The mixing effect of alkaline earth metal halides on ammonia absorption−desorption behavior
was studied to develop a new ammonia storage material to be used for the pressure-swing
absorption method. The halide mixtures with different cations (having a common anion) did
not form the solid solution after drying of the mixed aqueous solution. The ammonia absorption
isotherms on those samples were identical with those of the single-phase halide having the higher
ammonia affinity among the two. The halide mixtures with a common cation (having different
anions) formed a solid solution through the same mixing method. The isotherms on those samples
showed an intermediate profile between the components. Among these kinds of combinations,
CaCl2−CaBr2 (actually CaClBr) showed a pronounced ammonia storage capacity (16.4 mmol
g-1) under the pressure-swing conditions of 60 and 10 kPa at 298 K, which was 12.6 times as
high as that of the Na form of the Y-zeolite.