scholarly journals Anodic oxidation of slaughterhouse wastewater on boron-doped diamond: process variables effect

2017 ◽  
Vol 76 (12) ◽  
pp. 3227-3235 ◽  
Author(s):  
Arwa Abdelhay ◽  
Inshad Jum'h ◽  
Enas Abdulhay ◽  
Akeel Al-Kazwini ◽  
Mashael Alzubi

Abstract A non-sacrificial boron-doped diamond electrode was prepared in the laboratory and used as a novel anode for electrochemical oxidation of poultry slaughterhouse wastewater. This wastewater poses environmental threats as it is characterized by a high content of recalcitrant organics. The influence of several process variables, applied current density, initial pH, supporting electrolyte nature, and concentration of electrocoagulant, on chemical oxygen demand (COD) removal, color removal, and turbidity removal was investigated. Results showed that raising the applied current density to 3.83 mA/cm2 has a positive effect on COD removal, color removal, and turbidity removal. These parameters increased to 100%, 90%, and 80% respectively. A low pH of 5 favored oxidants generation and consequently increased the COD removal percentage to reach 100%. Complete removal of COD had occurred in the presence of NaCl (1%) as supporting electrolyte. Na2SO4 demonstrated lower efficiency than NaCl in terms of COD removal. The COD decay kinetics follows the pseudo-first-order reaction. The simultaneous use of Na2SO4 and FeCl3 decreased the turbidity in wastewater by 98% due to electrocoagulation.

Author(s):  
Kouakou Etienne Kouadio ◽  
Ollo Kambiré ◽  
Konan Sylvestre Koffi ◽  
Lassine Ouattara

Electrochemical oxidation of paracetamol on boron-doped diamond (BDD) anode has been studied by cyclic voltammetry and preparative electrolysis. Quantification of paracetamol during electrolysis has been mainly realized by differential pulse voltammetry technique in the Britton-Robinson buffer solutions used as the supporting electrolyte. Various parameters such as current intensity, nature of the supporting electrolyte, temperature, and initial concentration of paracetamol have been investigated. The electrochemical characterization by the outer sphere Fe(III)/Fe(II) redox couple has also been performed, showing the metallic character of BDD electrode. The obtained linear dependency of the oxidation peak current intensity and paracetamol concentration indicates that BDD electrode can be used as an electrochemical sensor for the detection and quantification of paracetamol. The investi­gation of paracetamol degradation during preparative electrolysis showed that: (i) the degradation rate of paracetamol increases with increase of current intensity applied; (ii) for the initial concentrations of 10, 6 and 1 mM of paracetamol, its oxidation rate reaches 60, 78 and 99 % respectively, after 1 h of electrolysis in 0.3 M H2SO4 (pH 0.6) at applied current density of 70 mA cm-2; (iii) at temperatures of electrolyte solution of 28, 55 and 75 °C, paracetamol oxidation rate reached 85, 92 and 97 % respectively, after 2 h at applied current density of 70 mA cm2. From the investigation of the effect of pH value of electrolyte solution, it appears that oxidation of paracetamol is more favorable in acidic solution at pH 3 than solutions of higher pH values.


Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5893
Author(s):  
Faléstine Souiad ◽  
Ana Sofia Rodrigues ◽  
Ana Lopes ◽  
Lurdes Ciríaco ◽  
Maria José Pacheco ◽  
...  

This paper studies the degradation of methiocarb, a highly hazardous pesticide found in waters and wastewaters, through an electro-Fenton process, using a boron-doped diamond anode and a carbon felt cathode; and evaluates its potential to reduce toxicity towards the model organism Daphnia magna. The influence of applied current density and type and concentration of added iron source, Fe2(SO4)3·5H2O or FeCl3·6H2O, is assessed in the degradation experiments of methiocarb aqueous solutions. The experimental results show that electro-Fenton can be successfully used to degrade methiocarb and to reduce its high toxicity towards D. magna. Total methiocarb removal is achieved at the applied electric charge of 90 C, and a 450× reduction in the acute toxicity towards D. magna, on average, from approximately 900 toxic units to 2 toxic units, is observed at the end of the experiments. No significant differences are found between the two iron sources studied. At the lowest applied anodic current density, 12.5 A m−2, an increase in iron concentration led to lower methiocarb removal rates, but the opposite is found at the highest applied current densities. The highest organic carbon removal is obtained at the lowest applied current density and added iron concentration.


