Penilaian Kerja Kursus Semester 2,
Sidang Akademik 2023/2024
Projek Mini
AMJ 21503 Geoenvironmental Engineering [Kejuruteraan Geopersekitaran]
Masa: May 2024
GROUP 8
No. GROUP MEMBERS MATRIC NUMBER
1 PUVENASWARI ANNAMALAI 221132044
2 NUR ASYIQIN BINTI AHMAD KHIDHIR 221132037
3 LEE YOU 221133455
CLASS : UR6526002
LECTURER'S NAME : DR. TENGKU NURAITI BINTI TENGKU IZHAR
SUBMISSION DATE : 24 MAY 2023
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TABLE OF CONTENTS
CHAPTER CONTENTS PAGES
1 1.1 INTRODUCTION 3-4
1.2 PROBLEM STATEMENT 4
1.3 OBJECTIVE 5
1.4 SCOPE OF PROJECT 5
2 2.1 TECHNOLOGY DESCRIPTION 6-7
2.2 ADVANTAGES OF ELECTROKINETIC REMEDIATION TECHNOLOGY 8
2.3 DISADVANTAGES OF ELECTROKINETIC REMEDIATION TECHNOLOGY 8
3 3.1 TRANSPORT MECHANISMS OF ELECTROKINETIC REMEDIATION 9-13
4 4.0 SYSTEM DESIGN AND IMPLEMENTATION 14-17
4.1ELECTROKINETIC REMEDIATION (EK) WITH PERMEABLE REACTIVE 14-16
BARRIER (PRB)
4.2 MECHANISM ANALAYSIS 17
5 CONCLUSION 18
6 REFERENCE 19-20
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CHAPTER 1
1.0 INTRODUCTION
The term "soil" refers to a particular body of solids (natural matter and minerals), gases, and fluid
that occurs on the surface of the land, takes up room, and is defined by either of the following:
layers, or horizons, that are distinguishable from the underlying material due to augmentations,
misfortunes, moves, and changes of energy and matter, or the capacity to support established plants
in a common habitat. The limits of soil are where it meets air, shallow water, living plants, or plant
materials that have already begun to rot. Regions are not regarded as having soil if the ground is
permanently submerged in water that is too deep (often more than 2.5 meters) for the growth of
established crops.
Soil contamination refers to the presence of hazardous substances or pollutants in the soil at levels
that exceed natural background levels and pose risks to human health, ecosystems, or
environmental quality. Soil contamination can result from various sources, including industrial
activities, agricultural practices, waste disposal, urbanization, and natural processes. Common
contaminants found in soil include heavy metals (such as lead, arsenic, mercury, and cadmium),
petroleum hydrocarbons, organic chemicals (such as pesticides, herbicides, and industrial
solvents), radioactive substances, and asbestos. Soil contamination can have adverse effects on
human health through direct exposure (e.g., ingestion, inhalation, dermal contact) or indirect
exposure (e.g., consumption of contaminated crops or groundwater). Contaminated soil can also
impact ecosystems by harming plants, animals, and microorganisms, disrupting soil fertility and
nutrient cycling, and contaminating surface water and groundwater resources. Preventing soil
contamination is also crucial and involves implementing pollution prevention measures, adopting
environmentally sustainable practices, managing waste properly, and adhering to regulatory
standards and guidelines. Soil contamination poses significant challenges to environmental
protection and public health, highlighting the importance of effective management and
remediation efforts to mitigate its impacts.
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Soil remediation refers to the process of restoring contaminated land to a condition suitable for its
use, whether for agriculture, construction, landscaping, or other purposes. Remediating soil
contamination often involves a combination of techniques and technologies, including soil
excavation and removal, soil washing, electrokinetics, bioremediation, phytoremediation,
chemical treatment, and containment or capping. The selection of a remedial approach depends on
factors such as the type and extent of contamination, site conditions, regulatory requirements, and
cost considerations. The remediation plan begins with the objectives, strategies, and technologies
that will be used to clean up the contaminated land. There are a number of suitable techniques that
can be used to overcome the problem of pollution, not only to clean up the pollution but also to
minimize its impact on the environment.
