Studies on EDTA Recycling via Formation of EDTA Iron(III) Sodium Salt

So far the absorption of NO by Fe II EDTA solution has not been put into commercial application due to its high cost. In this paper recycling EDTA via formation of EDTA iron (III) sodium salt was presented for the purpose of offering a new pathway to solve this issue. The invalid solution was fully oxidized after NO absorption by Fe II EDTA solution. Ion chromatogram were used to detect the remained ions in solution. It was found that the original ions such as SO 3 2- , NO 2 - and so on were all oxidized to SO 4 2- and NO 3 - . Solubility measurement was carried out and it was revealed that the separation and purification could be performed by decreasing the temperature to 306 K. Fourier transformation infrared spectrophotometer (FTIR) and X-ray diffractometer (XRD) were applied to determine the transformation product of EDTA. The results indicated that FeNaEDTA was formed. Inductively coupled plasma and atomic absorption spectroscopy (ICP-AAS) demonstrated that the practical solubility of FeNaEDTA reached 78.7% at pH 7.