Kinetics and Mechanism of Se-Catalyzed Disproportionation of Bisulfite: The Critical Role of Selenosulfate

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• 作者：Bentao Yang ; Liyuan Chai ; Fangfang Zhu ; Xu Yan ; Kaisong Xiang ; Hui Liu
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：April 27, 2016
• 年：2016
• 卷：55
• 期：16
• 页码：4435-4442
• 全文大小：455K
• 年卷期：0
• ISSN：1520-5045

文摘

Se-catalyzed disproportionation of bisulfite (HSO₃^–) is a facile and potential wet flue gas desulfurization. In this paper, the kinetics and mechanism of Se-catalyzed disproportionation of HSO₃^– were systematically investigated. The Se-catalyzed disproportionation of HSO₃^– is found to be pseudo-first-order with respect to the HSO₃^– and Se concentrations, and is zeroth-order with respect to the initial pH value. More importantly, the kinetics of Se-catalyzed disproportionation of HSO₃^– can be divided into two stages, i.e., a rate-controlling stage and an acceleration stage. In the rate-controlling stage, the reaction rate is slow and the intermediate HSeSO₃^– forms. This intermediate is decisive to accelerate the HSO₃^– disproportionation, and thus, it plays an important role in the Se-catalyzed process. Furthermore, a kinetic equation is determined according to the results: r₀ = k₁[HSO₃^–]^0.94[Se]^1.13, where k₁ = (10.88 ± 0.04) × 10^–2 M^–1.07·min^–1. This kinetics prediction model is fitted well with the experimental data, indicating that this model can satisfactorily describe the experimental kinetic data of Se-catalyzed disproportionation of HSO₃^–.