Efficiency and toxicity: comparison between the Fenton and electrochemical processes

2016 ◽  
Vol 74 (5) ◽  
pp. 1143-1154 ◽  
Author(s):  
Marcela Gomes Tavares ◽  
Danilo Henrique da Silva Santos ◽  
Sheyla Jaqueline Albuquerque Torres ◽  
Wagner Roberto Oliveira Pimentel ◽  
Josealdo Tonholo ◽  
...  
Keyword(s):  
Fenton Reaction ◽  
High Current Density ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
High Current ◽  
Experimental Conditions ◽  
Electrochemical Processes ◽  
Treated Effluent ◽  
Dye Oxidation ◽  
Germination And Growth

This study aimed to determine the best method to treat a textile effluent containing the dye basic blue 99 (BB). Treatments by the electrochemical and the Fenton processes were compared by means of a 23 experimental design, and the interaction of experimental conditions for BB oxidation were determined. The electrochemical treatment gave better results in the presence of NaCl as electrolyte and high current density (30 mA cm−2); the Fenton reaction provided better results at H2O2 and Fe2+ concentrations of 10 mg L−1 and 0.5 mmol L−1, respectively. Electrochemical treatment was 23 times faster than the Fenton reaction because formation of chlorinated species during electrooxidation significantly contributed to dye oxidation. Although the electrochemical process was more efficient, the resulting treated effluent was more toxic to Lactuca sativa germination and growth, which indicated some biotoxicity. Results demonstrated that both processes efficiently remediated effluents containing the dye BB, but they need to be combined with other processes to ensure complete adequacy of the effluent for disposal.

Development of a system for treatment of coconut industry wastewater using electrochemical processes followed by Fenton reaction

2014 ◽  
Vol 69 (11) ◽  
pp. 2258-2264 ◽  
Author(s):  
Lúcio de Moura Gomes ◽  
José Leandro da Silva Duarte ◽  
Nathalia Marcelino Pereira ◽  
Carlos A. Martínez-Huitle ◽  
Josealdo Tonholo ◽  
...  
Keyword(s):  
Fenton Reaction ◽  
New Technologies ◽  
Liquid Waste ◽  
Oxygen Demand ◽  
Industrial Effluents ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Synthetic Wastewater ◽  
Processing Industry ◽  
Electrochemical Processes

The coconut processing industry generates a significant amount of liquid waste. New technologies targeting the treatment of industrial effluents have emerged, including advanced oxidation processes, the Fenton reaction, and electrochemical processes, which produce strong oxidizing species to remove organic matter. In this study we combined the Fenton reaction and electrochemical process to treat wastewater generated by the coconut industry. We prepared a synthetic wastewater consisting of a mixture of coconut milk and water and assessed how the Fenton reagents' concentration, the cathode material, the current density, and the implementation of associated technologies affect its treatment. Electrochemical treatment followed by the Fenton reaction diminished turbidity and chemical oxygen demand (COD) by 85 and 95%, respectively. The Fenton reaction followed by the electrochemical process reduced turbidity and COD by 93 and 85%, respectively. Therefore, a combination of the Fenton and electrochemical technologies can effectively treat the effluent from the coconut processing industry.

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 Elucidation and Characterization of New Chlorinated By-Products after Electrochemical Degradation of Hydrochlorothiazide Using Graphite–Poly Vinyl Chloride Electrode

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 540
Author(s):  
Zainab Mussa ◽  
Fouad Al-Qaim ◽  
Ali Yuzir ◽  
Hirofumi Hara ◽  
Shamila Azman ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Treatment Process ◽  
Oxidation Process ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Experimental Conditions ◽  
E Coli ◽  
Flight Mass Spectrometry ◽  
Negative Ionization ◽  
By Products

This paper describes an electrochemical treatment process of hydrochlorothiazide (HDZ) under different conditions such as initial concentration, sodium chloride and applied voltage. In this present study, HDZ was treated by electrochemical oxidation process using graphite-PVC composite electrode as anode and Platinum (Pt) as cathode. All results were analyzed using liquid chromatography-time of flight/mass spectrometry (LC-TOF/MS). It was found that at high applied voltages, and high amounts of NaCl, the electrochemical treatment process was more efficient. The removal% of HDZ was 92% at 5 V after 60 min. From the obtained results, the electrochemical oxidation process of HDZ followed pseudo first order with rate constant values ranged between 0.0009 and 0.0502 min−1, depending on the experimental conditions. Energy consumption was also considered in this study, it was ranged between 0.9058 and 5.56 Wh/mg using 0.5, 0.3 and 0.1 g NaCl within interval times of (10, 20, 30, 40, 50, 60, 70, and 80 min). Five chlorinated and one non-chlorinated by-products were formed and analyzed in negative ionization (NI) mode during the electrochemical process. Due to the strong oxidizing potential of the chlorine (Cl2) and hypochlorite ion (ClO−), HDZ and its by-products were removed after 140 min. Furthermore, a novel synthesis of chlorothiaizde as one of the new by-products was reported in this present study. Toxicity was impacted by the formation of the by-products, especially at 20 min. The inhibition percentage (I%) of E. coli bacteria was decreased to be the lowest value after 140 min.

