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The effect of electrode type on (a) Copper, (b) Nickel, (c) Total Chromium and (d) Zinc removal with electrocoagulation (V: 500 mL, pH; ~1.8, Current density: 100 A/m 2 ).

The effect of electrode type on (a) Copper, (b) Nickel, (c) Total Chromium and (d) Zinc removal with electrocoagulation (V: 500 mL, pH; ~1.8, Current density: 100 A/m 2 ).

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It is known that wastewater produced by the metal-plating industry contains several heavy metals, which are acidic in nature and therefore toxic for the environment and for living creatures. In particular, heavy metals enter the food chain and accumulate in vital organs and cause serious illness. The precipitation of these metals is mostly achieved...

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... carried out by precipitation in the form of metal hydroxides and high pH. The most important operating parameter for metal removal is considered to be the pH. It is very difficult to remove metals at low pH values. As a result, the study was conducted to show both the effect of low pH and the effect of time on the removal of metals, as shown in Fig. 5. The removal of Cu, Ni, Zn and Cr was ...
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... the facility where the wastewater is generated, nickelplating processes are carried out intensively. In this case, nickel forms part of the wastewater. In the studies conducted, both the iron and aluminum electrodes were used to analyze the ability to remove nickel simultaneously with other components. The results obtained are given in Fig. 5(b). When Fig. 5(b) is examined, it can be observed that a removal of Ni at a 50% level could be achieved. However, it should be noted that the original pH (pH ~1.8) value of the plant was used in this study. As a matter of fact, the metals are treated by using their ability to precipitate in the form of metal hydroxides, especially when ...
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... where the wastewater is generated, nickelplating processes are carried out intensively. In this case, nickel forms part of the wastewater. In the studies conducted, both the iron and aluminum electrodes were used to analyze the ability to remove nickel simultaneously with other components. The results obtained are given in Fig. 5(b). When Fig. 5(b) is examined, it can be observed that a removal of Ni at a 50% level could be achieved. However, it should be noted that the original pH (pH ~1.8) value of the plant was used in this study. As a matter of fact, the metals are treated by using their ability to precipitate in the form of metal hydroxides, especially when the pH value is ...
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... into Cr 3+ by a controlled process. While this first stage is carried out at low pH values, Cr 3+ s must be precipitated in the second stage. The need for high pH values in this case makes heavy metal removal extra difficult. In electrocoagulation, it is aimed to perform these two operations in one stage. The results obtained are demonstrated in Fig. 5(c). Total chromium removal efficiencies for aluminum and iron electrodes used for the different types are shown in Fig. 5(c). Over 90% removal efficiency can be achieved especially with the use of iron electrodes. The main reason for this can be explained by the fact that the raw pH of the wastewater is about 2 as a result of the ...
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... in the second stage. The need for high pH values in this case makes heavy metal removal extra difficult. In electrocoagulation, it is aimed to perform these two operations in one stage. The results obtained are demonstrated in Fig. 5(c). Total chromium removal efficiencies for aluminum and iron electrodes used for the different types are shown in Fig. 5(c). Over 90% removal efficiency can be achieved especially with the use of iron electrodes. The main reason for this can be explained by the fact that the raw pH of the wastewater is about 2 as a result of the electrolytic reactions, and therefore Cr 6 + is converted to Cr 3+ in a very short time due to the ferric ions given to the water ...
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... study stages for the removal of zinc were carried out for the other metal parameters. Figure 5(d) shows the effects of different electrode types on the removal of zinc. Iron and aluminum electrodes show significant similarity with respect to efficiency. ...

Citations

... To determine the energy required for removing Congo red dye from simulated water by using a combined system (EC-EO), by using the composite electrodes (C and A) as anode for the EO process besides Al as anode for the EC process, Table 6 would represent the energy consumption for the cathode (C) and Table 7 would represent the energy consumption for the anode (A), Eq. 12 was used to calculate energy consumption [54]. ...
