Investigation of the dissolution kinetics of molybdenum in citric acid solution with hydrogen peroxide

In this thesis study, the dissolution of metallic molybdenum (Mo) in a citric acid (C₆H₈O₇) solution containing hydrogen peroxide (H₂O₂) and its dissolution kinetics were investigated. In the experiments, the effects of disk rotational speed, C₆H₈O₇ concentration, H₂O₂ concentration, disk surface area, and temperature on the dissolution kinetics were examined. The experimental results showed that disk rotation speeds ranging from 207 to 942 rad/min positively affected the dissolution of molybdenum. In addition, Mo dissolution was favorably influenced by citric acid concentrations in the range of 0.2–1.0 M. While a significant increase in Mo dissolution was observed at hydrogen peroxide concentrations between 0.2 and 0.4 M, the dissolution rate was found to decrease at concentrations between 0.4 and 1.0 M. The dissolution rate was observed to increase proportionally with the disk surface area. The dissolution of Mo increased with increasing temperature. However, the dissolution rate decreased in the temperature range of 20–40 °C, whereas rapid dissolution was observed above 40 °C. The dissolution kinetics of molybdenum in the citric acid solution containing hydrogen peroxide (H₂O₂) were determined using the Levich equation. The activation energy was calculated to be 55.78 kJ/mol, indicating that the dissolution process follows a surface chemical reaction–controlled model.