scholarly journals OXIDAÇÃO ANÓDICA PARA DESCONTAMINAÇÃO DE UM EFLUENTE CONTAMINADO COM O HERBICIDA GLIFOSATO UTILIZANDO ANODO DE DIAMANTE DOPADO COM BORO

Química Nova ◽  
2021 ◽  
Author(s):  
Maycon Lima ◽  
Ana Fajardo ◽  
Elaine Santos ◽  
Aline Sales-Solano ◽  
Djalma Silva ◽  
...  
Keyword(s):  
Negative Impact ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Operating Conditions ◽  
Boron Doped Diamond ◽  
Recirculation Flow ◽  
Electrochemical Systems ◽  
Boron Doped ◽  
Magnetic Stirring ◽  
Initial Ph

ANODIC OXIDATION FOR DECONTAMINATION OF CONTAMINATED EFFLUENT WITH GLYPHOSATE HERBICIDE USING BORON DOPED DIAMOND ANODE. Glyphosate is one of the most widely used herbicides in various crops. Based on the existing literature, this herbicide has carcinogenic characteristics, being able to be found in water courses, not only for its leaching in soils, but also in the effluents of the industries that produce it. Due to its negative impact on living beings, this work aims to investigate the applicability of the electrochemical treatment of a synthetic solution containing glyphosate with boron-doped diamond anode. Two electrochemical systems were tested (magnetic stirring and recirculation flow) for studying the applied current density (j = 30-200 mA cm-2), initial glyphosate concentration (250-850 mg L-1) and initial pH (3-9) as operating conditions. Best removal efficiencies were achieved at 100 mA cm-2, 850 mg L-1 of glyphosate and the natural effluent pH (≈5,0). The performance of the electrochemical systems was evaluated in terms of removal of chemical oxygen demand (COD) and energy requirements. After 120 min of treatment, comparing the magnetic stirring system to the recirculation it was verified that the first one is the most economically viable with an energy consumption of 56 kWh m-3. However, the results at both electrochemical systems are mor

scholarly journals Electrochemical treatment of real petrochemical effluent: current density effect and toxicological tests

2020 ◽  
Vol 82 (11) ◽  
pp. 2304-2315
Author(s):  
Jaqueline Ferreira de Melo ◽  
Danyelle Medeiros de Araújo ◽  
Djalma Ribeiro da Silva ◽  
Paola Villegas-Guzman ◽  
Carlos Alberto Martínez-Huitle
Keyword(s):  
Petrochemical Industry ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Stem Growth ◽  
Active Chlorine ◽  
Boron Doped Diamond ◽  
Bdd Anode ◽  
Boron Doped ◽  
Short Time ◽  
Northwest Region

Abstract This work aims to investigate the electrochemical treatment of petrochemical industry effluents (from the northwest region of Brazil) mediated by active chlorine species electrogenerated at ruthenium-titanium oxide supported in titanium (Ti/Ru0.3Ti0.7O2) and boron doped diamond (BDD) anodes by applying 15 and 45 mA cm−2. Chemical oxygen demand (COD) determinations and toxicity analyses were carried out in order to evaluate the process extension as well as the possible reuse of the wastewater after treatment. Toxicity was evaluated by assessing the inhibition of lettuce (Lactuca sativa) stem growth, seed germination, and the production of nitrite (NO−2) and nitrate (NO−3) species. Results clearly showed that the best COD reduction performances were reached at the BDD anode, achieving almost 100% of removal in a short time. Degradation of nitrogen-organic compounds generated NO−2 and NO−3 which act as nutrients for lettuce. Toxicity results also indicated that the electrogenerated active chlorine species are persistent in the effluent after the treatment, avoiding the stem growth, and consequently affecting the germination.

scholarly journals Electrochemical Treatment of synthetic and Actual Dyeing Wastewaters Using BDD Anodes

2010 ◽  
Vol 3 ◽  
pp. ASWR.S3639 ◽  
Author(s):  
Nasr Bensalah ◽  
Ahmed Abdel-Wahab
Keyword(s):  
Supporting Electrolyte ◽  
Great Influence ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Operating Conditions ◽  
Anode Surface ◽  
Boron Doped Diamond ◽  
Potential Region ◽  
Toc Removal ◽  
Boron Doped

