Reductive Dissolution of Colloidal Manganese Dioxide in Aqueous Phosphoric Acid Solution: A Kinetic Approach
Reductive Dissolution of Colloidal Manganese Dioxide in Aqueous Phosphoric Acid Solution: A Kinetic Approach
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DOI：
10.1166/jcsb.2013.1057
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发表时间：
2013-09-01
期刊：
影响因子：
--
通讯作者：
Rahman, M. Muhibur
中科院分区：
文献类型：
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作者：
Islam, Md. Aminul;Rahman, M. Muhibur
本研究采用分光光度法，在25℃下观察胶体MnO2在390 nm处的消失。对MnO2的浓度-时间分布进行了动力学分析。溶解速率随磷酸浓度和反应时间的变化而变化。随着磷酸浓度的增加，溶解速率逐渐增大。在整个测量过程中，产品混合物是透明的，表明胶体二氧化锰没有凝固。已发现这种胶体被磷酸还原。溶解动力学随磷酸浓度呈分数阶（1.20）变化。MnO2浓度也呈分数阶（0.50）。测定了反应速率常数。对反应过程中锰的平均氧化态进行了评价。提出了该反应的机理。
In the present work, the monitoring reaction was carried out spectrophotometrically at 25 degrees C by observing the disappearance of colloidal MnO2 at 390 nm. The concentration-time profiles of MnO2 species were evaluated for kinetic analysis. The rate of dissolution was determined as a function of phosphoric acid concentration and reaction time. The dissolution rate gradually increased with increasing phosphoric acid concentration. The product mixture was transparent throughout the course of measurements indicated that colloidal MnO2 was not coagulated. The colloid has been found to be reduced by phosphoric acid. The dissolution followed fractional order (1.20) kinetics with respect to phosphoric acid concentration. It also presented a fractional order (0.50) in MnO2 concentration. The rate constants were determined. The average oxidation state of manganese species during the reaction has also been evaluated. A mechanism for the reaction is proposed.