偏硼酸锂溶液物种分布和物化性质

测量了不同浓度LiBO2溶液分别在298.15和323.15 K的密度、电导和pH,通过测得的pH和硼酸根离子化学平衡常数计算得到溶液中硼酸根离子的物种分布。根据获得的物种分布结果,推测溶液中各硼酸根离子之间的相互转化过程,并分别用偏摩尔体积公式和Onsager方程对溶液偏摩尔体积及摩尔电导率进行计算并拟合。对计算得到偏摩尔体积值和极限摩尔电导率值与文献报道的数据进行对比,计算结果与文献报道值吻合较好。     

四硼酸铯溶液的Raman光谱和物化性质研究

由摩尔比为1∶2的Cs2CO3和H3BO3反应得到四硼酸铯样品,用FT-IR和Raman等方法对其溶液结构进行表征并分析其中的阴离子类型。同时测定了四硼酸铯溶液在298.15 K和333.15 K下的密度、电导及p H,通过298.15 K下的pH测量值和相关硼酸盐平衡常数,计算298.15 K下四硼酸铯溶液的化学物种分布,并对其相互转换反应进行推测。研究表明,298.15 K下四硼酸铯溶液中存在的主要物种有B(OH)4-、B(OH)3、B3O3(OH)4-、B3O3(OH)52-和B4O5(OH)42-,与Raman光谱所得结果基本一致。     

硼酸盐水溶液中硼物种的存在形式及影响因素

根据以往相关的研究报道,综述了含硼水溶液中硼物种的存在形式,及其与总硼浓度、溶液pH值、溶液离子强度、温度、压力等因素的关系。随着总硼浓度的提高,硼氧配阴离子的聚合度加大,在pH值较高或较低时,聚硼离子的含量较少,主要以H3BO3和B(OH)4-的形式存在;同时,指出含硼水溶液存在普遍的过饱和现象,我国含硼盐湖卤水中的硼物种可以用B4O72-的综合统计形式表示。总结了硼酸盐水溶液中各种硼氧配阴离子的FT-IR,Raman和NMR的归属。     

K2B4O7和KBO2溶液pH和拉曼光谱研究

用合成的水合四硼酸钾和偏硼酸钾晶体,配制一系列溶液,研究了pH与浓度变化的关系,并计算硼酸根离子的摩尔分数-浓度(δ-c)关系图。用拉曼光谱方法研究四硼酸钾和偏硼酸钾溶液,给出其拉曼光谱图,并对各峰进行了归属。研究表明,四硼酸钾溶液中存在的物种主要有[B4O5(OH)4]2-、[B3O3(OH)4]-和[B(OH)4]-,而其它物种所占摩尔分数很小;在偏硼酸钾水溶液中,[B(OH)4]-占绝大多数,有很少量H3BO3、[B4O5(OH)4]2-和[B3O3(OH)4]3-。硼酸盐离子浓度越低,越容易水解为聚合度较低的简单物种。     

五硼酸铷溶液的物化性质及物种分布

碳酸铷、硼酸化学计量比混合,蒸发溶液,直至五硼酸铷RbB5O8·4H2O晶体析出。经粉末X射线衍射（XRD）、拉曼光谱（Raman spectroscopy）、热重/微商热重/差示扫描量热（TG/DTG/DSC）、原子吸收光谱等实验方法,确定其化学组成及结构。298.15、333.15K时测量溶液的物理化学性质（密度、电导、pH）,并与经验方程进行拟合,研究五硼酸铷溶液的物化性质随浓度、温度的变化规律。根据文献报道的平衡常数,实验测量的pH数据,采用牛顿迭代法进一步研究五硼酸铷溶液中主要存在的硼酸根离子对类型、含量以及物种的形成。     

五硼酸钾、偏硼酸钾和四硼酸钾溶液中硼酸根离子类型、密度及电导率研究

利用牛顿迭代方法计算给出硼酸钾溶液中硼酸根离子的物种分布图。研究给出溶液中硼酸根离子的类型、含量以及各硼酸根离子间相互转化方程式,并简单谈论了温度和浓度对硼酸根离子类型和含量的影响。在五硼酸钾溶液中主要硼酸根离子物种为B3O3(OH)4-,B4O5(OH)42-和B(OH)3,而B5O6(OH)4-含量非常低,可以忽略不计;偏硼酸钾溶液中主要离子为B(OH)4-;在高浓四硼酸钾溶液中主要物种为B3O3(OH)4-,B4O5(OH)42-和B(OH)4-。最后用Otakar和Casteel-Amis经验方程式分别研究了硼酸钾溶液的密度和电导率。     

