LAUSR

Abstract By combination of the nano zero–valent iron (nZVI) nanoparticles and clinoptilolite (Cl) natural zeolite and by chemical reduction method, the nZVI–Cl nanocomposite was produced. The physical and chemical characteristics of the produced nanocomposite were examined using FE–SEM, EDX, VSM and zeta potential analyses and its fine structure was confirmed. The produced nanocomposite was applied for efficient As(V) heavy metal ions removal from aqueous media as a novel eco–friendly adsorbent. The adsorption process was optimized using a minimum number of designed experiments by Design–Expert software using central composite design (CCD) and response surface methodology (RSM) and the adsorption optimum conditions were determined as solution pH of 4, nZVI–Cl dosage of 1 g L−1 and As(V) concentration of 50 mg L−1 by the numerical optimization of the software. In these conditions, the removal efficiency was 88.10% and desirability parameter was 0.986. The adsorption kinetic study showed that the chemisorption effectively controls the adsorption process by a better fit of pseudo–second order model with the experimental data. The adsorption isotherms study demonstrated that the Langmuir model had the best fit with the experimental data, proving homogeneous surface of nZVI–Cl adsorbent and monolayer adsorption of As(V) ions on it. The adsorption thermodynamic study illustrated that the adsorption is thermodynamically spontaneous and exothermic in nature. Also, the adsorbent reusability test verified the adsorbent stability after five consecutive adsorption–desorption cycles without a tangible reduction in removal efficiency.