Synthesis, characterization and application of anionic metal complex azo dyes as potential substitutes for Cr-complex dyes

Abstract

The synthesis and characterization of Cu-, Al-, Zn-, Ni-, Mn- complexes as substitutes for the Cr- and Co-complex acid azo dyes with lower toxicity was carried out and the subsequent use of ultra-filtration was studied with the aim of purifying the metal complex dyes and thus increasing dye strength and solubility and additionally reducing the free metal present in the final dye. A drastic reduction in the content of inorganic additives and free metal was achieved by the ultra-filtration process. The ultra-filtrated and non-ultra-filtrated dyes were used to dye wool and nylon fabrics. Color measurements and fastness properties were performed on the dyeings produced on wool and polyamide and compared with the Cr-complex dyeing, thus examining the possibility of using successfully these complex dyes as possible replacement of the Cr- and Co-complex dyes.