Chelating ability and solubility of DTPA, EDTA and β-ADA in alkaline hydrogen peroxide environment

The abilities of diethylenetriaminepentaaceticacid (DTPA), ethylenediaminetetraaceticacid (EDTA), β-alaninediacetic acid (ADA), separately and in combination, to bind and transport transition metals (Fe, Mn) were studied in four pilot-plant recirculation systems simulating alkaline (pH 10-11) hydrogen peroxide bleaching environments. Gas chromatography, atomic absorption spectroscopy and distribution computing were applied in the analyses and calculations. DTPA was able to bind 60% of manganese, EDTA 100% and β-ADA 40%. EDTA could bind only 10-20% of iron. The ligands appeared more soluble in the presence of iron and manganese probably due to the significant solubility of the manganese complexes.