Monopolar Aluminium Research Articles

Monitoring Alkalinity and Hardness During Treatment of Different Water Types

Alkalinity and hardness are crucial factors in water treatment procedures, such as electrocoagulation (EC) and traditional coagulation–flocculation. Two types of water were employed in this study to investigate the use of EC: river water and discarded reverse osmosis system water. With bipolar and monopolar aluminum electrodes, continuous flow tests were conducted to evaluate the effects of different parameters on the variations in alkalinity and hardness versus time. The examined factors were flow rate (600 and 1,000 L/h) and number of electrodes (2 and 4). Polarity reversal was also studied. The water passed through the plates in a zigzag pattern. Results showed that the hardness under all operating conditions decreased with time, and alkalinity exhibited an oscillating behaviour. The ideal hardness removal for treating river and concentrated water was obtained using four plates with polarity reversal and a flow rate of 1,000 L/h, which were equal to 37.5% and 33.3%, respectively.

Electrocoagulation technique and statistical analysis for treatment of real effluent from the pulp and paper industry

The electrochemical treatment of Organic Pollutants is a promising technique for substances with biodegradability resistance. In this research, the black liquor effluent originating from the Rakta Paper and Paper Company's mill, which employs rice straw as a raw material for paper fiber production, was subjected to treatment using the electrocoagulation method utilizing monopolar aluminum electrodes. The experiments were carried out using a 2.5 L electrochemical cell equipped with monopolar aluminum electrodes connected in parallel. The study examined the impact of operating parameters such as initial pH, current density, number of plates and electrolyte concentration on percentage removal and power consumption. The results revealed a positive correlation between the percentage of color removal and the duration of electrolysis, current density, sodium chloride concentration, and the number of electrodes used. The maximum color removal was observed at initial solution pH 6.5, experimental time 120 min, current density 61.8 A m−2, initial NaCl solution concentration 2 g L−1 and six aluminum plates. The statistical and mathematical data based on experimental results were analyzed using the central composite design from response surface methodology (RSM). The quadratic model is deemed appropriate owing to its substantial coefficient of determination (R2 = 0.99) and statistically significant p-value (≤ 0.0002), suggesting the model's significance. The experimental results indicate that the utilization of electrocoagulation as a treatment method for paper mill effluents has demonstrated superior efficacy compared to the adsorption technique.

Cationic surfactants influencing the enhancement of energy efficiency for perfluorooctanoic acid (PFOA) removal in the electrocoagulation-flotation (ECF) system

From an environmental perspective, approaching sustainability requires a fundamental conceptual shift from the wastewater treatment process toward integrated treatment systems that consider efficient and effective utilization. This study aims to investigate the effects of different surfactants on the removal of perfluorooctanoic acid (PFOA). We used cationic surfactants as both frothers and collectors in the electrocoagulation-flotation (ECF) method to improve the removal efficiency of PFOA. The results showed that, under a monopolar aluminum electrode and with an initial PFOA concentration of 0.25 mM, the ECF method with decyl-trimethyl-ammonium bromide (DTAB) was able to remove over 98% of PFOA within 10 min. Cationic surfactants with a similar linear alkyl chain shape to PFOA, but a longer chain length, are more effective at removing PFOA through the ECF process. The removal mechanism is thought to involve co-precipitation with aluminum hydroxides through Al–F bonding, co-flotation with cationic surfactants, and mixed micelle formation with cationic surfactants. The optimal conditions were tested in both synthetic and realistic wastewater matrices and produced similar results. It has the potential for real wastewater application. The energy yield (G50) of ECF with 5 mM DTAB is 497 g·kWh−1, superior to other treatments, and is an extremely energy-effective method for separating PFOA from wastewater.

Application of Electrocoagulation in Street Food Wastewater

Street food is commonly known as ready-to-eat and go foods and beverages, which is very famous in Thailand and other Asian countries. The street food daily generates high organic content and oily wastewater from washing and rinsing plates. The discharge of street food wastewater to public drains leads to a clogged drain line and unpleasant smell. In this work, an electrocoagulation (EC) system with monopolar aluminum (Al) electrodes was developed to treat two well-known street foods; Hainanese chicken rice (HC) and noodles and dumplings (ND). The results revealed that excellent chemical oxygen demand (COD) and fat, oil, and grease (FOG) removals were achieved under a specific operating condition (i.e., an electric current of 20 mA/cm2 and electrolytic time of 10 min). The initial COD of HC wastewater decreased from 40.6 g/L to 1.9 g/L, approximately 95%, whereas the FOG decreased from 310 mg/L to 50 mg/L, approximately 84%. The lower initial COD and FOG concentrations of ND wastewater obtained approximately 98% for COD removal and 86% for FOG removal; the effluent contained 0.5 g/L of COD and 25 mg/L of FOG. In addition, a relatively low Al concentration of 0.02–0.08 mg/L was observed in the effluents. The appropriate design factors together with ease of use and fast pollutants removal were significant advantages of this study; the EC system has potential to apply to on-site street food treatment.

