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

Abstract

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.