Mesoporous aluminosilicate ropes with improved stability from protozeolitic nanoclusters

摘要

Mesoporous aluminosilicate ropes with improved hydrothermal stability have been prepared through S+X-I+ route via self-assembly of protozeolitic nanoclusters with cetyltrimethylammonium bromides (CTAB) template micelles in HNO3 solution. SEM observation confirmed that high-yield aluminosilicate ropes could be produced under proper HNO3 concentration. NO3- ions had strong binding strength to the CTA(+) ions and tended to form more elongated surfactant micelles, thus fibrous products were fabricated under the direction of these long rod micelles in shearing flow. At the same time, the NO3- ions combining with CTA(+) ions generated more active (CTA(+)NO(3)(-)) assembly, which effectively catalysed the polymerization of protozeolitic nanoclusters with large volume into highly ordered mesostructures. Compared with normal MCM-41 silica synthesized through S+X-I+ route in acidic media, the hydrothermal stability was improved considerably. These protozeolitic nanoclusters survived strongly acidic media and entered into mesostructured framework, which contributed to the improvement of hydrothermal stability. (c) 2006 Elsevier Inc. All rights reserved.