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以Mg（NO3）2.6H2O为镁源、Al（NO3）3.9H2O为铝源,采用水热法制备Mg/Al水滑石。鉴于水滑石中广泛存在的氢键相互作用,以多羟基醇为共溶剂,对比分析了水、水/乙醇、水/乙二醇、水/丙三醇及水/季戊四醇等5种溶剂条件下水热合成得到的Mg/Al水滑石的结构和热性质。利用XRD、SEM、IR、DSC等的分析结果表明,随着共溶剂中醇羟基数目的增多,所得水滑石中结晶水的水合程度提高。共溶剂与水滑石之间水滑石,晶粒形貌类似于纯水得到的水滑石。而以水/丙三醇及水/季戊四醇为溶剂得到的水滑石,晶形变的不规则,且伴随着粒径尺寸变小和晶粒团聚现象。同时,随着共溶剂中醇羟基数目的增多,层间结合水的释放温度提高,而层间CO2脱除和基本层上的羟基脱水温度则相应降低。

The hydrothermal synthesis method was employed to prepare the magnesium-aluminium layered double hydroxides（LDHs） by using Mg（NO3）2·6H2O and Al（NO3）3·9H2O as the raw materials.Considering the hydrogen bonding interactions existing in the LDHs,the co-solvents of polyhydric alcohols will have a great influence on the preparation of the LDHs.To investigate these effects,we respectively employed five kinds of solvents： pure water,water/ethanol,water/glycol,water/glycerin,and water/pentaerythritol.The microstructures and thermal properties of the prepared LDHs were contrastively investigated by XRD,SEM,IR and DSC.With the increasing number of the hydroxyl groups in the co-solvents,the hydration levels of the crystal water in the LDHs were elevated.The interactions between the co-solvent and the LDHs affect the nucleation and subsequent growth of LDHs,resulting in the variation of crystallinity and thermal stability.The LDHs prepared using water/ethanol and water/glycol as solvent,respectively,have similar crystalline shapes to that synthesized with pure water.But for the LDHs respectively synthesized using glycerin and pentaerythritol as co-solvents,the crystalline shapes became irregular with smaller grain size and the aggregation of grains.In addition,as the number of the hydroxyl groups in the co-solvents is increased,the temperatures for releasing crystal water were elevated,but the corresponding temperatures for the dehydration of basic layer and the release of carbon dioxide were decreased.