In this work, the treatment of synthetic wastewaters containing methylene blue (MB) and rhodamine B (RB) and actual textile wastewaters (ATW) using boron doped diamond (BDD) anodic oxidation was investigated. Voltammetric study has shown that both MB and RB can be oxidized directly at the anode surface in the potential region where the electrolyte salt is stable. Galvanostatic electrolyses of synthetic and actual industrial wastewaters have led to total abatement of COD and TOC at different operating conditions (electrolyte salt and initial pollutant concentration and current density) and the efficiency of the electrochemical process was governed only by mass-transfer limitations. The nature of the supporting electrolyte has a great influence on the rate and the efficiency of the electrochemical oxidation of dyes. The treatment in the presence of NaCl appears to be more efficient in the COD removal, while in the presence of Na2SO4 improves the TOC removal. From the experimental results it seems that the primary mechanisms in the oxidation of dyes are the mediated electro-oxidation by hydroxyl radicals and other oxidants electro-generated from supporting electrolyte oxidation.

Electrochemical Treatment of Simulated Dye Wastewater

2012 ◽  
Vol 441 ◽  
pp. 555-558
Author(s):  
Feng Tao Chen ◽  
San Chuan Yu ◽  
Xing Qiong Mu ◽  
Shi Shen Zhang
Keyword(s):  
Current Density ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Dye Wastewater ◽  
Electrolysis Time ◽  
Electrochemical Degradation ◽  
Mild Conditions ◽  
Thermal Decomposition Method ◽  
Initial Ph ◽  
Effects Of Ph

The Ti/SnO2-Sb2O3/PbO2 electrodes were prepared by thermal decomposition method and its application in the electrochemical degradation of a heteropolyaromatic dye, Methylene blue (MB), contained in simulated dye wastewater were investigated under mild conditions. The effects of pH, current density and electrolysis time on de-colorization efficiency were also studied. Chemical oxygen demand (COD) was selected as another parameter to evaluate the efficiency of this degradation method on treatment of MB wastewater. The results revealed that when initial pH was 6.0, current density was 50 mA·cm2, electrolysis time was 60 min, Na2SO4 as electrolyte and its concentration was 3.0 g·dm3, the de-colorization and COD removal efficiency can reach 89.9% and 71.7%, respectively.

Property of Cu2O-CuO/ZSM-5 nanocomposite and degradation process of azo dye AO7 without sacrificial agent (H2O2)

2016 ◽  
Vol 73 (11) ◽  
pp. 2747-2753 ◽  
Author(s):  
Wusong Kong ◽  
Hongxia Qu ◽  
Peng Chen ◽  
Weihua Ma ◽  
Huifang Xie
Keyword(s):  
Catalytic Activity ◽  
Aqueous Solutions ◽  
Photoelectron Spectroscopy ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Surface Element ◽  
Impregnation Method ◽  
X Ray ◽  
Initial Ph ◽  
Sacrificial Agent

In this study, Cu2O-CuO/ZSM-5 nanocomposite was synthesized by the impregnation method, and its catalytic performance for the destruction of AO7 in aqueous solutions was investigated. The morphology, structure and surface element valence state of Cu2O-CuO/ZSM-5 were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The operating conditions on the degradation of AO7 by Cu2O-CuO/ZSM-5, such as initial pH values, concentration of AO7 and catalyst dosage were investigated and optimized. The results showed that the sample had good catalytic activity for destruction of AO7 in the absence of a sacrificial agent (e.g. H2O2): it could degrade 91% AO7 in 140 min at 25 °C and was not restricted by the initial pH of the AO7 aqueous solutions. Cu2O-CuO/ZSM-5 exhibited stable catalytic activity with little loss after three successive runs. The total organic carbon and chemical oxygen demand removal efficiencies increased rapidly to 69.36% and 67.3% after 120 min of treatment by Cu2O-CuO/ZSM-5, respectively.

scholarly journals A Comparative Electrochemical-Ozone Treatment for Removal of Phenolphthalein

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
V. M. García-Orozco ◽  
C. E. Barrera-Díaz ◽  
G. Roa-Morales ◽  
Ivonne Linares-Hernández
Keyword(s):  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Ozone Treatment ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Diamond Electrodes ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Electrochemical Processes ◽  
Density Values

