Windshield-waste-driven synthesis of hydroxy sodalite

We demonstrated the synthesis of hydroxy sodalite (HS) via a simple hydrothermal process using windshield waste as the source material. Acid-treated waste glass was directly used as the silicate precursor. The syntheses were conducted under various NaOHprecursor contents for 1, 12, and 24 h. The crystal structure and morphology of the HS were identified by X-ray diffraction and field-emission scanning electron microscopy. As per the results of the analyses, the HS and zeolite-A phases formed with low NaOH content, but HS was successfully synthesized in a single phase with a Na₂O:SiO₂:Al₂O₃ molar ratio of 2.2:1:1 over the course of 24 h. For uniform and high-purity HS crystals, the sizes of the particles of windshield waste were reduced via a highenergy milling process, and then we conducted the hydrothermal procedure under same conditions. Finally, uniformly sized HS crystals were produced with an average diameter of 3μm. These optimized conditions were not only scientifically valuable to understand the formation process, but this process should also accelerate windshield-waste recycling.