College of Chemical Engineering, National and Local Joint Engineering Research Center for High Value Utilization of Coal-based Solid Waste, Inner Mongolia Key Laboratory of Efficient Cyclic Utilization of Coal-Based Solid Waste, Inner Mongolia University of Technology, Hohhot 010051, People's Republic of China.
Nanotechnology. 2023 Jun 19;34(36). doi: 10.1088/1361-6528/acda9f.
A novel controllable magnesium silicate nanotube (MSN) material derived from coal fly ash was successfully synthesized via a hydrothermal process for the first time, and the reaction conditions and mechanism of synthesizing MSN materials from magnesium oxide and sodium silicate extracted from the fly ash were studied. The optimal preparation conditions are temperature = 220 °C, pH = 13.5, and Mg: Si molar ratio = 3:2, and the tubular structure gradually appeared and showed controllable and regular growth with the increase of synthesis time. The mechanism revealed that with the gradual dissolution of brucite into the sodium silicate solution, the reaction product begins to crystallize and transform from an initial sheet-like structure to a tubular structure, and finally becomes a uniformly arranged nanotube. The formation process of MSN follows Pauling's fourth rule, Si-O tetrahedral coordination and Mg-OH octahedral coordination is further condensed to form a two-layer structure by the action of active oxygen, then the sheet is rolled into a tube under its structural stress. The growth of both outer tubular diameter and inner tubular diameter has good linear law and controllable, and the growth rate are 0.289 nm hand 0.071 nm h, respectively.
一种新型可控硅酸镁纳米管（MSN）材料首次通过水热法从粉煤灰中成功合成，研究了从粉煤灰中提取的氧化镁和硅酸钠合成 MSN 材料的反应条件和机理。最佳制备条件为温度=220°C，pH=13.5，Mg：Si 摩尔比=3：2，随着合成时间的增加，管状结构逐渐出现并呈现出可控且规则的生长。揭示的机理表明，随着水镁石逐渐溶解在硅酸钠溶液中，反应产物开始从初始片状结构结晶转化为管状结构，最终成为排列均匀的纳米管。MSN 的形成过程遵循鲍林的第四规则，Si-O 四面体配位和 Mg-OH 八面体配位通过活性氧的作用进一步缩合形成双层结构，然后在其结构应力下将片状物卷成管状。内外管直径的生长均具有良好的线性规律和可控性，生长速率分别为 0.289nm/h 和 0.071nm/h。
