Aluminum Electrodes Research Articles

Application of batch electrocoagulation treatment system with aluminium electrodes for simultaneous removal of organic and heavy metal contaminants from Borneo urban rivers

The challenges of sludge management and complex water treatment systems hinder the effectiveness of chemical coagulation in treating heavily contaminated urban river water. Realizing these issues, this study aims to develop a batch electrocoagulation system using aluminum electrodes to generate in-situ aluminum hydroxide coagulants for simultaneous removal of organic contaminants and heavy metals from Borneo urban river water. Subsequent, the treatment system achieves a reduction of 91.67 % of turbidity, 98.29 % of color, 95.16 % of total suspended solids (TSS), 97.78 % of iron, 94.21 % of lead, 21.94 % of pH, and 98.58 % of chemical oxygen demand (COD) with an electric current of 5 A and a residence time of 25 min. Besides, the treated water meets the Malaysia National Water Quality Standards for Class I which making it suitable for domestic consumption. The energy consumption cost for the treatment is only RM 1.48 (USD 0.31) per cubic meter of treated water. Additionally, the analysis of the electrocoagulation flocs reveals the presence of carbon, iron, lead, and various dissolved minerals which indicates effective contaminant removal from urban river. Overall, this study demonstrates the potential of the batch electrocoagulation treatment system as an effective and cost-efficient solution for treating urban river water in Borneo industrial areas.

Theoretical and experimental studies of cephalexin adsorption on aluminium as a new alternative of removal from wastewater

ABSTRACT Cephalexin (CPX) is an antibiotic widely used to treat many infections. CPX has become an emerging pollutant present in wastewater. On the other hand, it is well known that organic compounds can be adsorbed over metal surfaces when the metal is in active state such as when it is rusting. This work proposes an alternative for the elimination of CPX from wastewater, applying electrochemical principles using a conventional and cheap substrate, aluminium. The first part consisted of obtaining the active states of aluminium electrodes carrying out voltametric curves at different pH (4, 7 and 9) to find the particular condition of interaction between CPX and metal surface. The potential was used in the potentiostatic tests to set the activation potential of metal at different times. After the treatment, electrolyte solutions were analysed using UV-vis spectra, and the aluminium surfaces were studied by optical micrographs and X-ray diffraction. In addition, aluminium-CPX interactions were corroborated by quantum-chemical calculations and adsorption isotherms. All results indicate that it was possible for the CPX removal at basic pH conditions, where the molecule adsorption on the aluminium substrate occurs due to a strong electrostatic interaction.

Electrode reactions on the aluminum electrode in 1-butyl-3-methylimidazolium chloride chloroaluminate ionic liquid: A comprehensive study

Mechanisms of Al electrochemical deposition/dissolution in acidic AlCl3–1-butyl-3-methylimidazolium chloride (BMImCl) ionic liquids are studied. Stationary polarization curves (SPCs) are obtained in the anodic range of potentials. The anodic SPCs are characteristic of electrode processes, which are complicated by passivation phenomena. The peaks intensity of AlCl4−, Al2Cl7− ions were obtained by in-situ Raman spectroscopy during the aluminum electrode polarization and correlated with the behavior of the SPCs. Based on the results obtained, a mechanism of electrochemical oxidation of aluminum in AlCl3–BMImCl IL is proposed. According to the mechanism in question, the anodic process is complicated by the presence of a following chemical reaction involving AlCl3. Chronopotentiometric studies were carried out to determine diffusion coefficients of Al2Cl7− anion, which are unaffected by the change in the molar ratio of AlCl3 to BMImCl (N). The activation energy (Ea) for the Al2Cl7− diffusion coefficient is independent of N and equals 14.5 ± 0.4 kJ mol−1. Exchange current density (i0) at the Al | AlCl3–BMImCl interface was determined using impedance spectroscopy for the compositions with 1.1 ≤ N ≤ 2.0 at temperatures from 303 to 386 K. The i0 increases from 0.54 ± 0.13 to 2.73 ± 0.22 mA cm−2 with the concentration of the electrochemically active Al2Cl7− anion in the concentration range indicated above at 303 K. The data on i0 is used to calculate the transfer coefficient of cathodic reaction (α = 0.18 ± 0.02), the electrochemical reaction rate constant (ks= (1.1 ± 0.3)∙10−6 cm s−1 (at T = 303 K)) and the Ea for the ks (Eaks = 36.5 ± 0.9 kJ mol−1), which do not depend on the IL composition.