武威市降水pH值和电导率对沙尘天气的指示意义

对武威市2013年7月至2014年6月收集的降水样品pH值、电导率和主要阴阳离子浓度进行测定和分析。结果表明：（1）降水样品的pH值6.69～8.84,平均值7.52。降水样品电导率33.9～766 μS·cm^-1,平均182.07 μS·cm^-1。（2）电导率冬季 >春季 >夏季 >秋季,pH值春季 >夏季 >秋季 >冬季。pH值与电导率呈显著的负相关,与风速呈正相关;电导率与降水量呈显著的负相关,与风速呈显著的负相关。（3）pH值和电导率都会随着沙尘事件的发生表现出增加的趋势。当沙尘事件发生的情况下,Na⁺、K⁺、Mg²⁺、Ca²⁺、SO₄^2-、Cl^-和NO₃⁺的离子浓度都呈现增加的趋势,但从各离子浓度变化幅度对沙尘事件的响应来看,Na⁺、K⁺和NO₃^-对沙尘天气比较敏感,反应强烈。     

含锂、钾硼酸盐水溶液体系固液相平衡研究

采用等温溶解平衡法测定了含锂、硼硼酸盐水溶液体系在35℃时的溶解度、密度和折光率，根据实验数据，绘制了相应的溶解度图、密度图、折光率图和pH值图。该体系溶解度相图包含一个共饱点，两个单盐结晶区，分别为结晶相区较大的（L+ Mg2B6O11·15H2O）和结晶相区较小的（L + K2B4O7·4H2O），溶液体系中没有固溶体和复盐产生。溶液的密度、折光率和pH值随着硼酸钾溶液的浓度增大而呈现与规律的变化，并采用半经验公式对溶液的密度和折光率进行计算，计算值和实验值吻合较好。     

五硼酸钾、偏硼酸钾和四硼酸钾溶液中硼酸根离子类型、密度及电导率研究（英文）

利用牛顿迭代方法计算给出硼酸钾溶液中硼酸根离子的物种分布图。研究给出溶液中硼酸根离子的类型、含量以及各硼酸根离子间相互转化方程式,并简单谈论了温度和浓度对硼酸根离子类型和含量的影响。在五硼酸钾溶液中主要硼酸根离子物种为B3O3(OH)4-,B4O5(OH)42-和B(OH)3,而B5O6(OH)4-含量非常低,可以忽略不计;偏硼酸钾溶液中主要离子为B(OH)4-;在高浓四硼酸钾溶液中主要物种为B3O3(OH)4-,B4O5(OH)42-和B(OH)4-。最后用Otakar和Casteel-Amis经验方程式分别研究了硼酸钾溶液的密度和电导率。     

五硼酸铷溶液的物化性质及物种分布

碳酸铷、硼酸化学计量比混合,蒸发溶液,直至五硼酸铷RbB_5O_8·4H_2O晶体析出。经粉末X射线衍射、拉曼光谱、热重/微商热重/差示扫描量热(TG/DTG/DSC)、原子吸收光谱等实验方法,确定其化学组成及结构,298.15、333.15K时测量溶液的物理化学性质(密度、电导、pH),并与经验方程进行拟合,研究五硼酸铷溶液的物化性质随浓度、温度的变化规律。根据文献报道的平衡常数、实验测量的p H数据,采用牛顿迭代法进一步探讨了五硼酸铷溶液中主要存在的硼酸根离子物种分布规律。     

