Potential of Mg–Zn–Al layered double hydroxide (LDH)/montmorillonite nanocomposite in remediation of wastewater containing manganese ions

Abstract

A Mg–Zn–Al (LDH)/MMT nanocomposite was prepared by physical interaction between Mg–Zn–Al layered double hydroxide (LDH) and montmorillonite (MMT) (20 wt%). The chemical structure of the prepared Mg–Zn–Al (LDH)/MMT nanocomposite was characterized by X-ray diffraction, Fourier transform infrared spectroscopy and N2-adsorption/desorption (BET) measurements. The Mg–Zn–Al (LDH)/MMT nanocomposite was evaluated as an adsorbent for the removal of Mn(II) metal ions from contaminated water. The effect of initial Mn(II) ion concentration (mg/L), solution pH, amount of adsorbent (g/L), stirring rate (rpm) and contact time (min) on the adsorption capacity of the Mg–Zn–Al (LDH)/MMT nanocomposite were studied at 298, 308 and 318 K. The results indicated that the Mg–Zn–Al (LDH)/MMT nanocomposite exhibits high adsorption efficiency in the removal of Mn(II) metal ions from contaminated water. The results showed that the optimum conditions of Mn(II) metal ions adsorption from the aqueous medium using the Mg–Zn–Al (LDH)/MMT nanocomposite adsorbent were: initial Mn(II) metal ion concentration of 80 mg/L at pH of 6.0 in the presence of 0.25 g/L of Mg–Zn–Al (LDH)/MMT nanocomposite using a stirring rate of 160 rpm for 105 min. The maximum adsorption capacities achieved in these conditions were 24.5, 26.4 and 28.9 mg/g at 298, 308 and 318 K, respectively.