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

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 (Fe 3 O 4 –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 Fe 3 O 4 –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 (pH pzc ) of the Fe 3 O 4 –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, Fe 3 O 4 –NaA nanocomposite amount, ultrasonic time, and initial analyte concentration. The optimal conditions (Fe 3 O 4 –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 Fe 3 O 4 –NaA adsorbent retained high performance over 5 adsorption/desorption cycles, with hydrochloric acid identified as the most effective eluent for regeneration. The efficacy of Fe 3 O 4 –NaA nanocomposite was further validated using real water samples, where it successfully removed contaminants with high efficiency. These findings highlight the potential of Fe 3 O 4 –NaA nanocomposites as cost-effective and environmentally-friendly adsorbents for the remediation of contaminated water.