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DOI: 10.1002/celc.201402071
Electrokinetic Remediation Technique: An Integrated
Approach to Finding New Strategies for Restoration of
Saline Soil and to Control Seawater Intrusion
Shadi H. Hamdan, Gomotsegang Fred Molelekwa, and Bart Van der Bruggen*[a]
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Many applications of electrokinetic remediation have focused
on the removal of heavy metals. However, the application of
electrokinetic technology in salt removal from contaminated
soils and groundwater has not been extensively explored.
Given the current global challenge and the impact of soil and
groundwater salinity, it is tempting to suggest that the research community should apply this technology to generate
in-depth knowledge for determining the feasibility and efficiency of electrokinetic remediation in salt removal, particularly
in addressing seawater intrusion in coastal aquifers, which is
creating growing challenges in the freshwater supply, mainly
in coastal and arid regions, in view of growing populations,
economic and industrial growth, and climate change. This
Review shows that there is a need to begin formulating
1. Introduction
It is known that the global demand for freshwater is rising
while the challenges for the supply of fresh water are increasing by the day. One of the threats to the availability of freshwater today is soil salinity. Soil salinity refers to the state of accumulation of soluble salts in the soil.[1] The most common
soluble salts in soils are cations (e.g. sodium, potassium, and
calcium) and anions (e.g. chloride, sulfate, and nitrate).[2] Soil
salinity is categorized into primary and secondary salinities. Primary salinity is mainly caused by natural processes, owing to
a high salt content of the parent material or in groundwater,
whereas secondary salinity occurs as a result of anthropogenic
activities such as irrigation practices,[3] which account for about
20 % of the world’s irrigated areas,[4] and over extraction of
groundwater, especially from coastal aquifers.[5] One of the
main causes of salinity in coastal areas is seawater intrusion,
which is the landward incursion of seawater through subsurface movement.[6] Seawater intrusion can degrade water quality to levels that exceed acceptable drinking and irrigation
water standards and endanger future water exploitation in
coastal aquifers. This problem is intensified by large population
growth, notably, because 70 % of the world population occupies coastal areas.[7] Secondary salinity seems to be taking the
upper hand. Szabolcs reiterated that about 100 000 km2 of irrigated land are abandoned each year, mainly owing to the adverse effects of secondary salinization and alkalinization.[8]
However, Gupta and Abrol warned that the availability of accurate data concerning salt-affected lands around the world are
rather scarce,[9] which, thus, suggests that the information
should be read or used with some degree of caution. They
argued that there is a lack of systematic surveys; there is a continuous change in the extent of salinization, owing to secondary salinization or seawater intrusion and the differences be[a] S. H. Hamdan, G. F. Molelekwa, Prof. B. Van der Bruggen
Department of Chemical Engineering
Process Engineering for Sustainable Systems (ProcESS), KU Leuven
W. de Croylaan 46, 3001 Leuven (Belgium)
Fax: (+ 32) 16-322991
E-mail: bart.vanderbruggen@cit.kuleuven.be
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemelectrochem.org
a knowledge base about categories of materials, efficiencies,
and limitations. Furthermore, the viability of this technology in
the real field suggests a need to gain more insight into electrokinetic applications in this area. The versatility of electrokinetic
remediation in different settings is demonstrated in this
Review, as is its capability to address diverse remediation challenges. The available literature is critically assessed; novel and
improved electrokinetic remediation and the important trends
in this field are outlined. The Review aims to summarize the
evolution and current status of electrokinetic remediation research with a view of starting a debate around the possibility
of applying it as a pretreatment mechanism to control seawater intrusion.
tween countries’ approaches for detecting and classifying saltaffected soils.[10] However, some valuable information regarding
global salinity is available. Statistics relating to the extent of
salt-affected areas vary according to authors, though generally,
estimates are close to 10 000 000 km2, which represent about
7 % of the earth’s continental surface area or approximately
10 times the size of a country such as Venezuela or 20 times
the size of France.[4, 11] In addition to these naturally salt-affected areas, about 770 000 km2 have been salinized as a consequence of human activities, with 58 % of these areas concentrated in irrigated lands.[4] On average, 20 % of the world’s irrigated lands are affected by salts, but in countries such as
Egypt, Iran, and Argentina, this figure increases to more than
30 %.[4]
Various intervention measures to address the problem of salinity have been developed and implemented. Among these,
electrokinetic remediation is worth special attention. This technology has been explored for many decades to understand
the various aspects of soil remediation.[12] The first electrokinetic remediation configuration was used in a field trial by Puri
and Anand in 1936 for the removal of sodium hydroxide from
soil.[13]
Electrokinetic processing of soil involves the application of
a low-density direct current through a wet-soil mass, which results in the development of electrical, hydraulic, and chemical
gradients. Thus, an electric field is created by inserting electrodes into the contaminated site and passing the current
through it, which makes the contaminant particles mobile in
the soil media.[14]
Following the work of Puri and Anand in 1936, many applications of electrokinetic remediation have been introduced,
and they have been focused mainly on the removal of heavy
metals (e.g. lead, chromium, arsenic, zinc, cadmium, copper,
and mercury),[15] particularly in low permeability soils and also
on the remediation of groundwater at waste disposal and spill
sites for which conventional methods such as pump-and-treat
fail.[14, 15b, 16] However, this shift has resulted in biased attention
for research in the field of salt removal. For instance, the removal of excess amounts of soluble salts, especially in sandy
soils, has not received the necessary attention. The real reason
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for this shift (i.e. from salt recovery to treatment of heavymetals-contaminated soils) is not known to the authors, however, it can be presumed that in those early years, the issue of
salt removal and recovery did not make good economic sense.
