Studies on EDTA Recycling via Formation of EDTA Iron(III) Sodium Salt
So far the absorption of NO by FeIIEDTA 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 FeIIEDTA solution. Ion chromatogram were used to detect the remained ions in solution. It was found that the original ions such as SO32-, NO2- and so on were all oxidized to SO42- and NO3-. 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.