Sulfate aerosols from atmospheric sulfite oxidation influence cloud condensation nuclei (CCN), weather, and climate. While gas- and aqueous-phase oxidants in this process are well studied, the role of solid-phase catalysts like clay minerals is less explored.This study mainly focuses on sulfite oxidation promoted by nontronite, with comparison to montmorillonite, which are both smectite clay minerals with large surface areas. Experiments were conducted under pH 5, with and without salinity (0.1M NaCl), monitoring sulfite concentration using UV-Vis spectrophotometry alongside XANES analysis.Results show that nontronite promotes sulfite oxidation, with salinity enhancing the reaction. These findings suggest clay minerals may act as heterogeneous catalysts in atmospheric sulfate formation.