1.2 PROBLEM STATEMENT
Nowadays, there are many human activities that will pollute the land around the activity area. This
is because most human activities will use chemicals/toxic substances or other pollutants in
industry, agriculture or mining that can cause soil pollution. In our case, the soil has been polluted
by chemicals which have chemical compounds such as hydrocarbons, PCBs and heavy metals
involved.
Based on our case, the plant was destroyed in the fire and not rebuilt. When the property is sold,
'declaration of uncontaminated land' is required. Investigations show arsenic contamination from
improper storage or disposal was found. This show, the soil was contaminated by an inorganic
chemical, Arsenic. Arsenic may be present in industrial emissions, effluents, and waste streams,
leading to contamination of soil and surrounding ecosystems.
Arsenic is a known carcinogen and can cause serious health effects even at low concentrations. in
humans will be through exposure routes, such as ingestion, inhalation, and skin contact, and
determine appropriate risk management measures to protect public health. To overcome the
problem, the chemicals need to be processed first before the land is rebuilt to reduce soil pollution
in the industry. There are many soil remediation technologies that can be used to treat soil
pollution. The appropriate method to overcome this problem is ex-situ methods of ‘Electrokinetic
remediation' to treat contaminated soil.
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1.3 OBJECTIVES
1. To study the technology and fundamental process of electrokinetic method of soil
remediation.
2. To propose the design a model of electrokinetic with permeable reactive barrier on
contaminated soil remediation.
3. To analyse the mechanism of electrokinetic with permeable reactive barrier.
1.4 SCOPE
The ex-situ electrokinetic method is a soil remediation technology that uses an electric field to
remove contaminants from excavated soil, including organic compounds, radionuclides, and heavy
metals. This procedure involves placing the contaminated soil into a soil box or reactor chamber
that has been carefully built, and then inserting electrodes into the soil. After that, an electric field
is created between the electrodes, which causes the impurities to move in the direction of the
electrodes according to their charge. The electrokinetic approach in ex situ can be;
• Removal of various pollutants
The ex-situ electrokinetic method can remove a wide range of pollutants from contaminated soils,
including heavy metals, organic compounds, and radionuclides. It is particularly effective for low-
permeability soils that are difficult to treat using other methods.
• Improving soil properties
In addition to removing contaminants, the ex-situ electrokinetic method can also improve the
engineering characteristics of problematic soils, such as increasing the strength and reducing the
compressibility of clay soils.
• Combination with other techniques
The ex-situ electrokinetic method can be combined with other remediation techniques, such as soil
washing, phytoremediation, and permeable reactive barriers, to enhance the removal efficiency
and broaden the scope of application.
• Potential for ex-situ applications
The ex-situ electrokinetic method is particularly suitable for applications where the contaminated
soil can be excavated and treated in a controlled environment, such as a specially designed reactor
chamber.
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CHAPTER 2
2.1 TECHNOLOGY DESCRIPTION
Electrokinetic remediation, also known as electrokinetics, electromigration, electrorestoration,
electroremediation and electroosmosis, removes the contaminants from soils by applying an
electrical potential. This technology involves applying an electrical potential across contaminated
soil through a pair of electrodes located at the anode and cathode. Due to a variety of processes,
contaminants are transported toward the electrodes. The contaminant-laden liquids are then
removed from the electrodes. Figure 1 illustrates how the electrokinetic system is implemented
under in-situ conditions.
Figure 1: Electrokinetic system
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The system consists of a minimum of two electrodes buried underground and connected
to a power supply. The electrodes are located a certain distance apart and are encased by reservoirs
or wells. The electrodes are called anodes and cathodes, the anode being the positively charged
component and the cathode the negatively charged component. In simple terms the anode attracts
contaminants that have a negative charge, and the cathode attracts positively charged
contaminants. In remediating unsaturated soils, water is injected into electrode wells or reservoirs.
