The ion exchange properties of nanosized cerium molybdo iodate and cerium phospho iodate

Nanoparticles of cerium molybdo iodate and cerium phospho iodate, tetravalent metal acid (TMA) salts were prepared by chemical co-precipitation method.The protons present in the structural hydroxyl groups indicate good potential for TMA salts to exhibit solid state proton conduction. The samples in its protonated form weresubjected to ion exchange capacity studies. The data revealed that the samples act as agood ion exchanger

Characterization, dielectric and optical studies of nano-cerium phospho iodate synthesized by chemical co-precipitation method

299-304Nanoparticles of cerium phospho iodate belong to the class of tetravalent metal acid (TMA) salt are synthesized by chemical co-precipitation method. The particle size obtained from X-ray diffraction spectrum is found to be in the range of 30 nm. Surface morphology is studied from SEM images. The chemical composition of the sample has been verified using EDAX. The optical studies are carried out using FTIR and UV techniques. The stretching and bending frequencies of the sample are studied using the FTIR spectrum. The optical direct band gap of the material calculated using the Tauc’s relation is found to be 3.4 eV. The dielectric behaviour of the samples is studied at various temperatures and frequencies and ac electrical conductivity is also calculated. It is found that dielectric constant decreases with increase in frequency

Characterization, dielectric and optical studies of cerium molybdo tungstate nanoparticles

893-898Nanoparticles of cerium molybdo tungstate (CMT) have been prepared by chemical co-precipitation method. The average particle size is determined from X-ray diffraction studies. The nanoparticle nature of the sample is verified using SEM, TEM and AFM images. The surface morphology of the sample is studied from SEM image. The FTIR spectrum has been used to study the stretching and bending frequencies of molecular groups in the sample. Temperature and frequency dependence of the dielectric constant and ac electrical conductivity have been investigated. The dielectric permittivities of the samples are evaluated from the observed capacitance values in the frequency range 100 Hz-1 MHz and in the temperature range 50°-110°C. It has been found that with increasing frequency, the dielectric constant decreases. The high value of dielectric constant at low frequencies may mainly be due to the space charge and rotational polarization. Also, the dielectric constant increases with increase in temperature for fixed frequencies. As the temperature increases more and more dipoles will be oriented resulting in an increase in molecular dipole moment. The ac electrical conductivity is evaluated from the permittivity studies. The absorption spectra of the sample in the UV range are recorded. From the analysis of the absorption spectra, the material is found to have a direct band gap of 3.2 eV

Electrical conductivity and ion exchange studies of nano sized cerium (IV) tungsto iodate — A new cation exchanger

488-490Nano particles of cerium tungsto iodate, a tetravalent metal acid salt, have been prepared by chemical co-precipitation method. The particle size of the sample has been calculated from its X-ray diffraction pattern and the average grain size is found to be 25 nm. The size is further characterized by SEM, TEM and FTIR analyses. Its dielectric behaviour at various temperatures (50<span style="mso-bidi-font-family: " times="" new="" roman""="" lang="EN-GB">°-110°C) and frequencies is also investigated. The dielectric constant values increase with the decrease in frequency and the increase in temperature. Moreover, the sample in its protonated form is subjected to ion exchange capacity studies. The data reveals that the sample works as a good ion exchanger. </span

Radiological assessment of cement and clay based building materials from southern coastal region of Kerala

372-376Building materials are one of the potential sources of indoor radioactivity because of the naturally occurring radio nuclides in them. External as well as internal exposures are the two pathways of radiation dose imparted to the human beings from the building materials. Natural clay is the main raw material for the production of bricks and tiles. In the present study, samples of cement, bricks, floor and wall tiles have been analyzed for the primordial radio nuclides namely, uranium, thorium and potassium using gamma ray spectrometry. Radon exhalation rates of these materials were also measured. Among the samples analyzed, the minimum radium equivalent activity was found in bricks (66.08 Bqkg−1) and the maximum was found in cement (225.46 Bqkg−1). External gamma dose, effective dose equivalent, internal and external hazard indexes resulting from the radio nuclides were also determined. The radon exhalation rates from building materials were found to vary between 10.5±2.8 and 82.8±8.2 mBqh−1m−2