Environment-friendly synthesis of Feldspar-KH2PO4 complexes by mechanochemical reaction

Abstract

Novel materials from Feldspar as clay material and KH2 PO4 (KHP) are prepared by grinding in a planetary ball mill in a mechanochemical process, one of the most effective ways to synthesize slow-release fertilizers. In two paths, tests were carried out with (3) weight ratio of Feldspar: KH2PO4 contents, at mill the incorporation of KH2PO4 and the liberation of K + and PO43− ions into solution were assessed at rotating speeds ranging from 200 to 700 rpm for 2◦h, and at milling periods ranging from 1, 2, and 3◦h. Thermal gravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and ion chromatography (IC) were employed to analyze the produced materials. The results confirmed that the mechanochemistry process is a sustainable chemistry method to produce amorphous Feldspars containing KH2PO4. After dispersing Feldspar and KH2PO4 in water for 24◦h, K+ and PO43− ions were measured. Based on these studies, it has been demonstrated that intercalated Feldspar could function as a carrier of K+ ions and release PO34− ions as a slow fertilizer.