Study on the mechanism of coupled oxidation and flocculation treatment of acid brilliant scarlet GR

Key words: 
• acid brilliant scarlet GR /
• coupled flocculation and oxidation /
• potassium permanganate /
• poly-silicic-ferric sulfate /
• mechanism

Abstract: Coupled flocculation and oxidation process has been used in treating acid brilliant scarlet dye wastewater．The color and COD removal rates reached 94.9％ and 55.2％，respectively，when potassium permanganate was used as oxidant and poly-silicic-ferric sulfate was used as flocculant．The reaction mechanism was primary conjectured after observing the aggregates morphology with biomicroscopy．The oxidative and reductive reaction outcome and aggregates were analyzed though UV-Vis adsorption spectrum and infrared adsorption spectrum．The results show that acid brilliant scarlet GR is oxidized into small organic molecules by potassium permanganate，then small organic molecules are adsorbed by the reduction product——newly formed hydrous manganese dioxide，which is enwrapped by poly-silicic-ferric sulfate in the next step，at last aggregates form and the color and COD are removed efficiently．Synergistic effect between oxidation and flocculation is produced in this process．