The issue of salt contamination was not as serious as it is
today; the issue of heavy metal contamination was considered
more serious, and given that their effects were already better
known, they needed immediate attention. Heavy metals in
Shadi Hamdan obtained his civil-engineering degree in 2002 from the IUGUniversity in Gaza. He worked as a project engineer in the environmental field
until 2006. He obtained his MSc in
water resources engineering (2008)
from the IUPWARE program organized
by the Katholieke Universiteit Leuven
and the Vrije Universiteit Brussels
(sponsored by VLIR). Currently, he is
a PhD candidate at KU Leuven. His research is focused on electrokinetic
technology as an innovative methodology to control seawater intrusion in coastal aquifers.
Prof. Bart Van der Bruggen is a chemical engineer by training. In 2004, he
obtained a permanent position at KU
Leuven in Belgium (professor since
2009), where he leads a group of 20
PhD students in the research division
“Process Engineering for Sustainable
Systems” within the Department of
Chemical Engineering. He has authored over 220 publications in international journals (current h-factor: 39)
and 25 book chapters. He has received
several national and international prizes in recognition of his work,
including the Prince Sultan Bin Abdulaziz International Prize for
Water.
Gomotsegang Fred Molelekwa holds
a National Certificate in Water Pollution Control (University of Johannesburg), an ND in Public Health, an NHD
in Environmental Health, a BTech in
Environmental Health (Tshwane University of Technology), and an MSc in
Environmental Management (University of the Free State). He is working towards a PhD in chemical engineeering
at KU Leuven, focusing on the synthesis of low-cost filtration membranes
for production of potable water for rural communities in developing countries. He has also worked the Provincial and Local Governments of South Africa, Tshwane University of Technology and the
UN Basel Convention Regional Centre.
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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larger quantities can be dangerous,[17] and their accumulation
in soil and plants has potential human health risks.[18] Nowadays, the problem of salinity is huge; it has never been more
serious, particularly the issue of seawater intrusion with its
complexity.[6] The question is, does electrokinetics remediation
have a role to play in addressing the problem of salinity with
respect to seawater intrusion? This paper reviews the available
literature in electrokinetic remediation. It further outlines novel
and improved electrokinetic remediation processes and important trends. The Review aims to summarize the evolution and
current status of electrokinetic remediation research with
a view of starting a debate around the possibility of applying
electrokinetic remediation as a pretreatment mechanism for
the control of seawater intrusion. The following electrokinetic
remediation research categories are considered: configuration/
application, performance, optimization (enhancement), and
hybridization.
2. Configurations
2.1. Approaches
Many articles have written extensively about the configuration
and application of electrokinetic remediation. Therefore, the
focus in this section is directed towards two important approaches based on the different electrokinetic phenomena.
Furthermore, the conditions under which electrokinetic remediation is applied and the environment in which it is performed are also explained. The first approach is the removal of
electrically charged ions by electromigration in which ions
move under an applied electric direct current (DC) field. Lageman, Pool, and Seffinga of Geokinetics developed this approach commercially for practical applications in the late
1980s.[19] The concept of this approach relies on circulating
electrolytes by inducing an electrical DC into the soil through
arrays of anodes and cathodes placed across a plume. The
electrodes are not in direct contact with the soil but hang in
ion-permeable wells in which the contaminants are removed
as they approach the fence. This approach functions as a soil
remediation and a barrier technology.[19a, 20] The second approach can act as a barrier, and it relies on the movement of
pore water through the electrical double layer created on
porous media by creating a countergradient flow to stop the
migration of contaminant under the hydraulic flow.[16c, 19a, 21]
Electrokinetic remediation technology can be applied in separate ways. For instance, Lageman et al. (2005) classified the application of electrokinetic remediation into four groups,
namely: in situ and ex situ, batch ex situ, electrokinetic fence,
and electrokinetic biofence.[19a]
In situ and ex situ applications of electrokinetic remediation
have been demonstrated. For instance, in the Netherlands,
four rows of electrodes have been installed at a galvanizing
plant in an in situ reclamation project of soil contaminated
with nickel and zinc.[22] During in situ application of electrokinetic remediation for which electrodes were placed directly in
the ground, contamination was recovered with minimal disturbance to the site. Batch ex situ configuration was applied
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on a contaminated media that was treated ex situ after it was
transported to a mobile batch facility.[23] Another configuration,
the electrokinetic fence, was introduced by Lageman, Pool,
and Seffinga in 1989.[24] This configuration consists of a row of
DC electrodes installed in the ground to halt the migration of
contaminated groundwater from a point source.[23, 24] Yeung
and Mitchel investigated the potential of electrokinetic fencing
as an effective measure to stop migration of contaminants
under a hydraulic gradient.[25] Figure 1 shows a scheme for the
Figure 1. Scheme of the electrokinetic barrier: a) One row of anodes–cathodes approach, contaminant ions deflected towards the oppositely charged
electrode. Adapted from Ref. [29]. b) Two rows of electrodes approach to
prevent contaminant migration. Adapted from Ref. [30].
