Effects of the Active Chlorine and the pH on Consumption of Graphite Anode in Chlor-Alkali Cells

Hine, Fumio; Yasuda, M.; Sugiura, Isao; Noda, Tokiti

doi:10.1149/1.2401784

Cited by 16 publications

(9 citation statements)

References 10 publications

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“…Corrosion of graphitic carbon in aqueous sodium chloride medium has been extensively studied in the literature. [60][61][62][63][64] According to Rabah et al, 60 during electrolysis of brine employing graphite electrodes, some carbon atoms are ionized followed by adsorption of chloride ions on certain active sites on the anode. The adsorbed chloride ions then react with partially ionized, positively charged carbon atoms to form C 4 OH 2 Cl, which is water-soluble and could decompose to carbon, carbon monoxide, carbon dioxide, chlorine, and water.…”

Section: A78mentioning

confidence: 99%

Gelatin Hydrogel Electrolytes and Their Application to Electrochemical Supercapacitors

Choudhury¹,

Sampath

Shukla

2008

J. Electrochem. Soc.

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Gelatin hydrogel electrolytes ͑GHEs͒ with varying NaCl concentrations have been prepared by cross-linking an aqueous solution of gelatin with aqueous glutaraldehyde and characterized by scanning electron microscopy, differential scanning calorimetry, cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic chronopotentiometry. Glass transition temperatures for GHEs range between 339.6 and 376.9 K depending on the dopant concentration. Ionic conductivity behavior of GHEs was studied with varying concentrations of gelatin, glutaraldehyde, and NaCl, and found to vary between 10 −3 and 10 −1 S cm −1 . GHEs have a potential window of about 1 V. Undoped and 0.25 N NaCl-doped GHEs follow Arrhenius equations with activation energy values of 1.94 and 1.88 ϫ 10 −4 eV, respectively. Electrochemical supercapacitors ͑ESs͒ employing these GHEs in conjunction with Black Pearl Carbon electrodes are assembled and studied. Optimal values for capacitance, phase angle, and relaxation time constant of 81 F g −1 , 75°, and 0.03 s are obtained for 3 N NaCl-doped GHE, respectively. ES with pristine GHE exhibits a cycle life of 4.3 h vs 4.7 h for the ES with 3 N NaCl-doped GHE. Polymer electrolytes are widely studied materials with applications in electrochemical devices. Although the ionic conductivity behavior of solid polymer electrolytes, such as polyethylene oxidesalt complexes, was reported as early as in 1973 by Wright, the potential of these materials as a new class of solid electrolytes for energy storage applications was envisaged by Armand in 1978. [1][2][3][4] Solid polymer electrolytes exhibit ionic conductivity between 10 −8 and 10 −7 S cm −1 that is too low to be significant for devices. Accordingly, efforts have been expended to enhance the ionic conductivity of polymer electrolytes.1,2 One such approach involves addition of plasticizer, a low-molecular-weight polar solvent, such as ethylene carbonate, to a polymer-salt system to realize polymer gel electrolyte ͑PGE͒.5-8 These PGEs are solid, have good adhesive properties, and exhibit high ionic conductivity of about 10 −3 S cm −1 at ambient temperatures. Although such nonaqueous PGEs have a wider potential window of about 4 V as compared to about 1 V for their aqueous counterpart, preparation and handling of the former require a moisture-free environment that is both involved and costintensive. Besides, organic solvents used as plasticizers with nonaqueous PGEs are environmentally toxic. 5Electrochemical supercapacitors ͑ESs͒ are electrochemical power systems with highly reversible charge-storage and delivery capabilities. ESs have properties complementary to secondary batteries and find usage in hybrid energy systems for electric vehicles, heavy-load starting assist for diesel locomotives, utility load leveling, and military and medical applications.9,10 Depending on the charge-storage mechanism, an ES is classified as an electrical double-layer capacitor ͑EDLC͒ or a pseudocapacitor. Higher energy density of EDLCs, as compared to dielectric capacit...