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The combined system of electrocoagulation (EC) and electro-oxidation (EO) is one of the most promising methods in dye removal. In this work, a solution of 200 mg/l of Congo red was used to examine the removal of anionic dye using an EC-EO system with three stainless steel electrodes as the auxiliary electrodes and an aluminum electrode as anode for the EC process, Cu-Mn-Ni Nanocomposite as anode for the EO process. This composite oxide was simultaneously synthesized by anodic and cathodic deposition of Cu (NO3)2, MnCl2, and Ni (NO3)2 salts with 0.075 M as concentrations of each salt with a fixed molar ratio (1:1:1) at a constant current density of 25 mA/cm 2. The characteristics structure and surface morphology of the deposited nano oxides onto the graphite substrates were determined by (XRD), (FE-SEM), (AFM), and (EDX). The results shown that nano Cu-Mn-Ni oxides were successfully deposited onto the anode and cathode. The crystal size and root mean square for the cathode were 30.79 nm and 79.36 nm, respectively, while for the anode, they were 24.19 nm and 41.88 nm, respectively. Furthermore, the combined system was examined for C.D, NaCl concentration, and time. In the EC-EO combined system, the cathode and anode were efficient when used as anodes for the EO process, besides aluminum. The cathode was more effective in the removal process than the anode due to its larger crystal size and the rough, granular shape of its surface. When current density (C.D) increased from 3 to 6 mA/cm², the removal efficiency shifted from 95% to 98%. However, excellent removal of 98% and 96.5% was attained with 1.665 and 2.0859 kWh/kg of dye as energy consumption in the presence and absence of NaCl salt, respectively by applying 6 mA/cm 2 within 20 min of electrolysis.
... Hydrogen gas is liberated from the water in the cathode zone in the form of tiny gas bubbles, which are the basis of the electroflotation (EF) process, allowing the pollutants to be removed from water during the EC process. Accordingly, the EF process makes the EC process perform better to remove the contaminants [26]. ...
Article
Combining different treatment strategies successively or simultaneously has become recommended to achieve high purification standards for the treated discharged water. The current work focused on combining electrocoagulation, ion-exchange, and ultrasonication treatment approaches for the simultaneous removal of copper, nickel, and zinc ions from water. The removal of the three studied ions was significantly enhanced by increasing the power density (4–10 mA/cm2) and NaCl salt concentration (0.5–1.5 g/L) at a natural solution pH. The simultaneous removal of these metal ions at 4 mA/cm2 and 1 g NaCl/L was highly improved by introducing 1 g/L of mordenite zeolite as an ion-exchanger. A remarkable removal of heavy metals was reported, as the initial concentration of each metal decreased from approximately 50 ppm to 1.19 for nickel, 3.06 for zinc, and less than 1 ppm for copper. In contrast, ultrasonication did not show any improvement in the treatment process. The extended Langmuir isotherm model convincingly described the experimental data; the Temkin and Dubinin-Radushkevich isotherm models have proven that the removal processes were physical and exothermic. Finally, the pseudo-second-order kinetics model appropriately explained the kinetics of the process with correlation coefficients of 0.9337 and 0.9016, respectively.
... g/L of NaCl, pH = 7 after 20 min from the operation start. Equation (15) was used to calculate energy consumption depending on CR removal [75]. ...
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Removing Congo red (CR) is critical in wastewater treatment. We introduce a combination of electrocoagulation (EC) and electro-oxidation (EO) to address the elimination of CR. We also discuss the deposition of triple oxides (Cu–Mn–Ni) simultaneously on both anodic and cathodic graphite electrodes at constant current density. These electrodes efficiently worked as anodes in the EC-EO system. The EC-CO combination eliminated around 98 % of the CR dye and about 95 % of the Chemical Oxygen demand (COD), and similar results were obtained with the absence of NaCl. Thus, EC-EO is a promising technique to remove CR in an environmentally friendly pathway.
