A first pre‐pilot system for the combined treatment of dye pollutants by electrocoagulation/EAOPs. Issue 8 (1st April 2014)

• Record Type: Journal Article
• Authors: Thiam, Abdoulaye; Zhou, Minghua; Brillas, Enric; Sirés, Ignasi
• Is Part Of: Journal of chemical technology & biotechnology. Volume 89:Issue 8(2014:Aug.)
• Page Start: 1136
• Page End: 1144
• Publication Date: 2014-04-01
• Subjects: Biotechnology -- Periodicals; Chemistry, Technical -- Periodicals; Chemical engineering -- Periodicals; Industries -- Environmental aspects -- Periodicals; 660
• DOI: 10.1002/jctb.4358
• Languages: English
• ISSNs: 0268-2575

Abstract

<abstract abstract-type="main" id="jctb4358-abs-0001"> <title>Abstract</title> <sec id="jctb4358-sec-0001" sec-type="section"> <title>BACKGROUND</title> <p id="jctb4358-para-0001">Based on promising results obtained at laboratory scale with a two‐step electrochemical treatment of Tartrazine solutions by electrocoagulation (EC) coupled with electrochemical advanced oxidation processes (EAOPs), this work addresses its scale‐up to degrade 1.85 dm<sup>3</sup> of solutions of this dye. Monopolar and bipolar configurations have been compared in EC. The effect of supporting electrolyte, pH, applied current, dye concentration and electrolysis time has been assessed.</p> </sec> <sec id="jctb4358-sec-0002" sec-type="section"> <title>RESULTS</title> <p id="jctb4358-para-0002">Electrocoagulation with four Fe electrodes was first optimized for the treatment of 278 mg dm<sup>−3</sup> Tartrazine solutions. The bipolar series configuration led to enhanced coagulation due to the larger electrode consumption. Solutions with 0.05 mol dm<sup>−3</sup> NaCl at pH 6.3 were quickly decolorized with 60% total organic carbon removal, being more convenient than Na<sub>2</sub>SO<sub>4</sub> and NaNO<sub>3</sub> electrolytes due to the synergistic action of coagulation and oxidation by active chlorine. Among the EAOPs, carried out with a Ti/IrO<sub>2</sub>‐RuO<sub>2</sub> anode and an air‐diffusion cathode to electrogenerate H<sub>2</sub>O<sub>2</sub>, electro‐Fenton (EF) with 0.5 mmol dm<sup>−3</sup> Fe<sup>2+</sup> was much better than electro‐oxidation owing to the oxidative action of active chlorine and <sup></sup>OH formed in the bulk from Fenton's reaction. Photoelectro‐Fenton (PEF) was even better by the additional photolysis of by‐products under incident UVA photons.</p> </sec> <sec id="jctb4358-sec-0003" sec-type="section"> <title>CONCLUSIONS</title> <p id="jctb4358-para-0003">The use of an EC reactor in bipolar configuration for 12.5 min at 1.50 A followed by PEF treatment for 360 min at 1.50–2.00 A ensured mineralization >90%, which encourages further optimization at larger scale for the treatment of a variety of organic pollutants in real wastewaters. © 2014 Society of Chemical Industry</p> </sec> </abstract>