Functionalized metal-organic frameworks for nitrogen recovery from fresh source-separated urine

Abstract

Recovering nitrogen from source-sepd. urine has become a sustainable soln. for wastewater management, as it can prevent eutrophication and provide fertilization products in the meantime. However, the majority of nitrogen in fresh source-sepd. urine exists in the form of urea which is difficult to be sepd. from water, and this has posed a great challenge for nitrogen recovery. In this work, a zirconium-based metal-org. framework (Zr-MOF) is rationally modified to provide both reacting sites to convert urea to ammonia in situ and adsorption sites to readily capture ammonium generated aforementioned, therefore serving as a versatile adsorbent platform for nitrogen recovery from fresh sourcesepd. urine. On top of the excellent total nitrogen removal capability of this MOF-based adsorbent, captured ammonium ions can be furthered exchanged with sodium to regenerate the adsorbent and to yield ammonium soln. as a ready-to-use fertilizer. This work opens up a new avenue of utilizing innovative nanomaterials by rational design as a soln. for environmental sustainability.