Synthesis and characterization of mesoporous aluminosilicate molecular sieve from K-feldspar

Abstract: Mesoporous aluminosilicate molecular sieves have been synthesized using K-feldspar, a natural ore rich in silicon and aluminum sources, as starting material. In this method, the mixture of K-feldspar and K2CO3 with mass ratio of 2:3 was first calcined at 880°C for 1.2h. The calcined materials were then dissolved in water together with cetyltrimethylammonium bromide as structure-directing agent, resulting in mesoporous molecular sieves after heating the solution at 130°C for 60h. Scanning electron microscopy and transmission electron microscopy observations indicated that the resulting materials were spherical particles with size of about 100nm. The mesoporous structure of the as-synthesized materials was confirmed by low angle X-ray diffraction and nitrogen sorption analysis. The BET surface area of the as-prepared material after calcined at 550°C was 507m2 g−1 and the pore volume was 0.854cm3 g−1. 27Al MAS NMR analysis showed that nearly all of aluminium is incorporated into the framework of the mesoporous material with 4-coordinated state. The acidity of the product was analyzed by FTIR spectroscopy of pyridine-adsorbed product. The product was treated in water at 100°C for 360h, and its mesoporous structure was still intact, suggesting its high hydrothermal stability. [Copyright &y& Elsevier]