Recent Progress on Structure of Aqueous Polyborate Solutions

The crystal structure of metal borates has been extensively investigated by X-ray and neutron diffraction,but,the structure of aqueous polyborate solutions are still largely unknown.Over the last decade,our group has focused on studying the structure of complex aqueous polyborate solutions of Li,Na,K,Rb,Cs,and Mg using synchrotron radiation X-ray scattering(XRS),EXAFS,Raman,NMR,and DFT,as well as determining the density,conductivity and pH of such solutions.Polyborate species distributions were calculated using pH measurements,and the main species in the solution have been confirmed by NMR and Raman spectra.For alkali-metal metaborates,the dominant species is always B(OH)-₄in a wide range of concentration,while the presence of others species is negligible.For alkali metal tetraborates,when concentration is in the extreme low range,only B(OH)₃ and B(OH)-₄ are present in these solutions.As the total boron concentration increases,B(OH)₃ and B(OH)-₄ polycondensated to form more complex oligomers.Of them,while B₄O₅(OH)2-₄ in the tetraborate solutions is the main species,B(OH)₃,B(OH)-₄,and B₃O₃(OH)-₄ are minor species,and B₃O₃(OH)2-₅ and B₅O₆OH)-₄ are present only in negligible amounts.As solution continues to concentrate,B₄O₅(OH)2-₄ eventually becomes the dominant species,which is consistent with the congruent compound M₂B₄O₇·nH₂O(M=Li,Na,K,Rb,Cs) in the system M₂O-B₂O₃-H₂O(M=Li,Na,K,Rb,Cs).For alkali metal pentaborates,B(OH)₃ and B(OH)-₄ are the main species at low concentrations.The species distribution,Raman and NMR spectroscopy results verified that the dominant species in concentrated pentaborate solutions with Li and Na is pentaborate B₅O₆OH)-₄,but it is surprising that the main species with K,Rb,and Cs is always the triborate monoanion B₃O₃(OH)-₄.Although all M[B₅O₆OH)₄]·nH₂O(M=Li,Na,K,Rb,Cs) are all congruent compounds in the system M₂O-B₂O₃-H₂O(M=Li,Na,K,Rb,Cs) ,the main species in aqueous solutions are quite different because of various cation hydration distance(d),hydration number(CN),and configuration,especially charge(Z).For bivalent Mg²⁺,three borate minerals,namely,Inderite(2MgO·3B₂O₃·15H₂O),Hungchaoite(MgO·2B₂O₃·9H₂O),and Mcallisterite(MgO·3B₂O₃·7.5H₂O),exist in the system MgO-B₂O₃-H₂O at 298K.Inderite is a congruent compound,but Hungchaoite and Mcallisterite are incongruent compounds.The species distribution and Raman spectra demonstrat that the predominant species in all the solutions with magnesium borates is bivalent triborate B₃O₃(OH)2-₅,while the subordinate species are B(OH)-₄ at a low B₂O₃/MgO ratio and B(OH)₃at a high B₂O₃/MgO ratio,and the other anions are negligible,as the high Z of the borate anion must match that of Mg²⁺.The disappearance of divalent B₄O₅(OH)2-₄ is in agreement with its incongruent nature.The DFT and XRS results showed that tetrahedral Li(H₂O)⁺₄(d=0.20 nm,CN=4),octahedral Na(H₂O)₆⁺(d=0.236 nm,CN=6),and Mg(H₂O)²⁺₆(d=0.210 nm,CN=6) in the first hydration shell belong to Platonic polyhedra.However,K(H₂O)⁺₈(d=0.28 nm,CN=8,XRS and DFT),Rb(H₂O)⁺₈(d=0.293 nm,CN=7.7-8.2,EXAFS),and Cs(H₂O)⁺₈(d=0.320-0.326 nm,CN=7.6-7.9,EXAFS) are inclined Voronoi polyhedra.Therefore,the effects of cation Z and d on the structure of polyborates in aqueous solutions are deterministic,while the effect of hydrated-cation symmetry is secondary.Their hydrolysis order was:Mg＞Li＞Na＞K＞Rb＞Cs,in step with hydration power.Among them,Mg²⁺ and Li⁺have a strong tendency towards hydrolysis,but Na⁺ scarcely hydrolyzes,especially Rb⁺ and Cs⁺ have a little protonation.X-ray scattering of aqueous alkaline sodium borohydride solutions confirmed that dihydrogen bonds exist in an aqueous solution.The four distinct features of dihydrogen bonds in aqueous solution-unidirectionality,divaricativity,multicentricity,and multidentativity have been also described here in brief.     

NH4Cl水溶液的微观结构和宏观物性研究

通过拉曼光谱、同步辐射X射线散射和密度泛函理论(DFT)模拟,研究了质量分数为1.0 %-28.0 %的NH₄Cl水溶液的微观结构变化。同时在室温下测量了粘度、接触角和电导率。由拉曼光谱和密度泛函理论模拟结果可知,当溶质浓度升高至10.0 %时,在2900 cm_-1^和3100 cm_-1^{附近出现了明显的}N-H作用峰,且随着质量分数的升高,NH₄Cl水溶液中的氢键类型发生了转变。X射线散射结果表明,当NH₄Cl水溶液质量分数升高至10.0 %时,差值对分布函数G(r)在2.98 ?附近出现明显双峰,表明在该浓度下溶液中NH₄₊^-Cl_-^{接触离子对开始成为主要微观作用形式。对}NH₄Cl水溶液的宏观物性研究表明,粘度、接触角和电导率均随着NH₄Cl水溶液质量分数的增加而增大。作者推断,NH₄Cl水溶液中氢键类型的转变、O-H...N键占比增多以及逐渐增加的NH₄₊^-Cl_-^{接触离子对},是粘度和接触角随溶质浓度增加而增加的微观本质因素;电导率的增加与溶液中有效导电离子数量增加有关。     

