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![Different electrodes' arrangement within the electrochemical cell: (a) monopolar electrodes in parallel connections; (b) monopolar electrodes in series connections; and (c) dipolar electrodes in series connections. [163]](profile/Mohammad-Al-Shannag/publication/319302382/figure/fig3/AS:544018188124160@1506715451598/Different-electrodes-arrangement-within-the-electrochemical-cell-a-monopolar.png)
Different electrodes' arrangement within the electrochemical cell: (a) monopolar electrodes in parallel connections; (b) monopolar electrodes in series connections; and (c) dipolar electrodes in series connections. [163]
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A vast number of publications have investigated the application of electrocoagulation (EC)
process heavy metal ions removal from wastewaters. Most of these studies were simple
lab-scale using synthetic wastewater with the absence of holistic and systematic approach
to consider the process complexity. This comprehensive review considers the fundamen...
Contexts in source publication
Context 1
... Monopolar-parallel electrodes (MP-P, Fig. 3a). In this arrangement, the EC cell consists of cathodes and anodes connected to each other and to the external DC supply. This configuration results in a relatively low potential difference since the current is divided between the electrodes. [138] In this arrangement, each pair of cathode/anode repre- sents a small electrolytic of the same voltage and an additive current. on its two sides where metal oxidation takes place on the positive side, whereas the negative side is the place for cathodic reactions. [164] It is clear that the performance of each electrode arrangement is different. For example, contrary to monopolar electrodes, bipolar electrodes require a high voltage and a lower current. For this reason, the choice of the best electrode arrangement is determined by the yield, efficiency, and the cost of a particular EC process. BP-S electrode arrangement is more efficient if the yield of the process is important rather than the cost and efficiency. [165] On the other hand, if the ratio of effectiveness-cost is the important parameter, mono- polar electrodes are more suitable since it consumes relatively low energy and enables a high pollutant removal. [166] However, bipolar arrangement needs less cost for operational maintenance cost forcing a new cost parameter that should be considered in addition to energy consumption in the selection of the most suitable arrangement. [167] Electrode shape Very limited studies have been performed to test the effect of electrode shape or orientation on the per- formance of the electrochemical cell. In addition, the most common rectangular shape of the electro- des, circular, and cylindrical geometries, punched holes type electrodes are sometimes used. In addi- tion, electrodes in few cases are horizontally settled in EC cell. It was reported that horizontal electrodes could produce in higher mixing efficiency in batch cells. [168] Kuroda et al. [169] used electrodes with and without punched holes to study the effect of elec- trode shape on the collector efficiency in an electrostatic precipitator. They found that punched- holes electrodes have discharge current and conse- quently higher collection efficiency than the plane electrode. This behavior can be attributed to the fact that the electric field intensity at the edge of punched-holes electrodes is 1.2 times higher than that of the plane ...
Context 2
... arrangement A simple electrochemical cell is usually composed of an anode and a cathode. However, in practical wastewater treatment processes, where a huge electrode surface area is required, the EC cells contain many anodes and cathodes arranged in different ways as shown in Fig. 3. As shown in Fig. 3, there are three different electrode arrangements in a complex EC cell system. These arrangements ...
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... arrangement A simple electrochemical cell is usually composed of an anode and a cathode. However, in practical wastewater treatment processes, where a huge electrode surface area is required, the EC cells contain many anodes and cathodes arranged in different ways as shown in Fig. 3. As shown in Fig. 3, there are three different electrode arrangements in a complex EC cell system. These arrangements ...
Context 4
... arrangement A simple electrochemical cell is usually composed of an anode and a cathode. However, in practical wastewater treatment processes, where a huge electrode surface area is required, the EC cells contain many anodes and cathodes arranged in different ways as shown in Fig. 3. As shown in Fig. 3, there are three different electrode arrangements in a complex EC cell system. These arrangements ...
Context 5
... arrangement A simple electrochemical cell is usually composed of an anode and a cathode. However, in practical wastewater treatment processes, where a huge electrode surface area is required, the EC cells contain many anodes and cathodes arranged in different ways as shown in Fig. 3. As shown in Fig. 3, there are three different electrode arrangements in a complex EC cell system. These arrangements ...
