| 초록 |
Vermiculite is a natural phyllosilicate mineral formed by the hydrothermal alternation of mica. Vermiculite flakes are exfoliated to produce concertina-shaped granules using a thermal shock or chemical treatments. In this work, we present vermiculite expansion methods based on using an aqueous solution of hydrogen peroxide. The expanded vermiculite samples were prepared by means of different processes and characterized by various material analysis methods. The expansion was explained with the exfoliation induced by active chemical reactions between vermiculite and H2O2, maybe being attributed to the Fenton-like mechanism. When using optimized conditions to expand vermiculite, an expansion ratio of ca. 20 and an ethanol-absorption capacity of 8 g/g were obtained. These values were found to be strongly depend on used expansion condition such as a H2O2 concentration, a reaction time, temperature and pressure. Compared with the thermal expansion, the H2O2 expanded sample revealed a higher expansion and better absorption performance. These results demonstrate that the chemical vermiculite process will be a new alternative method to produce expanded vermiculite in mass quantity. |
