Decolourisation of Metal-azo Dyes in Wastewaters by Sodium Peroxodisulphate: A Template for Experimental Investigations

Background: It has long been recognized that the presence of azo metal complex dyes and their non-complexed counterparts in wastewaters, which is due to manufacturing use textile industries, renders natural waterways intensely coloured, therefore aesthetically unacceptable. Azo dye moieties are also known be precursors human carcinogenicity. Objective: This work aimed at decolourisation metal-azo present wastewaters so pollution bodies water can prevented. Decolourisation indicative destruction metal-ligand complex, allowing retrieval transition ions, contaminants. Fracturing bond itself minimizes potential for carcinogenicity these dyes. Methods: achieved by oxidative action free radicals furnished Na 2 S O 8 , sodium salt peroxodisulphuric acid (Marshall’s acid). Raman spectroscopy characterizes (ligand) as “Eriochrome Black T (EBT)” a peak 1425 cm -1 . Dismantling its molecular structure peroxodisulphate will lead accompanied collapse peak. Concomitantly, EBT ligands fracture cease chelate, metallic ions released, oxidized higher oxidation state, precipitated insoluble compounds alkaline media. Results: The concentration aqueous phase found substantially reduced. successfully treated solutions mostly clear colourless; Beer-Lambert absorbances range 0.02 ≤ absorbance 0.05. treatment Ni(II), Co(II) Fe(II)-EBT straightforward; Cu(II) Cr(III)-EBT require additional included above range. least responsive treatment. evinced Spectroscopy. Conclusion: A template investigate feasibility metal-complex pioneered recommended.