Optimization of heavy metals and dyes removal from aqueous solutions by magnetic zeolite nanocomposite using central composite design

Abstract Water pollution caused by heavy metals and dyes has emerged as a pressing global issue due to their adverse effects on human health and ecosystems. In this study, magnetic zeolite nanocomposite (Fe3O4–NaA) was employed as an efficient magnetic adsorbent to remove cadmium (Cd), lead (Pb), malachite green (MG), and methylene blue (MB) from aqueous solutions. The Fe3O4–NaA adsorbent was synthesized and characterized through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. The results confirmed nanostructure, high surface area, and high adsorption capacity of this adsorbent. The point of zero charge (pHpzc) of the Fe3O4–NaA was determined to be 6.2, demonstrating its versatility for various pH ranges. Process optimization was conducted using a central composite design (CCD) matrix combined with response surface methodology (RSM) to evaluate the influence of key factors, including solution pH, Fe3O4–NaA nanocomposite amount, ultrasonic time, and initial analyte concentration. The optimal conditions (Fe3O4–NaA nanocomposite amount of 0.04 g, pH of 7, initial analyte concentration of 17 mg L-1, and ultrasound time of 16 min) resulted in removal efficiencies ranging from 91.11% to 96.09%. Reusability tests revealed that the Fe3O4–NaA adsorbent retained high performance over 5 adsorption/desorption cycles, with hydrochloric acid identified as the most effective eluent for regeneration. The efficacy of Fe3O4–NaA nanocomposite was further validated using real water samples, where it successfully removed contaminants with high efficiency. These findings highlight the potential of Fe3O4–NaA nanocomposites as cost-effective and environmentally-friendly adsorbents for the remediation of contaminated water.