Rhodamine B Degradation through Sulfite Activation by Vernadite: Kinetics characteristics and Reaction Mechanism

Vernadite is often used for pollutant adsorption, oxidation and interfacial catalysis due to its diverse structure, high reactivity and environmental friendliness. Rhodamine B was employed as a model organic contaminant in this study to investigate the capability of Vernadite-activated sulfite for organic pollutant degradation and to elucidate the activation mechanism of sulfite in the Vernadite/sulfite system. Vernadite was able to partially decolorize approximately 90.3% of Rhodamine B (RhB) due to its strong surface activity. Upon the addition of sulfite, RhB was fully degraded within 20 minutes, and the solution was observed to change from red to colorless. It was discovered that dissolved oxygen was crucial to the process. As the sulfite content rose, the degradation efficiency first rose and then decreased, but it rose as the mineral dosage increased. The system was effective within the pH range of 3-7, though efficiency declined as pH increased. The presence of common coexisting ions had minimal impact on the performance, particularly in the presence of humic acid (HA), where degradation remained effective. Mn (III) and singlet oxygen ( 1 O 2 ) were confirmed to be the primary reactive species in charge of RhB degradation by electron paramagnetic resonance (EPR) and quenching studies. These results demonstrate the possible uses of minerals containing manganese dioxide as heterogeneous catalysts for environmental remediation under realistic wastewater treatment conditions.