Abstract:

Two approaches were employed to prepare a novel high performance composite heat storage material by using expanded vermiculite, magnesium sulphate and Trilatone X-100 as the layered porous substrate, reactive salts, and hydrophilicmodifier, respectively. Two different modification methods were used in the study and the performance of the composites prepared by the two methods was compared. The test results of scanning electron microscopy (SEM) and X-ray diffractometer (XRD) showed that magnesium sulfate/expanded vermiculite modified composites were successfully synthesized. The influences of modification approach, mass of the added Trilatone X-100, and relative humidity on the adsorption performance of composite materials were discussed. Thermal gravimetric analyzer (TG) and differential scanning calorimeter (DSC) were utilized to measure energy storage density of the adsorbed composites, the results indicated that the hydrophilic functionalized composite fabricated by the modified expanded vermiculite with the mass ratio of expanded vermiculite to Trilatone X-100 of 10 and magnesium sulphate exhibited the best heat storage performance, whose water uptake, desorption rate, and heat storage density were improved by 2.5%, 4.1%, and 9.1%, respectively, as compared to the non-functionalized one. After 10 cycles of adsorption-desorption testing, the water uptake of the hydrophilic functionalized composite was only reduced by 20.4%, showing favorable thermal stability.

Key words: expanded vermiculite, magnesium sulphate, hydrophilic modification, adsorption, desorption, heat storage, mass transfer

摘要：

为强化硫酸镁在中低湿度环境下的吸附性能，采用亲水型活性剂曲拉通X-100制备硫酸镁/膨胀蛭石改性复合材料。采用两种不同改性方法制备复合材料并比较其性能。扫描电子显微镜（SEM）和X射线衍射仪（XRD）的测试结果表明成功地合成了硫酸镁/膨胀蛭石改性复合材料。利用恒温恒湿箱和热重分析仪（TG）、差式量热仪（DSC）对复合材料的吸附和储热性能进行测试，探讨了改性方法、活性剂添加量和相对湿度对吸附性能的影响，结果表明，在25℃、70%相对湿度条件下，先对膨胀蛭石亲水改性，且膨胀蛭石与活性剂质量比为10∶1时，改性复合材料具有最佳储热性能，相较于未改性复合材料，吸附量增加2.5%，脱附率提高4.1%，储热密度提升9.1%，且表现出良好的循环稳定性。

关键词: 膨胀蛭石, 硫酸镁, 亲水改性, 吸附, 脱附, 储热, 传质