Faculty of Bioscience and Applied Chemistry, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo, 184-8584, Japan.
Faculty of Science, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan.
Sci Rep. 2021 Dec 10;11(1):23811. doi: 10.1038/s41598-021-03133-x.
Mesoporous silica was successfully synthesized for the first time using geothermal water from the Onuma Geothermal Power Plant, Akita Prefecture, Japan. Cetyltrimethylammonium bromide (CTAB) was used as an organic template for the synthesis. CTAB with a concentration of 2.4 × 10 mol/L was reacted for 30 min with geothermal water at a temperature of 90 °C, which had a total silicic acid concentration of 475 mg/L (SiO), at pH 7.0, pH 8.2 (raw water) and pH 9.0. By calcination of the resulting precipitate at 550 °C, mesoporous silica with a pore size of about 2.8 nm and a specific surface area of > 800 m/g was formed. The total silicic acid concentration in the solution after formation of the mesoporous precipitates was reduced to < 280 mg/L, indicating efficient recovery of supersaturated silicic acid from geothermal water. The monosilicic acid in geothermal water plays an important role in the formation of mesoporous silica. Production of mesoporous silica by our method will contribute not only to prevention of silica scale formation in the piping systems of geothermal power plants but also to its use as an industrial resource.
首次利用日本秋田县大沼地热发电所的地热水成功合成了中孔硅。十六烷基三甲基溴化铵（CTAB）被用作合成的有机模板。在 pH 值为 7.0、8.2（原水）和 9.0 时，将浓度为 2.4×10-3mol/L 的 CTAB 与温度为 90°C、总硅酸浓度为 475mg/L（SiO）的地热水反应 30min。将所得沉淀物在 550°C 下煅烧，形成孔尺寸约为 2.8nm 和比表面积>800m2/g 的中孔硅。形成中孔沉淀物后溶液中的总硅酸浓度降低至<280mg/L，表明从地热水中有效回收了过饱和硅酸。地热水中的单硅酸在地孔硅形成过程中起着重要作用。我们的方法生产的中孔硅不仅有助于防止地热发电厂管道系统中硅垢的形成，而且还有助于将其用作工业资源。