Removal of contaminants can be achieved by pumping the contaminated water in the reservoirs or
wells or by electroplating, precipitation, coprecipitation at the electrodes. Removal of
contaminants from the soils can be optimized by using enhancement solutions, such as weak acids,
surfactants, and complexing agents, at the reservoirs.
In the field, electrodes are arranged according to the desired effect. The electrodes may
be placed in a two long rows of anodes and cathodes if the contamination is narrow and long. If
the contamination is rather large, alternating rows of anodes and cathodes may be needed.
Electrodes can be arranged to prevent only the migration of contaminants or their removal.
This technique can be used to remediate soils with high clay or humic content. It can be
also used in heterogeneous soils. It can be also be used on both saturated or unsaturated soils.
Electrokinetics can be used to treat a wide range of contaminants, such as heavy metals,
radionuclides, and organic contaminants.
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2.2 ADVANTAGES OF ELECTROKINETIC REMEDIATION
TECHNOLOGY
1. Applicable to low permeability soils and heterogeneous soils.
2. Applicable for a wide range of contaminants; metal contamination can be moved because
of its charge, while noncharged contaminants can be moved with the induced flow.
3. Flexible to use as both in-situ and ex-situ technology.
4. Less expensive than other remediation techniques.
5. Tailored to site specific contamination.
2.3 DISADVANTAGES OF ELECTROKINETIC REMEDIATION
TECHNOLOGY
1. Electrolysis reactions near the electrodes may change the soil pH significantly from anode
to the cathode, leading to complex geochemical interactions.
2. Buried metal objects may short -circuit the current path, changing the voltage gradient,
which will affect the extraction rate.
3. Acidic conditions and electrolytic decay can corrode materials used in anode.
4. There are stagnant zones between wells where the rate of migration is slow.
5. VOCs will probably be stripped from the soil and will therefore increase the soil vapor
concentration.
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CHAPTER 3
3.0 FUNDAMENTAL PROCESSES
Applying an electrical potential to soil induces the transport of water and the contaminants. The
main transport mechanisms included electroosmosis, electromigration, electrophoresis, and
diffusion. These transport mechanisms are affected by physical-chemical processs: electrolysis,
adsorption-desorption, precipitation-dissolution, and oxidation-reduction.
3.1 TRANSPORT MECHANISMS OF ELECTROKINETIC REMEDIATION
3.1.1 ELECTROOSMOSIS
Electroosmosis is the advective transport or movement of water or moisture under an electric field.
Typically, the surfaces of fine-grained soil particles are negatively charged. Cations in the pore
water will align themselves along the negatively charged surfaces. Water molecules then align
themselves around the excess cations. When there are no excess cations, water molecules will
orient themselves around the negatively charged surface of the soil, forming a boundary layer. The
water molecules closet to the soil surface are held tighter, due to electrical attraction, and they are
free to move in the double layer.
During electrokinetic remediation on the application of an electrical field, water molecules that are
positively charged will move toward the cathode. The soil’s zeta potential will affect the movement
of water molecules in the double layer. The zeta potential is defined as the potential between the
stationary and movable parts of the double layer surrounding the soil particles. The zeta potential
is typically negative for clays and silts that are saturated and range from 10 to 100 mV(Probstein
and Hicks, 1993). When the zeta potential is negative, electroosmosis flow will move toward the
cathode. Electoosmotic flow can be reversed to the anode if the zeta potential becomes positive,
which can occur if the contaminant concentration is high. The transport of contaminants included
by electroosmotic flow depends on the pore water viscosity, ion concentration, temperature,
dielectric constant, and the mobility of ions(Mitchell, 1993). The quantity of water moved per unit
time (qe) by electroosmotic flow can be quantified by the Helmholtz equation,
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where E the electrical potential, D the dielectric constant, ζ the zeta potential, ղ the viscosity, and
L the length of the specimen. When compared with hydraulic gradients, the flow due to electric
gradients is a few orders of magnitude higher in fine-grained soils (Mitchell, 1993). This is also
supported by Acar and Alshawabkeh (1993), who concluded that electroosmosis is effective only
in fine-grained soils with micrometer-sized pores.
