Electrochemical degradation of the dye reactive orange 16 using electrochemical flow-cell

Abstract

As remoções eletroquímicas de cor e do conteúdo orgânico de soluções do corante laranja reativo 16 (RO16) foram efetuadas usando uma célula em fluxo e um eletrodo de trabalho de Pt. As influências das variáveis do sistema, tais como fluxo, concentração de NaCl, potencial aplicado e pH da solução, foram estudadas. A melhor remoção de cor foi de 93% (l = 493 nm) após 60 min de eletrólise potentiostática a 2,2 V vs. ERH, usando 1,00 g L -1 NaCl como eletrólito suporte. Os aumentos na concentração de NaCl e do potencial aumentam a velocidade de remoção de cor. A melhor remoção de carbono orgânico total (57%) foi obtida com a aplicação de 1,8 V, sem membrana de separação, indicando que as melhores condições para remoção de cor não são necessariamente as melhores para remover conteúdo orgânico. A eficiência de degradação diminui com a diminuição do pH da solução.Electrochemical removals of color and organic load from solutions containing the dye reactive orange 16 (RO16) were performed in an electrochemical flow-cell, using a platinum working electrode. The influence of the process variables flow-rate, such as NaCl concentration, applied potential and solution pH, were studied. The best color removal achieved was 93% (l = 493 nm) after 60 min at 2.2 V vs. RHE electrolysis, using 1.00 g L -1 NaCl as supporting electrolyte. The rises in the concentration of NaCl and applied potential increased the color removal rate. The best total organic carbon removal (57%) was obtained at 1.8 V, without the separating membrane, indicating that the ideal conditions for the color removal are not necessarily the same as those to remove the total organic carbon. The degradation efficiency decreased with the solution pH decrease.Keywords: decolorization, textile effluent, electrochemical degradation, reactive dye, Pt electrode IntroductionWhen untreated textile effluents are discharged into receiving water bodies many environmental problems can occur. The principal problems are that the presence of dyes (even at concentrations of < 1 ppm) that can cause considerable coloration in water courses, affect transparency to natural light (reducing photosynthesis), reduce gas solubility and may also present carcinogenic and mutagenic properties. 1,2Wide varieties of dyes are used in the textile industry and can be classified according to the manner in which they are fixed to the textile fiber (e.g., direct, reactive) or by their chemical structure (e.g., azo, anthraquinone). In the textile industry, reactive dyes are widely used due to their relatively easy application in the dyeing process and stability during wear. As a result of this stability, reactive dyes may require more complicated systems to achieve their removal from effluent flows. A number of methods presented in the literature are traditionally used to treat textile effluent and they are generally based on physical, chemical and biological treatments.3-5 Physical treatment methods tend to simply transfer the pollutant to a different phase and biological methods can be prolonged and ...

Photo-assisted electrochemical degradation of simulated textile effluent coupled with simultaneous chlorine photolysis

“…The literature demonstrates that the photo-assisted treatments and those with NaCl as supporting electrolyte are advantageous for reduction in wastewater color. The higher the concentration of NaCl, the greater the rate of formation of Cl 2 /ClO − as well as the greater the removal of color (Martínez-Huitle and Brillas 2009;Gomes et al 2011;Garcia et al 2007). Rajkumar and Kim (2006) assert that, depending of the type of dye, for instance Reactive Blue, Reactive Black, and Reactive Red, the chromophore group can be removed in 20, 25, or 30 min of electrolysis.…”

“…3 has been shown to be a function of applied current and chloride concentration. The greater the concentration of NaCl, or the greater the applied current, the faster the rate of formation of Cl 2 /OCl − (Martínez-Huitle and Brillas 2009; Gomes et al 2011). Competitively, pollutants might be destroyed by direct anodic oxidation, other reactive species of oxygen or weaker oxidants generated from anodic oxidation of water or of electrolyte anions, as given in Eqs.…”

“…Competitively, pollutants might be destroyed by direct anodic oxidation, other reactive species of oxygen or weaker oxidants generated from anodic oxidation of water or of electrolyte anions, as given in Eqs. 4 and 5 (Gomes et al 2011;Gutowska et al 2007;Bilgi and Demir 2005).…”

Electrochemical degradation of tetracycline in artificial urine medium

“…The electric contact between the electrochemical cell and the reference electrode was made with a commercial cationic membrane strip, in which one end was assembled within the silicon and Teflon® spacers and the other was placed in a solution of 0.5 mol L −1 H 2 SO 4 . More details about the cell configuration can be found in previously published reports [31][32][33]. The flow cell reactor was connected to a peristaltic pump and reservoir by silicon tubes.…”

Adsorption Characteristics of Magnesium-Modified Bentonite Clay with Respect to Acid Blue 129 in Aqueous Media

“…Wastewater treatment methods such as coagulation [8], ozonation and filtration [9], oxidation, [10], sedimentation, flotation, [11] reverse osmosis, nano filtration [12], electrochemical oxidation [13], and photo-electrochemical oxidation [14] are used to treat water-containing dyes from the textile industries, but all these processes must be considered for economic reasons. Adsorption has proven to be very efficient at removing dye pollutants from effluent [4,[15][16].…”