Mechanism of Interaction of Titanates with Aqueous Solutions of Sulfuric Acid

Abstract

The article presents a simulation of the dissolution process of K, Ca, Fe, and Pb titanates. To understand the mechanism of reactions occurring on the surface of titanates, the dissolution process is simulated during anodic polarization of a passive titanium electrode in 14.5 M sulfuric acid. A scheme of a parallel-sequential mechanism of the anodic process of passivation film dissolution is proposed, which made it possible to establish the reasons for the equality of the rates of release into solution of the titanyl ion TiO²⁺ and the cation Fe²⁺. The partial currents of all stages of the dissolution mechanism are calculated. Based on the calculation of the degrees of coating of the titanium electrode surface, the distribution of existing forms of titanium hydroxides is proposed depending on the electrochemical potential. The article establishes that with an increase in the electrochemical potential, the stability of the forms in higher degrees of oxidation increases, which determine the kinetics of anodic dissolution. The peak region on the anode polarization curve corresponds to the transition of titanium(III) hydroxide to titanium(IV) hydroxide. The results of the analysis of the dissolution mechanism of the studied titanates show that an increase in the dissolution rate is associated with the transition of an intermediate hydrated complex of the composition [HO -- Fe -- TiO_aq²⁺] into the solution. It is determined that an increase in the dissolution rate of K₂TiO₃ and FeTiO₃ is achieved by adding reducing agents to the solution. The maximum rate of dissolution of the studied titanates is observed at a potential value of -- 0.3 V

Please cite this article in English as:

Artamonova I.V., Kramer S.M., Godunov E.B., et al. Mechanism of interaction of titanates with aqueous solutions of sulfuric acid. Herald of the Bauman Moscow State Technical University, Series Natural Sciences, 2025, no. 2 (119), pp. 52--64 (in Russ.). EDN: JULRRN

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