Vinit K. Mittal

Studies on Sorption of Antimony on Carbon Steel Surface in Chemical Decontamination Medium

Antimony(III) in a mixed solution of nitrilo tri acetic acid, ascorbic acid, and citric acid, known as a chemical decontamination solution, was found to be deposited on a carbon steel (CS) surface under deaerated condition. The deposited antimony on the CS surface was characterized by X-ray photoelectron spectroscopy and X-ray diffraction technique. The deposited material was found to contain elemental Sb and the Fe-Sb-O compound. The characterization results showed the initial adsorption of Sb on CS and the subsequent surface precipitation of the Fe-Sb-O compound. A commercial organic inhibitor Rodine 92B was used to stop the initial adsorption of Sb(III) and further growth of the Fe-Sb-O compound on the CS surface. Nitrogen in the inhibitor was observed to act as the bridging agent between Fe and the inhibitor for growing a layer of the inhibitor that stopped the adsorption of Sb. The work has direct relevance to nuclear reactors in terms of prevention of deposition of radioactive antimony on CS surfaces during chemical decontamination.

XPS studies on in-situ heating of ferrites

Ferrites like ZnFe2O4 and NiFe2O4 are heated in-situ in XPS chamber upto 300°C. It has been observed from XPS that ZnFe2O4 undergoes surface enrichment of Fe after 250°C whereas NiFe2O4 does not show such changes. The minute chemical changes are interpreted from the changes in Fe2p and Ni2p peaks due to heating.

Adsorption of nano-ZrO2 on 304L stainless steel in aqueous medium

Adsorption of nano-ZrO2 (size 8-10 nm) on oxidized stainless steel has been studied. The adsorption behavior was seen to be influenced by composition of the oxidized surface and the surfactant in the aqueous medium. It was observed that the Fe2O3 phase on the surface is most favorable oxide for attracting ZrO2 nano particles in suspension. XPS, XRD and TEM techniques have been used for the above study.