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D0I:10.13374/i.issnl00It03.2009.12.013 第31卷第12期 北京科技大学学报 Vol.31 No.12 2009年12月 Journal of University of Science and Technology Beijing Dee.2009 共沉淀法合成三硅酸镁及其微观分析 冯凌李敏刘国强韩磊杨儒 北京化工大学材料科学与工程学院化工资源有效利用国家重点实验室，北京100029 摘要由N20·nSiO2和Mg(N03)2经沉淀法合成了三硅酸镁，用450℃煅烧或酸化方法对合成的样品进行改性.采用 XRD,R,TG/DTA和BET等表征手段，考察了原料加入顺序，酸化和煅烧过程对样品的结晶度和表面织构的影响规律，并对 其影响机理进行了探讨.结果表明，不同滴定顺序和不同活化方法制得的样品均为非晶态物质，TG/DTA分析显示不同滴定 顺序样品的组成相同，pH对样品的表面织构有明显的影响.BET分析表明，Mg(NO3)2滴加入泡花碱溶液合成的样品为微孔 材料，以1~3nm和0.70.9m的微孔为主，比表面积达568.93m2g1,水合硅酸镁含量较高·泡花碱滴加入Mg(N03)2合 成的样品为大孔材料，比表面积为179.40m2g1,水合硅酸镁含量降低.煅烧和酸处理增加样品的结晶度，减少样品比表面 积，并改变样品的孔径分布·煅烧使中孔含量增加，形成中孔材料.酸处理使Mg+被H取代，表面形成硅羟基基团，材料以 中孔为主， 关键词三硅酸镁：水合硅酸镁：氨气吸附：孔道结构 分类号TQ424.25 Synthesis of magnesium trisilicate by a reverse strike method and its microscopic analysis FENG Ling.LI Min,LIU Guo-qiang.HAN Lei,YANG Ru State Key Laboratory of Chemical Resource Engineering.College of Materials Science and Engineering.Beijing University of Chemical Technology Beijing 100029.China ABSTRACT Magnesium trisilicate was synthesized by precipitation using Na20.nSiO2 and Mg(NO3)2 as raw materials.The pre- cipitate was subject at 450C or activated by 15%H2S04.following which the samples were characterized by XRD.IR.TG/DTA and BET to investigate the effects of strike methods,acidic activation and calcination on the crystal phase and surface texture.It is shown that the samples activated by different methods are amorphous.TG/DTA analysis indicates that the samples have the same composition as magnesium silicate hydrate with different contents.pH in the reaction has significant effect on the surface texture of the samples.BET analysis reveals that the sample synthesized by adding Mg(NO3)2 to the sodium silicate solution is microporous with the specific surface area of 568.93mgand exhibits a multimodal pore width distribution at the micropore regions of I to3nm and 0.7 to 0.9nm.The sample with the specific surface area of 179.4mgsynthesized by adding Mg(NO3)2to the sodium silicate so- lution is mesoporous.Calcination and acidic activation increase the crystalline degree,reduce the specific surface area and change the distribution of pore width.The reactive mechanism was discussed primarily.Calcination increases the quantity of mesopores.Acidic activation makes Hreplaced by Mg to form the Si-OH.and most of the acidic activation samples are mesoporous. KEY WORDS magnesium trisilicate:magnesium silicate hydrate:nitrogen adsorption:porous structure 由于高比表面积的多孔材料可以提供特异的分 孔结构和大的比表面积，从而具有较好的吸附性能 子场作用力，因此日益受到人们的广泛关注·硅酸 和分子筛功能，在医药中间体[)]、食品添加剂、橡胶 盐的品种繁多，并具有优异的化学与物理性能和独 填充剂、脱臭剂和陶瓷行业]等领域具有广阔的应 特的分子结构，三硅酸镁分子式为MgSi308· 用前景， nH20,为组成不定的含水硅酸镁山，具有较发达的 煅烧和酸化等活化方法可以提高硅酸盐材料的 收稿日期：2009-03-04 作者简介：冯凌(1984一)，女，硕士研究生：杨儒(1963一)，男，教授，博士生导师，Ema1l:yangru@bbn-cn共沉淀法合成三硅酸镁及其微观分析 冯 凌 李 敏 刘国强 韩 磊 杨 儒 北京化工大学材料科学与工程学院化工资源有效利用国家重点实验室北京100029 摘 要 由 Na2O·nSiO2 和 Mg（NO3）2 经沉淀法合成了三硅酸镁用450℃煅烧或酸化方法对合成的样品进行改性．