盐卤硼酸盐化学Ⅹ Ⅹ Ⅴ Ⅲ硼氧酸盐结晶液固相硼同位素组成

实验研究了硼氧酸盐在水溶液结晶沉淀后液固相硼同位素组成，结果表明，硼氧酸盐结晶固相的硼同位素组成与溶液相ｐＨ、总硼浓度及析出固相后固液相硼摩尔比有关，不仅存在正的硼同位素分馏效应，而且存在负的硼同位素分馏效应。     

硼特效树脂离子交换法分离硼的研究

本文对AmberliteIRA743硼特效树脂交换分离础的特性及其影响因素进行了研究.它适用于各种地质作品中硼的分离提取，特别是在硼同位素地球化学研究时。必须进行础纯化的场合。     

硼氧酸盐^11BNMR波谱学研究

系统地总结和讨论了固体硼氧酸盐１１ＢＭＡＳＮＭＲ和硼氧酸盐水溶液１１ＢＮＭＲ波谱学研究结果。对于固体硼氧酸盐１１ＢＭＡＳＮＭＲ谱．虽然可以从中定量计算ＢＯ３与ＢＯ４比值，但因为１１Ｂ化学位移变化小，很难将配位多面体与它们的配位环境相联系，用其作为表征固体硼氧酸盐尚缺少特征性。而对于硼氧酸盐水溶液１１ＢＮＭＲ谱，由于在ＮＭＲ谱仪时间规模下一些硼氧酸盐阴离子中不同化学位置上Ｂ核交换速率影响，在１１ＢＮＭＲ波谱上没有观察到信号。实践证明，溶液１１ＢＮＭＲ波谱与Ｒａｍａｎ光谱的联合使用，将是研究水溶液中硼氧酸盐阴离子结合最直接和有力的手段。     

A Raman investigation on the boron form occurring in salt lake brine during evaporation

Boron resources are abundant in Da Qaidam salt lake of Qaidamu Basin. It has been given great attention for the polyborate species present in brine. In this study, the Raman spectroscopy was applied to investigate the existing-form of boron in brine during evaporation. The prepared solutions of MgO·2B2O3-H2O, MgO·2B2O3-MgCl2 -H2O, and MgO·2B2O3-MgSO4-H2O was also evaporated and recorded to study the influence of boron concentration, pH, and electrolytes on the borate speciation in brine. The mononborates of B(OH)3 and B(OH)4- were found to be the only forms present in the original salt lake brine. Brine evaporation promotes the formation of polyborate anions B3O3(OH)4-, B5O6(OH)4-, and B6O7(OH)62- and also disappearance of the B(OH)4- ion in brine with boron concentration of more than 11 g/L in B2O3. The pentaborate ion of B5O6(OH)4- was sensitive to the solution pH and found to be appeared under the pH value of 8.0. While the hexaborate ion of B6O7(OH)62- was observed more dependent on the electrolyte of magnesium chloride due to its special properties, such as promoting boron accumulation, lowering solution pH, and also the strong af?nity for water molecules, which is beneficial to the polymerization of borate ions in brine. The interaction mechanisms among polyborate anions during evaporation had also been proposed.     

A Raman Investigation on the Boron form Occurring in Salt Lake Brine during Evaporation

Boron resources are abundant in the Da Qaidam Salt Lake of the Qaidamu basin in China,which has generated significant attention due to the presence of polyborate species in brine from this lake. In this study,Raman spectroscopy was used to investigate the existing form of boron in brine during evaporation. MgO·2 B_2 O_3-H_2 O,MgO·2 B_2 O_3-MgCl_2-H_2 O,and MgO·2 B_2 O_3-MgSO_4~-H_2 O solutions were also studied to determine the influence of boron concentration,pH,and electrolytes on the borate speciation from brine. The mononborates B( OH)_3 and B( OH)_4~-were found to be the only forms present in natural salt lake brine. Brine evaporation promoted the formation of the polyborate anions B_3 O_3( OH)_4~-,B_5 O_6( OH)_4~-,and B_6 O_7( OH)_6~(2-)and also promoted the disappearance of the B( OH)_4~-ion from brine at boron concentrations of more than 11 g/L B_2 O_3. The pentaborate ion B_5 O_6( OH)_4~-was sensitive to the solution pH and appeared only at p H values less than 8. 0. Meanwhile,the hexaborate ion B_6 O_7( OH)_6~(2-)was observed to be more dependent on the electrolyte magnesium chloride due to its special properties,such as promoting boron accumulation,lowering solution pH,and also its strong affinity for water molecules,which were all beneficial for the polymerization of borate ions in brine. Interaction mechanisms between polyborate anions during evaporation are also proposed herein. ake; evaporation; polyborate species; interaction mechanism.