偏硼酸钾水合物溶解热的测定及其热力学性质研究  

Dissolution enthalpy and thermodynamic properties of potassium metaborate hydrate

作　　者：袁菲 李华 李珑 郭亚飞 王士强 邓天龙 Fei Yuan;Hua Li;Long Li;Yafei Guo;Shiqiang Wang;Tianlong Deng(Key Laboratory of Marine Resource Chemistry and Food Technology(TUST),Ministry of Education,College of Chemical Engineering and Materials,Tianjin University of Science and Technology,Tianjin 300457,China;Key Laboratory of Marine Resource and Chemistry,College of Marine and Environmental Sciences,Tianjin University of Science and Technology,Tianjin 300457,China)

机构地区：[1]海洋资源化学与食品技术教育部重点实验室,天津科技大学化工与材料学院,天津300457 [2]天津市海洋资源与化学重点实验室,天津科技大学海洋与环境学院,天津300457

出　　处：《中国科学：化学》2022年第5期752-757,共6页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(编号:22073068,22103056);教育部创新团队发展计划(编号:IRT_17R81)资助项目。

摘　　要：不同形态硼酸盐焓、熵、吉布斯自由能等热力学参数极为缺乏,其准确测定对丰富和发展盐湖硼酸盐化学理论至关重要,而且也有利于促进我国盐湖资源的开发利用.本文采用TAMⅣ微量热计测定了偏硼酸钾水合物(KBO_(2)·4/3H_(2)O)的溶解热.根据设计的热化学循环、Pitzer电解质模型和热力学基本公式,获得了KBO_(2)·4/3H_(2)O在298.15 K下的标准生成焓(△^(θ)_(f,KBO_(2)·4/3H_(2)O)-1315.14 k J mol^(-1))、标准生成熵(△^(θ)_(f,KBO_(2)·4/3H_(2)O)69.13 J mol^(-1)K;)、标准生成吉布斯自由能(△^(θ)_(f,KBO_(2)·4/3H_(2)O)-1335.75 k J mol^(-1))、溶解平衡常数(K,8.19 mol^(-1)kg;)、活度系数(γ,0.52)、渗透系数(Φ,0.96)等热力学参数,结果表明KBO_(2)·4/3H_(2)O的溶解是吸热、自发和熵驱动的过程.The thermodynamic parameters such as enthalpy,entropy,and Gibbs free energy of different forms of borates are scarce.Accurate determination of these parameters is essential for us to enrich and develop the theory of salt lake borate chemistry and promote the development of salt lake resources in our country.In this article,the heat of dissolution of potassium metaborate hydrate(KBO_(2)·4/3H_(2)O)was measured by TAMⅣmicrocalorimeter.According to the designed thermochemical cycle,Pitzer electrolyte model and basic thermodynamic formula,a series of thermodynamic parameters including standard enthalpy of formation((△^(θ)_(f,KBO_(2)·4/3H_(2)O)-1315.14 kJ mol^(-1)),standard entropy of formation(△^(θ)_(f,KBO_(2)·4/3H_(2)O 69.13 J mol^(-1)K;),standard Gibbs free energy(△^(θ)_(f,KBO_(2)·4/3H_(2)O)-1335.75 kJ mol^(-1)),dissolution equilibrium constant(K,8.19 mol~2kg;),activity coefficient(γ,0.52)and permeability coefficient(Φ,0.96)were obtained at 298.15 K for the first time.The results showed that the dissolution of KBO_(2)·4/3H_(2)O is an endothermic,spontaneous,and entropy-driven process.

关 键 词：溶解热 溶解平衡常数 生成焓 钾硼酸盐 

分 类 号：O642[理学—物理化学]