Electrochemical and Photoelectrochemical Decoloration of Amaranth Dye Azo Using Composited Dimensional Stable Anodes

Abstract

In this paper we report the results of our experimental work conducted to decoloration of a well-known highly toxic Amaranth dye by electrochemical and photoelectrochemical methods. Used throughout this investigation were two different Dimensional Stable Anode (DSA) electrodes, namely, IrO 2 -Ru 2 O-SnO 2 -TiO 2 /Ti and Ru 2 O-SnO 2 -TiO 2 /Ti. The experimental results show that IrO 2 -Ru 2 O-SnO 2 -TiO 2 /Ti electrode has higher performance on amaranth decoloration than Ru 2 O-SnO 2 -TiO 2 /Ti electrode, but with the disadvantage of higher energy consumption. For higher degradation of Amaranth dye with both DSA electrodes, the process was carried out via photoelectrochemical method. Our experimental results clearly shown the decrease in absorbance of all UV-Vis peaks due to the mineralization of the azo dye; also, it was noteworthy photoelectrochemical process consumes less energy under the same experimental conditions than electrochemical process. The IrO 2 -Ru 2 O-SnO 2 -TiO 2 /Ti electrode reaches a higher degradation degree of Amaranth solutions than Ru 2 O-SnO 2 -TiO 2 /Ti electrode using a photoelectrochemical technique.

Decolorization of Amaranth aqueous solution by atmospheric-pressure plasma jet irradiation

“…Higher and lower absorption peaks were observed at λ = 517 and 332 nm, respectively, in the spectrum obtained before plasma irradiation. Similar absorption spectra were reported by Karkmaz et al, 40) Pavanelli et al, 41) Salazar-Gastélum et al, 35) and Barros et al 38) With increasing irradiation time, the absorbance at the peaks decreased. Because the absorbance is proportional to the Amaranth concentration, the observed decrease in the absorbance indicates a decrease in the Amaranth concentration.…”

“…However, its risks to human health have been pointed out; Amaranth is considered carcinogenic and may damage DNA, reduce the pregnancy rate, and induce hives. [32][33][34][35] The use of Amaranth has been prohibited in some countries, such as the US, Russia, and Norway. [36][37][38] Many researchers have studied the decomposition of Amaranth molecules (the decolorization of Amaranth aqueous solutions) by various methods.…”

“…41) Salazar-Gastelum et al reported that an Amaranth aqueous solution (500 ml; 50 ppm) with 0.1 M NaCl was decolorized when a voltage of 1.6 V was applied between a chemically synthesized IrO 2 -Ru 2 O-SnO 2 -TiO 2 /Ti electrode and a gold (Au) electrode in the solution for 5 min. 35) Barros et al applied a 50 mA cm −2 current between a boron-doped diamond/Si laminated electrode and a circular net platinum (Pt) electrode in an Amaranth aqueous solution (400 ml; 100 mg l −1 ) with pH adjusted to 12 by adding K 2 SO 4 and reported that the solution was decolorized when directly irradiated with 20 kHz ultrasonic waves for 90 min. 38) Rosu et al added 4 mg of a composite photocatalyst of silver (Ag)-supported TiO 2 microparticles and graphene to an Amaranth aqueous solution (20 ml; concentration not specified) and reported that the solution was decolorized when irradiated with ultraviolet light for 4 h. 42) Thus, although various methods have been studied, they require time or effort.…”

Improvement in treatment of soak liquor by combining electro-oxidation and biodegradation

“…In the present study, the anode potential was in the range of 1.32-1.7 V vs. SCE. Salazar-Gastélum et al 23 noticed the formation of hypochlorite at 1.7 V vs. SCE. In the present study, the oxidation of the organic complex is due to indirect electrooxidation at the TSIA electrode.…”

“…24 The presence of a high concentration of sodium chloride (17.08 g L À1 ) in soak liquor makes it even more compatible for the TSIA electrode with a current density of 0.012 A cm À2 which is necessary for indirect oxidation. 23 Sundarapandiyan et al 10 performed electrooxidation of tannery saline wastewater for 120 minutes by employing a graphite electrode, where the COD removal efficiency at a current density of 0.012 A cm À2 was only about 89.11%. In the present study, the electro-oxidation time of soak liquor was reduced to 30 minutes employing TSIA electrodes thus, the energy consumption can be reduced which helped to overcome the shortcomings of the work done by the previous group.…”