Stability of MCM-48 in aqueous solution as a function of pH

✍ Scribed by A. Doyle; B.K. Hodnett

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 413 KB
• Volume: 63
• Category: Article
• ISSN: 1387-1811
• DOI: 10.1016/s1387-1811(03)00431-1

✦ Synopsis

The stability of MCM-48 was investigated as a function of pH. The material was treated with aqueous solutions of varying pH and the stability was determined by comparison with the untreated MCM-48. In acidic conditions of pH < 5.4, the MCM-48 structure was stable and the BET surface area remained high (>1000 m 2 g À1 ), while the mean pore diameter decreased by approximately 20%. In neutral conditions, this phase was completely removed, characterised by the absence of an X-ray diffraction pattern and a dramatic reduction in surface area to 450 m 2 g À1 at pH 6.9. Treatment at pH 9.1 caused a transformation to a poorly ordered material, while further increased basic conditions caused significant structural collapse.