Adsorption of Congo Red from Aqueous Solution using Doped Strontium Hexaferrite – Zero Valent Iron Nanocomposite: Kinetic, Isotherm, and Thermodynamic Studies

Abstract

This study has dealt with synthesis of doped strontium hexaferrite / zero-valent iron nanocomposite (SrFe12O19/nZVI) and adsorption of Congo Red (CR) dye by the nanocomposite from aqueous solution was evaluated. The adsorbent was characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) analysis and Scanning Electron Microscopy (SEM). Optimization of experimental conditions such as pH, initial concentration of pollutant, adsorbent weight, contact time, and temperature was done. Maximum removal efficiency was achieved at pH of 8.5, initial concentration of CR=20 μg mL-1, adsorbent weight of 0.12 g with 15 min contact time and 25ºC temperature. Langmuir isotherm with R2=0.9959 seems to have best fit to the CR adsorption results. Also, kinetic studies revealed that adsorption of CR was fitted to the pseudo-second-order model with R2=0.9969. In addition, thermodynamic parameters were evaluated.