Evaluation of a Blue Indigo Dye Degradation with Electrochemical Peroxidation by UV-Vis Spectrophotometry

Abstract

In this work an aqueous solution containing a concentration of the dye 5,5',7-indigo trisulfonic acid of 100 mg L-1 have been degraded by an environmentally friendly electrochemical method. Two different supporting electrolytic media, phosphoric acid and sodium sulfate, were used to investigate their contribution in the efficiency of the degradation process. The electrochemical process used is electrochemical peroxidation (ECP), which uses an undivided cell with iron sheets as cathodes and requires the addition of hydrogen peroxide. As a result, the system promotes the production of hydroxyl radicals (.OH) from the Fenton's reaction that takes place between electro generated Fe (II) and the added H2O2. Under optimal conditions a complete color removal is achieved whereas the COD removal is 97%. The sludge generated from the treatment carried out in phosphate media is a fine white powder composed by oxihydroxi Fe-phosphate species. ECP is a highly efficient method for the degradation of the synthetic indigoid dye.

Reductive Degradation of Organic Compounds Using Microbial Nanotechnology

“…[7][8][9][10][11] In the presence of a suitable electron donor, these nanomaterials can catalyze the reduction of pollutants, thereby rendering them insoluble. 1,12,13 A variety of inorganic pollutants such carcinogenic hexavalent chromium, and hexavalent uranium are soluble in their highly oxidized form and become sparingly soluble on reduction (to trivalent chromium and tetravalent uranium in the above case, respectively). On the other hand, several organic compounds such as organic dyes, fertilizers, pharmaceutical compounds and intermediates undergo reductive degradation.…”