scholarly journals Electrocoagulation coupled with adsorption for effective removal of eosin yellow and nigrosin dyes in aqueous solution

2019 ◽  
Vol 11 (1) ◽  
pp. 97-106
Author(s):  
Vinothkumar K ◽  
Sugumaran T. ◽  
Venkateshwari S

This paper deals with the study of suitability and efficiency of electrocoagulation (EC) coupled with adsorption to remove dye from synthetic dye solution. The EC cell consisted of mild steel (MS)/copper plates as electrodes and dye solution as electrolyte. The effects of operating time, concentration, supporting electrolyte, current density and pH have been investigated to find out the optimum operating conditions for EC. The concentration of dye was successfully reduced (EY) ?50% and Nigrosin dye ?99% during EC under the optimum operating conditions of initial concentration 0.5ppm, 20ppm, current density 0.04 A/cm2, 0.015 A/cm2, supporting electrolyte 4g, 4g, electrolysis time 20min, 10min, Eosin Yellow and Nigrosin dye respectively, the removal efficiency of the dyes were found 46.69% and 99%, electrical conductivity were 125.0 S/m and 105.7 S/m and TDS left in the EC treated solution were 82.0 and 69.3 ppt. Further proceedings with solution for adsorption process help to improve the dye removal. Results of the studies are electrical conductivity 20 S/m and TDS 30 ppt for EY, for Nigrosin 64.2 S/m and 42.1 ppt.

2012 ◽  
Vol 4 (2) ◽  
pp. 304-309 ◽  
Author(s):  
A. K. Chopra ◽  
Arun Kumar Sharma

The present investigation observed the effect of operating time, current density, pH and supporting electrolyte on the removal efficiency of Turbidity (TD) and Biochemical oxygen demand (BOD) of secondarily treated sewage (STS) using electrochemical process. A glass chamber of 2 litre volume was used for the experiment with two electrode plates of aluminum, each having an area of 125 cm2 and 2 cm distance apart from each other. The treatment showed that the removal efficiency of TD and BOD increased to 87.41 and 81.38 % respectively with theincrease of current density (1.82 -7.52 mA/cm2), time (5 - 40 mins.) and different pH (4-8) of the STS. The most effective removal efficiency was observed around the pH 7. Further, 0.5 g/l NaCl as a supporting electrolyte for electrochemical treatment of STS was found to be more efficient for an increase to 95.56 % and 86.99 % for the removal of TD and BOD at 7.52 mA/cm2 current density in 40 mins. respectively. The electrode and energy consumption was found to vary from 2.52 x10-2 to 10.51 x10-2 kg Al/m3 and 2.76 kwh/m3 to 45.12 kWh/m3 depending on the operating conditions.The kinetic study results revealed that reaction rate (k) increased from 0.0174 to 0.03 min-1 for TD and 0.0169 to 0.024 min-1 for BOD with increase in current density from 1.82 to 7.52 mA/cm2.


Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1720
Author(s):  
Sabrina Campagna Zignani ◽  
Massimiliano Lo Faro ◽  
Stefano Trocino ◽  
Antonino Salvatore Aricò

NiFe electrodes are developed for the oxygen evolution reaction (OER) in an alkaline electrolyser based on an anion exchange membrane (AEM) separator and fed with diluted KOH solution as supporting electrolyte. This study reports on the electrochemical behaviour of two different NiFe-oxide compositions (i.e., Ni1Fe1-oxide and Ni1Fe2-oxide) prepared by the oxalate method. These catalysts are assessed for single-cell operation in an MEA including a Sustainion™ anion-exchange membrane. The electrochemical polarization shows a current density of 650 mA cm−2 at 2 V and 50 °C for the Ni1Fe1 anode composition. A durability test of 500 h is carried out using potential cycling as an accelerated stress-test. This shows a decrease in current density of 150 mA cm−2 mainly during the first 400 h. The performance achieved for the anion-exchange membrane electrolyser single-cell based on the NiFeOx catalyst appears promising. However, further improvements are required to enhance the stability under these operating conditions.


