Facile synthesis and evaluation of Fe-Metal Organic Framework (Fe-MOF) as nutrient-slow-releasing agent

Abstract

Fe-Metal Organic Framework (MOF) was uniquely synthesized hydrothermally at mild conditions from ferric chloride, dipotassium hydrogen phosphate, urea, and oxalic acid (OXA) and duly characterised. The FTIR results showed that -OH of OXA; P-O of phosphate and C=O of OXA participated in the structural formation of the MOF. Whereas, NH₄⁺ and K⁺ were embedded into the layers of the MOF product. SEM result confirmed the image of the crystalline nature of the Fe-MOF at different magnifications with actual crystal size of 1.1 μm. The x-ray diffraction pattern gave major peaks as (110) and (111) corresponding to 200 at 28° and 31°, respectively implying the metal-carbonyl linkage for the MOF; as similarly observed in the FTIR absorptions. These results confirmed Face (111) and Body (110) Centered crystals (FCC and BCC).In the results of nutrient-slow-releasing capability of the iron-MOF, the trend of the release was: PO₄^3- (2.75 mg/L) < Fe³⁺ (3.30 mg/L) < NH₄⁺ (3.36 mg/L) < K⁺ (406 mg/L). Therefore, the synthesized MOF is recommended for real-life tests as slow-releasing fertilizer. The use of such products would also ensure food security, soil sustainability, and lessen pollution against the fast-releasing fertilizers. More so, the synthesis is handy and utilizes inexpensive reagents.