Living diatoms are unicellular,eukaryotic algae found in waters worldwide.Their cell shells,called frustules,have raised interest in the field of material science because of their novel porous biosilica structures.They show a promise for applications in various fields in particular for the fabrication of micro/nano devices.In order to remove the organic matter,the purification of diatom frustules and the preparation of diatom products often involve a high temperature process.