scholarly journals Simultaneous removal of Cd2+ and Zn2+ from aqueous solution using an upflow Al-electrocoagulation reactor: optimization by response surface methodology

2019 ◽  
Vol 79 (7) ◽  
pp. 1297-1308
Author(s):  
Vianey Ariadna Burboa-Charis ◽  
Eddy Jonatan Moreno-Román ◽  
Juan Antonio Vidales Contreras ◽  
Celestino García-Gómez

Abstract The presence of heavy metals in the environment has increased, and cadmium (Cd) and zinc (Zn) are considered to be among the most dangerous. An upflow Al-electrocoagulation reactor was used to remove Cd2+ and Zn2+ ions from aqueous media. The system consisted of perforated aluminum circular electrodes for fluid distribution with elimination of external agitation. The effect of different parameters, i.e. current intensity, electrolysis time, concentration of Cd2+ and Zn2+ ions and electrolytic support dose were optimized by response surface methodology. The results indicated that increasing the current intensity and the electrolysis time had a positive effect on the elimination efficiency of the pollutant ions. Likewise, increasing the dose of electrolytic support and decreasing the concentration of the pollutants improved the efficiency of the system. The optimal results were: current intensity of 0.4 A, electrolysis time of 40 min, ion concentration of 44.6 mg·L−1 and electrolytic support dose of 0.56 mg·L−1, with the maximum elimination percentages of 96 ± 3.8% and 96 ± 2.7% for Cd2+ and Zn2+, respectively. This study showed that the electrocoagulation process in an upflow electrocoagulation reactor could be successfully applied to remove pollutants from water.

Author(s):  
Negar Jafari ◽  
Afshin Ebrahimi ◽  
Karim Ebrahimpour ◽  
Ali Abdolahnejad

Introduction: Microcystin-leucine arginine (MC-LR) is a toxin with harmful effects on the liver, kidney, heart, and gastrointestinal tract. So, effective removal of MC-LR from water resources is of great importance. The aim of this study was to remove microcystin-LR (MC-LR) from aqueous solution by Titanium Dioxide (TiO2). Materials and Methods: In the present study, TiO2, as a semiconductor, was used for photodegradation of MC-LR under ultraviolet light (UV). The Response Surface Methodology was applied to investigate the effects of operating variables such as pH (A), contact time (B), and catalyst dose (B) on the removal of MC-LR. The MC-LR concentration was measured by high-performance liquid chromatography (HPLC). Results: The results showed that single variables such as A, B, and C had significant effects on MC-LR removal (pvalue < 0.05). In other words, increase of the contact time and catalyst dose had a positive effect on enhancing the removal efficiency of MC-LR, but the effect of pH was negative. The analysis of variance showed that BC, A2, and C2 variables had a significant effect on the MC-LR removal (pvalue < 0.05). Finally, the maximum removal efficiency of MC-LR was 95.1%, which occurred at pH = 5, contact time = 30 minutes, and catalyst dose = 1 g/l. Conclusion: According to the findings, TiO2, as a photocatalyst, had an appropriate effect on degradation of the MC-LR.


2014 ◽  
Vol 22 (8) ◽  
pp. 5831-5841 ◽  
Author(s):  
Jefferson E. Silveira ◽  
Juan A. Zazo ◽  
Gema Pliego ◽  
Edério D. Bidóia ◽  
Peterson B. Moraes

2017 ◽  
Vol 19 (2) ◽  
pp. 67-71 ◽  
Author(s):  
Ha Manh Bui

Abstract The COD removal efficiency from an instant coffee processing wastewater using electrocoagulation was investigated. For this purpose, the response surface methodology was employed, using central composing design to optimize three of the most important operating variables, i.e., electrolysis time, current density and initial pH. The results based upon statistical analysis showed that the quadratic models for COD removal were significant at very low probability value (<0.0001) and high coefficient of determination (R2 = 0.9621) value. The statistical results also indicated that all the three variables and the interaction between initial pH and electrolysis time were significant on COD abatement. The maximum predicted COD removal using the response function reached 93.3% with electrolysis time of 10 min, current density of 108.3 A/m2 and initial pH of 7.0, respectively. The removal efficiency value was agreed well with the experimental value of COD removal (90.4%) under the optimum conditions.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
P. Arulmathi ◽  
G. Elangovan ◽  
A. Farjana Begum

Distillery industry is recognized as one of the most polluting industries in India with a large amount of annual effluent production. In this present study, the optimization of electrochemical treatment process variables was reported to treat the color and COD of distillery spent wash using Ti/Pt as an anode in a batch mode. Process variables such as pH, current density, electrolysis time, and electrolyte dose were selected as operation variables and chemical oxygen demand (COD) and color removal efficiency were considered as response variable for optimization using response surface methodology. Indirect electrochemical-oxidation process variables were optimized using Box-Behnken response surface design (BBD). The results showed that electrochemical treatment process effectively removed the COD (89.5%) and color (95.1%) of the distillery industry spent wash under the optimum conditions: pH of 4.12, current density of 25.02 mA/cm2, electrolysis time of 103.27 min, and electrolyte (NaCl) concentration of 1.67 g/L, respectively.


2021 ◽  
Vol 9 (2) ◽  
pp. 470-479

The removal percentage of color from institutional wastewater was studied using an electrocoagulation process with different electrode combination at the anode and cathode. This was done by considering operational parameters such as pH at (3, 6 and 9), current at (0.03A, 0.06A and 0.09A) and reaction time at (20, 40 and 60 minutes). When electrode combined in the form of Al-Al (anode-Cathode/Cathode-Anode) and Fe-Fe (anode-Cathode/Cathode-Anode) the percentage removal of color was up to 95.50% and 97.24% respectively. On the other hand around 98.03% and 91.95% of color was removed when Al-Fe (Anode-Cathode) and Fe-Al (Anode-Cathode) combined at pH 9 and 60 minutes of reaction time respectively. Central composite design from response surface methodology was used up to analysis the statistical and mathematical data based on experimental results such as the model was significant for all electrode combinations. Similarly a quadratic model was used for further study of operational effects on the removal (%) of color from institutional wastewater. The value of coefficient of the determination (R2) also indicated the model was a good fit as well as optimization was done by Response Surface Methodology.


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