Preparation of porous material from waste bottle glass by hydrothermal treatment

Porous materials were prepared from colored waste glass by hydrothermal treatment with Na ₂CO ₃ aqueous solution. The resultant specific surface area was approximately 140 m ²/g at maximum. Specific surface area increased at first, reached a maximum, and decreased gradually to be constant at approximately 60 m ²/g depending on the period of hydrothermal treatment, irrespective of the concentration of Na ₂CO ₃ aqueous solution. However, the period at which the specific surface area reached maximum shortened with an increase in Na ₂CO ₃ concentration. On the other hand, the mass of the sample decreased and eventually saturated at approximately 30 mass% of the initial weight during the hydrothermal treatment. Both the dissolution of the mother glass and the formation of crystalline deposits, which were identified as calcite, zeolite-P and analcime, affected the porous structure of the treated samples.