Sacrificial Electrodes Research Articles

Application of Central Composite Design for Commercial Laundry Wastewater Treatment by Packed bed Electrocoagulation using sacrificial iron electrodes.

This research paper deals with a novel method utilizing packed bed electrocoagulation (PBEC) comprising of sacrificial iron electrodes and coupled with extracellular polymeric substances (EPS) used as flocculent agents for the treatment of commercial laundry wastewater (LWW). The study employs stainless steel cathodes, graphite anodes, and scrap iron pieces as sacrificial electrodes, ensuring efficient treatment in dynamic batch mode operation with enhanced contact time facilitated by serpentine flow. The initial characteristics of LWW were COD 579 ± 30 mg/L, TSS of 60 ± 10 mg/L, TS of 622 ± 20 mg/L, turbidity of 110 ± 5 NTU, pH of 9 ± 0.5, NPEOs of 570 ±150 μg/L and conductivity of 494 ± 20 mS/cm. The results demonstrate effective removal of turbidity (98 ± 2%), TS (95 ± 3%), COD (89 ± 5%), and NPEOs (53 ± 2%) under optimized current intensity: 2.99A, treatment time: 58.8 minutes and enhanced EPS dose from 5.8 mg/L to 8.0 mg/L. The economic feasibility analysis reveals energy consumption as the primary expenditure, with a treatment cost of 1.20$CAN/m3. This research introduces sustainable treatment for commercial LWW, meeting Quebec's reuse standards, implying reuse potential and responsible wastewater management.

Removal of Inorganic Pollutants and Recovery of Nutrients from Wastewater Using Electrocoagulation: A Review

Water pollution is a major concern due to its detrimental effects on the environment and public health. The particular danger of inorganic pollutants arises from their persistent toxicity and inability to biodegrade. Recently, electrocoagulation (EC) has been demonstrated as an alternative sustainable approach to purifying wastewater due to the increasingly strict pollution prevention rules. In particular, EC has been used to remove inorganic pollutants, such as Cr, Zn, Pb, or As. EC has emerged as a sustainable tool for resource recovery of some inorganic pollutants such as N and P that, when recovered, have value as plant nutrients and are critical in a circular economy. These recovered materials can be obtained from diverse agricultural drainage water and recycled as fertilizers. In this work, a state-of-the-art technique is reviewed describing the advances in contaminant removal and nutrient recovery using EC through an in-depth discussion of the factors influencing the contaminant removal process, including operating pH, time, power, and concentration. Furthermore, limitations of the EC technology are reviewed, including the high-power consumption, fast deterioration of the sacrificial electrodes, and the types of contaminants that could not be efficiently removed. Finally, new emerging constructs in EC process optimization parameters are presented.

Boosting BOD/COD biodegradability of automobile service stations wastewater by electrocoagulation

ABSTRACT This study investigates the application of electrocoagulation for enhancing the biodegradability of organic matter in automobile service station wastewater, notorious for its contamination with polyaromatic hydrocarbons, heavy metals, and surfactants. Optimization of key variables such as electrode material, current density, and electrical consumption is conducted, with correlation analysis assessing their impact on water quality. Experimental setups utilize a vertical configuration comprising eight monopolar steel electrode plates as cathodes and eight counter electrodes (either iron or aluminum) connected in parallel. Results indicate that employing iron as the sacrificial electrode significantly increases the biochemical oxygen demand/chemical oxygen demand (BOD/COD) ratio, highlighting the efficacy of heightened power levels in enhancing organic matter degradation. Optimal removal efficiencies, including 87.5 for COD, 96.01 for BOD, and 92.2% for total solids, are achieved at a current density of 42 A/m2 and energy consumption of 360 kWh/m3, while maintaining pH levels between 6 and 9. The findings underscore the potential of electrocoagulation with Fe, Al as anodes, and stainless-steel cathodes as an efficient wastewater treatment approach, particularly for COD, BOD, and solid particle removal, thus contributing significantly to environmental sustainability.