Flexible Aluminum-Air Batteries

Wearable and flexible electronics have a wide range of applications. Making a flexible power source for them is essential. Aluminum-air batteries are attractive for powering portable, lightweight devices due to their inexpensive, light, and powerful energy source. In this project, the Al-air battery was made using activated carbon and aluminum electrodes, chloride-based electrolytes with ionic liquid additives. Various mixtures of 1-ethyl-3-methylimidazolium chloride, aluminum chloride, sodium hydroxide, and sodium chloride were studied. Fundamental properties of room-temperature ionic liquids, such as lower conductivity and density, improved the performance of aluminum-air batteries. Cell capacity, cyclic voltammetry behavior, and cell interfacial impedance with various electrolytes were optimized using the design of experiments. The battery's electrical power output and cell capacity were lower than those obtained using an activated carbon air cathode. The cell capacity over repeated electrochemical reactions was stable. The Al-air battery had regular cyclic voltammetry behavior. Aluminum hydroxide was not found on the anode electrode when an ionic liquid electrolyte was used. The interfacial cell impedance did not decrease after electrochemical reactions over a long time.

MoS2 Modified Aluminum Electrode for Detection of Calcium Oxalate through Electrochemical Oxidation

The disposal of electronic waste (E-waste), encompassing discarded items such as computers, televisions, fridges, cellphones, and associated cabling, presents a significant challenge to both societal welfare and environmental health. Addressing e-waste management is critical to achieving several of the Sustainable Development Goals (SDGs). This study introduces a novel approach to repurposing aluminum from discarded electrical cables for the creation of high-efficiency electrodes that can detect oxalic acid in human urine samples. The process involves stripping 2mm thick cables to yield 7cm long aluminum rods. These rods are then coated with MoS2 nanoparticles via a hydrothermal synthesis technique. X-ray diffraction (XRD) analysis confirms the presence of MoS2 in the 1T phase, while Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy provide insights into the vibrational modes and chemical composition. Field emission scanning electron microscopy (FESEM) imaging depicts the MoS2 as having a flower-like nanostructure composed of interwoven nanosheets. The resulting nanocomposite sensor demonstrates an enhanced electrical current response, along with notable selectivity and stability, likely due to the combined effects of the MoS2 materials. The sensor’s amperometric signal is directly correlated with the oxalate ion concentration within a range of 10 to 300 μM and exhibits a detection threshold as low as 2 μM. This sensor technique was evaluated alongside a standard colorimetric assay for measuring oxalic acid levels in urine specimens. Findings indicated a strong correlation (R=0.954) between oxalic acid concentrations assessed using the biosensor and those obtained through the colorimetric approach.Keywords: E-waste, Aluminum Electrodes, MoS2 Nanoparticles, Oxalic Acid Detection, and Electrochemical Sensing, Figure 1

(Invited) Electrolysis of Liquid Dairy Cow Manure into Clean Reusable Water

Livestock wastewater management is a critical concern in the United States, with an annual production of 1.2 to 1.37 billion tons of waste, surpassing human waste by three to twenty times. This mismanagement poses significant threats to freshwater sources, ecosystems, and public health. Agriwater’s project proposes an innovative solution using electrocoagulation (EC) treatment. The EC technique is a process involving the intentional corrosion of aluminum or iron electrodes to introduce trivalent ions, facilitating the co-precipitation and coagulation of contaminants, making their removal as sludge easier. The project's primary objective is to use electrolysis to convert liquid animal waste into clean water for irrigation, drinking, and farm maintenance. This solution is vital for various farms, including those facing drought, zero-discharge, and EPA-permitted farms discharging manure into rivers. Preliminary research shows EC's potential to significantly reduce turbidity and phosphate levels in livestock wastewater, forming the basis for scalable on-site treatment. The project team, with expertise in electrolysis, wastewater treatment, and agricultural engineering, ensures the development of an industrial-grade water treatment system. This project is in collaboration with Oak Ridge National Laboratory and the University of Tennessee's Dairy Farm and addresses immediate environmental challenges that contribute to a more sustainable and responsible agricultural industry.