2020 ◽  
Vol 10 (21) ◽  
pp. 7435
Author(s):  
Annabel Fernandes ◽  
Christopher Pereira ◽  
Susana Coelho ◽  
Celso Ferraz ◽  
Ana C. Sousa ◽  
...  

The ecotoxicity of methiocarb aqueous solutions treated by electrochemical oxidation was evaluated utilizing the model organism Daphnia magna. The electrodegradation experiments were performed using a boron-doped diamond anode and the influence of the applied current density and the supporting electrolyte (NaCl or Na2SO4) on methiocarb degradation and toxicity reduction were assessed. Electrooxidation treatment presented a remarkable efficiency in methiocarb complete degradation and a high potential for reducing the undesirable ecological effects of this priority substance. The reaction rate followed first-order kinetics in both electrolytes, being more favorable in a chloride medium. In fact, the presence of chloride increased the methiocarb removal rate and toxicity reduction and favored nitrogen removal. A 200× reduction in the acute toxicity towards D. magna, from 370.9 to 1.6 toxic units, was observed for the solutions prepared with NaCl after 5 h treatment at 100 A m−2. An increase in the applied current density led to an increase in toxicity towards D. magna of the treated solutions. At optimized experimental conditions, electrooxidation offers a suitable solution for the treatment and elimination of undesirable ecological effects of methiocarb contaminated industrial or agricultural wastewaters, ensuring that this highly hazardous pesticide is not transferred to the aquatic environment.


2001 ◽  
Vol 71 (3) ◽  
pp. 397-404
Author(s):  
Dimitrios Stergiopoulos ◽  
Konstantinos Dermentzis ◽  
Kokkoni Karakosta ◽  
Panagiotis Giannakoudakis

The treatment of aqueous phenol solutions is studied using the electrooxidation process with boron doped diamond (BDD) electrodes. The reduction of phenol concentration is followed by measurements of UV-Vis spectrophotometry and COD. Parameters affecting the efficiency of the electrooxidation process, such as solution pH, applied current density, initial phenol concentration, flow rate and conductivity are investigated. Effective and complete removal of phenol (]99 %) is achieved from solutions with initial phenol concentration of 100 mg/L in both, batch and continuously operated pocess.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Ali Baddouh ◽  
Brahim El Ibrahimi ◽  
Elhassan Amaterz ◽  
M. Mohamed Rguiti ◽  
Lahcen Bazzi ◽  
...  

The electrochemical oxidation of the Rhodamine B dye (Rh-B) was carried out using dimensionally stable type anode (DSA, Ti/Ru0.3Ti0.7O2). The work was performed using the electrochemical flow cell system. The effect of several operating factors, such as supporting electrolytes, current density, electrolysis time, temperature, and initial concentration of Rh-B dye, were investigated. The UV-visible spectroscopy and chemical oxygen demand (COD) measurements were conducted to monitor the removal and degradation of Rh-B. The best color removal achieved was found to be 98.3% after 10 min applying 3.9 mA·cm−2 as a current density using 0.07 mol·L−1 of NaCl. Meanwhile, the highest COD removal rate (93.0%) was obtained for an applied current density of 3.9 mA·cm−2 as the optimal operating condition after 180 min reaction time, with 2.98 kW h·m−3 as energy consumption. This shows that the best conditions for color removal are not certainly the same as those for the COD removal. The rises in the concentration of NaCl, and applied current increased the Rh-B color removal rate. The decline in Rh-B dye concentration followed pseudo-first-order kinetics. The obtained values of apparent rate constant were increased by increasing chloride ion concentration. It is concluded that the electro-oxidation on DSA electrode using a flow cell is a suitable process for the removal of Rh-B dye in aqueous solutions.


