Investigation of States of Water in Hydrous Minerals

为了弄清含水矿物中水的状态，本工作研制了平衡水蒸气压温度依赖性测量装置（TDEP）、绝热气体吸附量热计（阿加）和绝热微量热计（AMC）。TDEP通过改进最初由Mizota等人（1989）开发的仪器，配备了高旋进数字压力计（MKS Baratron 127 A）。阿加和AMC都由微型计算机控制，用于测量和数据处理。所采用的热敏电阻温度计的温度精度为0.0001K。高精度。能够以相对少量的样品（0.11g）准确地测定水化能。测定了几种天然沸石和合成沸石的水化能。以5A分子筛为例，在45 ℃左右测得其热力学熵为50 J·K·<-1>mol·L-1<-1>，与绝热热容量热计测得的绝对零开尔文热力学熵值相当。由阿加法得到的这些沸石的水化焓为-55kJ/mol（H2O），其一致地解释为水的蒸发热（约44 kJ/mol）和由AMC得到的水化热的总和。这表明通过这三种方法得出的焓值相互交叉检查。剩下的问题将是改进更精确地确定三种仪器中的每一种的脱水量的方法。TDEP是定量研究水分子状态的合适方法，因为水的微分吸附热和构型熵都可以在一定温度和水合材料的水合水平下测量。

To clarify states of water in hydrous minerals, three instruments have been made and developed during this work, suchas equipment for temperature dependence of equilibrium water vapor pressure measurement (TDEP), adiabatic gas adsorption calorimeter (AGA) and adiabatic micro-calorimeter (AMC). TDEP was equipped with high precession digital manometer (MKS Baratron 127A) by improving the instrument initially developed by Mizota et al. (1989). Both AGA and AMC are controlled by a microcomputer for measurements and for data processing. The thermister-thermometer adopted for them has the temperature precision of 0.0001K. The high precision. enables accurate determination of hydration energy with relatively small amount of sample (0.11g). Hydration energies were measured for several natural zeolites and synthetic zeolites. Configurational entropy of molecular sieve 5A zeolite was obtained, for example, to be 50JK^<-1>mol^<-1> at around 45ﾟC, the value of which is comparable with those obtained by adiabatic heat capacity calorimeter from absolute zero-kelvine. Hydration enthalpy of these zeolites obtained from AGA method were -55kJ/mol(H20) which is consistently explained as a total of the heat of evaporation of water (about 44kJ/mol) and the hydration heat obtained from AMC. This indicates that enthalpy values derived through these three methods were cross-checked with each other. A remaining problem will be to improve the method of determining more accurately the dehydration amount of water for each of three instruments. TDEP is a suitable method for investigating, states of water molecules quantitatively, because both of the differential heat of adsorption of water and the configurational entropy can be measured at a temperature and at a hydration level of a hydrated material.