Chemistry of copper trimercaptotriazine (TMT) compounds and removal of copper from copper-ammine species by TMT

Abstract

The acid dissociation constants of 2,4,6-trimercaptotriazine (H3 TMT) were determined by acid-base titration and now can be employed in the preparation of complexes having specific Cu-TMT ratios. IR, EA and TGA characterized the compounds. We analyzed the relevant IR spectra and attribute 2910-2925, 3030-3250 and 3430 cm-1 to triazine ring overtone, N-H stretching vibrations and water in the TMT complexes, respectively. The solubility of Cu-TMT complexes was determined with ICP-AES. The results indicate that Cus (TMT)2 · 2H2O (3) is much more insoluble and more stable than Cu (H2TMT)2 (1), Cu (HTMT)·0.5H2O (2) and CuS. The extremely small value of K SP for compound 3 (2.11 × 10-46) indicates that Na3TMT is a very advantageous chelating agent in precipitating complex copper (e.g. copper-ammine species) from industrial wastewaters. The influences of ammonia concentration, pH and settling time on the effectiveness of copper precipitation were investigated. Also, a 'real world' printed circuit board factory effluent initially containing 350.9 ppm of Cu was treated and it was found that more than 99.9% of the copper was removed from the solution as an insoluble compound 3. Copyright © 2006 John Wiley & Sons, Ltd.