CuCl ₂ –CuBr ₂ Mixtures with Different Cl/Br Molar Ratios for Efficient Ammonia Absorption

Metal chloride has the advantages of high absorption capacity and easy to obtain high purity ammonia and, thus, has a broad application prospect in the absorption and storage of ammonia. In this paper, CuCl2–CuBr2 mixtures with different Cl/Br molar ratios were prepared by the wet impregnation method, and the effect of temperature and number of cycles on the NH3 absorption capacity was further investigated. The experimental results revealed that the absorbent with the Cl/Br molar ratio of 1:1 exhibited the highest NH3 absorption capacity up to 0.61 g of the NH3/g absorbent. The efficient NH3 absorption capacity of the CuCl2–CuBr2 mixtures was mainly attributed to the mutual coordination of NH3 and Cu2+. Meanwhile, the good pore structure and high specific surface area of the absorbents are beneficial to the high absorption performance. Moreover, the CuCl2–CuBr2 mixtures with different Cl/Br molar ratios maintained a great NH3 absorption capacity after more than 10 cycles. This study demonstrated that CuCl2–CuBr2 mixtures are promising candidates for NH3 absorption.