Composites of MCM-41 silica with rice husk: Hydrothermal synthesis, characterisation and application for perchlorate separation

Mesoporous MCM-41 silica and rice husk composites were synthesised under hydrothermal conditions using cetyltrimethylammonium bromide (CTAB) as an organic template, aqueous ammonia solution (NH₄OH) and rice husk, the latter as a silica source and substrate for the deposition of MCM-41. Both untreated and carbonised rice husks were used for preparing composites at a temperature of 100-120°C for 24-48 h. The as synthesised composites or hybrid materials were characterised by using XRD and SEM and they were found to be useful for the uptake of perchlorate. These composites could be used to separate perchlorate from solutions in column operation without the necessity for their pelletisation because the rice husk substrates are several millimetres in size.