... Proper treatment and disposal of this type of wastewater are mandatory because it is considered hazardous and may pose serious risks to public health and the environment owing to its bioaccumulation and nondegradable properties. Several technologies have been employed to treat wastewater, including ion-exchange processes [2], adsorption [3,4], chemical precipitation [5,6], membrane filtration [7], chemical coagulation [8,9], and electrochemical processes [10][11][12][13], including microbial fuel cell [14]. Chemical precipitation and coagulation are extensively used in wastewater treatment to remove heavy metals, oils, and organic and inorganic compounds [15]. ...
Article
A continuous-flow electrocoagulation unit was used to replace the existing chemical coagulation in plastic plating industry wastewater treatment plants, aiming to enhance pollutant removal and cost efficiency. This study was conducted at an on-site wastewater treatment plant, with the electrocoagulation process monitored for nine consecutive months. A novel electrocoagulation unit equipped with multi-rod helical systems (i.e., made of an iron anode and a stainless-steel cathode) was used in this study, with the treatment flow adjusted to optimize the operational costs. The results indicate that energy consumption can be maintained at 7200 kWh/month while achieving >99 % removal of heavy metals (Cr, Ni, and Cu), with removal rates of 78.64 ± 0.13 mg/L.day (Cr), 105.47 ± 0.07 mg/L.day (Ni), and 38.30 ± 0.09 mg/L.day (Cu). The chemical cost was reduced by approximately 50 %. Furthermore, an over 50 % reduction in sludge production was achieved, with the acid and alkaline by-products entirely recycled. Compared to the previously applied chemical coagulation, electrocoagulation can reduce operational costs from US6.11toUS 6.11 to US 2.87 per m3 of wastewater treated. These results confirm that electrocoagulation can be optimized and implemented to replace conventional chemical coagulation.
... Wastewater from metal plating plants can be both alkaline and acidic. Cyanidecontaining wastewater or water used in rinsing baths has a very high pH, while wastewater from chromium, copper and nickel baths is acidic [16,25]. ...
Article
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Water pollution is one of the major problems for humankind. Various pollutants could be detected in wastewater because of human activities such as industrialization, agriculture, domestic waste and etc. Removal of pollutants such as heavy metals, dyes, oils and pesticides are of great importance which affects human life negatively. Many methods have been extensively used to provide “clean water” for environment and human. Heavy metals are important industrial pollutants that need to be quickly removed from wastewater due to their high toxicity and non-biodegradable structure. In this paper, the heavy metals including copper, nickel and zinc have been examined in real wastewater from metal plating industry in Bursa, Türkiye. Concentrations of pollutants (Cu, Ni, Zn, chemical oxygen demand (COD) and SO4) in the effluent as a result of coagulation-flocculation process were determined and their compliance with sewage discharge standards was investigated. Moreover, the removal efficiencies of the pollutants were examined (Cu and Ni: 97-100%; Zn: 82-98%; COD: 32-54%; SO4: 16-23%) and the effect of the coagulant doses used on the operating cost, sludge quantity were also discussed.
... A cell with dimensions of 14.1 cm x 10.5 cm x 18 cm was designed for a volume of 1.5 L ( Figure 1). Additionally, a power supply (Hurricane-Power) was used to stabilize the voltage and current of the system (Ilhan et al., 2019). Commercial 1050 aluminum electrodes were used for both anode and cathode, which were cut into plate shapes with dimensions of 6 cm x 9 cm x 3 mm. ...
Article
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Efficient removal of heavy metals from wastewater is crucial due to their harmful effects on health and the environment. Electrocoagulation is an alternative treatment technique that applies electric current to metallic electrodes, forming coagulants and precipitating contaminants. This study evaluated the efficiency of electrocoagulation in removing copper (Cu) and cadmium (Cd) from aqueous solutions. An experimental study was conducted to assess the simultaneous and independent removal of each metal. Electrodes based on 1050 aluminum alloy were used, and different pH values (2.6, 5, and 7) and electric current densities (1, 2, and 3 mA/cm²) were evaluated. The treatments were carried out for 40 min at room temperature (25 ± 1 °C). Atomic absorption spectroscopy technique was employed for monitoring and quantification of both metals. The results showed the complete removal of Cd in mixture and almost complete removal of Cu (>99 %) when used independently. The removal efficiency increased with pH and electric current density, and it was found that removal was more efficient under neutral or slightly alkaline pH conditions. The findings of this study can be useful for the implementation of this technology in the industry for the treatment of wastewater contaminated with both metals.