Effect of current density variation in the electrocoagulation process for the treatment of brewery wastewater

Breweries generate substantial amounts of wastewater, typically ranging from 3 L to 10 L per liter of beer produced. This wastewater possesses acidic characteristics and carries a high organic load, making it a suitable candidate for electrocoagulation (EC) treatment. EC treatment uses aluminum electrodes to generate an on-site coagulating agent, reducing the concentration of solids, organic load, and color in the wastewater. In this study, the present data were used to compare the efficiencies of different current densities (CD) applied to the EC process for treating raw brewery wastewater (RBW). The RBW underwent treatment with aluminum electrodes, with a CD of 12.00 A∙cm-2 and 13.23 A∙cm-2. The raw and treated samples were analyzed, and the data was analyzed statistically. Both CDs demonstrated effectiveness in reducing pollutant content. The process successfully reduced turbidity (99.9 %). Furthermore, the process effectively removed color across all wavelengths analyzed. The treatment process also showed promise in removing solid content, with a maximum removal efficiency of 84.5 % for suspended solids. Statistical analysis of the collected data indicates that treatment with a CD of 13.23 A∙cm-2 was more effective in treating brewery wastewater without significantly increasing the concentration of Al3+. The data presented in this study strongly supports the proposed treatment's efficacy in reducing pollutant concentrations in brewery wastewater.

Effects of current intensities on material removal rate, electrode wear rate, and surface roughness of machining high carbon high chromium steel

AbstractThe electrical discharge machining is very successful and generally recognized for producing complicated shapes and small openings with exceptional precision. The objective of this study is to assess the impact of different electrical discharge machining parameters on the attributes of the machining process. The evaluation of the machining process was conducted based on the workpiece‘s material removal rate, the rate at which the electrodes wear, and the level of surface roughness. Simultaneously achieving a high material removal rate, low electrode wear rate, and high surface roughness is not possible with a specific combination of approaches due to their contradicting nature. Frequently, it is necessary to independently apply many measures instantaneously in order to assess their impact on various responses. This research investigates the machining of high carbon high chromium steel making use of electrical discharge machining with aluminum, copper, and graphite electrodes. The study focuses on the impact of different current intensities on the rate of material removal, electrode wear, and surface roughness. The experimental results demonstrate that the highest material removal rate (mmcubicmin−1) is achieved at a current density of 12 A when using a copper electrode (54.67), as opposed to aluminum electrode (22.91) and graphite electrode (29.43).

Electrocoagulation treatment of debrominated wastewater: A critical observation and analysis

Present study deals with the treatment of highly polluted dibrominated wastewater (DWW) using electrocoagulation process. The study methodology utilized 2 L batch reactor with four parallel aluminum (Al) electrodes with varying electrode gaps, current density and pH. The results show optimum value of 1.5 cm for electrode gap, 50 Amp/m2 forcurrent density and pH 9. For these optimal valus, the removal efficiencies emerged as: 34.09 % for COD, 29.80 % for TDS, 56.17 % for color and 20 % for turbidity. At pH 9, the maximum total metal loss (TML) was 1.77 g/L, while the highest power consumption was 2.4 Wh/L at pH 3. While pH 3 exhibited the most efficient settling rate, pH 9 resulted in maximum residue and foam weight of 8.42 g/L. Further, electrodes and residue were characterized using SEM, EDX, XRD and FTIR techniques. Investigation given detail information about applicapability of EC process to treat DWW. Results demonstrated that EC process is well applicable to treat DWW.

Electrocoagulation efficiency probed using electrochemical impedance spectroscopy

Electrocoagulation efficiency probed using electrochemical impedance spectroscopy

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.

Challenges in using Electrocoagulation Process in Removal of Nickel Metal in Wastewater: a Literature Review

In recent years, the surge in nickel production, driven by the growing demand for electric vehicle batteries, has raised concerns regarding environmental consequences. The nickel mining and processing industries contribute to increased nickel levels in wastewater, presenting a serious threat to aquatic ecosystems and human health. This article emphasizes the urgency of developing effective technologies for treating nickel-contaminated wastewater. Electrocoagulation emerges as a promising method, providing high efficiency, minimal sludge production, and cost-effectiveness. The article critically and systematically reviews the potential of the electrocoagulation process in nickel removal from wastewater. In the review, we identify and analyze nearly 32 studies published from 2013 to 2023. We discuss contaminant removal mechanisms and analyze trends in the use of operational parameters. This article identifies the most commonly applied conditions: aluminum electrodes, inter-electrode spacing ≥ 1 cm, current density ≤ 10 mA/cm², initial pH 6 ≤ pH < 11, electrolysis time < 60 min, batch operation, and initial nickel concentration > 50 mg/L. This comprehensive review serves as a foundational resource for advancing electrocoagulation technology in the removal of heavy metals from nickel wastewater.