Pollutants removals and energy consumption in electrochemical cell for pulping processes wastewater treatment: Artificial neural network, response surface methodology and kinetic studies

Response surface methodology (RSM) and artificial neural network (ANN) were used for modelling the electrocoagulation removal of pollutants from wastewater from pulping processes. The Design of Experiment based on central composite design was used to investigate the combine effects of pH (5.4–9.0), time (10–45 min) and current density (j) (9–39 mA/m2), on the removal efficiency of the Chemical Oxygen Demand (COD), Total Dissolve Solids (TDS) as well as Turbidity while Energy consumption (EC) was estimated per kg [COD] removed. The kinetics of the process was modelled with pseudo first and second order models. The removability of the COD, TDS and Turbidity were found to be 76.4, 57.0 and 97.13% with Energy consumption of 2.72 kWh/kg[COD] at optimal pH 6.83, current density of 22.06 mA/m2, and reaction time of 45 min. The ANN model gave a better fitting of the electrocoagulation process than the RSM, considering the R2 of 0.999 and MSE of 0.00753 obtained for the former. The pseudo first order model gave a better analysis of the kinetic data. The characterization of the sludge produced showed the potential of its use as adsorbent for organic or mineral contaminants and recovery of aluminium and other metals. Thus, electrocoagulation with monopolar aluminium electrodes displayed effective and a viable alternative for the pollutants removal from pulp processing wastewater.

Treatment of vinegar industry wastewater by electrocoagulation with monopolar aluminum and iron electrodes and toxicity evaluation.

We present electrocoagulation (EC) treatment results of vinegar industry wastewater (VIW) using parallel plate aluminum and iron electrodes, and analyze the toxicity of the treatment processes. Due to the chemical complexity of vinegar production wastewater, several parameters are expected to alter the treatment efficiency. Particularly, current density, initial pH, Na2SO4 as support electrolyte, polyaluminum chloride (PAC) and kerafloc are investigated for their effects on chemical oxygen demand (COD) removal. Following several treatment experiments with real wastewater samples, aluminum-plate electrodes were able to reach to a removal efficiency of 90.91% at pH 4, 10 mg/L PAC and an electrical current density of 20.00 mA/cm2, whereas iron-plate electrodes reached to a removal efficiency of 93.60% at pH 9, 22.50 mA/cm2 current density. Although EC processes reduce COD, the usefulness of the system may not be assessed without considering the resultant toxicity. For this purpose, microtox toxicity tests were carried out for the highest COD removal case. It was observed that the process reduces toxicity, as well as the COD. Consequently, it is concluded that EC with aluminum and iron electrodes is COD removal-wise and toxicity reduction-wise a plausible method for treatment of VIW, which has high organic pollutants.

Kajian Perbandingan Pemulihan Air Tasik: Pengentalan Kimia dan Elektrokoagulasi

Water scarcity worldwide has reached the alarming rate and received the greatest attention. The increasing of pressure attributed by world water demand had inspired researchers on use of alternative water sources such as wastewater, a new norm. However, it is a critical need to find out the proper treatment technique to treat the wastewater. In this study, the reclamation and reuse of lake water (wastewater source) was conducted through chemical coagulation and electrocoagulation processes. Aluminium sulphate Al2(SO4)3 was utilized in this study as the coagulant for chemical coagulation process. The dosage of Al2(SO4)3 was manipulated in the range of 2 mg/L - 8 mg/L to investigate the optimal Al2(SO4)3 dosage which brings to greatest removal of chemical oxygen demand (COD), colour, and turbidity from the collected wastewater sample. Whereas, electrocoagulation process was conducted in a lab-scale electrocoagulation reactor with two parallel monopolar aluminium electrodes. The electrocoagulation operation duration and DC power supply to the electrocoagulation reactor were varied in studying the performance of electrocoagulation process. Results obtained from this study depicted that both chemical coagulation and electrocoagulation processes were attractive for the treatment of lake water. However, chemical coagulation presented greater removal efficiency compared to electrocoagulation where it managed to remove COD, colour, and turbidity up to 93.04%, 93.86%, and 93.98%, respectively at the optimal Al2(SO4)3 dosage of 6 mg/L. Sweep coagulation which comprises the adsorption and entrapment of pollutant particles onto aluminium hydroxides was the major mechanism for flocs formation in chemical coagulation process. Besides, the percentage of removal for electrocoagulation process is due to the applied voltage and operation duration. The percentage removal of COD, colour, and turbidity were increased with the increment of DC power supply voltage and pro-longed the operation duration. Results shown that the highest percent of removal is achieved by electrocoagulation reactor operated at 10 V for 45 min in this study, where the percentage of removal for COD, colour, and turbidity was 73.91%, 92.98%, and 71.44%, respectively.

