Layered Double Hydroxides as Hosting Matrices for Storage and Slow Release of Phosphate Analyzed by Stirred-Flow Method

The objective of this work was to synthesize and characterize Layered Double Hydroxides (MgAl-LDHs, MgFe-LDHs, and MgAlFe-LDHs) containing phosphate anions and study P release kinetics was conducted with the prepared materials. The release kinetics tests were performed in water by the stirred-flow method to verify the P release profile from LDHs materials. Results showed LDHs have similar characteristics to those of reactive sources of P, such as thermophosphates. The LDHs presented gradual P release and the LDH prepared with the molar ratio of cations Mg:Al = 2:1 showed a more sustained profile of P release compared to other produced materials. Thus, the chemical and structural characteristics of the LDHs make them potential materials for the use and storage of slow P release fertilizer.