A Sustainable Free-Standing Triboelectric Nanogenerator Made of Flexible Composite Film forBrake Pattern Recognition in Automobiles.

In recent years, the automotive industry has made significant progress in integrating multifunctional sensors to improve vehicle performance, safety, and efficiency. As the number of integrated sensors keeps increasing, there is a growing interest in alternative energy sources. Specifically, self-powered sensor systems based on energy harvesting are drawing much attention, with a main focus on sustainability and reducing reliance on typical batteries. This paper demonstrates the use of triboelectric nanogenerators (TENGs) in a computer mouse for efficient energy harvesting and in automobile braking systems for safety applications using SrBi2Ta2O9 (SBTO) perovskite, blended PDMS composite operating in free-standing mode with an interdigitated patterned aluminum electrode. This self-powered sensor is capable of distinguishing between normal and abnormal braking patterns using digital signal processing techniques. It is noteworthy that the addition of 15%wt. of the SBTO in PDMS composite-based TENG delivered 13.5V, 45nA, and an output power of 0.98µW. This new combination of energy harvesting and safety applications enables real-time monitoring and predictive maintenance in the automotive industry.

PERFORMANCE EVALUATION OF A SIMPLE ELECTROCHEMICAL TREATMENT MODEL FOR SALINE WASTEWATERS: PART A

This paper investigated the performance of the electrochemical treatment technique in removing chloride from saline (salty) wastewaters (brine). Saline wastewaters (between 10 x 103 mg/l and 40 x 103 mg/l of chloride) were prepared and subjected to electrochemical treatment using developed carbon–resin (anode) and aluminium (cathode) electrodes. Electrochemical treatment of the simulated brine was conducted on a laboratory scale. The influence of selected factors on the performance of the electrochemical process was monitored using fractional factorial experiments. These selected factors were optimized using steepest descent technique (between the minimum and maximum concentrations) and rate change of chloride removal efficacy through Microsoft Excel Solver. The optimum values of these selected factors were used to purify typical raw saline water. Efficacies of the process in removing chloride ions from the typical raw saline water was used to predict efficacy of the system using typical chloride concentration in seawater based on literature and previous studies. The study revealed the relationship between chloride removal efficacy (%), initial concentration of chloride, current through the wastewater and separation distance between the electrodes were best in the form of exponentials with coefficient of determination of 0.979, 0.920 and 0.977, respectively. The optimum values of these selected factors such as current, pH, treatment period and separation distance between the electrode (centre to centre of the electrode) were 10.5 A equivalent to 0.795 A cm-2 , 6.7, 2.75 hr and 42mm, respectively. It was concluded that electrochemical treatment with carbon electrodes is an effective tool for removing chloride from saline wastewater during electrochemical treatment.

Removal of formaldehyde from the air flow in an electrochemical process

This study employed an electrochemical process to eliminate formaldehyde from contaminated air streams. Various factors that influence the process, including electrode material, inter-electrode distance, air injection site, applied voltage, electrical power, current density, pH, reaction time, electrolyte type, concentration, and formaldehyde's initial concentration were investigated. Findings revealed optimal percentage decrease in concentration (χ), reaching 100 %, using aluminum (Al) electrodes with a 1 cm gap between them. Potassium Persulfate (PP) was found to have superior χ compared to sodium thiosulfate (STH). Regarding the air injection site, the higher χ was noted at the cathode (98.9 ± 0.85 %) than at the anode (95.2 ± 0.99 %). Efficiency escalated from 85.1 % at 7.5 volts to 100 % at 15 volts and, for current density, from 89.18 % at 0.042 amps to 100 % at 0.159 amps. Conversely, efficiency for air flow diminished from 100 % at 0.1 l/min to 27.32 ± 2.7 % at 4.4 l/min. Additional factors were also explored, including removing formaldehyde in the reactor's liquid phase and mineralization. Outcomes suggest that formaldehyde reacts with water, eventually transforming into carbon dioxide. Moreover, the reaction kinetics for both electrolytes demonstrated a tendency toward a second-order kinetic model.