2014 ◽  
Vol 50 (2) ◽  
pp. 198-209 ◽  
Author(s):  
Malika Aoudjehane ◽  
Mohamed Elghazali Benatallah

A procedure of electrocoagulation (EC) using iron electrodes has been used for the treatment of the wastewaters produced by the Beni-Tamou dairy in Algeria. The effect of the operating conditions, such as the current intensity, the electrolysis time, the pH of the solution and the electrical conductivity, on the removal efficiency of chemical oxygen demand (COD) and the total suspended solids (TSS) has been studied. An inter-electrode distance of 1 cm has been maintained constant during the tests. It has been found that an increase in electrolysis time and current density improved the treatment significantly, albeit with a greater consumption of energy as well as an increased electrode consumption. The results of the electrocoagulation treatment under various operating conditions show that the optimal efficiency has been obtained under the following conditions: 60 minutes of electrolysis, a current density of 200 A/m2, a pH 8, an electrical conductivity of 4.72 mS/cm and a consumption energy of 13.57 kWh/m3. Under these conditions, the removal efficiency for the COD and TSS parameters is 93.26 and 99.3%, respectively. The optimal treatment conditions of dairy wastewaters have resulted in final COD and TSS concentrations of 41.5 and 27 mg/L, respectively, values that are conform to industrial liquid effluents discharge norms.


2013 ◽  
Vol 68 (10) ◽  
pp. 2220-2227 ◽  
Author(s):  
Elif Senturk

This paper investigates the treatment of zinc-cyanide electroplating rinse water using an electrocoagulation process (ECP). The effects of operating parameters such as electrode material, current density (2.5–40 A/m2), operating time (0–60 min), initial pH (5–12) and electrode connection mode (monopolar parallel (MP-P), monopolar series and bipolar series) on the ECP were evaluated to find the optimum operating conditions. At 20 A/m2, 60 min, the highest removal efficiencies were obtained with 85 and 99% for Fe and 64 and 33% for Al electrodes, for cyanide and zinc, respectively. The optimum operating conditions were found to be 30 A/m2 and 40 min, for the Fe electrode at the original pH (9.5) of the rinse water. Considering efficiency and economy, the MP-P connection mode was determined as the optimum connection mode.


2019 ◽  
Vol 79 (6) ◽  
pp. 1134-1143 ◽  
Author(s):  
Ada Azevedo Barbosa ◽  
Ramon Vinicius Santos de Aquino ◽  
Naiana Santos da Cruz Santana Neves ◽  
Renato Falcão Dantas ◽  
Marta Maria Menezes Bezerra Duarte ◽  
...  

Abstract This work investigated the efficiency of polyethylene terephthalate (PET) as support material for TiO2 films in the photocatalytic degradation of red Bordeaux and yellow tartrazine dyes. The optimum operating conditions were determined by a factorial design, which resulted after 180 min of treatment in degradations of 99.5% and 99.1% for the UVC/H2O2/TiO2Sup and solar/H2O2/TiO2Sup systems, respectively. For the kinetic study, the experimental data fitted to the pseudo-first-order model and the calculated kinetic constants (k) values were 0.03 min−1 for the UVC/H2O2/TiO2Sup system and 0.0213 min−1 for the system solar/H2O2/TiO2Sup. It was verified that TiO2 supported in the PET remained with high degradation efficiency even after five cycles of reuse, indicating a good stability of the photocatalyst in the support. A significant reduction of TOC content was also observed along the reaction time. The phytotoxicity bioassay with Lactuca sativa demonstrated that after treatment with UVC/H2O2/TiO2Sup and solar/H2O2/TiO2SUP, an increase in IC50 and consequently lower toxicity was observed.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Y. S. Mohammad ◽  
E. M. Shaibu-Imodagbe ◽  
S. B. Igboro ◽  
A. Giwa ◽  
C. A. Okuofu

Modeling of adsorption process establishes mathematical relationship between the interacting process variables and process optimization is important in determining the values of factors for which the response is at maximum. In this paper, response surface methodology was employed for the modeling and optimization of adsorption of phenol onto rice husk activated carbon. Among the action variables considered are activated carbon pretreatment temperature, adsorbent dosage, and initial concentration of phenol, while the response variables are removal efficiency and adsorption capacity. Regression analysis was used to analyze the models developed. The outcome of this research showed that 99.79% and 99.81% of the variations in removal efficiency and adsorption capacity, respectively, are attributed to the three process variables considered, that is, pretreatment temperature, adsorbent dosage, and initial phenol concentration. Therefore, the models can be used to predict the interaction of the process variables. Optimization tests showed that the optimum operating conditions for the adsorption process occurred at initial solute concentration of 40.61 mg/L, pretreatment temperature of 441.46°C, adsorbent dosage 4 g, adsorption capacity of 0.9595 mg/g, and removal efficiency of 97.16%. These optimum operating conditions were experimentally validated.