Experimental Investigation of Tannery wastewater by Electrocoagulation method

Abstract Treating tannery wastewater poses a significant challenge due to its composition, comprising biogenic materials from hides and a diverse range of organic and inorganic chemicals. Experimental procedures were conducted using an electrochemical reactor employing sacrificial electrodes—mild steel as both anode and cathode—in a unceasing process. Numerous working parameters such as current density and electrolysis duration were examined to achieve optimal reduction in presence of turbidity, total solids, COD, BOD, TDS, and Chromium content. Enhanced reductions in COD, BOD, TDS, and chromium content were observed at higher flow rates. The applied current density also notably impacted the reduction efficiency of COD, BOD, TDS, and chromium content. Investigation into the electro coagulation method employing short cell current (1A) and solvable mild steel electrodes revealed their efficacy compared to aluminium electrodes, particularly in chromium removal, achieving over 90% removal efficiency. However, the use of mild steel electrodes resulted in the formation of a black precipitate characteristic of iron (II) sulphides during the treatment, although effectively reducing effluent coloration. The removal efficiency of chloride, however, remained lower, at less than 12%. A comprehensive discussion on the mechanisms involved in the removal of COD, chromium, total dissolved salts, total solids, chloride and coloration using soluble mild steel electrodes was presented. The predominant role of the electrode was highlighted by treating tannery wastewater with mild steel electrodes, followed by filtration, resulting in removal rates of 68.0% for chemical oxygen demand, 43.1% for chromium, 55.1% for total dissolved salts and 84.3% for coloration, considering initial concentrations of 2850 mg/L, 230 mg/L, 100 mg/L, 100 mg/L, and a 256- fold dilution, respectively.

Electro-Fenton process based on sacrificial Iron electrode for Ponceau 4R removal

Electro-Fenton process based on sacrificial Iron electrode for Ponceau 4R removal

One‐Step Synthesis and Deposition of Metal Oxides: NiO Quantum Dots as a Transport Layer for Perovskite Photovoltaics

One‐step synthesis and deposition of nickel oxide quantum dots using a gas‐phase microplasma process is demonstrated and their applicability as a transport layer for solar cell devices is shown. The process uses a solid nickel metal wire as sacrificial electrode, and the concentration of oxygen gas required in the synthesis is investigated. The quantum dots are characterized for physical, chemical, and optical properties and critical process parameters such as the process throughput are also estimated. Direct one‐step deposition directly on perovskite solar cells is carried out using a computer‐controlled x–y stage and the performance of the solar cell device is assessed.

Aluminum corrosion–passivation regulation prolongs aqueous batteries life

Aluminum current collectors are widely used in nonaqueous batteries owing to their cost-effectiveness, lightweightness, and ease of fabrication. However, they are excluded from aqueous batteries due to their severe corrosion in aqueous solutions. Here, we propose hydrolyzation-type anodic additives to form a robust passivation layer to suppress corrosion. These additives dramatically lower the corrosion current density of aluminum by nearly three orders of magnitude to ~10−6 A cm−2. In addition, realizing that electrochemical corrosion accompanies anode prelithiation, we propose a prototype of self-prolonging aqueous Li-ion batteries (Al ||LiMn2O4 ||TiO2), whose capacity retention rises from 49.5% to 70.1% after 200 cycles. A sacrificial aluminum electrode where electrochemical corrosion is utilized is introduced as an electron supplement to prolong the cycling life of aqueous batteries. Our work addresses the short-life issue of aqueous batteries resulting from the corrosion of the current collector and lithium loss from side reactions.

Application of Na2CO3 as a Sacrificial Electrode Additive in Na‐ion Batteries to Compensate for the Sodium Deficiency in Na2/3[Fe1/2Mn1/2]O2

