镁铝水滑石的水热合成及表征

摘要/Abstract

摘要：

用一步水热法制得的氢氧化镁作为镁源,采用高过饱和共沉淀水热法制备镁铝水滑石。考察了水热温度、水热时间、氢氧化镁合成条件、晶种等条件对合成水滑石的晶体结构、尺寸、形貌及比表面积的影响。结果表明：采用水热温度为150 ℃、水热时间为3 h合成的氢氧化镁作为原料时,在水热温度为190 ℃、水热时间为12 h条件下制得水滑石的比表面积最小,形貌和结构规整;原料氯化镁中三氧化二硼杂质质量分数为0.020%时,会促进水滑石晶粒径向尺寸和厚度的增加;添加晶种会明显减小水滑石的比表面积,最佳添加量为0.5%（质量分数）。在以上最佳条件下,最终制得水滑石的比表面积达到10.33 m ²/g,水合粒径为878 nm。

关键词: 镁铝水滑石, 高过饱和共沉淀水热法, 晶体结构

Abstract:

Mg-Al Hydrotalcite was prepared by a high super-saturation co-precipitation hydrothermal method using Mg（OH）₂ as magnesium source.Mg（OH）₂was synthesized by one-step hydrothermal method.The effect of hydrothermal temperature,hydrothermal time,synthesis conditions of Mg（OH）₂ and seed addition on the crystal structure,size,morphology and BET of LDHs were studied.The results showed that when the hydrothermal temperature was 190 ℃ and the hydrothermal time was 12 h,the specific surface area of the obtained hydrotalcite was the smallest,and the morphology and structure were regular.When the magnesium hydroxide synthesized at 150 ℃ for 3 h was used as the raw material.When the mass fraction of boron impurities in the raw material was 0.020%,the grain size and thickness of the hydrotalcite were promoted;the addition of the seed crystals significantly reduced the specific surface area of the hydrotalcite,and the optimum addition amount was 0.5%（mass fraction）.The product synthesized under optimum conditions exhibited a specific surface area of 10.33 m ²/g and a thermal particle of 878 nm.

Key words: Mg-Al Hydrotalcite, high super-saturation co-precipitation hydrothermal method, crystal structure

中图分类号:

吕品,施春辉,李伟,仲剑初. 镁铝水滑石的水热合成及表征[J]. 无机盐工业, 2019, 51(6): 29-33.

Lü Pin,Shi Chunhui,Li Wei,Zhong Jianchu. Controllable synthesis and characterization of thermal stabilizer Mg-Al-LDHs[J]. Inorganic Chemicals Industry, 2019, 51(6): 29-33.

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参考文献 13

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温度/℃	d₀₀₃/nm	d₁₁₀/nm	a/nm	c/nm	D₁₁₀/nm	D₀₀₃/nm	D₁₁₀/D₀₀₃
150	0.766 0	0.152 6	0.305 2	2.298 0	38.208 3	35.506 3	1.076 1
170	0.766 3	0.152 6	0.305 2	2.298 9	39.069 5	35.576 8	1.098 2
190	0.770 2	0.152 7	0.305 4	2.310 6	43.547 1	36.144 1	1.204 8

水热温度/ ℃	比表面积/ （m²·g^-1）	水合粒径/ nm	水热温度/ ℃	比表面积/ （m²·g^-1）	水合粒径/ nm
150	20.57	474.1	190	13.30	772.0
170	15.95	592.8

氢氧化镁合成温度/℃	比表面积/ （m²·g^-1）	水合粒径/nm	氢氧化镁合成温度/℃	比表面积/ （m²·g^-1）	水合粒径/nm
60	12.18	816.1	150	13.30	772.0
130	13.56	690.1	170	11.27	875.8

w（B₂O₃）/ %	d₀₀₃/nm	d₁₁₀/nm	a/nm	c/nm	D₁₁₀/nm	D₀₀₃/nm	D₁₁₀/D₀₀₃
0.006	0.770 2	0.152 7	0.305 4	2.310 6	43.335 5	35.736 0	1.212 7
0.010	0.768 0	0.152 6	0.305 2	2.304 0	44.143 3	37.102 2	1.189 8
0.020	0.767 6	0.152 6	0.305 2	2.302 8	44.843 1	40.091 0	1.118 5
0.030	0.783 7	0.153 1	0.306 2	2.351 1	39.026 4	31.210 6	1.250 4

w（B₂O₃）/ %	比表面积/ （m²·g^-1）	水合粒径/ nm	w（B₂O₃）/ %	比表面积/ （m²·g^-1）	水合粒径/ nm
0.000	13.30	772.0	0.020	12.91	797.2
0.010	13.17	780.1	0.030	13.83	689.7

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