Context 6
... Monopolar-parallel electrodes (MP-P, Fig. 3a). In this arrangement, the EC cell consists of cathodes and anodes connected to each other and to the external DC supply. This configuration results in a relatively low potential difference since the current is divided between the electrodes. [138] In this arrangement, each pair of cathode/anode repre- sents a small electrolytic of the ...
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Citations
... Cathode : 8H + (aq) + 8e − ↔ 4H 2(g) (6) Overall : 4Fe 2+ (aq) + 10H 2 O (I) + 10O 2 (g) ↔ 4Fe(OH) 3 (s) + 4H 2(g) (7) Both gravity and buoyancy forces determine the separation method of the produced sludge in the EC treatment step. In addition, many parameters influence the performance of the continuous EC process, including the flow rate of the pollutants in and out of the EC cell, as Table 2 shows [39]. Table 2 shows the operational parameters determining the performance of continuous and batch EC processes that are similar except for one new parameter, the pollutant flow rate. ...
... Nowadays, the freshwater available for humans is less than 1%, while saltwater in the oceans and seas represents more than 97% of the total water on earth [1]. That 1% is decreasing due to its contaminant due to industrial, urban, and agricultural activities, where industrial development represents 20% of this worldwide decrease [2]. ...
... In the treatment of water with electrocoagulation, its use is reported for the removal of heavy metals such as chromium, cadmium, and nickel, among others, as well as other inorganic contaminants [1], [11], such as fluorides, phosphates and nitrates [12], [13], [14]. It has also been applied for the treatment of turbid water [15], as well as the removal of organic contaminants such as surfactants like linear alkylbenzene sulfate [3], phenolic substances [16] or distillery effluents [17]. ...
The objective of the present study was to analyze the removal efficiency of red dye 40 by electrocoagulation process using aluminum electrodes. The methodology used includes a first stage taking into account the operating parameters of the electrolyte concentration (0-0.5 g/L NaCl), pH of the solution (4.5-9.1), number of electrodes (2-4), distance between electrodes (1-2 cm), with the best results of this stage, a multilevel factorial experimental design with two variables was performed: (10, 15 and 20) V voltages and electrocoagulation duration of (3, 6, 10, 20, 40 and 60) min. The results show the main role of several parameters to maximize the removal efficiency and minimize the energy consumption. According to the experimental results, the maximum removal efficiency obtained is 85.29 % with an energy consumption of 14.08 kJ.
... Thus, as a result of the formation of metal hydroxides, it is possible to adsorb and precipitate various pollutant parameters in water [10]. pH, one of the independent variables of the EC process, is considered the most important variable in the removal process of heavy metals [45]. In addition, the activity in the anode region and the EO mechanism can partially occur here [46]. ...
... EC performance is influenced by water electrolysis, redox reactions of contaminants at the electrode surface, electrostatic effects, and ion migration. However, the main EC steps include, generation of cationic metal ions at the anode and hydroxide ions (OH -) at the cathode solution interface, transport of metal ions and OH-to the bulk solution, generation of metal hydroxide coagulants, and aggregation (agglomeration) of coagulants along with the contaminants [7,13,[17][18][19]. The proposed mechanism of chemical reactions in the EC process is illustrated through the main reactions at the aluminum electrodes (1-5) [20][21][22][23][24]: ...
The presence of chromium (Cr) in synthetic wastewater has become a serious environmental issue. Therefore, main aim of this work was to investigate Cr removal from synthetic wastewater via electrocoagulation (EC) with a natural coagulant using aluminum electrodes. The central composite design (CCD) of the response surface methodology (RSM) method was used to optimized the operating variables of solution pH (5–9), initial Cr concentration (225–475 mgL-1), reaction time (30–40 min), and applied current (0.35–0.55 A). The ANOVA results clearly show that the quadratic model (p < 0.0001) was sufficient to best predict the removal performance of Cr (R2 = 0.9994 for electrode distance of 0.5 cm and 0.9924 for 1 cm). The maximum removal (99.836 % for electrode distance of 0.5 cm, and 98.175 % for 1 cm) of Cr was achieved with optimized conditions of solution pH 7.053, initial Cr concentration 337.795 mgL−1, reaction time 37.148 min, and applied current of 0.505 A. This finding proved that the EC process assisted with natural coagulant, an efficient, cost-effective method for removing Cr from synthetic wastewater.
