Adsorption of heavy metals from aqueous solution by magnetite nanoparticles and magnetite-kaolinite nanocomposite: equilibrium, isotherm and kinetic study

Nano magnetite (Fe3O4) and its composite with kaolinite were synthesized and tested for heavy metals (copper, lead, cadmium, chromium, and nickel) adsorption. The prepared magnetite- kaolinite (Mag-KL) nanocomposites were characterized by Transmission Electron Microscopy, powder X-ray diffraction, Fourier Transform Infrared spectroscopy, and the Brunauer-Emmett-Teller method. Various factors influencing the adsorption of metal ions such as contact time, initial metal concentration, pH, and the amount of adsorbent were investigated to optimize the operating conditions for the use of Mag-KL nanocomposites. The adsorption capacity of the magnetic composite increased with time. Adsorption reaches equilibrium in 120 min and the adsorption increases with the increase in pH. The composite was investigated for regeneration studies and the results confirmed that it could be reused for the adsorption of metal ions from aqueous solutions over five cycles without change in the sorption capacity.