Eberbach Michaela C, Huinink Henk P, Shkatulov Aleksandr I, Fischer Hartmut R, Adan Olaf C G
Eindhoven University of Technology, Den Dolech 2, 5600 MB Eindhoven, The Netherlands.
EIRES, Horsten 1, 5612 AX Eindhoven, The Netherlands.
Cryst Growth Des. 2023 Feb 10;23(3):1343-1354. doi: 10.1021/acs.cgd.2c00821. eCollection 2023 Mar 1.
The hydration of salts has gained particular interest within the frame of thermochemical energy storage. Most salt hydrates expand when absorbing water and shrink when desorbing, which decreases the macroscopic stability of salt particles. In addition, the salt particle stability can be compromised by a transition to an aqueous salt solution, called deliquescence. The deliquescence often leads to a conglomeration of the salt particles, which can block the mass and heat flow through a reactor. One way of macroscopically stabilizing the salt concerning expansion, shrinkage, and conglomeration is the confinement inside a porous material. To study the effect of nanoconfinement, composites of CuCl and mesoporous silica (pore size 2.5-11 nm) were prepared. Study of sorption equilibrium showed that the pore size had little or no effect on the onsets of (de)hydration phase transition of the CuCl inside the silica gel pores. At the same time, isothermal measurements showed a significant lowering of the deliquescence onset in water vapor pressure. The lowering of the deliquescence onset leads to its overlap with hydration transition for the smallest pores (<3.8 nm). A theoretical consideration of the described effects is given in the framework of nucleation theory.
在热化学储能领域，盐的水合作用备受关注。大多数水合盐在吸水时膨胀，在解吸时收缩，这会降低盐颗粒的宏观稳定性。此外，盐颗粒的稳定性可能会因转变为盐溶液（即潮解）而受到影响。潮解通常会导致盐颗粒结块，从而阻碍通过反应器的质量和热流。在宏观上稳定盐以防止其膨胀、收缩和结块的一种方法是将其限制在多孔材料内部。为了研究纳米限域效应，制备了CuCl与介孔二氧化硅（孔径2.5 - 11 nm）的复合材料。吸附平衡研究表明，孔径对硅胶孔内CuCl的（脱）水相变起始点几乎没有影响或没有影响。同时，等温测量表明潮解起始点的水汽压力显著降低。对于最小孔径（<3.8 nm），潮解起始点的降低导致其与水合转变重叠。在成核理论框架内对上述效应进行了理论探讨。