... Electrocoagulation is an electrochemical process that removes contaminants from water sources with the aid of in-situ metal hydroxide coagulants [8,20,39,51,52,57]. The in-situ coagulant namely aluminium hydroxide is an environmentally friendly adsorbent that separates contaminants from water sources [48]. ...
Urbanization activities on Borneo Island have degraded the water quality of some urban rivers due to increased anthropogenic activities which leading to elevated levels of total organic carbon (TOC) and reduced access to clean water sources. As such, this study aims to develop a batch electrocoagulation treatment system to reduce the TOC levels in Borneo urban river for domestic consumption. Correspondingly, this study analyses the effect of electric current and residence time on TOC reduction efficiency. Subsequent, this study has found that the TOC levels in treated urban river water met domestic consumption safety standard by utilizing a batch electrocoagulation treatment system at 5 A of electric current and 25 minutes of residence time. The treatment system achieves 82.83% of maximum TOC reduction efficiency by decreasing the initial TOC levels from 5.65 mg/L to 0.97 mg/L. The energy operating cost analysis done in this study has reported that electrocoagulation treatment system could generate 116.51 g Al(OH)3 per meter cubic of urban river water at a cost of United States Dollars (USD) 0.32 per m3. Additionally, the reduction of TOC levels in urban river by using in-situ aluminium hydroxide coagulants follows Freundlich isotherm model with a regression coefficient of 0.99, thus, exhibiting a multilayer adsorption. The aluminium hydroxide coagulants could reduce TOC from urban river at 1.40 min−1 of adsorption rate and 0.20 mg/g of maximum adsorption capacity. From the energy dispersive X-ray analysis conducted, this study has observed the presence of electrocoagulation flocs that are constituted with aluminium hydroxide coagulants and carbon element which indicated the occurrence of adsorption process. Overall, this study demonstrates that the batch electrocoagulation treatment system could be utilized to reduce the TOC level from Borneo urban river with an adsorption process which is deemed suitable for domestic consumption at a reasonable cost.
... This can be attributed to the fact that various types of Al ions can be produced based on pH value. At pH from (5)(6)(7)(8), Al(OH) +2 , Al(OH) 2 + , Al(OH) 3 , Al 2 (OH) 2 ...
The removal of congo red (CR) is a critical issue in contemporary textile industry wastewater treatment. The current study introduces a combined electrochemical process of electrocoagulation (EC) and electro-oxidation (EO) to address the elimination of this dye. Moreover, it discusses the formation of a triple composite of Co, Mn, and Ni oxides by depositing fixed salt ratios (1:1:1) of these oxides in an electrolysis cell at a constant current density of 25 mA/cm2. The deposition ended within 3 hours at room temperature. X-ray diffractometer (XRD), field emission
scanning electron microscopy (FESEM), atomic force microscopy (AFM), and energy dispersive X-ray (EDX) characterized the structural and surface morphology of the multi-oxide sediment. Marvelously, the deposition has simultaneously occurred on both anodic and cathodic graphite electrodes. These electrodes besides aluminum (Al) are employed as anodes in the EC-EO system, and the results were optimized by response surface methodology (RSM). The optimum operating conditions were a current density of 6 mA/cm2, pH = 7, and NaCl of 0.26 g/L. The results showed that the combined system eliminated more than 99.91% of the congo red dye with a removal of chemical oxygen demand (COD) of around 97% with 1.64 kWh/kg of dye of the consumed energy. At low current density, the current delivered for the composite anode was more than for the Al anode with the same surface area. On top of this superiority, the EC-EO scenario is a practical hybrid process to remove CR in an
environmentally friendly pathway.