The degradation of aqueous solutions containing phenolphthalein was carried out using ozone and electrochemical processes; the two different treatments were performed for 60 min at pH 3, pH 7, and pH 9. The electrochemical oxidation using boron-doped diamond electrodes processes was carried out using three current density values: 3.11 mA·cm−2, 6.22 mA·cm−2, and 9.33 mA·cm−2, whereas the ozone dose was constantly supplied at 5±0.5 mgL−1. An optimal degradation condition for the ozonation treatment is at alkaline pH, while the electrochemical treatment works better at acidic pH. The electrochemical process is twice better compared with ozonation.

scholarly journals On the Role of the Cathode for the Electro-oxidation of Perfluorooctanoic Acid

2020 ◽  
Author(s):  
Alicia Garcia-Costa ◽  
André Savall ◽  
Juan A. Zazo ◽  
Jose A. Casas ◽  
Karine Groenen Serrano
Keyword(s):  
Electrochemical Techniques ◽  
High Strength ◽  
Perfluorooctanoic Acid ◽  
Reduction Reaction ◽  
Adsorbed Hydrogen ◽  
Boron Doped Diamond ◽  
Bdd Anode ◽  
Boron Doped ◽  
Initial Ph

Perfluorooctanoic acid (PFOA), C7F15COOH, has been widely employed over the past fifty years, causing an environmental problem due to its dispersion and low biodegradability. Furthermore, the high stability of this molecule, conferred by the high strength of the C-F bond makes it very difficult to remove. In this work, electrochemical techniques are applied for PFOA degradation in view to study the influence of the cathode on defluorination. For this purpose, boron doped diamond (BDD), Pt, Zr and stainless steel have been tested as cathodes working with BDD anode at low electrolyte concentration (3.5 mM) to degrade PFOA at 100 mg/L. Among these cathodic materials, Pt improves the defluorination reaction. The electro-degradation of a PFOA molecule starts by a direct exchange of one electron at the anode and then follows a complex mechanism involving reaction with hydroxyl radicals and adsorbed hydrogen on the cathode. It is assumed that Pt acts as an electrocatalyst, enhancing PFOA defluorination by the reduction reaction of perfluorinated carbonyl intermediates on the cathode. The defluorinated intermediates are then more easily oxidized by HO• radicals. Hence, high mineralization (xTOC: 76.1%) and defluorination degrees (xF-: 58.6%) were reached with Pt working at current density j = 7.9 mA/cm2. This BDD-Pt system reaches a higher efficiency in terms of defluorination for a given electrical charge than previous works reported in literature. Influence of the electrolyte composition and initial pH are also explored.

scholarly journals On the Role of the Cathode for the Electro-Oxidation of Perfluorooctanoic Acid

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 902
Author(s):  
Alicia L. Garcia-Costa ◽  
Andre Savall ◽  
Juan A. Zazo ◽  
Jose A. Casas ◽  
Karine Groenen Serrano
Keyword(s):  
Electrochemical Techniques ◽  
High Strength ◽  
Perfluorooctanoic Acid ◽  
Reduction Reaction ◽  
Adsorbed Hydrogen ◽  
Boron Doped Diamond ◽  
Bdd Anode ◽  
Boron Doped ◽  
Initial Ph

Perfluorooctanoic acid (PFOA), C7F15COOH, has been widely employed over the past fifty years, causing an environmental problem because of its dispersion and low biodegradability. Furthermore, the high stability of this molecule, conferred by the high strength of the C-F bond makes it very difficult to remove. In this work, electrochemical techniques are applied for PFOA degradation in order to study the influence of the cathode on defluorination. For this purpose, boron-doped diamond (BDD), Pt, Zr, and stainless steel have been tested as cathodes working with BDD anode at low electrolyte concentration (3.5 mM) to degrade PFOA at 100 mg/L. Among these cathodic materials, Pt improves the defluorination reaction. The electro-degradation of a PFOA molecule starts by a direct exchange of one electron at the anode and then follows a complex mechanism involving reaction with hydroxyl radicals and adsorbed hydrogen on the cathode. It is assumed that Pt acts as an electrocatalyst, enhancing PFOA defluorination by the reduction reaction of perfluorinated carbonyl intermediates on the cathode. The defluorinated intermediates are then more easily oxidized by HO• radicals. Hence, high mineralization (xTOC: 76.1%) and defluorination degrees (xF−: 58.6%) were reached with Pt working at current density j = 7.9 mA/cm2. This BDD-Pt system reaches a higher efficiency in terms of defluorination for a given electrical charge than previous works reported in literature. Influence of the electrolyte composition and initial pH are also explored.

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