Punica grantum peel extract decorated Al-MOF scaffold as Solid-State Sensor/Concentrator for the Sensing/Reduction of Cr(VI) and its extended utility as a corrosion inhibitor in Al-Air batteries

The growing presence of hexavalent chromium in environmental and industrial settings highlights the importance of developing an eco-benign platform for real-time in-situ sensing/screening and decontamination. This research presents a facile and portable solid-state optical sensor using waste Punica Granatum, i.e., pomegranate peel extract (PPE) adorn onto Aluminium-based Metal-Organic Frameworks (Al-MOFs) for the sensing of carcinogenic Cr(VI) and its decontamination to benign Cr(III). The sensor fabrication entails a hydrothermal synthesis to form Al-MOF scaffolds decorated with PPE through direct immobilization. Al-MOF exhibits a large surface area with well-defined pore channels that facilitate PPE’s voluminous/uniform anchoring in restricted orientations to serve as an ion-selective probe for specifically targeting ultra-trace Cr(VI). The surface/structural morphology and porosity of the Al-MOF-PPE material are characterized using scanning/transmission electron microscopy and BET/BJH analysis. The reduction of Cr(VI) by the Al-MOF-PPE is validated by electron spectroscopy for chemical analysis, corroborated by a conspicuous color transition from light yellow to dark brown. The efficient reduction of Cr(VI) by Al-MOF-PPE is achieved at pH 2–3, in the linear response range of 0.3–300 ppb and a detection limit of 0.23 ppb for Cr(VI). The sensory system prefers minimal PPE probe content (4 mg) and sensor dosage (5 mg) for ion-sensing and decontamination studies, highlighting its remarkable operational efficacy. Post Cr(VI) reduction, electrochemical studies confirm the utility of Al-MOF-PPE-Cr(III) as a corrosion inhibitor for metal surfaces. Tafel plots demonstrate that Al-MOF-PPE-Cr(III) exhibits cathodic and anodic inhibition characteristics, ensuring excellent surface protection for aluminum electrodes upto 220 min in Al-air batteries. The proposed Al-MOF-PPE offers dual functionality as a naked-eye platform for Cr(VI) decontamination, and the Al-MOF-PPE-Cr(III) material is an excellent corrosion inhibitor for energy storage devices.

Separation and recovery of elements from drainage water arising in soilless tomato cultivation − Application of electrocoagulation

Soilless tomato cultivation requires significant water and nutrient inputs, resulting in the generation of drainage water (DW) with varying macro- and micronutrient compositions. This poses challenges for effective nutrient’s reuse due to technological and economic constraints. This study investigates the feasibility of using electrocoagulation, employing aluminum electrodes, to treat DW. The experiment involved three different current densities (2 A/m2, 4 A/m2, and 8 A/m2) and a 24-hour hydraulic retention time (comprising 4 h of electrocoagulation followed by 20 h of stirring). Treatment performance, kinetics, sludge characteristics, and energy consumption were evaluated. The elemental composition of the electrocoagulation-treated DW, including P, N, S, Cl, Ca, Mg, K, Na, Mo, Mn, Fe, Zn, Cu, B, organic compounds, and Al, was analyzed. The results showed that higher current densities resulted in increased pollutant removal rates and efficiencies. Importantly, the electrocoagulation process facilitated phosphorus recovery at pH < 7.0, ranging from 95.3 ± 0.6 % (at 2 A/m2) to 99.9 ± 0.1 % (at 8 A/m2), with corresponding energy consumption between 6.03 kWh/kgP and 29.98 kWh/kgP. Electrocoagulation as a drainage water treatment not only offers phosphorus recovery, but can also recovery B, and – to a certain extent – S, Mg, K, Mn, Zn and Cu. Other elements, such as Na and Cl, remained at stable levels. This allows for the separation of valuable elements (P) from those that interfere with cultivation (Na, Cl). This research could contribute to the development of a precise treatment process to address nutrient and pollutant management challenges in agricultural wastewater.

Optimization of electrocoagulation process parameters for the treatment of oil industry drill site wastewater.

