Browse Prior Art Database

Photochemical Oxidation of Organic Chelate Complexes

IP.com Disclosure Number: IPCOM000062193D
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Foery, M: AUTHOR [+2]

Abstract

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.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Photochemical Oxidation of Organic Chelate Complexes

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. By adding an oxidation aid, such as sodium peroxodisulfate (Na2S2O8), at a quantitative ratio of oxidation aid to EDTA of 2 : 1, the reaction time could be reduced considerably. When the most favorable oxidation conditions were determined, it was found that in a pH range of 2 to 3 and at higher temperatures (about 55OEC) the chelate ion is completely decomposed during UV- irradition.

1