Browsing by Author "N. Srinivasu"

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Ion exchangers in radioactive waste management - IV. Radiotracer studies on adsorption of strontium ions over sodium titanate
(Kluwer Academic Publishers, 1992) S.P. Mishra; N. Srinivasu
Adsorption of strontium ions from aqueous solution of Sr(NO3)2 on synthetic sodium titanate [(NaO)x(TiO)y(OH)z] powder has beet investigated as a function of contact time, Sr(II) concentration and temperature. X-ray diffraction studies indicated poor crystallinity of the synthetic sodium titanate, which became more crystalline after annealing at ca. 1173 K for 6 h in air. The adsorption of strontium ions on sodium titanate was favored at higher concentrations of the adsorbate and at lower temperatures. The kinetics of the process follows a first-order rate law with respect to adsorptive concentration and obeys the Freundlich isotherm in the entire range of adsorptive concentration. The process of adsorption in the present system has been found to be of the ion-exchange type. © 1992 Akadémiai Kiadó.
Ion exchangers in radioactive waste management-V. A case of efficient removal of Ba(II) from aqueous solutions by TiO2 powder-radiotracer study
(1992) Shuddhodan P. Mishra; N. Srinivasu; Dhanesh Tiwary
The adsorption behaviour of Ba(II) on titanium(IV) oxide in an aqueous solution was studied by means of batch technique as a function of Ba(II) concentration, temperature and solution pH using Ba-140 as radiotracer. The results show that adsorption is essentially complete in ca 2 h and that the steady state values of adsorption at various concentrations agree well with the classical Freundlich isotherm and follow first order kinetics. The pH and temperature of the solution markedly affect the extent of adsorption. The nature and mechanism of adsorption are discussed. © 1992.
Ion Exchangers in Radioactive Waste Management. Part VI*: Radiotracer Studies on Adsorption of Barium Ions on Potassium Titanate
(1993) Shuddhodan P. Mishra; N. Srinivasu
[No abstract available]
Radiotracer technique in adsorption study-IX. Adsorption of iodide ions on titanium(IV) oxide powder
(1992) Shuddhodan P. Mishra; N. Srinivasu
The adsorption of iodide ions on titanium(IV) oxide powder has been investigated as a function of concentration (10-7-10-2 M), temperature (303-328 K) and pH (1.9-11.9) of the adsorptive solution, employing the radiotracer technique. The rate of uptake of I- was fast initially, slowly decreased with time and finally reached a plateau within ca 6 h. The uptake of iodide ions follows first order kinetics, obeys the Freundlich isotherm and increases with the increase in concentration and decrease in temperature and pH of the adsorbate. Pretreatment of the oxide adsorbent with neutrons and γ-radiations from a 300 mCi (RaBe) neutron source has been associated with decrease in the adsorption capacity of the oxide. The adsorption process involved in the present system is thought to be chemical (ion exchange type) in nature. © 1992.
Removal of barium ions from aqueous solutions by barium titanate using radiotracer technique:
(2014) S.P. Mishra; N. Srinivasu
The adsorption of barium ions on barium titanate in an aqueous solution was studied by means of batch technique as a function of Ba(II) concentration, temperature and solution pH using Ba-140 as radiotracer. The results show that adsorption is essentially complete in ca 180min and the steady state values of adsorption at various concentrations agree well with the classical Freundlich isotherm and follow first order kinetics. The pH and temperature of the solution markedly affect the extent of adsorption. Exposure of the activated barium titanate adsorbent to neutrons and γ irradiation from a (Ra-Be) neutrons source having an integral flux of 3.85x106 neutrons/cm2 sec and associated with a nominal γ does of Ca 172 rads/h, affects its adsorption capacity markedly.