Adsorptive and Kinetic Studies of the Extraction of Toxic Metal Ion from Contaminated Water Using Modified Montmorillonites

In present scenario, there is need to develop adsorbent based and cost-effective water purifier for removal of radiological and toxic metal ion contaminants viz. cesium, strontium and cobalt from contaminated water. In this regard, modified montmorillonite was prepared using reaction with hydrogen peroxide and potassium di-hydrogen phosphate and obtained product was characterized by different spectroscopic techniques viz. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The obtained modified montmorillonite was evaluated for removal of Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) from contaminated water. Various factors which affect adsorption of metal ions on modified montmorillonite viz. contact time, initial concentration of metal ions and pH were studied. The batch method has been employed to determine adsorption capacity for metal ions in solution from 1000-10 000 mu g/L, contact time 5-30 min, pH 4-10 and material quantities 50-200 mg at room temperature. The obtained adsorption data were fitted to Freundlich and Langmuir isotherm models; both models were found applicable for the metal ions adsorption on modified montmorillonite. The adsorption data were shown to follow pseudo second order reaction kinetics as per kinetic studies. The maximum adsorption capacity obtained 1.65-2.82 mg/g for Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) metal ions. The results show that modified montmorillonite have great potential to remove Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) from aqueous solutions through chemisorption and physio-sorption. Modified montmorillonite can be used for removal of radiological and toxic metal ion contaminants from contaminated water.