Fe-Based Metal-Organic Frameworks for the Controlled Release of Fertilizer Nutrients

Due to the controlled-delivery function of metal-organic frameworks (MOFs) for gases, drugs, and pesticides, iron-based MOFs (Fe-MOFs) were explored in the laboratory as a novel fertilizer, which showed potential for use in the fertilizer industry; the challenge in the industrial scale application of Fe-MOFs in practical crop production was mainly the impact of scaling-up to energy and heat transfer, as well as the reaction yield. In this study, Fe-MOFs were hydrothermally synthesized both in the laboratory scale and in the pilot scale, their structure and components were characterized using various spectroscopic techniques, and then their nutrient release and degradation behaviors were investigated. The results showed that Fe-MOFs were successfully synthesized in both scales with similar yields around 27%, and the Fe-MOFs showed a similar structure with the molecular formula of C₂H₁₅Fe₂N₂O₁₈P₃. The nutrients N, P, and Fe were present in the Fe-MOFs with the average contents of 6.03, 14.48, and 14.69%, respectively. Importantly, the nutrient release rate and pattern of Fe-MOFs well matched with the crop growth, which greatly promoted the rice yield. Therefore, the environmentally friendly compounds of Fe-MOFs could be industrially produced and used as an innovative fertilizer with unique features of varied nutrients and controlled release.