Binary salt mixture barium bromide-barium chloride for sorption applications

Abstract

Large temperature ‘jump’ and ‘ramp’ techniques, along with thermogravimetric analysis (TGA), were employed to characterise the sorption reactions of halide salt mixtures with ammonia. Using LTJ and FTR methods, a 1:1 mixture containing 50 % BaCl₂ and 50 % BaBr₂ by molar weight was studied but remained inconclusively characterised. To investigate further, samples with different BaCl₂ and BaBr₂ molar ratios (1:3, 1:1, and 3:1) were prepared. TGA results confirmed the presence of a new compound with sorption properties that vary in proportion to the molar ratios of the component salts. The effect of altering these molar ratios was evident: BaCl₂-rich mixtures resembled pure BaCl₂ salt behaviour, while BaBr₂-rich mixtures behaved more like pure BaBr₂ salt. Adsorption and desorption findings indicated an optimal bromide content at 50 %, beyond which the position of the reaction band becomes relatively stable—a pattern not observed in BaCl₂-heavy mixtures. These distinct reaction “bands” expand the temperature operating range of sorption technologies by up to 30 °C, suggesting that tailored anion halide salt mixtures could be developed for advanced heat pumping and thermal storage applications.