AbstractOwing to their high discharge capacities, P2‐type transition metal layered oxides have attracted attention for use as positive electrode materials in Na‐ion batteries. However, owing to the Na‐deficient compositions of these oxides, additional Na+ must be supplied using a Na‐metal negative electrode to attain a high capacity in a half‐cell configuration. In this study, solid Na2CO3 powder was introduced into the P2−Na2/3Fe1/2Mn1/2O2 composite positive electrode as a sacrificial salt to compensate for the Na deficiency. Na+ was supplied through the electrochemical oxidative decomposition of Na2CO3 during the initial charging process; the decomposition mechanism responsible for this process was investigated in detail. Online electrochemical mass spectrometry confirmed that Na2CO3 was oxidatively decomposed in combination with the decomposition of the ethylene carbonate electrolyte. This reaction produced CO2, wherein the carbon source was derived from both Na2CO3 and the electrolyte. Consequently, Na+ supplementation improved the reversible capacity of the Na‐ion full cell. This study offers practical insights and a mechanistic understanding of the pre‐doping technique for Na‐free negative electrodes. This approach also compensates for the irreversible reductive capacity in a process that can be easily applied to practical sodium‐ and lithium‐ion batteries and capacitors.

Electrochemical synthesis of cadmium chelates at sacrificial anode

The synthesis of cadmium chelates through an electrochemical technique, involving the anodic oxidation of a sacrificial metallic electrode (cadmium) within an H-type cell, is reported. This process utilizes acetonitrile as a solvent with organic compounds containing abstractable hydrogen RH2 (nitroethane, 2-nitropropane, malononitrile and diethylmalonate) serving as the reactants. This study encompasses the coordination complexes of cadmium with ligands, 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen). The electrochemically synthesized products have been confirmed through various physical measurements, elemental analyses and infrared spectral studies. This one-step electrochemical technique is highly effective in obtaining metal complexes and their coordination complexes. The determination of current efficiency for these synthesized complexes serves to elucidate the underlying reaction mechanism.

Electrochemical reduction of benzoic acid esters using water as a H/D source

Benzoic esters are reduced with water as a hydrogen/deuteron source in DC/AC electrolysis in an undivided cell without a sacrificial electrode.

Non-equilibrium defect chemistry in oxygen-rich zinc oxide nano-tetrapods synthesized using atmospheric pressure microplasma

We demonstrate the synthesis of zinc oxide (ZnO) nanoscale tetrapods (nTPs) using an atmospheric pressure microplasma with a metal wire as a sacrificial electrode.

Strategic usage of redox active materials and sacrificial Zn electrodes for spontaneous hydrogen evolution reaction

Spontaneous green hydrogen production and power production system.

Enhance electrocoagulation-flotation (ECF) removal efficiency perfluorohexanoic acid (PFHxA) by adding surfactants

This research focuses on the application of electrocoagulation-flotation (ECF) in the removal of perfluorooctanoic acid (PFHxA), a prevalent short-chain perfluoroalkyl substance in semiconductor manufacturing, especially at concentrations of industrial wastewater levels. We explored the effectiveness of ECF, which employs sacrificial electrodes to create metal ions and bubbles for pollution extraction. The study particularly examines the role of various surfactants in augmenting PFHxA removal. We observed that at an initial PFHxA concentration of 1 mM, both anionic and cationic surfactants modestly increased removal efficiency, with limited impact from electrostatic repulsion. Significantly, at a higher concentration of 5.0 mM, cationic surfactants, notably DTAB with its short carbon chain, markedly enhanced PFHxA elimination. The superior performance of DTAB is attributed to its facilitation in Al(OH)3 crystal formation, promoting PFHxA adsorption, efficient micelle or bubble formation with PFHxA, and the stability of resulting flocs. Our findings underscore the efficacy of DTAB as a surfactant in ECF for high-concentration PFHxA scenarios, emphasizing the importance of surfactant and electrode material selection in optimizing PFAS treatment in wastewater systems. This study contributes valuable insights into refining PFAS remediation strategies in real industrial wastewater applications.