3.1.2 ELECTROMIGRATION
Electromigration is the movement of ions or charged species toward their respective electrodes.
Anions move toward the anode, and cations toward the cathode. Electromigration occurs 10 times
faster than advective transport caused by electroosmosis (Acar and Alshawabkeh 1993). During
electrokinetic remediation, electromigration may be the dominant transport mechanism for ions
and charged species. The electromigration rate is a function of ionic mobility, valence of the
species, and total electrolyte concentration (Acar and Alshawabkeh 1993). The velocity of ions in
solution due to electromigration is quantified by the equation (Lindgren et al., 1993)
Where I is the applied current (A), the ion velocity, A the total cross sectional area(m2), PW the
pore water resistivity (Ω . cm), τ the tortuosity, θ the volumetric moisture content (cm3/cm3).
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3.1.3 ELECTROPHORESIS
Electrophoresis is the movement of charged colloids to their respective electrodes, similar to
electromigration. However, this process is ineffective if the soil is tightly packed, thus restricting
movement of the colloids.
3.1.4 DIFFUSION
Diffusion is the spreading of contaminants due to a concentration gradient. Fick’s first law
describes the diffusion of any charged species that are under chemical potential. Diffusion depends
on the porosity and tortuosity of the porous medium and the molar concentration of the species.
The diffusion rate (Udiff) equation is
Where is the mobility, R the gas constant, T the temperature, c the concentration gradient, and
c the concentration of contaminant in moles. During the electrokinetic remediation, diffusion is
slow compared to the electromigration rate. The diffusion rate is typically one to two orders of
magnitude slower than the electromigration rate. Therefore, this does not have a significant role in
transporting the contaminants in the electrokinetic remediation process.
3.1.5 ELECTROLYSIS
When an electric field is applied, electrolysis reactions occur at the anode and cathode. Near the
anode, hydrogen ions (H+) and oxygen gas (O2) are generated. Reactions at the cathode generate
hydroxyl ions (OH-) and hydrogen gas (H2). These reactions can be written as follows:
The rate of production of H+ and OH- ions depends on the current applied. Secondary reactions are
also possible, such as the reduction of H+ to H2, or the reduction of a metal to a lower valence state.
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Oxygen and hydrogen gases are generated due to electrolysis, which can alter the redox
conditions of the porewater. An acid front is generated due to the formation of H+ ions at the anode,
and a base front is generated at the cathode due to the formation of OH- ions. The pH at the anode
drops to approximately 2, while at the cathode it rises to 12, depending on the current applied. H+
ions tend to move toward the cathode and the OH- toward the anode. The movement of these ions
occurs due to electromigration as well as diffusion caused by concentration gradients. The mobility
of H+ ions greater than OH- ions, because of a smaller ionic radius. This causes the acid front
migration to occur twice as fast as the base front migration. The extent of migration of the acid
front depends on the acid buffering capacity (capacity to neutralize the acidity) of the soil. In a
low-buffering-capacity soil, such as kaolinite, the acid front migration can occur easily. However,
in a high-buffering-capacity soil such as glacial till, the H+ ions are consumed to neutralize
buffering constituents in the soil (Reddy et al.,1997).
The acid front will desorb and dissolve typical cations (Ni and Cd) from the soil surface,
or if precipitated, will increase cation removal. If the contaminants are anionic [Cr(VI)], the acid
front increases the adsorption and hinders contaminant removal. The pH changes induced by
migration of the acid and base fronts will affect the zeta potential of the soil, therefore affecting
the electroosmotic flow (Eykholt and Daniel,1994).
3.1.6 ADSORPTION-DESORPTION
Adsorption is the partitioning of the solute contaminants from the pore fluid to the soil surface.
Soil surfaces are typically negative in charge; however, this depends on the pH of the soil. The pH
at which soil has net zero charge is called the point of zero charge (PZC). If the pH of the pore
water is below the PZC, adsorption of anions will be significant. When the pH is above the PZC,
adsorption of cations will be significant. Adsorption depends on the type of contaminant (anionic
or cationic), soil type, surface of area of the soil, surface charge on the soil, concentration of
cationic species, presence of organic matter and carbonates in the soil, and pore fluid charateristics.
