Application of ultrasound and methanol for rapid removal of surfactant from MCM-41

Abstract

Ultrasound waves have been successfully applied for removing template from the mesoporous MCM-41 molecular sieve. The method uses a 28 KHz ultrasound irradiation in a methanol solvent for disrupting micellar aggregation of the surfactant molecules, cetyltrimethylammonium bromide, which have filled the pores of the as-synthesized MCM-41. In 15 min sonication at moderate temperature of 40 ?C, a majority of surfactant molecules are removed out from powder MCM-41. The template removal rate using ultrasound irradiation (15 min) is faster than the rate via thermal calcination and a perfect hexagonal pore structure was obtained after the template removal using ultrasound irradiation, according to the characterization using the X-ray diffraction (XRD), and nitrogen adsorption analyses, while high temperatures in calcination will cause shrinkage which is affected on the surface properties of materials. In this procedure, the surfactant molecules are released into methanol and can be recovered for reuse. The effectiveness of the sonicated prepared MCM-41 as an adsorbent has been confirmed using the adsorption reaction with Methylene Blue (MB).