Porous glass-ceramics derived from MgO-CuO-TiO2-P2O5 glasses with different additions of Fe2O3

Different amounts (0 similar to 12.5 mol%) of Fe2O3 were added into quaternary 25MgO center dot 30CuO center dot 15TiO(2)center dot 30P(2)O(3) system to prepare glass frits by quenching the melts in water. After the samples had been heat-treated and acid-leached in hydrochloric solution (1 similar to 3 M) at 100 degrees C for 24 similar to 72 h. Porous glass-ceramics, with different crystalline phases, textural properties and morphologies, were obtained. The main phases in the final products prepared with 0 and 2.5 mol% Fe2O3 were Mg2P2O7. Poorly crystallized products with pure anatase phase were obtained with the additions of 5 and 7.5 mol% Fe2O3. With further increasing the addition of Fe2O3 to 10 and 12.5mol%, porous glass ceramics were formed, containing both anatase and ferric phosphate hydroxide Fe-4(PO4)(3)(OH)(3) phases. It was found that the surface area of porous glass-ceramics could be increased by prolonging the acid treatment time or raising the acid concentration. The sample with 7.5 mol% of Fe2O3 and treated in 1 M HCl solution for 72 h has the largest surface area of 128 m(2) g(-1). This sample was selected to adsorb methylene blue (MB) in aqueous solution with a concentration of 5 mg l(-)(1). It turned out that the adsorption was quick in the first 0.5 h with a removal of 61% and reached equilibrium at 2 h with the total removal of MB by 89%.