... 4,6 Copper is used in mining operations, pharmaceutical equipment manufacturing, paper industry and kitchenware manufacturing. 17 Zinc is used in batteries, anti-corrosion coating, cans, paints, cosmetics, rubber industries, pigments and as Zn alloys. 18 Arsenic is used in the industries of pesticides, mining, insecticides, ceramics, metallurgy, textile, veterinary medicine productions and also in the tanning process. ...
... Mercury causes retardation, genetic defects, teratogenic effects, rheumatoid arthritis, protoplasm poisoning. 16,17,22 It is a neurotoxin and high ...
... Nickel is spread via industrial process batteries manufacturing paint, mining, metal finishing & forging. 17 Petroleum refining, electroplating are also other sources of nickel contamination. 13 ...
Water is an indispensable need for the survival of living ecosystems. Industrialization and urbanization gifted a sophisticated life as well as a polluted environment. Water is getting polluted by various means like human activities, industries, and sewage. One of the serious issues around the globe in the upcoming days is heavy metal pollution. A voluminous amount of heavy metals are let into the environment from various sources like agricultural, industry, sewage, and mining. It causes adverse effects on the environment and human beings when the heavy metals concentration is beyond the expected permissible limit. Innovative processes are developing day by day for the operational deletion of heavy metals. This review article provides a consolidated report of the treatment techniques used for heavy metals removal of with excellent efficiency like precipitation, ion-exchange process, adsorption, solvent extraction, electrocoagulation and membrane processes.
... Aluminum and iron metals are widely used as electrodes in the EC processes due to their ease of oxidation and effectiveness as coagulants [31]. The detailed redox reactions involved in the EC processes could be summarized as follows [32,33]: ...
... Beyond climatic imperatives dictating the imperative for wastewater treatment, the compulsion to address industrial effluents containing elevated concentrations of heavy metals and natural organic matter arises from their heightened toxic potential, posing significant threats to both environmental integrity and human health [5,6]. Notable examples include copper, nickel [7,8], and humic acid (HA). The indiscriminate release of industrial effluents laden with heavy metals into the environment is fraught with peril and is universally acknowledged as a principal causative factor in various contaminations afflicting surface and groundwater sources [9,10]. ...
Industrial effluents laden with heavy metals and organic matter necessitate diligent treatment, owing to their pronounced threat to both biota and human populations, attributed to their enduring persistence, inherent toxicity, and proclivity for bioaccumulation. This investigation centers on the eradication of copper, nickel, and humic acid (HA) through the utilization of the electrocoagulation- électrofloculation process (EC-EF) employing aluminum electrodes. In an endeavor to enhance the efficacy of the EC process, a comprehensive examination of various EC parameters including solution pH, current density (J), electrolyte concentration, and connection mode was conducted. Optimal outcomes, characterized by minimal residual concentrations and diminished energy consumption, were achieved under specific conditions: pH 5 for Cu and Ni, pH 4 for HA, current density of 1.388 mA cm-2, electrolyte concentration of 1 g L-1 for Cu, 1.5 g L-1 for Ni, and 0.15 g L-1 for HA, with monopolar connection mode. Under these optimized parameters, complete HA elimination and notably low residual concentrations of Cu (0.4 mg L-1) and Ni (2.354 mg L-1) were attained, translating to elimination rates of 100%, 99%, and 94.65% for HA, Cu, and Ni, respectively, from industrial wastewater. This accomplishment was realized within modest electrolysis duration of 20 min, with a commendably low energy consumption of 0.04 kW.m-3. The demonstrated 100% elimination rate of HA underscores the superior efficacy of EC in organic matter removal when compared to its efficacy in heavy metal removal. These compelling results posit EC as a cost-effective and viable technique for the treatment of industrial wastewater.
... Thus, the effective removal of heavy metal ions from the environment has grabbed much impetus in the past few years. Different strategies such as chemical precipitation [141], coagulation [142], ion exchange [143], reverse osmosis [144], adsorption [145] etc. is available for the exclusion of heavy metals. Out of these, adsorption is the most effective and economical method for the exclusion of toxic metals from water streams [146]. ...
