Hydrogen Peroxide Stability in Silica Hydrogels

Hydrogen peroxide (H₂O₂) entrapment in silica hydrogels has potential to be used in various industrially important applications to increase H₂O₂ stability. In this study, optimum conditions for hydrogel formation and H₂O₂ stability were determined by varying the sodium content and initial H₂O₂ concentration. Higher retention and better stability of H₂O₂ were achieved with hydrogels at room temperature at low sodium concentration. Retention values of 89% were obtained with initial H₂O₂ concentrations up to 10 wt %. H₂O₂ decomposition in hydrogels followed a first-order reaction. Hydrogels were characterized by measuring their surface area, pore size, and pore size distribution by Brunauer–Emmett–Teller analysis and scanning electron microscopy. Mesoporous (3–24 nm) hydrogels with high surface area (1000–1400 m²/g) were obtained. In addition, the melting point of the entrapped H₂O₂-water mixture in the hydrogels was studied by low temperature differential scanning calorimetry