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Section: A78mentioning

confidence: 99%

Gelatin Hydrogel Electrolytes and Their Application to Electrochemical Supercapacitors

Choudhury¹,

Sampath

Shukla

2008

J. Electrochem. Soc.

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“…In concentrated chloride solutions the presence of sulphate ions in the solution strongly increased the graphite anodic corrosion, but it was not noticed in dilute solutions [23]. The corrosion of graphite composite has been investigated by Beck et al [24] in 1-18 M H 2 SO 4 and 1-12 M HClO 4 .…”

Section: Local Analysismentioning

confidence: 99%

“…The corrosion of carbon was studied by many authors [20][21][22][23][24][25][26][27][28]. Kinoshita and Bett [20,21] reported that the formation of a surface oxide and evolution of carbon dioxide (CO 2 ) occurred during the electrochemical oxidation of different carbons in H 3 PO 4 solution at temperatures up to 135 • C. A protective oxide (graphite oxide) and a surface oxide were found to form when the anodic current was imposed during the electrolysis of carbon electrodes in HCl [22].…”

Section: Introductionmentioning

confidence: 99%

Classic and local analysis of corrosion behaviour of graphite and stainless steels in polluted phosphoric acid

Iken¹,

Basseguy

Guenbour³

et al. 2007

Electrochimica Acta

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In phosphoric acid solution (40% H 3 PO 4 ), the corrosion behaviour of graphite and stainless steels was studied by the use of different electrochemical methods, namely polarization curve analysis, electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). The combined effect of chemical impurities and the increase of medium temperature was studied to approach the real conditions in the process of phosphoric acid manufacturing. It was found that the current density measured by polarization curves increased with the presence of chloride and sulphate ions in the acid solution whatever the tested material. Compared to stainless steels, graphite had the best corrosion resistance in polluted phosphoric acid. However, for graphite the increase of temperature from 20 to 80• C induced an increase of the corrosion rate and potential and a decrease of the resistance confirmed by EIS results. Subsequently, local currents were detected at the surface of the sample by using the scanning vibrating electrode technique. From the data obtained, graphite surface manifested a distinctive behaviour from that of stainless steels. A generalized corrosion was occurred on graphite whereas a localized corrosion was observed for stainless steels. These results show a clear interest of graphite as component material in some of the equipments of the phosphoric acid industry.

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“…During the electrolysis of a brine solution, carbon anode electrodes undergo oxidation, slow mechanical disintegration, and eventual failure [ 39 , 40 , 45 ]. This process occurs not only on the surface of the electrodes but also within their high-porosity structure.…”

Section: Methodsmentioning

confidence: 99%

“…Before use, the electrodes were rinsed with tap water and brushed with a nylon brush to remove loose carbon particles. The carbon gouging rods, shown in Fig 2, allow for chlorine production while gradually degrading due to oxidation [39][40][41]. Despite the undesirability of electrode disintegration, the use of low-cost carbon is preferred over other alternatives such as stainless steel, which rusts in the presence of chloride ions [42][43][44].…”

Section: Reactor Materials and Designsmentioning

confidence: 99%

Low-cost, local production of a safe and effective disinfectant for resource-constrained communities

Naranjo-Soledad,

Smesrud,

Bandaru

et al. 2024

PLOS Glob Public Health

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Improved hygiene depends on the accessibility and availability of effective disinfectant solutions. These disinfectant solutions are unavailable to many communities worldwide due to resource limitations, among other constraints. Safe and effective chlorine-based disinfectants can be produced via simple electrolysis of salt water, providing a low-cost and reliable option for on-site, local production of disinfectant solutions to improve sanitation and hygiene. This study reports on a system (herein called “Electro-Clean”) that can produce concentrated solutions of hypochlorous acid (HOCl) using readily available, low-cost materials. With just table salt, water, graphite welding rods, and a DC power supply, the Electro-Clean system can safely produce HOCl solutions (~1.5 liters) of up to 0.1% free chlorine (i.e.,1000 ppm) in less than two hours at low potential (5 V DC) and modest current (~5 A). Rigorous testing of free chlorine production and durability of the Electro-Clean system components, described here, has been verified to work in multiple locations around the world, including microbiological tests conducted in India and Mexico to confirm the biocidal efficacy of the Electro-Clean solution as a surface disinfectant. Cost estimates are provided for making HOCl locally with this method in the USA, India, and Mexico. Findings indicate that Electro-Clean is an affordable alternative to off-the-shelf commercial chlorinator systems in terms of first costs (or capital costs), and cost-competitive relative to the unit cost of the disinfectant produced. By minimizing dependence on supply chains and allowing for local production, the Electro-Clean system has the potential to improve public health by addressing the need for disinfectant solutions in resource-constrained communities.

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Effects of the Active Chlorine and the pH on Consumption of Graphite Anode in Chlor-Alkali Cells

Cited by 16 publications

References 10 publications

Gelatin Hydrogel Electrolytes and Their Application to Electrochemical Supercapacitors

Gelatin Hydrogel Electrolytes and Their Application to Electrochemical Supercapacitors

Classic and local analysis of corrosion behaviour of graphite and stainless steels in polluted phosphoric acid

Low-cost, local production of a safe and effective disinfectant for resource-constrained communities

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