Zinc oxide nanoparticles were synthesized using a simple precipitation method with zinc sulfate and sodium hydroxide as starting materials. The synthesized sample was calcined at different temperatures for 2 h. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and proton-induced X-ray emission (PIXE) analysis. SEM images show various morphological changes of ZnO obtained by the above method. The average crystallite sizes of the samples were calculated from the full width at half maximum of XRD peaks by using Debye-Scherrer's formula and were found to be in the nanorange. EDS shows that the above route produced highly pure ZnO nanostructures. PIXE technique was used for trace elemental analysis of ZnO. The optical band gaps of various ZnO powders were calculated from UV-visible diffuse reflectance spectroscopic studies.

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Zirconia-modified vermiculite (ZrMV) was prepared by mixing of zirconium oxycation with vermiculite followed by calcination at 523 K for two hours. Vermiculite and ZrMV were characterized by surface area and X-ray diffraction patterns. Sorption of strontium as a function of pH, strontium ion concentration, time, and temperature was studied on ZrMV, and the results were compared with those of vermiculite. The percentage sorption of strontium on vermiculite and ZrMV increased with increase in pH and lowering concentration of Sr2+. The rate of uptake of strontium by ZrMV was found to be much faster than that for vermiculite. The distribution coefficient of strontium on ZrMV is of the order of 104 mL/g at pH 3, and the amount of strontium sorbed on ZrMV was always found to be much higher than that on the parent clay. The sorption data were fitted to Langmuir adsorption model for obtaining the sorption capacity of the sorbent. Increase of temperature increases the distribution coefficient of strontium on both ZrMV and vermiculite. Distribution of strontium on ZrMV was also determined from the groundwater samples obtained from the waste disposal site at Kalpakkam.