Optimizing Distillery Effluent Treatment through Sono-Electrocoagulation: A Response Surface Methodology Approach

This work is an effort to remediate rice grain-based biodigester effluent (BDE) by applying the sono-electrocoagulation (SEC) process using Iron as a sacrificial electrode to accomplish this process. A batch reactor is used for the investigation. The effect of the SEC process on the reduction of chemical oxygen demand (COD) and color from the wastewater was studied by varying operating parameters including ultrasonic power (U), current density (j), initial pH (pHi), and electrolysis time (t) in the ranges of 20-60 W, 49.5-247.5 A/m2, 2-10 and 12-60 minutes respectively. The results obtained were optimized by using central composite design (CCD) which is a special feature of the response surface method (RSM). This tool is well applicable in the SEC process to explores the relationships between different varying operating parameters with two responses namely COD and color removal efficiency. The RSM is to use a sequence of designed experiments to obtain an optimal response. The analysis demonstrated that the quadratic regression model fitted well with SEC-generated data. Moreover, no significant difference was found between experimental and predicted data. The coefficient of determination (R2) of 0.9995 and 0.9895 were observed for COD and color removal efficiency. Results indicated that the COD removal efficiency of 93% and color removal efficiency of 88% were found at optimum conditions U of 50, J of 198 A/m2, pHi of 7, and t of 48 minutes.

Electrochemical Recovery of Phosphorus from Simulated and Real Wastewater: Effect of Investigational Conditions on the Process Efficiency

The development of recovery processes has become essential in recent years as a strategy to minimize environmental pollution while boosting circular economy and sustainable development. Due to the exponential growth in agricultural production and the increased pollution of waterbodies, the production of fertilizers from recovered phosphorus has become an alternative to phosphate rock-based production. In this work, the effect of different operational parameters in the efficiency of the electrochemical recovery of phosphorus, from organic and inorganic sources, was investigated. Among the studied variables, the most significant was the electrode material utilized in the system. The use of magnesium sacrificial electrodes, as AZ31 alloys, led to phosphorus removal from solution of above 90%, allowing the recovery of both orthophosphates and organic phosphorus (glyphosate) as struvite, brucite, and other amorphous compounds. Since there is a lack in the literature about the use of magnesium electrodes in real wastewater electrochemical treatment, system efficiency was also evaluated using a sanitary landfill leachate, reaching 96% of phosphorus recovery. The specific energy consumption and faradaic efficiency of the phosphorus recovery process were also assessed.

Recent Advances in Electrochemical Reductive Transformation of C−C and C−O Multiple Bonds

AbstractIn recent decades, electro‐organic synthesis is indubitably emerging as a cornerstone of modern organic chemistry. Electrochemical organic transformations especially reduction reactions have made massive advancements in the last few years because of their sustainable and environ‐friendly nature. Electro‐reductive protocols can be used as a promising substitute for conventional reductants by expelling the requirement of the stoichiometric amount of metal reductants. The major challenges for these electro‐reductive reactions are primarily the use of a sacrificial electrode and divided cells. These limitations can be resolved through smart reaction planning by employing cheap sacrificial reagents or paired electrolysis without compromising the sustainable viewpoint. Considering the rapid enhancement in this field, imparting an intangible understanding of this evolving area is essential and substantial. In this review, we portrayed the electrochemical reductive transformations of C−C and C−O bonds after 2015 along with detailed mechanistic insights.

Integration of patterned electrolyte film and sacrificial substrate serpentine electrode of low curvature for high stretch supercapacitor, physiological signal detection

Optimizing electrode structures is a promising solution for wearable electronics and flexible power sources. Nevertheless, there are still significant challenges in how to get rid of the constraints of the substrate and electrolyte on the electrode structure, thereby reducing the impact of such constraints on the elongation of supercapacitors and stabilizing the electrochemical output. In this work, a serpentine structure of low curvature (SSLC) was designed and fabricated by comparing the effect of the curvature of the turning structure on the performance of the serpentine structure. The superiority of SSLC electrodes over existing electrode structures is verified using finite element analysis (FEA) and stability experiments. Further, the SSLC electrode is used for physiological signal detection (ECG, EMG, GSR), showing excellent stability and low electrode–skin contact impedance, which is better than the medical wet electrode. A high-stretch supercapacitor (SSC) was prepared by sacrificing the substrate of the SSLC electrode and integrating the patterned electrolyte film. When the scan rate is 10 mV·s−1, the area specific capacitance of SSC is as high as 197.9 mF·cm−2. Under extreme deformation conditions (stretch 100%, bend 180°, twist 180°) SSC can maintain stable output. And after 10,000 charge–discharge cycles, the SSC can still output 91.96% of the initial power stably, indicating that the prepared SSC has high stretchability and stability. With highly stretchable and stable low-curvature serpentine structure electrodes, the SSC coupled with patterned electrolyte films and sacrificial substrate electrodes in this paper offer a promising solution for stretchable flexible power supplies and wearable electronics.

