过饱和硼酸镁溶液结晶过程的原位FTIR研究  

In-Situ FTIR Study on the Crystallization Process of Supersaturated Magnesium Borate Solution Process

作　　者：贾力凡 宋露露 杜以法 张韫宏 潘建明[5] 周永全[1] 朱发岩[1] JIA Li-fan;SONG Lu-lu;DU Yi-fa;ZHANG Yun-hong;PAN Jian-ming;ZHOU Yong-quan;ZHU Fa-yan(Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining 810008,China;University of Chinese Academy of Sciences,Beijing 100049,China;School of Chemistry and Chemical Engineering,Linyi University,Linyi 276005,China;School of Chemistry and Chemical Engineering,Beijing Institute of Technology,Beijing 100081,China;School of Chemistry and Chemical Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海省盐湖资源化学重点实验室,青海西宁810008 [2]中国科学院大学,北京100049 [3]临沂大学化学化工学院,山东临沂276005 [4]北京理工大学化学与化工学院,北京100081 [5]江苏大学化学化工学院,江苏镇江212013

出　　处：《光谱学与光谱分析》2024年第12期3353-3363,共11页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金盐湖化工联合基金重点项目(U22A20413);青海省科技计划项目(2022-GX-152)资助。

摘　　要：基于自制的湿度连续可调装置,结合衰减全反射傅里叶变换红外光谱(ATR-FTIR)技术,深入探究了镁硼酸盐体系的动态行为,包括章氏硼镁石、三方硼镁石和多水硼镁石三种硼镁石过饱和溶液的相转变与结晶过程。实现了样品池内环境相对湿度的连续调节,在蒸发过程中能够连续监测到镁硼酸盐过饱和溶液的动态化学行为,基底表面所制备的过饱和溶液液膜逐渐蒸发水分浓缩为超浓态,最终形成包含多种镁硼酸盐晶体的多相混合物。对基底表面镁硼酸盐过饱和溶液及相转化、结晶得到的镁硼酸盐晶体的红外光谱的连续测量,结合基于密度泛函理论计算的多种镁硼酸盐晶体的红外振动模式,阐明三种镁硼酸盐过饱和溶液中多聚硼酸根的存在形式、相变过程中多聚硼酸根离子的分布变化及最终结晶形成的镁硼酸盐晶体种类,总结了三种镁硼酸盐体系的硼酸盐物种分布变化的区别,给出相转变结晶全过程的反应机理并对比“稀释成盐”现象进行解释。研究结果:(1)在三种硼镁石过饱和溶液中,主要存在的多硼酸根离子是B_(3)O_(3)(OH)^(2-)_(5)。三种硼镁石过饱和溶液随着蒸发结晶后晶体中均可观察到章氏硼镁石[B_(4)O_(5)(OH)^(2-)_(4)],这是B_(3)O_(3)(OH)^(2-)_(5)发生聚合反应形成的稳定物种;(2)镁硼酸盐晶体中的三配位硼氧键非对称伸缩振动νas(B(3)-O)主要表现为向内伸缩,而溶液中的硼酸根离子主要表现为向外伸缩,这一振动方向的差异可以作为区分晶体和溶液中硼酸根离子存在的依据;(3)“稀释成盐”得到的镁硼酸盐中不存在B_(5)O_(6)(OH)^(-)_(4),本研究中B_(5)O_(6)(OH)^(-)_(4)仅在章氏硼镁石过饱和溶液相转变结晶过程中出现,解释为章氏硼镁石过饱和溶液中B_(4)O_(5)(OH)^(2-)_(4)更易发生聚合反应生成B_(5)O_(6)(OH)^(-)_(4)。研究拓展了硼酸盐体系研究的传统浓度范围,详细刻画了镁硼酸盐�The magnesium borate system's dynamic behavior was investigated using ATR-FTIR and a self-made continuous humidity adjustable device.The supersaturation transformation and crystallization process of the three kinds of Ascharite,including Hungchaoite,Mcallisterite,and Inderite,were studied.Continuous adjustment of the relative humidity of the environment in the pool was achieved,allowing continuous monitoring of the dynamic chemical behavior of the magnesium borate supersaturation during evaporation.The supersaturation liquid film prepared on the substrate surface gradually evaporated and condensed into an ultra-concentrated state,eventually forming a multiphase mixture containing various magnesium borate crystals.Continuous measurement of infrared spectra of magnesium borate supersaturation on the substrate surface and magnesium borate crystals obtained by phase transformation and crystallization,combined with density functional theory calculations of infrared vibration patterns of various magnesium borate crystals,the supersaturation of poly borate in the three magnesium borates,the distribution of poly borate ions during the phase transformation,and the types of magnesium borate crystals formed by the final crystallization were described,the difference of species distribution of borates in three kinds of magnesium borate systems was summarized,and the reaction mechanism of the whole crystallization process was given.Research results:(1)In the three supersaturated solutions of Ascharite,the main polyborate ion is B_(3)O_(3)(OH)^(2-)_(5).After evaporation and crystallization of the three supersaturated solutions of Ascharite,Hungchaoite[B_(4)O_(5)(OH)^(2-)_(4)]can be observed in the crystals,which is a stable species formed by the polymerization reaction of B_(3)O_(3)(OH)^(2-)_(5);(2)The asymmetric stretching vibration of the three-coordinated boron-oxygen bondνas(B(3)—O)in the magnesium borate crystal is mainly inward stretching.In contrast,the borate ions in the solution mainly stretch outward.The difference

关 键 词：硼镁石 相转变机理 聚合反应 原位傅里叶变换红外光谱 

分 类 号：O433.4[机械工程—光学工程]