... Treatment schemes for industrial effluents are shaped by referring to the results of treatability and modelling studies (Li et al. 2019;Germirli Babuna et al. 1998a;1998b;1999) that yields the lowest treatment costs (Ilhan et al. 2019;Erdogan et al., 2004). For some cases energy neutrality gains importance (Ødegaard, 2016) along with costs. ...
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Treatability studies are performed on industrial wastewaters before defining a proper treatment scheme. Segregated effluents are of concern for industrial sectors such as textile, leather, metal etc. where wastewater characterization differs substantially depending on the various processes applied. Conclusions are drawn from the results obtained by checking the removal efficiencies. A treatment train is recommended based on the pollutant removal efficiencies. This type of inadequate evaluation is doomed to fail as it lacks the cross media effects and a whole spectrum of environmental impacts. In this context, the current study targets merging treatability results with the sustainability assessment. A segregated textile wastewater that contains hydrolyzed Reactive Black 5 dye (RB5) is subjected to treatability tests with UV-C activated persulfate (PS) and UV-C activated percarbonate (PC). The results that show 100% RB5 removal are evaluated via life cycle assessment (LCA). By doing so, the treatment alternative that yields minimal environmental impacts is stated. The life cycle assessment methodology used is structured according to the ISO 14040/14044 guidelines. The GaBi software version 7.3 is adopted. The CML is used to estimate the life cycle environmental impacts. The following environmental impact categories are investigated: Global warming potential (GWP), abiotic depletion potential (ADP fossils and elements), acidification potential (AP), eutrophication potential (EP), freshwater aquatic ecotoxicity potential (FAETP), human toxicity potential (HTP), ozone depletion potential (ODP), photochemical ozone creation potential (POCP) and terrestrial ecotoxicity potential (TETP).
... In recent years, electrocoagulation (EC) technologies has garnered recognition as a water and wastewater treatment method that is both effective and environmentally friendly, and it is able to remove a wide variety of contaminants [1,2]. It has been suggested that EC is an efficient approach for the treatment of a variety of wastewaters, including those from the dairy wastewater [3], slaughterhouse wastewater [4], metal-plating wastewater [5], municipal wastewater [6], reactive dye bath wastewater [7], marble processing wastewater [8], heavy metal wastewater [9], mining industry [10], etc. Most EC research has so far been done in batch reactors that are small enough to operate in laboratories to wastewater treatment [11][12][13]. ...
Article
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The environmental industry has demonstrated an increasing interest in employing electrocoagulation (EC) process to treat industrial wastewater/effluent for recycling/drinking purposes. An iron (Fe)/aluminum (Al) plate-based batch recirculation electrocoagulation technology for wastewater treatment in the distillery industry is discussed in this work. The impact of different operational parameters, including COD, wastewater pH, current, inter-electrode spacing, combination of electrodes, recirculation flow rate, concentration of electrolytes, and treatment duration on % color, % COD reduction efficiency, and energy consumption was examined. The experimental outcomes demonstrated that, the color removal was 100%, COD removal was 99.90%, and energy consumption was 7.73 kWh m-3 for COD of 3600 mg L-1, current of 0.56 Amp, combination of electrodes of Fe/Fe, inter-electrode spacing of 1 cm, wastewater pH of 7, flow rate of 15 L h-1, concentration of electrolytes of 5 g L-1, and treatment time of 180 min, respectively. It was found that, a longer treatment period, higher electrolyte concentrations and current, lower COD concentrations and recirculation flow rates, Fe/Fe electrode pairings, a pH of 7, and a smaller inter-electrode spacing all contributed to increased % COD reduction efficiency. The quantity of solid sludge formed were studied with the help of operational parameters, and the results were reported. Under the optimized process conditions, the wastewater treated can be fully recovered as clean water. As a consequence of this, the results of the experiments have shown that the batch recirculation electrocoagulation process has the potential to be a more promising solution to the problem of eliminating contaminants from wastewater and industrial effluent.