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Desorption, the opposite of adsorption, is the partitioning of contaminants from the soil surface
to the pore fluid. If the pH of the pore water is below the PZC, the desorption of cations will be
significant. When the pH is above the PZC, sorption of cations will occur. When applying an
electric field in low-buffering soils, low-pH conditions are present at the anode due to electrolysis
reactions, and high-pH conditions are present at the cathode. Cationic adsorption and anionic
desorption occur at the cathode, while anionic adsorption and cationic adsorption occur at the
anode.
3.1.7 PRECIPITATION-DISSOLUTION
During application of an electric field, the pH of the soil changes. Precipitation-dissolution
reactions are pH dependent. Precipitation occurs when the amount of ions equals or exceeds the
solubility product of that solid. Dissolution is the opposite of precipitation. Because of the pH
changes experienced during the electrokinetic process, contaminants may be precipitated or
dissolved depending on the contaminant’s location. When contaminants precipitate, their removal
by electrokinetic remediation is hindered; however, when the contaminants are dissolved, they can
be removed easily.
3.1.8 OXIDATION-REDUCTION
Redox conditions are also altered during the electrokinetic process (Chinthamreddy and
Reddy,1999). Electrons that are removed at the anode causes oxidation, and the electrons that are
pushed in at the cathode cause reduction. Near the cathode, metal cations reduce and then
precipitate. Gases produced during electrolysis can also cause oxidation-reduction if not allowed
to escape the anode and cathode. Some metals may be present in different valence states,
depending on the redox conditions. The valence state controls the solubility of the metal and may
have an effect on removal of the metal.
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CHAPTER 4
SYSTEM DESIGN AND IMPLEMENTATION
Case Study
At a site, Supervolmansalt D (Na2HASO4.7H2O) was used to impregnate timber. The plant was
destroyed in a fire and was not rebuilt; when the property was sold, a 'statement of unpolluted soil'
was needed. An investigation showed arsenic contamination from improper storage or disposal
was found. The contamination of heavy clay was 2 m deep and 10m x 10m in size in one area and
1m x 10m x 5m for a total of volume of polluted soil equal to 250 m3. Arsenic 3concentrations for
the entire area were 110 ppm on average.
4.1 ELECTROKINETIC REMEDIATION (EK) WITH PERMEABLE
REACTIVE BARRIER (PRB)
Arsenic has attracted broad concerns due to its high toxicity and strong carcinogenicity to human
beings and animals. Traditionally, the remediation technologies of arsenic contaminated soil
include solidification/stabilization, phytoremediation, soil leaching, and electrokinetic (EK)
remediation. Among these methods, EK is known as a promising technique for in situ remediation
because it can remove multiple-heavy metals simultaneously [5,6]. Remediation of pollutants in
soil by EK is considered to promote the ionization of pollutants and drive ionic pollutants to leave
the soil in a designated direction, but this process may be hindered to cause compromised
remediation effect. Coupling EK with permeable reactive barriers (PRB), especially when the PRB
is installed in an appropriate location, could effectively enhance the remediation result [7–9]. As
the arsenic could be transferred into and captured by the reactive materials in PRB through
electromigration, electrodialysis, and electrophoresis [10,11]. Researches have shown that the
arsenic removal of the combined EK-PRB was 1.6–2.2 times greater than that of EK alone [12].
Moreover, heavy-metal removal was also dependent on the type of PRB materials [13]. In this case
study, EK-PRB with Fe/Mn/C-LDH materials as PRB filler was employed to remediate the
arsenic-contaminated soils.
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4.1.1 Preparation of Fe/Mn/C-LDH
1. The Fe/Mn/C-LDH material was prepared by using bamboo as bio-templates. The bamboo
slices were boiled in 5% dilute ammonia water at 100 °C for 6 h, dried at 80 °C for 24 h
and then annealed in a muffle furnace at 600 °C for 3 h.
