Synergistic Role of Pumice Surface Composition in Hydroxyl Radical Initiation in the Catalytic Ozonation Process

This study investigated the catalytic ozonation of p-chloronitrobenzene (p-CNB) in aqueous solution by using different pumice surface compositions as catalysts. The results indicate that the surface hydroxyl groups of metal oxides on pumice play an important role in ozone decomposition to generate the hydroxyl radical (•OH). An increase in the mass ratio of SiO₂/metal oxides results in the acceleration of ozone adsorption on the catalyst surface. The synergistic mechanism confirms that SiO₂ induced ozone enrichment on the pumice surface and increased the probability of reaction between surface hydroxyl groups on metal oxides and ozone molecules to initiate •OH from ozone decomposition and to stimulate p-CNB degradation.