scholarly journals Low-coherence photonic method of electrochemical processes monitoring

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Monika Kosowska ◽  
Paweł Jakóbczyk ◽  
Michał Rycewicz ◽  
Alex Vitkin ◽  
Małgorzata Szczerska

AbstractWe present an advanced multimodality characterization platform for simultaneous optical and electrochemical measurements of ferrocyanides. Specifically, we combined a fiber-optic Fabry–Perot interferometer with a three-electrode electrochemical setup to demonstrate a proof-of-principle of this hybrid characterization approach, and obtained feasibility data in its monitoring of electrochemical reactions in a boron-doped diamond film deposited on a silica substrate. The film plays the dual role of being the working electrode in the electrochemical reaction, as well as affording the reflectivity to enable the optical interferometry measurements. Optical responses during the redox reactions of the electrochemical process are presented. This work proves that simultaneous opto-electrochemical measurements of liquids are possible.

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2178 ◽  
Author(s):  
Shaili Falina ◽  
Sora Kawai ◽  
Nobutaka Oi ◽  
Hayate Yamano ◽  
Taisuke Kageura ◽  
...  

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
V. M. García-Orozco ◽  
C. E. Barrera-Díaz ◽  
G. Roa-Morales ◽  
Ivonne Linares-Hernández

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.


Author(s):  
Alicia Garcia-Costa ◽  
André Savall ◽  
Juan A. Zazo ◽  
Jose A. Casas ◽  
Karine Groenen Serrano

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.


Author(s):  
Katelyn Sellgren ◽  
◽  
Christopher Gregory ◽  
Michael Hunt ◽  
Ashkay Raut ◽  
...  

Electrochemical disinfection has gained interest as an alternative to conventional wastewater treatment because of its high effectiveness and environmental compatibility. Two and a half billion people currently live without improved sanitation facilities. Our research efforts are focused on developing and implementing a freestanding, additive-free toilet system that treats and recycles blackwater on site. In this study, we sought to apply electrochemical disinfection to blackwater. We compared commercially available boron-doped diamond (BDD) and mixed metal oxide (MMO) electrodes for disinfection efficiency in E. coli–inoculated model wastewater. The MMO electrodes were found to be more efficient and thus selected for further study with blackwater. The energy required for disinfection by the MMO electrodes increased with the conductivity of the medium, decreased with increased temperature, and was independent of the applied voltage. Fecal contamination considerably increased the energy required for blackwater disinfection compared to model wastewater, demonstrating the need for testing in effluents representing the conditions of the final application.


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.


Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 902
Author(s):  
Alicia L. Garcia-Costa ◽  
Andre Savall ◽  
Juan A. Zazo ◽  
Jose A. Casas ◽  
Karine Groenen Serrano

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.


Author(s):  
Christian E. Alvarez-Pugliese ◽  
Paola Moreno-Wiedman ◽  
Fiderman Machuca-Martínez ◽  
Nilson Marriaga-Cabrales

AbstractElectrochemical oxidation of pretreated distillery wastewater was performed using a boron doped diamond anode (BDD). The role of direct oxidation of organic matter was assessed with experiments of linear sweep voltammetry, noting that the deactivation of the electrode surface occurs in the region of potentials below oxygen evolution. Then, galvanostatic bulk electrolyses were conducted during 4 hours at current densities (20 mAcm


Author(s):  
Huimin Qiu ◽  
Pingping Fan ◽  
Xueying Li ◽  
Guangli Hou

Abstract Nonsteroidal anti-inflammatory drugs (NAIDS) have been widely detected in wastewater and surface water, which indicates the removal of NAIDS by wastewater treatment plants was not efficiency. Electrochemical advanced oxidation technology is considered to be an effective process. This study presents an investigation of the kinetics, mechanism and influencing factors of Diclofenac (DCF) degradation by an electrochemical process with the boron doped diamond anodes. Relative operating parameters and water quality parameters are examined. It appears that the degradation follows the pseudo-first-order degradation kinetics. DCF degradation was accelerated with the increase of pH from 6 to 10. The degradation was promoted by the addition of electrolyte concentrations and current density. HA and HCO3− significantly inhibited the degradation, whereas Cl− accelerated it. According to the inhibition tests, hydroxyl radicals (•OH) and sulfate radicals (SO4•–) contributed 76.5% and 6.5%, respectively, to the degradation. Sodium sulphate remains a more effective electrolyte, compared to sodium nitrate and sodium phosphate, suggesting the quenching effect of nitrate and phosphate on •OH. Major DCF transformation products were identified. According to the degradation products detected by liquid chromatography-mass spectrometry, hydroxylation and decarboxylation are the main pathways to DCF degradation; meanwhile, dechlorination, chlorination and nitro substitution are also included.


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