- 作者: 李麗君
- 作者服務機構: Department of Geosciences, National Taiwan University, Taipei 106, Taiwan, R.O.C.
- 中文摘要:
Silica gel was used as the starting material to synthesize nano-sized quartz in the presence of alkaline solution. The experiments were carried out in autoclaves under the conditions of 0.25 M NaOH solution, 210 °C, and vapor pressure.
SiO2-X2 and a-cristobalite appear as the intermediate unstable phases during the synthesis of quartz which occurs as a single stable phase in the synthetic product after 26 hour experiments. The growth of quartz can be separated into a fast linear growth with the rate of 75.3 nm/hr and a slow one with the rate of 1.4 nm/hr. It is shown that quartz begins to grow at 16.1 hours and the fast growth changes abruptly to the slow one at about 26.7 hours after the start of the experiments. On the other hand, nucleation occurs from 20 to 28 hours.
For the synthetic quartz, an amount of about 32% of the population is nano-sized, but most of the population (about 78%) lies between 50 nm and 300 nm, and the geometric mean size is about 182 nm.
From the results of this preliminary study, it is encouraging that a high percentage of nano-sized quartz could possibly be produced if suitable experimental conditions are chosen. - 英文摘要: --
- 中文關鍵字: Silica gel; Autoclaves; Nano-sized quartz.
- 英文關鍵字: Silica gel; Autoclaves; Nano-sized quartz.