Article

Degradation of a Textile Dye CI Direct Red 80 by Electrochemical Processes

Portugaliae Electrochimica Acta 01/2004; 22:279-294. DOI: 10.4152/pea.200403279

ABSTRACT The electrochemical removal of the textile dye C. I. Direct Red 80 (DR80) was carried out using three different materials as anodes: iron, polypyrrole (PPy) and boron doped diamond (BDD). Iron electrodes are consumed during the electrolysis, and promote flocculation/coagulation of the dye. Polypyrrole, a conducting polymer, was prepared by chemical/electrochemical precipitation over a cotton cloth; it enables the precipitation of the dissolved dye through a conversion reaction in a less soluble compound. Boron doped diamond electrode was used to achieve the complete mineralization of the dye. Bulk electrolysis were studied using Na 2 SO 4 as electrolyte. In the case of the PPy electrode, NH 4 NO 3 was also used as electrolyte. The variation of the dye concentration was followed by UV-visible absorbance measurements and chemical oxygen demand (COD) tests were also performed, to compare the rates of colour and COD removal in each case. From the COD measurements over the time of electrolysis, using the BDD anode, a mass transfer coefficient for the DR80 molecule was determined. The obtained results show an almost complete colour removal for all the electrodes tested and a COD removal between 50 and 90 %, being the best results obtained with the BDD electrode.

0 Bookmarks
 · 
117 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this research, the zinc–aluminum layered double hydroxide (Zn–Al LDH) was synthesized and structurally and morphologically characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and N2 adsorption–desorption techniques. The obtained nano-structured inorganic material was employed as an innovative nano-sorbent for separation of Reactive Yellow 84 (RY84) dye from aqueous solutions, which can be spectrophotometrically monitored at λ = 359 nm. The effect of several parameters such as type of interlayer anion in Zn–Al LDH structure, pH, sample flow rate, elution conditions, amount of nano-sorbent, sample volume and co-existing ions on the retention efficiency was investigated and optimized. The results showed that trace amounts of the RY84 could be retained using a column packed with 300 mg of the Zn–Al(NO3−) LDH at pH 8 and stripped by 2.5 mL of 3.0 mol L−1 NaOH. Under the optimum experimental conditions, the limit of detection and the relative standard deviation were 0.04 μg mL−1 and 1.8 %, respectively. The calibration graph using the presented solid phase extraction system was linear in the range of 0.15–1.5 μg mL−1 with a correlation coefficient of 0.9982. The method was successfully applied to removal of RY84 from several textile wastewater effluents.
    Journal of the Iranian Chemical Society 12/2013; · 1.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present study was motivated by innovative reports published by De Battisti and co-workers (Martínez-Huitle et al., Electrochim Acta 50:949, 2004; Martínez-Huitle et al., J Appl Electrochem 35:1087, 2005) in 2004, on the electrochemical oxidation of chloroanilic and oxalic acids using electrolytic flow cell with parallel plate electrodes. These studies were few of the pioneering studies employing different design and configuration of electrochemical flow cells. Therefore, in this work, the applicability of single flow cell and dual flow cell (serial mode of SFC) systems was investigated for removing organic pollutants. Galvanostatic electrolyses were performed using the two electrochemical systems for degrading synthetic dye effluents (Remazol Red RB and Novacron Yellow), employing as electrocatalytic materials: Ti/Pt and Ti/Pt–SbSn. The electrochemical treatment of dye solutions led to complete discoloration and partial organic matter removal at different operating conditions (current density and flow cell configuration). The influence of these parameters was examined, in order to compare the use of single flow cell or dual flow cell, based on the energy consumption and costs. From the results obtained using dual flow cell configuration; higher color and organic matter removals were achieved in short times of electrolysis, confirming that this treatment process can be a suitable pre-treatment alternative for depuration of textile effluents decreasing the energy consumed when a single flow cell is employed.
    Electrocatalysis. 12/2013;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: As pollution becomes one of the biggest environmental challenges of the XXI century, pollution of water threatens the very existence of humanity, making immediate action a priority. The most persistent and hazardous pollutants come from industrial and agricultural activities, therefore effective treatment of this wastewater prior to discharge into the natural environment is the solution. Advanced oxidation processes (AOPs) have caused increased interest due to their ability to degrade hazardous substances in contrast to other methods, which mainly only transfer pollution from wastewater to sludge, a membrane filter or an adsorbent. Among a great variety of different AOPs, a group of electrochemical advanced oxidation processes (EAOPs); including electro-Fenton, is emerging as environmentally friendly and effective treatment process for the destruction of persistent hazardous contaminants. The only concern which slows down a large-scale implementation is energy consumption and related investment and operational costs. A combination of EAOPs with biological treatment is an interesting solution. In such a synergetic way, removal efficiency is maximized, while minimizing operational costs. The goal of this review is to present cutting-edge research for treatment of three common and problematic pollutants and effluents: dyes and textile wastewater; olive processing wastewater; pharmaceuticals and hospital wastewater. Each of these types is regarded in terms of recent scientific research on individual electrochemical, individual biological and a combined synergetic treatment.
    Environmental Science and Pollution Research 07/2014; 21:8493-8524. · 2.76 Impact Factor

Full-text (3 Sources)

Download
15 Downloads
Available from
May 21, 2014