The effluent from the oil drilling site is a complex mixture of hazardous chemicals that causes environmental impacts on its disposal. The treatment of oil drill-site wastewater has not been explored much, and understanding its characteristics and optimizing the treatment process are required. In the present study, we have optimized the electrocoagulation process with aluminum electrodes for drill-site wastewater treatment. A multi-level factorial center composite design using response surface methodology is applied to optimize the effect of current density (CD), pH, and inter-electrode distance (IED) on chemical oxygen demand (COD) removal. The increasing current density shows a significant increase in COD removal, and a similar trend was observed with a decreased pH. It was found that with current density and inter-electrode distance, the maximum COD removal achieved was 70% at the CD of 19.04mAcm-2 and IED 2.6cm. By varying pH and current density, the COD removal reached up to 90% at pH 6 and CD 19.04mAcm-2. The study shows that the current density is the dominant factor for the process's energy consumption and operating cost, followed by pH. This study's findings could be effectively used to develop large-scale treatment processes through electrocoagulation.

Deciding on the priority of process parameters using the analytical hierarchy process in electrochemical wastewater treatment and investigation of paint wastewater treatability

In planning electrochemical treatment processes, it is thought that decision-making tools should be used in the selection of the main parameters that are likely to affect pollutant removal. According to detailed research in the literature, no previous study has systematically prioritized process parameters in electrochemical wastewater treatment using the analytical hierarchy process (AHP). In this study, published articles in the literature on the subject were used to determine which parameters were used in the treatment processes and with what frequency. Using the obtained results, the priorities of the process parameters were estimated with the help of AHP within the scope of the removal efficiencies and treatment cost criteria. According to the AHP analysis results, it was determined that the most effective parameters for both electrocoagulation and electrooxidation processes were pH (0.241), current density (0.171), voltage (0.171), conductivity (0.107), concentration (0.105) and reaction time (0.094). Four of the independent parameters were selected and treatability studies were carried out using both electrocoagulation (with Al electrode pair and Fe electrode pair) and electro oxidation (with Graphite electrode pair and Ti electrode pair) methods for different levels of each parameter. The pH, current density, voltage, and reaction time were chosen as independent parameters based on decision making process. Unit costs for removal of chemical oxygen demand with Al, Fe, graphite, and Ti electrodes were obtained as 1.05, 2.56, 0.074, and 14 USD per m3 wastewater, respectively. Unit costs for removal of color with Al, Fe, graphite, and Ti electrodes were obtained as 0.68, 1.20, 0.074, and 14 USD per m3 of wastewater, respectively. In addition, nine batch kinetic studies were conducted for optimum conditions obtained from pre-treatment studies with Al and Fe electrodes. Removal of chemical oxygen demand was achieved at 64 % with aluminum and iron electrodes at 40 and 70 min, respectively. The results obtained from kinetic studies showed that adsorption of organic substances fit the 2nd-order kinetic model and the correlation coefficient was 0.95 and 0.96 for aluminum and iron electrodes, respectively.

Improved bacterial elimination in wastewater through electrocoagulation: hydrogen generation, adsorption of colloidal bacteria-flocks, and electric field bactericidal action

ABSTRACT Electrocoagulation (EC) has emerged as a promising method for wastewater treatment, offering efficient removal of various contaminants, including bacteria. This study investigates the mechanisms underlying bacterial removal in EC processes, mainly the hydrogen-mediated foam, the effect of operational parameters, including initial pH, current density, and reaction time, and evaluates the associated energy consumption. The EC reactor employed aluminum electrodes and operated at a current intensity of 3.0 A. It demonstrated a notable bacterial removal efficiency, with 120.102 UFC ml−1 of mesophyll floral aerobic bacteria removed through colloid bacteria-flocs precipitation, 440.102 UFC ml−1 via bacterial-bulls flotation from foam, and 117.102 UFC ml−1 through attraction at the electrodes’ plate surface. We found that the EC process leads to the formation of aluminum hydroxide and ferrous hydroxide precipitates, which adsorb bacteria and facilitate their removal from the wastewater via electrostatic forces with an energy consumption of 45 kWh/m3. Overall, this research provides valuable insights into the mechanisms governing bacterial removal in EC and highlights the importance of energy consumption analysis for optimizing wastewater treatment processes.