... Other anodes with oxygen evolution over potential 1.9 V, such as PbO 2 and SnO 2 , are very effective at oxidizing pollutants; however, corrosion and lower performance in high chloride-content wastewater are drawbacks (Banti et al. 2023). Other electrode materials like iron, BDD, platinum, iron, and aluminum have been reported to be effective in electroplating wastewater treatment (Tran et al. 2017;Ilhan et al. 2019;Moersidik et al. 2020;Ho et al. 2021). ...
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The graphene oxide (GO) deposited TiO2 nanotube (GO/TiO2) electrode on a titania plate was prepared using a simple anodization method. The morphological and structural properties of TiO2 and GO/TiO2 electrodes have been studied using field emission scanning electron microscopy energy dispersive spectroscopy (FESEM-EDS), X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), Raman spectroscopy, Fourier transform infrared spectra (FT-IR), and X-ray photoelectron spectroscopy (XPS). FESEM-EDS analysis confirmed that the 13.56% wt of GO nanoparticles was formed over the TiO2 substrate, with the thickness of the wall to be ∼300 nm. The crystallite size of GO/TiO2, i.e., 19.53 nm, was confirmed by XRD analysis. Analysis of the UV-DRS spectrum showed the bandgap of the synthesized GO/TIO2 nanotube electrode to be 3.052 eV. Box-Behnken design (BBD) under response surface methodology (RSM) was used to design the experiments. The effect of operating input parameters like pH, current (i), and degradation time (t) on % COD degradation (X1) and energy consumed (X2) were also examined. At optimum process parameters, the value of X1 and X2 were 57.61% and 15.00 kWh/m³, respectively. Possible intermediates were identified based on the GC–MS data analysis. Scavenger tests showed that •OH radical plays a major role in electroplating effluents degradation. Based on the results, the EO process using GO/TiO2 electrodes could be considered a promising technique for electroplating effluent degradation due to high degradation efficiency. Graphical Abstract
... They experimented with three different electrode setups: Fe, Al, and Mg. Their main goal was to understand how to harvest marine microalgae, evaluate the metal-air fuel cell EC, and compare the electricity produced during the EC process using fuel cells to the electricity produced during the EC process using a traditional power source [37] and concluded that the metal-air fuel cell system was better than the conventional EC system and Mg as an anode was the highest recovery efficiency when compared to other metals it had less HRT time and more algae formation. ...
... When the current density was raised to 20 mA/cm 2 , however, the removal effectiveness was limited due to the increasing temperature of the liquid solution caused by the higher current density, resulting in coagulation process instability [25]. Since higher currents result in higher economic costs, an optimum current value needs to be selected [36][37][38]. ...
Article
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The continued increase in urbanisation and industrialisation across the world has dramatically increased the amount and variety of waste, and, in particular, wastewater, being generated. Wastewaters contain a large variety of both organic and inorganic contaminants. Various wastewater treatment technologies have been developed over the last few decades to address the increasing concern around effective contaminant removal from wastewater. Electrocoagulation (EC) is one such technology that is broad-based, highly reliable, and cost-effective. It also has a high pollutant removal efficiency and generates less sludge when compared with other techniques. However, despite being effectively used to treat a wide range of wastewater, a thorough examination of its efficiency under various process variables has not been critically examined. Various operating factors, such as pH, current density, the conductivity of the solution, electrode material, and mixing conditions, impact the electrocoagulation system. This paper aims to provide a comprehensive overview of the electrocoagulation technique and examine the current challenges to the efficiency of the technique due to the various operating conditions. Some recent advances in the EC technology that present opportunities to improve treatment efficiency and increase the scope to treat newer varieties of wastewater are addressed.