The Investigation of the Removal of Reactive Orange 16 DYE From Textile Wastewater by Using Electrocoagulation Process

Treatment of textile wastewater by electrocoagulation using Al and Fe electrodes was aimed in this study. Removal of color, chemical oxygen demand (COD) and turbidity from Remazol Brilliant Orange 3R Spec Gran (Reactive Orange 16) reactive textile dyestuff solutions was investigated in the study. For this purpose, effects of pH, current density, conductivity and operating time on process performance have been researched in an electrochemical reactor in which parallel connected monopolar aluminum and iron electrodes were used. Furthermore, operating costs depending on energy and electrode consumption were calculated. Optimum conditions for electrocoagulation process using aluminum electrode have been determined to be pH:6, current density:100A/m2, conductivity:500µS/cm and operating time:20min. 79,5% color, 60,2% COD and 91,9% turbidity removal efficiencies were obtained under these conditions. Optimum experimental conditions, for the iron electrode, have been determined to be pH:8, current density:75A/m2, conductivity:1000µS/cm and operating time:20min which resulted in 99,07% color, 42,26% COD and 91,89% turbidity removal efficiencies. Operational costs for aluminum and iron electrodes were calculated to be 1,489$/m3 and 0,504 $/m3 respectively.

Electrochemical Decolorization of Reactive Dye from Synthetic Wastewater by Mono-Polar Aluminum Electrodes System

Azo dyes are important groups of chromospheres having a particular structure in color-contaminated wastewater. In the present study, Reactive Red 198 (RR198) dye was chosen as a model of azo dyes group. Electrocoagulation technique as an effective and environmental-friendly process for wastewater treatment was applied. Hence; to determine the extent of decolorization process, the main different parameters such as pH (4-11), contact time (80 min), initial concentrations (25-400 mg/L), current density (1.9-23.1 mA/cm2), distance between gaps (1-4 cm), and effect of supporting electrolytes were evaluated. Results show that optimum conditions were 20 min of operation time, 1 cm distance between electrodes, pH equal to 4 and optimum initial concentration of dye equal to 100 mg/L as well as NaCl was identified as the best electrolyte. Under these optimum conditions and also at both aeration and non-aeration operating conditions decolorization efficiency was more than 90%. The results also demonstrated that total organic carbon removal efficiency as (TOC), during 120 min of contact time was about 80.95%. XRF analyses show that a large portion of deposited sludge (58.282%) was aluminum oxide.

Experimental study on electrocoagulation of textile wastewater by continuous horizontal flow through aluminum baffles

We investigated the feasibility of applying a continuous textile wastewater (TWW) treatment, which was accomplished by using electrocoagulation (EC) unit with zigzag horizontal flow across a series of mono-polar aluminum plate baffles. The effects of operating parameters such as current density (20-80 A/m2) and detention time (5-40 min) on turbidity, color, chemical oxygen demand (COD), total suspended solids (TSS) and total dissolved solids (TDS) removal were studied. The optimum conditions were determined as 60 A/m2 and 20min by monitoring zeta potential (ζ) of effluent. At the optimum conditions, removal efficiencies for turbidity (97.63%), color (87.87%), COD (93.3%), TSS (94.02%), and TDS (52.13%) were observed. Further, addition of 4mg/L of NaCl dose in the TWW modified conductivity suitably, thereby reducing electrical energy consumption per cubic meter of waste water and specific electrical energy consumption (SEEC) from 13.33 to 2.67kWh/m3, and 23.84 to 4.77kWh/kg Al, respectively. Comparing the EC with conventional coagulation process, EC showed better pollutant removal efficiency.

Electrocoagulation treatment of mine water from the deepest working European metal mine – Performance, isotherm and kinetic studies

Abstract Electrocoagulation was investigated for the removal of copper, silicon, manganese, aluminum, iron and zinc as well as sulfate from real mine water. Batch experiments with monopolar iron anode and stainless steel cathode as well as monopolar aluminum anode and stainless steel cathode were conducted separately to identify the best electrocoagulation conditions. The removal efficiency in mine water increased with increasing reaction time and increasing current density and the type of electrodes affected the metals and sulfate removal as could be shown by the adsorption isotherms. Copper and silicon were obeying a Langmuir isotherm with an iron anode, whereas they were following a Freundlich isotherm when an aluminum anode was applied. The aluminum electrode resulted in a higher Langmuir constant q max for all metals, while the iron electrode showed a better efficiency for removing the metals. This might be a result of the higher kinetic rate of iron compared to aluminum. Sulfate removal was better with aluminum electrodes resulting in removal rates of up to 41%, removing up to 5700 mg/L sulfate from the initial sulfate concentrations, whereas iron could only remove 3833 mg/L of sulfate from the real mine water. Furthermore, sulfate removal by aluminum electrode was faster compared to iron electrode.