2. Then, the bamboo charcoals were soaked in concentrated HNO3 at 110 °C for 2 h, washed
with deionized water and dried at 80 °C to obtain bamboo charcoal bio-templates.
3. Afterwards, the bamboo charcoal bio-templates were immersed in deionized water, a
mixed solution of Fe and Mn (Fe/Mn molar ratio = 2:1) with a total concentration of 1 M
was added.
4. Subsequently, the solution pH was adjusted to 11.5 by the mixture solution of 3.2 M NaOH
and 0.1 M Na2CO3.
5. Finally, the mixed solution was continuously stirred for 2 h, aged at 60 °C for 24 h, filtered
and freeze-dried to obtain Fe/Mn/C-LDH material.
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4.1.2. Construction and Operation of EK-PRB Device
In this case study an electrokinetic with permeable reactive barrier (EK-PRB) remediation device
was used as shown in Figure 2, which was mainly composed of a polymethyl methacrylate
chamber (300 cm × 100 cm × 50 cm), including electrode, direct current (DC) power supply and
PRB filler. Graphite plates (100 cm × 10 cm × 50 cm) were served as both anode and cathode, and
the Fe/Mn/C-LDH material was used as the PRB filler. The contaminated soil was excavated from
2m depth and dried naturally after removal of stones and plant residues. For each 96 h run, 600 g
of the arsenic-contaminated soil was placed in the soil chambers. The voltage used in this treatment
device is 3V/cm.
Figure 2: Electrokinetic with permeable reactive barrier (EK-PRB) remediation device.
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4.2 MECHANISM ANALAYSIS
FIGURE 3
Figure 3 shows the possible arsenic removal mechanisms in soil by Electrokinetic with Permeable
Reactive Barrier (EK-PRB). In the EK-PRB system, arsenic existed in soil solution in the form of
anion. Additionally, exchangeable and carbonate fractions of As could exchange ions with −OH
or −OH2 on the surface of soil particles like Fe, Al and Mn oxides, so as to be strongly adsorbed
on the coordination site of metal ions. The pH value of soil changed under the action of electric
field. Higher pH was observed near the cathode, which caused the metal precipitation near the
cathode, thereby blocking soil pores and hindering the remediation process. Additionally, it was
more conducive to the desorption of arsenic on soil particles with the increase of pH value. Besides,
electric current had a dominant effect on temperature changes, which caused the soil moisture
content to rise with the decreasing of pH. The increase of pH could also suppress the formation of
arsenic compounds such as H2AsO4 − or H3AsO4, which declines the efficiency of electrokinetic
remediation. Various arsenic ions in soil interstitial water separated from the soil and entered the
aqueous phase. Meanwhile, electroosmotic flow and electromigration were also carried out under
the influence of electric drive. Arsenic ions migrated to the anode through electromigration, and
to the cathode with the action of electroosmotic flow, the arsenic distribution was concordant with
the voltage drops distribution, which indicated the voltage loss played a critical role in arsenic
migration. In this process, arsenic ions would enter PRB and then react with Fe/Mn/C-LDH
through a series of reactions, such as electrostatic adsorption, ion exchange, surface functional
group complexation, physical adsorption, etc., to achieve better removal of arsenic from soil.
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CHAPTER 5
CONCLUSION
A novel remediation technique by coupling electrokinetic (EK) with the PRB of Fe/Mn/C-LDH
composite was applied for the remediation of arsenic-contaminated soils. The Fe/Mn/C-LDH PRB
fillers synthesized by using bamboo as a template retained the porous characteristics of the original
bamboo. From this study, its proven that the electrokinetic with permeable reactive barrier
technology is better and works more efficient in the removal soil contaminants such as heavy
metals than the electrokinetic method without any combination of technology. Besides that, we
get to analyze and discover the mechanism of the electrokinetic with permeable reactive barrier in
the removal of Arsenic contaminants in the soil. In the mechanism itself, we get to know what are
the ions attracted in each of the electrodes, anode and cathode. This technology also proves that
the duration taken for the soil remediation is shorter than the electrokinetic without the
combination of permeable reactive barrier. Overall, we can conclude that the electrokinetic with
permeable reactive barrier is one of the most effective methods of soil remediation.
