Langmuir isotherm accurately described MNZ adsorption on nZVI/Copper Slag, and kinetic modeling showed that the experimental data fit well with the pseudo-first-order. The adsorption of MNZ onto the adsorbent is spontaneous and exothermic, with ∆G° < 0 and ∆S° < 0, indicating thermodynamic favorability and increased order at the solid–solution interface. Furthermore, it indicated excellent reusability and regeneration performance over six consecutive cycles.