Electrocoagulation of Landfill Leachate with Monopolar Aluminum Electrodes

In this paper, the removal of COD from landfill using aluminum electrode by the electrocoagulation method was investigated. The studies were run with the parallel plate monopolar aluminum electrodes and the effect of pH and current density on removal efficiency of COD and energy consumption were determined. The initial COD concentration of 4100 mg/L was reduced to 1763 mg/L with the removal efficiency of 57% at the current density of 75 mA/cm 2 and pH 5. Index Terms—Aluminium electrode, landfill leachate, treatment. I. I NTRODUCTION The most common and desirable integral indispensable solid waste management strategy is sanitary landfilling because it is simple and has low exploitation and capital costs. Up to 95% of the total municipal solid waste collected in the world is disposed of in landfills (1). Physico-chemical and biological conversions are occurred during the landfilling process and a result of conversions degregated organic compounds that soluble in rainwater are formed. Any liquid material that drains from land material is called leachate and it is highly toxic liquid with dissolving organic compounds, heavy metals and different soluble materials derived from the material that it has passed through. The composition of from a landfill depends on the age of the landfill and the type of waste that it contains. Leachate can potentially contaminate nearby surface and ground water if left untreated. Therefore landfills require close environmental monitoring during their design, operation, and long-term post-closure period. Leachate must be treated before discharging to environment. Many different physico-chemical techniques such as adsorption (2), chemical precipitation (3), coagulation/flocculation (4), chemical oxidation (5) and biological methods (6) have been being applied for the treatment of landfill leachate. Electrocoagulation, one of the most useful electrochemical methods, is a comparatively new technique for wastewater treatment. Also, electrocoagulation has some advantages such as, short retention time, easy operation, not needed the chemical addition, simple equipment, high sedimentation velocity and possibility of complete automation (7).

Improvement of NO3- Removal from Wastewater by Using Batch Electrocoagulation Unit with Vertical Monopolar Aluminum Electrodes

Improvement of NO3- Removal from Wastewater by Using Batch Electrocoagulation Unit with Vertical Monopolar Aluminum Electrodes

Fluoride removal by a continuous flow electrocoagulation reactor

Long-term consumption of water containing excessive fluoride can lead to fluorosis of the teeth and bones. Electrocoagulation (EC) is an electrochemical technique, in which a variety of unwanted dissolved particles and suspended matter can be effectively removed from an aqueous solution by electrolysis. Continuous flow experiments with monopolar aluminium electrodes for fluoride removal were undertaken to investigate the effects of the different parameters such as: current density (12.5–50 A/m 2), flow rate (150–400 mL/min), initial pH (4–8), and initial fluoride concentration (5–25 mg/L). The highest treatment efficiency was obtained for the largest current and the removal efficiency was found to be dependent on the current density, the flow rate and the initial fluoride concentration when the final pH ranged between 6 and 8. The composition of the sludge produced was analysed using the X-ray diffraction (XRD) spectrum. The strong presence of the aluminium hydroxide [Al(OH) 3] in the above pH range, which maximizes the formation of aluminium fluoride hydroxide complex [Al n F m (OH) 3 n− m ], is the main reason for defluoridation by electrocoagulation. The results obtained showed that the continuous flow electrocoagulation technology is an effective process for defluoridation of potable water supplies and could also be utilized for the defluoridation of industrial wastewater.

An empirical model for defluoridation by batch monopolar electrocoagulation/flotation (ECF) process

Excessive presence of fluoride concentration in community water supplies can cause fluorosis that affects the teeth and bones. Batch experiments with monopolar aluminium electrodes for fluoride removal were conducted and an empirical model is developed using critical parameters such as current concentration, electrode distance, and initial fluoride concentration. Fluoride ions were removed electrochemically from solution by electrocoagulation/flotation (ECF) process. The electrolytic dissolution of aluminium anodes in water produced aqueous Al 3+ species and hydrogen bubbles at the aluminium cathodes. The fluoride removal efficiency increases steadily with increasing current values from 1 to 2.5 A. In the batch monopolar ECF process, the optimal detention time ( d to) was found to be 55 min when the operational parameters including initial F − concentration, current value, and inter electrode distance were respectively kept at 10 mg/l, 1.5 A, and 5 mm. The experimental results showed that the rate constant ( K) for defluoridation by monopolar ECF process depends on the current concentration ( I/ V), electrode distance ( d) and initial fluoride concentration ( C 0). The Al 3+/ F − mass ratio is found to be not significantly different between monopolar and bipolar ECF systems. Overall, the results showed that the electrocoagulation technology is an effective process for defluoridation of water.