(704g) Iron-Based Metal-Organic Framework for Superfast Adsorption of Uncharged Urea from Water: Synthesis, Characterization and Mechanism

Urea is widely used in fertilizer production for agricultural purposes which risks runoff into soil and water sources. An excess of urea can result in algal or toxic blooms which can poison wildlife or even humans by accumulation in food sources. Much research has been conducted on a variety of methods to remove environmental using adsorbents, but most of them lack effective removal, long (> 2 h) process time, lack re-generality, and losing materials after a few adsorption processes. Metal organic frameworks (MOFs) are the new generation of adsorbents with excellent structural and functional group tunability. In this study, we synthesized

MIL-100 (Fe), an iron-based metal-organic framework (MOF), as an efficient adsorbemt for removal of uncharged urea from water. The urea adsorption capacity of MIL-100 (Fe) was tested under varying experimental conditions such as pH (2-10), temperature (25-45°C), MOF concentration (25-400 ppm), and urea concentration (10-1000 ppm). Removal data showed the superfast adsorption (reached almost 90% removal within 1 min) of neutrally charged urea molecules. The MOF was able to reach a maximum adsorption efficiency of around 98% with a maximum uptake capacity of 4430 mg/g. MIL-100 (Fe) retained up to 88% removal efficiency after regeneration. In addition, the adsorption kinetics, mechanism and behavior of urea on Fe-MOF were studied at different temperatures and pH.