Facile fabrication of a potential slow-release fertilizer based on oxalate-phosphate-amine metal-organic frameworks (Opa-mofs)

This work demonstrates a simple, reproducible and scalable method of producing a potential slow-release fertilizer material. In this study, oxalate-phosphate-amine metal organic frameworks (OPA-MOFs) powder was synthesized from the hydrothermal treatment of ferric chloride (FeCl3•6H2O), orthophosphoric acid (H3PO4), oxalic acid dihydrate (H2C2O4•2H2O), and a common fertilizer, urea (CO(NH2)2). Being a structure directing agent (SDA)-type of MOF, the material is expected to slowly release urea via cation exchange, and eventually trigger the collapse of the framework, thus resulting to the subsequent release of the phosphates and iron-oxalate complexes. Elemental analysis revealed that the synthesized samples contains a promising amount of incorporated nitrogen and phosphorus. In this particular study, increasing in the amount of urea during the synthesis however revealed minimal change in the %N in the final product which tells us that maximum loading has already been achieved. P and N release experiments shall still be done bothinvitroand in actual soil samples to monitor the release delivery kinetics and efficiency of the OPA-MOFs for fertilizer release applications.