Synthesis and catalytic performance of renewable mesoporous silicas for the removal of emerging contaminants in water

Abstract

Due to the stability of industrial dyes, this work evaluates the performance of sustainable mesoporous nanomaterials in the degradation of Orange Acid 7 (AO7) through Wet Oxidation with Air (OHA). The solids were synthesized by the sol-gel route using glyceryl monostearate (MEG) as a renewable template, and incorporating iron directly (Si/Fe = 10). The nanomaterials (M-MEG and Fe-(10)-M-MEG) exhibited a well-defined mesoporous hexagonal arrangement, with specific areas of 300-390 m²/g and pore diameters of 10-11 nm. In the degradation of AO7 by OHA, the matrix initially achieved a removal of 65.69% compared to the solid with iron, 26.57%. However, tests under N₂ flux and FT-IR analysis demonstrated that the matrix would operate as a support for the adsorption of the dye by the nested silanols present in the structure, while the solid with iron would favor degradation up to 87% after 5 weeks, evidencing a delayed mechanism mediated by free radicals. Both materials are positioned as sustainable alternatives to optimize the elimination of persistent organic contaminants in aqueous effluents.