XPS Study of Surface Layer Formed on AISI 316L after High-Current Density Electropolishing

2015 ◽  
Vol 227 ◽  
pp. 155-158 ◽  
Author(s):  
Krzysztof Rokosz ◽  
Tadeusz Hryniewicz ◽  
Sławomir Rzadkiewicz
Keyword(s):  
Surface Layer ◽  
Current Density ◽  
High Current Density ◽  
Electrochemical Treatment ◽  
Passive Layer ◽  
Aisi 316L ◽  
High Current ◽  
Degree Of Oxidation ◽  
Chromium Compounds ◽  
Xps Study

In the paper, there are presented XPS results of surface layer formed after electrochemical polishing of AISI 316L (EN 1.4404) stainless steel at high current density of 2000 A/dm2. For the investigation, electrolyte based on orthophosphoric (H3PO4) and sulfuric (H2SO4) acids in proportions 3:2, was used. The obtained results have shown, that high current density has considerably influences the composition of passive layer formed after electrochemical treatment. The study was focused mainly on the amount of carcinogenic nickel, sensitization chromium compounds on the sixth degree of oxidation as well as the [(Cr+3.3∙Mo)/Fe] coefficient.

scholarly journals Disinfection of municipal wastewater by TiO2 photocatalysis with UV-A, visible and solar irradiation and BDD electrolysis

2013 ◽  
Vol 11 (3) ◽  
pp. 357-363
Keyword(s):  
Municipal Wastewater ◽  
Electrochemical Process ◽  
Solar Irradiation ◽  
Initial Population ◽  
Order Kinetic ◽  
Boron Doped Diamond ◽  
Experimental Conditions ◽  
Tio2 Photocatalysis ◽  
Treated Effluent ◽  
Artificial Uv

The efficiency of TiO2 photocatalysis induced by ultraviolet and visible irradiation and salt-free electrolysis over boron-doped diamond electrodes to inactivate total (TC) and fecal (FC) coliforms in secondary treated municipal wastewater was evaluated. Photocatalytic experiments were conducted with two types of titania (Degussa P25 and sulfur-doped catalyst) at loadings in the range 0.1-0.5 g l-1 and three types of irradiation, i.e. artificial UV-A, artificial visible and solar. Electrolysis was conducted in a flow-through cell at anodic current densities of 14.3 and 28.6 mA cm-2 without the addition of auxiliary chemicals. Inactivation followed a first-order kinetic expression with regard to bacteria population and the rate was dependent of the experimental conditions in question. In general, electrochemical disinfection was up to about two orders of magnitude faster than photocatalysis; for instance, TC population decreased to less than 5% of the initial population after 9 and 4 min at 14.3 mA cm-2 and 28.6 mA cm-2 respectively. Similar efficiencies with TiO2 photocatalysis would require at least 30 min of contact time. Interestingly, energy consumption for the electrochemical process was computed to about 0.5 kWh per m3 of treated effluent, well below the respective value for photocatalysis.

A durable VO2(M)/Zn battery with ultrahigh rate capability enabled by pseudocapacitive proton insertion

2020 ◽  
Vol 8 (4) ◽  
pp. 1731-1740 ◽  
Author(s):  
Lishang Zhang ◽  
Ling Miao ◽  
Bao Zhang ◽  
Jinsong Wang ◽  
Jia Liu ◽  
...  
Keyword(s):  
Current Density ◽  
Cathode Surface ◽  
High Current Density ◽  
Rate Capability ◽  
Electrochemical Process ◽  
High Current ◽  
Long Term Stability ◽  
Hydrate Deposition ◽  
Sulfate Hydrate

Reversible hydroxyzinc sulfate hydrate deposition/dissolution in electrochemical process could be observed on cathode surface. Good long term stability retention could also be achieved at high current density of 20 A g−1.

Galvanostatic dissolution of mercury from the surface of glassy carbon into thiocyanate solution

1980 ◽  
Vol 45 (1) ◽  
pp. 169-178 ◽  
Author(s):  
František Opekar ◽  
Karel Holub
Keyword(s):  
Glassy Carbon ◽  
Electrode Surface ◽  
High Current Density ◽  
High Current ◽  
Nernst Equation ◽  
Potential Oscillations ◽  
Thiocyanate Solution ◽  
Theoretical Assumptions ◽  
Solution Proceeds ◽  
Dissolution Current

The galvanostatic dissolution of mercury from the surface of glassy carbon into a thiocyanate solution proceeds in accord with theoretical assumptions, as manifested by the constant product of the dissolution current and transition time. Under certain relations between the amount of oxidised mercury and concentration of thiocyanate at the electrode surface, however, a small part of the mercury dissolves at more positive potentials than correspond to the Nernst equation. This dissolution can be accompanied by potential oscillations. The anomalous behaviour is elucidated by the concept about coverage of a certain part of mercury with a film of sparingly soluble compounds of SCN- ions with mercury. This film is formed at the end of the galvanostatic dissolution on certain places of the electrode surface covered with mercury droplets, where SCN- ions are much exhausted as a result of a high current density.

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