Decolorization of ethyl orange azo dye by oxidation process with acidified chloramine-T: spectrophotometric, kinetic and mechanistic approaches

Abstract

A B S T R A C TEthyl orange (EO) is a mono-azo dye, which is chiefly used as a dye in textile, food, and cosmetic industries. Removal of this dye from wastewater generated by these industries is a main concern in wastewater treatment. Hence, there is a need for a simple and inexpensive method to abolish this dye present in wastewater. A search through literature revealed that very few reports are available on the decolorization of EO dye and also no kinetic and mechanistic studies have been carried out about this dye. Consequently, an attempt is made to develop an oxidative decolorization method for EO dye with chloramine-T (CAT). The present study also aims to investigate the kinetics and mechanism of oxidative decolorization of EO dye with CAT in HClO 4 medium spectrophotometrically (λ max = 474 nm) at 303 K. The reaction exhibits a first-order dependence of rate on [EO] ], respectively. The dielectric effect is positive. Activation parameters have been deduced. Oxidation products were identified as N-(4-diethylamino-phenyl)-hydroxyamine and 4-nitroso-benzenesulfonic acid. Suitable mechanism and related rate law have been worked out. Importantly, the present decolorization method is definitely an advantageous alternative technique in treating the EO dye present in wastewater.

Chemical Degradation and Decolorization of Reactive Black B With an Inorganic Oxidant in Acidic Medium

“…k¼A:e Ea RT (1) Where A, R and T are Arrhenius factor, the energy of activation, gas constant and absolute temperature respectively. From the slope of the linear plot of lnk obs versus 1/T shown in Figure 9, the energy of activation was calculated.…”

“…These dyes cause major economic, environmental, and health problems. To overcome the above problems, it is necessary to explore a method to reduce the dyes or colored compounds from industrial effluent [1–8] . Azo dyes have been examined broadly because of their remarkable thermal and optical properties in applications such as optical recording medium, [9] toner, [10] inkjet printing, and oil‐soluble light fast dyes.…”

“…To overcome the above problems, it is necessary to explore a method to reduce the dyes or colored compounds from industrial effluent. [1][2][3][4][5][6][7][8] Azo dyes have been examined broadly because of their remarkable thermal and optical properties in applications such as optical recording medium, [9] toner, [10] inkjet printing, and oil-soluble light fast dyes. They have one or more azo groups-N=N-, as the essential chromophore, attached with two or more aromatic or heterocyclic structures.…”

Mechanistic Investigation of Oxidative Decolorization of an Azo Dye Metanil Yellow by Chloramine - T in Hydrochloric Acid Medium: A Spectrophotometric Approach

“…Along with the above convenient facts, Chloramine -T is easily available, non-toxic, water soluble or water tolerant and easy to handle. Though much of the information is available on mechanistic aspects of many of the reactions of Chloramine -T, literature survey indicates that, only few references are available on the kinetics and the mechanistic studies of oxidation of azo dyes [24][25][26].In this background, the current investigation was taken up with the purpose of studying decolourization of an azo dye Metanil yellow by using CAT as an oxidant.…”