关键词: 氮肥, PM_2.5, 氨气, 吸附剂, 金属有机骨架, 可逆转化

Abstract:

Ammonia(NH₃) is the main raw material of nitrogen fertilizer production, and it is also an important indirect source of PM_2.5.The ammonia emission reduction and recycling are the necessary ways for green development, especially under the green industrial production cycle.Adsorption method has the noteworthy feature of the ammonia capture without phase change and the advantages that enrichment of ammonia can be directly related to carbon dioxide synthesis of nitrogen fertilizer(such as urea).This work studies the ammonia adsorption properties of the flexible reversible transformation MOFs material Cu(BDC).Three dimensional dense structure of Cu(BDC)(DMF) is prepared by hydrothermal method, and one-dimensional pore structure Cu(BDC) was obtained after the removal of DMF under heating at high temperature with changed crystal structure.The Cu(BDC) has the surface area of 535 m²·g^-1 and the adsorption capacity of pure ammonia up to 18.4 mmol·g^-1 in an atmospheric pressure, which is higher than the traditional adsorbent and other new porous materials such as MOFs and COFs.By reducing the pressure and vacuum heating, the Cu(BDC) can be progressively regenerated and thus has excellent “ammonia” characteristics.Additionally, Cu(BDC)(DMF) can be converted into Cu(BDC)(NH₃)₂ in the ammonia environment, eliminating the process of Cu(BDC) preparation.

Key words: nitrogen fertilizer, PM_2.5, ammonia, adsorbents, metal-organic frameworks, reversible transformation