Bisnan, Ysabel Mari M. Sir Cristopher B. Parmis
BSESSDP-T-1A-T August 3, 2022
Critique Paper
I. Introduction
The study Removal of nickel, copper, zinc and chromium from synthetic and industrial
wastewater by electrocoagulation by Dermentzis, K., Christoforidis, A., & Valsamidou, E. (2010)
is about the wastewaters from electroplating industries contain high amounts of heavy metal ions.
This became a concern because they are non-biodegradable, highly toxic, and probably
carcinogenic. Examples of the heavy metals found in rinse waters are chromium, nickel, copper,
cadmium, and zinc. The focus of this paper is the Electrocoagulation process. Electrocoagulation
is an electrochemical water treatment process that destabilizes and aggregates contaminant
particles such as heavy metals by using an electrical charge from an anode and a cathode. This
process separates flocculated materials from water.
II. Research Design/Methodology
This study employs a quantitative - quasi-experimental research design that utilizes a
natural experiment. A quantitative research design measures and establishes a connection
between different variables using numerical data. A natural experiment usually takes place in
laboratories or in field experiments. Some researchers use random assignments but natural
experiments are not considered to be true experiments because they are observational in nature
(Thomas, 2020). Researchers can exploit this event after the fact to study the effect of the
treatment because the researchers have no control over the independent variable.
III. Interpretation of Findings
The electrocoagulation process was conducted in the pH range of 4-8. The removal efficiency of
the metals after 20 minutes is as follows, >97% for Cu, Ni, Zn, and >80% for Cr. The current
density determines the coagulant dosage rate, the floc growth, and the bubble production rate and
size. The removal rates of all studied metals increased, with increasing current density. When the
concentration is higher at the beginning, the electrocoagulation process is more effective than at
the end of the operation when the concentration is low.
IV. Significance of the study
The results of this study will benefit the residents near the electroplating industries that release
wastewater that contains heavy metals which are highly toxic and dangerous for human health.
This study will also benefit the environment as it will remove the heavy metals from the
wastewater to achieve reusable water for other purposes. For the researchers, this study will help
them assess the efficiency of the electrocoagulation process in removing heavy metals.
V. Conclusion
The efficacy of electrocoagulation is at best with the use of aluminum electrodes. The highest
removal capacity was achieved in the pH range of 4-8. The results also showed that the removal
rate of the heavy metals increased as the current density also increased. It was also observed that
the electrocoagulation process is faster than the chemical coagulation where it takes several hours
to complete and higher coagulant dosage. Therefore, electrocoagulation is more efficient in
removing metallic pollutants from wastewater.
VI. References
Electrocoagulation in Water Treatment - What Is it? (2019, August 10). Water Vision.
Thomas, L. (2022, July 21). Quasi-Experimental Design | Definition, Types & Examples. Scribbr.
GCU. (2021, November 22). Quantitative Research Design Methods for Writing Dissertations.
BSESSDP-T-1A-T August 3, 2022
Critique Paper
I. Introduction
The study Removal of nickel, copper, zinc and chromium from synthetic and industrial
wastewater by electrocoagulation by Dermentzis, K., Christoforidis, A., & Valsamidou, E. (2010)
is about the wastewaters from electroplating industries contain high amounts of heavy metal ions.
This became a concern because they are non-biodegradable, highly toxic, and probably
carcinogenic. Examples of the heavy metals found in rinse waters are chromium, nickel, copper,
cadmium, and zinc. The focus of this paper is the Electrocoagulation process. Electrocoagulation
is an electrochemical water treatment process that destabilizes and aggregates contaminant
particles such as heavy metals by using an electrical charge from an anode and a cathode. This
process separates flocculated materials from water.
II. Research Design/Methodology
This study employs a quantitative - quasi-experimental research design that utilizes a
natural experiment. A quantitative research design measures and establishes a connection
between different variables using numerical data. A natural experiment usually takes place in
laboratories or in field experiments. Some researchers use random assignments but natural
experiments are not considered to be true experiments because they are observational in nature
(Thomas, 2020). Researchers can exploit this event after the fact to study the effect of the
treatment because the researchers have no control over the independent variable.
III. Interpretation of Findings
The electrocoagulation process was conducted in the pH range of 4-8. The removal efficiency of
the metals after 20 minutes is as follows, >97% for Cu, Ni, Zn, and >80% for Cr. The current
density determines the coagulant dosage rate, the floc growth, and the bubble production rate and
size. The removal rates of all studied metals increased, with increasing current density. When the
concentration is higher at the beginning, the electrocoagulation process is more effective than at
the end of the operation when the concentration is low.
IV. Significance of the study
The results of this study will benefit the residents near the electroplating industries that release
wastewater that contains heavy metals which are highly toxic and dangerous for human health.
This study will also benefit the environment as it will remove the heavy metals from the
wastewater to achieve reusable water for other purposes. For the researchers, this study will help
them assess the efficiency of the electrocoagulation process in removing heavy metals.
V. Conclusion
The efficacy of electrocoagulation is at best with the use of aluminum electrodes. The highest
removal capacity was achieved in the pH range of 4-8. The results also showed that the removal
rate of the heavy metals increased as the current density also increased. It was also observed that
the electrocoagulation process is faster than the chemical coagulation where it takes several hours
to complete and higher coagulant dosage. Therefore, electrocoagulation is more efficient in
removing metallic pollutants from wastewater.
VI. References
Electrocoagulation in Water Treatment - What Is it? (2019, August 10). Water Vision.
Thomas, L. (2022, July 21). Quasi-Experimental Design | Definition, Types & Examples. Scribbr.
GCU. (2021, November 22). Quantitative Research Design Methods for Writing Dissertations.
