Preparation of porous material from waste bottle glass by hydrothermal treatment

Porous materials were prepared from colored waste glass by hydrothermal treatment with Na2CO3 aqueous solution. The resultant specific surface area was approximately 140 m2/g at maximum. Specific surface area increased at first, reached a maximum, and decreased gradually to be constant at approximately 60 m2/g depending on the period of hydrothermal treatment, irrespective of the concentration of Na2CO3 aqueous solution. However, the period at which the specific surface area reached maximum shortened with an increase in Na2CO3 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.