Photochemical Oxidation of Organic Chelate Complexes
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Organic chelates, which are soluble in water and which, by forming complexes with heavy metals, are detrimental to the environment, may be decomposed by irradiation with ultraviolet light in a wavelength range of about 185 to 254 nm and thus be non-detrimentally disposed of. Tests have been made with several solutions used for printed circuit board processes, which contained about 1 g/l ethylenediaminetetraacetic acid (EDTA). During those tests, EDTA decomposition curves (concentration according to time) were prepared for solutions containing EDTA and EDTA metal complexes. The solutions were irradiated with an UV lamp that was introduced into the solutions. During irradiation, EDTA oxidizes according to the reaction equations ClOH16O8N2 + 8.5 O2 T 10 CO2 + 5H2O + 2NH3 and 2NH3 + 4.5 O2 + 2e- T 2NO3- + 3H2O.