Author(s):  
Thanh Son Le ◽  
Khải Cao Lê ◽  
Hà Thị Nguyễn ◽  
Linh Tuấn Đoàn ◽  
Anh Thị Đoàn

In this paper, an electrocoagulation reactor was set up to investigate the ammonium removal in Nam Son landfill leachate. The research focused on studying several factors that affect to the ammonium removal namely current intensity, operating time, initial pH and electrode materials. Mono-polar electrocoagulation reactor was conducted in a batch system with iron electrodes and 1.8 L leachate. The research indicated that current intensity and operating time are directly proportional with NH4+ treatment performance. When applied current increased from 1 to 4A, the NH4+ removal percentage went up from 14.03 to 24.99% after a 1 hour treatment. The effect of initial pH in range of 5 to 10 has showed that the best NH4+ treatment efficiency in neutral and mild alkaline conditions. It is noticeable that iron electrodes had higher NH4+ removal than aluminum one during nearly the first 40 min, however this trend has been reversed later with the advantage belonging to aluminum anode. The optimum operating conditions found are aluminum electrodes, applied current of 3A, electrolysis time of 60 min, raw pH of 8, resulting in NH4+ treatment performance of approximately 24%. As a result, the electrocoagulation method is not really effective in NH4+ removal and might be applied as a pre-treatment.


2021 ◽  
Vol 16 (3) ◽  
pp. 393
Author(s):  
Syamsul Hidayat ◽  
Sri Yulianti ◽  
Dian Anggreini ◽  
Syamsul Bahtiar

Study of nickel leaching using sulfuric acid and phosphoric acid on the selectivity of low-grade laterite nickel ore under atmospheric conditions has been successfully carried out. In this study, the laterite nickel leaching process was carried out by varying the solution concentration and operating time. The concentrations of sulfuric acid and phosphoric acid solutions were varied at 5 M and 6 M concentrations, while the operating time was varied at 4 hours and 6 hours. For other operating conditions, it is kept constant with an operating temperature of 90 ℃, pulp density 15% w / v, particle size ≤ 200 mesh. After that, the analysis stage was carried out using an atomic absorption spectroscopy (AAS) tool to determine the nickel content in the sample. The results showed that the highest nickel recovery was obtained at the concentration of 5 M sulfuric acid solution of 2.60% and 5 M phosphoric acid of 2.59% with the optimum operating time at 4 hours of operating time.


2020 ◽  
Vol 1008 ◽  
pp. 213-221
Author(s):  
Rehab M. Ali ◽  
Mohamed A. Hassaan ◽  
Marwa R. Elkatory

Granular activated carbon (GAC) is utilized as an adsorbent for the malachite green (MG) dye removal from aqueous solutions. The GAC was characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) to realize the GAC chemical and physical features effects on the adsorption efficiency. Batch adsorption processes were carried out with different variables like pH, GAC dose, initial MG concentration and time. The response surface methodology (RSM) was used to design the experiments, model the adsorption process, optimize the operating conditions and predict the response. A 24 full factorial central composite design (CCD) was performed for the experimental design and the analysis of the results. Analysis of variance (ANOVA) was employed to determine the significance of the factors and explore the interaction between the various experimental parameters. An empirical model was derived to correlate the experimental results and predict the behavior of the GAC for the adsorption process. The model showed a good agreement with the experimental results of R2 = 0.9968 and evidenced that the optimum operating parameters are pH 10, 2 g GAC/L, 200 mg/L of MG initial concentration and 113 min adsorption time for complete removal of MG.


2013 ◽  
Vol 5 (2) ◽  
pp. 475-481 ◽  
Author(s):  
Arun Kumar Sharma ◽  
A. K. Chopra

The present investigation observed the effect of current density (CD), operating time (OT), inter electrode distance (IED), electrode area (EA), initial pH and settling time (ST) using Fe-Fe electrode combination on the removal of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) from biologically treated municipal wastewater (BTMW) of Sewage Treatment Plant (STP). The maximum removal of COD (92.35%) from BTMW was found with the optimum operating conditions of CD (2.82 A/m2), OT (40 mins.), IED (0.5 cm), EA (160 cm2), initial pH (7.5) and ST (60 min.), while the maximum removal of BOD (84.88%) was found with the ST (30 min.) at the same operating conditions. There was no need of pH adjustment of the BTMW during ET as the optimal removal efficiency was close to the pH of 7.5. Under optimal operating conditions, the operating cost was found to be 54.29 Rs./m3 / 1.08 US$/m3 in terms of the electrode consumption (78.48 x 10-5 kg Al/m3 ) and energy consumption (108.48 Kwh/m3).


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