Study on the reaction kinetics of simultaneous recovery of iron phosphate from hypophosphite in perferite oxidation plating waste

Abstract

Phosphorus is an indispensable and irreplaceable element in the ecosystem. Based on the ability of ferrate(VI) to remove phosphate by producing iron phosphate, a new method for using ferrate(VI) to treat hypophosphite has been studied. In this study, ferrate was added to the hypophosphate solution in a controlled manner, and the oxidation efficiency of ferrate(VI) on hypophosphate was studied under various initial pH conditions, when the pH value of 6.0, the hypophosphate oxidation rate reached 14.0%. Research findings, Ferrate recovered hypophosphate through precipitation and adsorption under various initial pH conditions. To further investigate the mechanism of hypophosphate recovery, the morphology and microstructure of the deposition were analysed using Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The kinetic process of ferrate recovery from hypophosphate was analysed. The recovery process follows second-order reaction kinetics, and the reaction rate is highest at pH 6.0. The value of kA1 is 1.742 × 10−2. This study shows that ferrate (VI) is a promising treatment tool for low-cost phosphate wastewater. Furthermore, this method offers a clean phosphorus recovery process without the generation of harmful substances.