Atomistic modelling of water transport and adsorption mechanisms in silicoaluminophosphate for thermal energy storage. (September 2019)

• Record Type: Journal Article
• Authors: Fasano, Matteo; Falciani, Gabriele; Brancato, Vincenza; Palomba, Valeria; Asinari, Pietro; Chiavazzo, Eliodoro; Frazzica, Andrea
• Is Part Of: Applied thermal engineering. Volume 160(2019)
• Publication Date: 2019-09
• Subjects: Thermal energy storage -- Molecular dynamics -- Monte Carlo -- SAPO-34 -- Water -- Adsorption; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2019.114075
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: First experimentally supported classical molecular force field of water in SAPO-34. Classical Monte Carlo correctly predicts S-shaped water adsorption isotherms. Four-fold improvement on the state-of-the-art of numerical isotherms. Simulations show preferential adsorption in bigger cages of zeotype framework. Abstract: SAPO-34 – a silicoaluminophosphate microporous material – has recently attracted a great attention in the field of sorption thermal storage, since it is characterized by good water adsorption behavior ( i.e. type V adsorption isotherms) and low regeneration temperature ( i.e. 80 °C, for instance available by standard solar thermal energy collectors). However, the nanoscale mechanisms of water transport and adsorption in the microporous framework of SAPO-34 cannot be fully unveiled by experiments alone. In this work, water adsorption onto SAPO-34 is for the first time studied by means of an atomistic model built upon experimental evidence. First, Monte Carlo simulations are employed to set up a convenient atomistic model of water/SAPO-34 interactions, and numerical adsorption isotherms are validated against experimental measures. Second, the validated model is used to study the water diffusion through SAPO-34 by molecular dynamics simulations, and to visualize preferential adsorption sites with atomistic detail. Such atomistic model validated against experiments may ease the investigation and in silico discovery of silicoaluminophosphates for thermal storage applications with tailored adsorption characteristics.