采用 XRD、IR、TG／DTA 和 BET 等表征手段考察了原料加入顺序、酸化和煅烧过程对样品的结晶度和表面织构的影响规律并对 其影响机理进行了探讨．结果表明不同滴定顺序和不同活化方法制得的样品均为非晶态物质．TG／DTA 分析显示不同滴定 顺序样品的组成相同．pH 对样品的表面织构有明显的影响．BET 分析表明Mg（NO3）2 滴加入泡花碱溶液合成的样品为微孔 材料以1～3nm 和0∙7～0∙9nm 的微孔为主比表面积达568∙93m 2·g －1水合硅酸镁含量较高．泡花碱滴加入 Mg（NO3）2 合 成的样品为大孔材料比表面积为179∙40m 2·g －1水合硅酸镁含量降低．煅烧和酸处理增加样品的结晶度减少样品比表面 积并改变样品的孔径分布．煅烧使中孔含量增加形成中孔材料．酸处理使 Mg 2＋被 H ＋取代表面形成硅羟基基团材料以 中孔为主． 关键词 三硅酸镁；水合硅酸镁；氮气吸附；孔道结构 分类号 T Q424∙25 Synthesis of magnesium trisilicate by a reverse strike method and its microscopic analysis FENG LingLI MinLIU Guo-qiangHA N LeiY A NG Ru State Key Laboratory of Chemical Resource EngineeringCollege of Materials Science and EngineeringBeijing University of Chemical Technology Beijing100029China ABSTRACT Magnesium trisilicate was synthesized by precipitation using Na2O·nSiO2and Mg （NO3）2as raw materials．T he precipitate was subject at 450℃ or activated by 15％ H2SO4following which the samples were characterized by XRDIRTG／DTA and BET to investigate the effects of strike methodsacidic activation and calcination on the crystal phase and surface texture．It is shown that the samples activated by different methods are amorphous．TG／DTA analysis indicates that the samples have the same composition as magnesium silicate hydrate with different contents．pH in the reaction has significant effect on the surface texture of the samples．BET analysis reveals that the sample synthesized by adding Mg（NO3）2to the sodium silicate solution is microporous with the specific surface area of568∙93m 2·g －1and exhibits a multimodal pore width distribution at the micropore regions of1to3nm and 0∙7to0∙9nm．T he sample with the specific surface area of179∙4m 2·g －1synthesized by adding Mg（NO3）2to the sodium silicate solution is mesoporous．Calcination and acidic activation increase the crystalline degreereduce the specific surface area and change the distribution of pore width．T he reactive mechanism was discussed primarily．Calcination increases the quantity of mesopores．Acidic activation makes H ＋ replaced by Mg 2＋ to form the S-i OHand most of the acidic activation samples are mesoporous． KEY WORDS magnesium trisilicate；magnesium silicate hydrate；nitrogen adsorption；porous structure 收稿日期：2009-03-04 作者简介：冯 凌（1984－）女硕士研究生；杨 儒（1963－）男教授博士生导师E-mail：yangru＠bbn．cn 由于高比表面积的多孔材料可以提供特异的分 子场作用力因此日益受到人们的广泛关注．硅酸 盐的品种繁多并具有优异的化学与物理性能和独 特的分子结构．三硅酸镁 分 子 式 为 Mg2Si3O8· nH2O为组成不定的含水硅酸镁［1］具有较发达的 孔结构和大的比表面积从而具有较好的吸附性能 和分子筛功能在医药中间体［2］、食品添加剂、橡胶 填充剂、脱臭剂和陶瓷行业［3］等领域具有广阔的应 用前景． 煅烧和酸化等活化方法可以提高硅酸盐材料的 第31卷 第12期 2009年 12月 北 京 科 技 大 学 学 报 Journal of University of Science and Technology Beijing Vol．31No．12 Dec．2009 DOI:10．13374／j．issn1001－053x．2009．12．013