Hexavalent Chromium Removal from Water and Wastewaters by Electrochemical Processes: Review

Hexavalent chromium (Cr(VI)) is a toxic, mutagenic, teratogenic, and carcinogenic species. Its origin is in industrial activities. Therefore, its effective control is realized on a source basis. Although chemical methods proved effective in removing Cr(VI) from wastewaters, more economic solutions with a minimum sludge production have been sought. Among them, the use of electrochemical processes has emerged as a viable solution to the problem. Much research was conducted in this area. The aim of this review paper is to make a critical evaluation of the literature on Cr(VI) removal by electrochemical methods, particularly electrocoagulation with sacrificial electrodes, and to assess the present data as well as to point out the areas that need further elaboration. Following the review of the theoretical concepts of electrochemical processes, the literature on the electrochemical removal of Cr(VI) was evaluated on the basis of important elements of the system. Among them are initial pH, initial Cr(VI) concentration, current density, type and concentration of supporting electrolyte, and the material of electrodes and their operating characteristics and process kinetics. Dimensionally stable electrodes that realize the reduction process without producing any sludge were evaluated separately. Applications of electrochemical methods to a wide spectrum of industrial effluents were also assessed.

Characterization of Sludge Resulting from Chemical Coagulation and Electrocoagulation of Pumping Water from Fishmeal Factories

In the fishmeal industry, seawater is used to transport fish to the factories. Due to this, “pumping water” with high concentrations of organic matter is generated that is treated via chemical coagulation before letting it into the sea. The objective of this study is to characterize and compare the sludge obtained from conventional chemical coagulation and the sludge from the electrocoagulation process. A pilot electrocoagulation plant was built next to a chemical coagulation plant. The sludge obtained from both methodologies was analyzed for its proximal composition, its iron and aluminum content, and the fatty acid profile in its contained fat. Electrocoagulation was found to produce sludge with a higher concentration of lipids and ash, which indirectly confirmed that it removes more organic pollutants and salts than chemical coagulation. The contents of aluminum and iron in the sludge obtained by electrocoagulation were 4.2% and 0.025%, respectively, while those in the sludge obtained from chemical coagulation were 0.01% and 4.8%, respectively. Aluminum comes from the sacrificial electrode of the electrocoagulation tank, while iron comes from the salts used in chemical coagulation. The sum of w-3 fatty acid values (EPA + DHA) was 12.5% and 18.8% for sludges from the electrocoagulation and chemical coagulation processes, respectively, so we can assume that electrocoagulation is a more oxidizing process than chemical coagulation. Due to their high organic load, both sludges must be assessed as an alternative feed ingredient.

Ibuprofen removal from synthetic effluents using Electrocoagulation-Peroxidation (ECP).

Concerning water resources, several ordinances and legislation determine standards and conditions for the discharge of effluents into water bodies. However, several contaminants are not covered by these guidelines due to little knowledge of their long-term effects and because they are found in low concentrations. These contaminants are called emergent and this category includes drugs, such as anti-inflammatory drugs. The electrocoagulation process associated with advanced oxidation comes up as an alternative to conventional effluent treatment processes, and the objective of this study was to evaluate this process using scrap iron as sacrificial electrodes in the treatment of synthetic effluents containing ibuprofen. High-performance liquid chromatography was used to quantify the drug in synthetic effluents. The Central Rotational Composite Design 24 was used in an experimental design, considering independent variables the concentration of contaminants, applied current, the concentration of the primary oxidizing agent H2O2, and the reaction time. The optimized conditions determined by statistical analysis were drug concentration of 5mg L-1, H2O2 concentration of 200mg L-1, current of 5 A, and 150min. The removals obtained under these conditions were higher than 92% in the aqueous phase, showing that electrocoagulation peroxidation technique has the potential to treat contaminants such as drugs present in effluents and waters.