Abstract:The electrochemical reduction of the dye Disperse Red-13 at a glassy carbon electrode in N,N-dimethylformamide was investigated. The dye was better determined using a mixture of DMF/Britton-Robinson buffer (1:1, v/v), which displayed a well-defined peak at −0.40 V vs Ag/AgCl due to reduction of the protonated nitro group. This method was successfully applied for electroanalytical determination of DR-13 via a very simple and inexpensive way. All of the differential pulse voltammetry parameters were optimized us… Show more
“…[24][25][26] Additionally, the electroanalytical determination of dyes in aqueous effluents using extraction aqueous phase has been described. 27 O 2 + 2H + + 2e − → H 2 O 2 [1] In the electro-Fenton (EF) process, the complex redox interaction between Fe (II) or Fe (III) ions present and the electrogenerated H 2 O 2 serves to increase the rate of formation of • OH. Moreover, it is believed that the Fe (II)/Fe (III) complexes so-formed play important catalytic roles in the further degradative reactions.…”
The increasing use of synthetic dyes in commercial food processing has heightened the need for more effective methods of treating industrial wastewaters prior to discharge into the environment. The present report describes the efficient electrodegradation of tartrazine dye in dilute aqueous solution using the electro-Fenton process with Fe (II) or Fe (III) as catalyst and a gas diffusion electrode modified with 5.0% cobalt phthalocyanine. The highest level of color removal (98.4% in 90 min) from solution and the most rapid decay in concentration (k app 6.0 × 10 −2 min −1 ) of tartrazine dye were achieved in the presence of 0.15 mmol Fe (II). Under these conditions, the amount of total organic carbon (TOC) removed in 90 min was maximal (75%) while energy consumed was minimal (219.0 kWh kg −1 TOC removed). The amount of residual iron was slightly higher than that allowed by the Brazilian authorities for dissolved Fe in wastewaters, indicating that further treatment of the effluent would be necessary.
“…[24][25][26] Additionally, the electroanalytical determination of dyes in aqueous effluents using extraction aqueous phase has been described. 27 O 2 + 2H + + 2e − → H 2 O 2 [1] In the electro-Fenton (EF) process, the complex redox interaction between Fe (II) or Fe (III) ions present and the electrogenerated H 2 O 2 serves to increase the rate of formation of • OH. Moreover, it is believed that the Fe (II)/Fe (III) complexes so-formed play important catalytic roles in the further degradative reactions.…”
The increasing use of synthetic dyes in commercial food processing has heightened the need for more effective methods of treating industrial wastewaters prior to discharge into the environment. The present report describes the efficient electrodegradation of tartrazine dye in dilute aqueous solution using the electro-Fenton process with Fe (II) or Fe (III) as catalyst and a gas diffusion electrode modified with 5.0% cobalt phthalocyanine. The highest level of color removal (98.4% in 90 min) from solution and the most rapid decay in concentration (k app 6.0 × 10 −2 min −1 ) of tartrazine dye were achieved in the presence of 0.15 mmol Fe (II). Under these conditions, the amount of total organic carbon (TOC) removed in 90 min was maximal (75%) while energy consumed was minimal (219.0 kWh kg −1 TOC removed). The amount of residual iron was slightly higher than that allowed by the Brazilian authorities for dissolved Fe in wastewaters, indicating that further treatment of the effluent would be necessary.
“…10,11 Recently, electrochemical techniques have obtained much attention and exhibited promising application in determination of synthetic dyes due to their high sensitivity, simplicity, low cost and convenient for insitu detection. [12][13][14][15][16] Electrochemical determinations for Ponceau-4R and Tartrazine were commonly based on the reduction and oxidation signals of Ponceau-4R 13,14 and Tartrazine 15,16 on the electrode. Ponceau-4R and Tartrazine always coexist together to give the orange color to food such as orange juice, so the development of simultaneous determination method for them based on electrochemical technique is necessary.…”
A novel electrochemical sensing platform was designed for simultaneous determination of Ponceau 4R and Tartrazine using an ionic liquid modified expanded graphite paste electrode (IL-EGPE). The IL-EGPE was prepared by mixing ionic liquid-expanded graphite composite (IL-EG) with solid paraffin. Based on the advantageous functions of IL and EG, IL-EGPE showed excellent electrocatalytic activity toward the simultaneous oxidation of Ponceau-4R and Tartrazine. Due to the electrocatalytic activity to Ponceau-4R and Tartrazine, a sensor for Ponceau-4R and Tartrazine was constructed based on IL-EGPE. Under optimal experimental conditions, the designed sensor exhibited wide linear responses to Ponceau 4R and Tartrazine ranging from 1.0 × 10 −8 to 5.0 × 10 −6 mol/L and 1.0 × 10 −8 to 2.0 × 10 −6 mol/L, respectively. The detection limits for Ponceau 4R and Tartrazine were 1.4 × 10 −9 mol/L (0.85 ng/mL) and 3.0 × 10 −9 mol/L (1.6 ng/mL) at a signal-to-noise ratio of 3, respectively. This sensor showed good reproducibility, stability and reusability. The proposed sensor was successfully applied in the simultaneous determination of Ponceau-4R and Tartrazine in soft drink with satisfactory results.
“…[10][11][12][13][14][15][16][17][18][19][20][21] Recently, several new materials and methodologies as functionalized membranes present a promising perspective for several analytes. [22][23][24][25][26][27][28][29][30][31][32] As an example, the potentiometric determination of lead can be achieved in a wide range of concentrations (10 −4 -10 −8 M) and low limit of detection (4 nM). 33,34 For carbonaceous electroactive materials, carbon fibers microelectrodes, 35 doped diamond, 36 carbon paste, 37,38 carbon nanotubes, 39 and, recently, graphene 40 are good examples.…”
In the present paper we report the production of vertically aligned carbon nanotubes exfoliated (at the tips) by oxygen plasma for electrochemical applications. The fast and dry process produces graphene oxide tips and oxygen functionalization. The electrodes are evaluated by cyclic voltametry by ferri/ferrocyanide redox couple and applied for electrochemical detection of lead (II) by differential pulsed anodic stripping voltammetry. The electrode presents high sensitivity (35.47 uA.uM −1 ) and low detection limit (48.3 pM). As far as we know, this is the lowest LoD in comparison with other works using CNT or graphene electrodes. The high electrochemical response is attributable to high density of functionalized edges on carbon nanotubes tips.
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