2019 ◽  
Vol 79 (5) ◽  
pp. 921-928 ◽  
Author(s):  
F. Agustina ◽  
A. Y. Bagastyo ◽  
E. Nurhayati

Abstract Electro-oxidation using a boron-doped diamond (BDD) anode can be used as an alternative to leachate treatment. Aside from the hydroxyl radical, BDDs are capable of generating chloride and sulfate radical species that play significant roles in the oxidation of pollutants. This research investigated the role of Cl−:SO42− ions at molar ratios of 237:1, 4:1 and 18:1, and the influence of applied current density (i.e. 50, 75 and 100 mA cm−2) on the removal of organic and ammonium contaminants. The results show that current density had considerable effects on chemical oxygen demand (COD) and colour removal, while ion composition of Cl−:SO42− at pH 3, 5 and 8.5 (original pH) gave different effects on COD and ammonium removal. The pH had a significant effect on the COD removal at the ratio of 237:1, but showed no dramatic effect at the ratio of 18:1, giving ∼40% of COD removal at all pHs tested. This indicates that electro-oxidation at the ratio of 18:1 could be effectively conducted at a wide range of pH. Furthermore, the optimum ammonium removal was obtained at pH 8.5 with the ratio of 237:1. This process was found to be ineffective in increasing the biodegradability index of the leachate; instead, it exhibited mineralization of organic content.


2020 ◽  
Vol 82 (4) ◽  
pp. 773-786
Author(s):  
Hao Li ◽  
Xinmou Kuang ◽  
Congping Qiu ◽  
Xiaolan Shen ◽  
Botao Zhang ◽  
...  

Abstract Petrochemical wastewater is difficult to process because of various types of pollutants with high toxicity. With the improvement in the national discharge standard, traditional biochemical treatment methods may not meet the standards and further advanced treatment techniques would be required. In this study, electrochemical oxidation with boron doped diamond (BDD) anode as post-treatment was carried out for the treatment of real biotreated petrochemical wastewater. The effects of current density, pH value, agitation rate, and anode materials on chemical oxygen demand (COD) removal and current efficiency were studied. The results revealed the appropriate conditions to be a current density of 10 mA·cm−2, a pH value of 3, and an agitation rate of 400 rpm. Moreover, as compared with the graphite electrode, the BDD electrode had a higher oxidation efficiency and COD removal efficiency. Furthermore, GC-MS was used to analyze the final degradation products, in which ammonium chloride, formic acid, acetic acid, and malonic acid were detected. Finally, the energy consumption was estimated to be 6.24 kWh·m−3 with a final COD of 30.2 mg·L−1 at a current density of 10 mA·cm−2 without the addition of extra substances. This study provides an alternative for the upgrading of petrochemical wastewater treatment plants.


2019 ◽  
Vol 31 (5) ◽  
pp. 1095-1099
Author(s):  
K. Vijayakumar ◽  
S. Geetha ◽  
M. Govindaraj

Photoelectrocoagulation treatment of aqueous solution containing, rhodamine B has been studied. Three different supporting electrolytes such as NaCl, NaNO3 and Na2SO4 were used for electrolysis. Only NaCl was found to be effective for the removal of colour from rhodamine B dye. Effects of the process variables such as pH, applied current density, electrode material, supporting electrolytes types, different concentration of electrolyte and treatment time were explored in order to find the best conditions for the degradation of rhodamine B. The complete degradation was obtained in 35 min of operating time for Fe electrode at optimum conditions such as initial pH 7.0, supporting electrolyte of 0.05 M NaCl and applied current density of 10 mA/cm2 and treatment time of 35 min. Sludge characterization was analyzed by FT-IR spectra and the morphology of sludge was characterized by SEM were discussed. The SEM image confirmed the characteristics of phases, which are amorphous or poorly crystalline in nature.


Author(s):  
Hassen Trabelsi ◽  
Nasr Bensalah ◽  
Abdellatif Gadri

AbstractThe electrochemical oxidation of 1,4 dihydroxybenzene, was studied by galvanostatic electrolysis using boron-doped diamond (BDD) as anode. The efficiency of the electrochemical process was found to depend mainly on the pollutant concentration present in the waste and on the applied current density. The voltammetric results showed that hydroquinone oxidation takes place in the same potential region as that of phenol where the supporting electrolyte is stable. Synthetic wastewaters containing hydroquinone have been treated in a bench-scale electrolysis plant. This plant operates in a discontinuous mode by recirculating the waste continuously through a single-chamber electrochemical flow cell. The complete mineralization of hydroquinone and the electro-generated pollutants is obtained in the electrolytic device. HPLC analyses show the formation of carboxylic acids as the main intermediates. The high efficiency of this technology can be explained in terms of the direct electro-oxidation at the BDD surface and the oxidation carried out by hydroxyl radicals and other electro-generated oxidants.


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