Preparation and characterization of sodium iron titanate ion exchanger and its application in heavy metal removal from waste waters

The ion exchange properties of sodium iron titanates, namely, NaFeTiO₄, Na₂Fe₂Ti₆O₁₆ and iron-doped sodium nonatitanate were investigated. Conventional solid state and sol-gel methods were used in the synthesis of the sodium iron titanates. Structural characterization of the materials was performed with powder X-ray diffraction (XRD), thermogravimetry (TG), scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) and with inductively coupled plasma optical emission spectrometry (ICP-OES). Based on TG analyses, the novel iron-doped sodium nonatitanate was proven to be a member of the layered titanate family. The different sodium iron titanates were compared based on the efficiency in separating Ni from aqueous streams by conducting batch experiments with a batch factor of 1000 ml/g. Iron-doped sodium nonatitanate exhibited the best ion exchange performance compared to the other sodium iron titanates studied. It was found to be selective for nickel over potassium and showed 99% removal efficiency for Ni.