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REFERENCES
1. Kim, S., Park, J., Lee, Y., Lee, J., & Yang, J. (2005). Application of a new electrolyte
circulation method for the ex situ electrokinetic bioremediation of a laboratory-prepared
pentadecane contaminated kaolinite. Journal of Hazardous Materials, 118(1–3), 171–
176. https://doi.org/10.1016/j.jhazmat.2004.10.016.
2. Chen, Y., Zhi, D., Zhou, Y., Huang, A., Wu, S., Yao, B., Tang, Y., & Sun, C. (2021).
Electrokinetic techniques, their enhancement techniques and composite techniques with
other processes for persistent organic pollutants remediation in soil: A review. Journal of
Industrial and Engineering Chemistry/Journal of Industrial and Engineering Chemistry -
Korean Society of Industrial and Engineering Chemistry, 97, 163–172.
https://doi.org/10.1016/j.jiec.2021.03.009.
3. Hari D.Sharma, Krishna R.Reddy, May 2004, 1st Edition, Geoenvironmental
Engineering: Site Remediation, Waste Containment, and Emerging Waste Management
Technologies, published by Wiley.
4. Zhu, Z.; Zhou, S.; Zhou, X.;Mo, S.; Zhu, Y.; Zhang, L.; Tang, S.;Fang, Z.; Fan, Y.
Effective Remediation of Arsenic-Contaminated Soils by EK-PRB of Fe/Mn/C-LDH:
Performance, Characteristics, and Mechanism. Int. J. Environ. Res.Public Health 2022,
19, 4389. https://doi.org/10.3390/ijerph19074389
5. Jeon, E.K.; Ryu, S.R.; Beak, K. Application of solar-cells in the electrokinetic
remediation of As-contaminated soil. Electrochim. Acta 2015, 181, 160–166.
6. Kim, H.A.; Lee, K.Y.; Lee, B.T.; Kim, S.O.; Kim, K.W. Comparative study of
simultaneous removal of As, Cu, and Pb using different combinations of electrokinetics
with bioleaching by Acidithiobacillus ferrooxidans. Water Res. 2012, 46, 5591–5599.
19 | P a g e
7. Dong, Z.Y.; Huang, W.H.; Xing, D.F.; Zhang, H.F. Remediation of soil co-contaminated
with petroleum and heavy metals by the integration of electrokinetics and biostimulation.
J. Hazard. Mater. 2013, 260, 399–408.
8. Vignola, R.; Bagatin, R.; Alessandra De Folly, D.; Flego, C.; Nalli, M.; Ghisletti, D.;
Millini, R.; Sisto, R. Zeolites in a permeable reactive barrier (PRB): One year of field
experience in a refinery groundwater-part 1: The performances. Chem. Eng. J. 2011, 178,
204–209.
9. Gibert, O.; De Pablo, J.; Cortina, J.L.; Ayora, C. In situ removal of arsenic from
groundwater by using permeable reactive barriers of organic matter/limestone/zero-valent
iron mixtures. Environ. Geochem. Health 2010, 32, 373–378.
10. Nasiri, A.; Jamshidi-Zanjani, A.; Darban, A.K. Application of enhanced electrokinetic
approach to remediate Cr-contaminated soil: Effect of chelating agents and permeable
reactive barrier. Environ. Pollut. 2020, 266, 115197.
11. Zhou, H.; Liu, Z.; Li, X.; Xu, J. Remediation of lead (II)-contaminated soil using
electrokinetics assisted by permeable reactive barrier with different filling materials. J.
Hazard. Mater. 2021, 408, 124885.
12. Ching, Y.; Tzu-Shing, C. The mechanisms of arsenic removal from soil by electrokinetic
process coupled with iron permeable reaction barrier. Chemosphere 2007, 67, 1533–
1542.
13. Chung, H.I.; Lee, M.H. A new method for remedial treatment of contaminated clayey
soils by electrokinetics coupled with permeable reactive barriers. Electrochim. Acta
2007, 52, 3427–3431.
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