different electrokinetic barrier approaches. They applied it on
clay with experiments aimed at mobilizing sodium chloride.[25, 26] Furthermore, in 2005, Lynch et al. evaluated the application of electrokinetic fence in one- and two-dimensional (1D
and 2D) configurations. Their results showed that such an application can significantly reduce heavy-metal contamination
spreading against a hydraulic gradient.[20b] Electrokinetic fences
have been successfully applied in a coupled configuration, in
which an electric field is applied perpendicular to the main direction of groundwater flow and contaminants can be removed at the electrodes solution.[20b, 27] The electrokinetic biofence (EBF), whereby a row of filters of nutrients are placed upstream of the chain of electrodes,[28] has also been tested. In
this configuration, groundwater transports the dissolved nutrients towards the electrodes under the influence of the electrical field, which thus disperses the electrically charged nutrients homogeneously between the electrodes and enhances
biodegradation in the process.[29] Such an EBF, which consisted
of 3 cathodes, 2 anodes, and 24 infiltration wells, was applied
as a pilot project in a chemical laundry at Wildervank in the
Netherlands to enhance the biodegradation of volatile organic
compounds in groundwater at the zone of the fence by dispersing dissolved nutrients upstream of the fence. The infiltra 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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tion wells were filled with nutrients and electron donors. These
compounds dissolved in the groundwater and were homogeneously dispersed through the soil under the influence of the
induced electrical field.[27, 28]
2.2. Closed and Open Electrokinetic Systems
Eid et al. have performed experimental laboratory tests to
study the nitrate gradient developed under the influence of an
electrical potential in two systems.[31] The first had no flow
(closed system) and different electrode materials were used
(i.e. carbon, copper, and stainless steel),[31] and the second had
flow opposite to the direction of the electrical current and
carbon electrodes were used.[32] In the closed system, results
show that the electrokinetic process effectively concentrates
and retains nitrate close to the anode by using either carbon
or copper electrodes. However, less movement of NO3 is reported if stainless steel electrodes are used.[31] The results also
indicate that the rate of nitrate migration is higher with closer
electrode spacing and with a lower initial nitrate concentration. Additionally, significant cleanup of Na + is observed after
application of an electrical current for 12 h in 70 % of the soil
sample close to the cathode.[31] In an open system, the results
reveal that electromigration can be an effective measure for
concentrating and retaining nitrate close to the anode in saturated sandy soil even under a hydraulic gradient.[31, 32] Moreover, in both systems the results show that the movement of
NO3 through a soil column is influenced by the pH gradient
developed during the electrokinetic process.[31] However, these
experiments are conducted on the basis of an uncontrolled
acid/base front that is generated during the experiments, and
this results in increased energy costs, especially if the current
density is constant.[31] In this regard, certain conditioning precautions are usually taken to control the large developed pH
to enable practical and economical applications.[31]
2.3. Electrode Materials and Configuration
An important aspect of electrokinetic remediation is electrode
configuration. Electrode configurations influence the active
area of the electric field, which is the major driving force to
remove metal contaminants toward oppositely charged electrodes.[33] Additionally, the spacing between same polarity electrodes has a significant role in cost calculations and process efficiency.[33a, b] Alshawabkeh et al. reported that the spacing between same-polarity electrodes is as significant in cost calculations and in process effectiveness as it is between anodes and
cathodes for 1D applications.[33b] Kim et al. investigated the influence of electrode configurations on the efficiency of electrokinetic remediation by applying four different setups of electrode in a rice field near a zinc refinery plant located in
Janghang, South Korea.[33c] They found that there was a correlation between the electrical energy consumption and both the
area covered by the electrodes and the current density under
a constant voltage gradient. They also advised that the
groundwater flow and soil temperature should be monitored
during the remediation process and that the configuration
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should be considered to minimize unnecessary transport of
contaminants. On the basis of theoretical modeling, Alshawabkeh et al. suggested that a 2D electrode configuration has
a smaller inactive electric field area than a 1D electrode configuration, as shown in Figure 2.[33b] Other research groups investigated 2D configurations such as rectangular or hexagonal.[34]
trode materials and their role in soil remediation has been
overlooked.[35] Aspects such as mechanical, thermal, economic,
and corrosion resistance require more research for optimal selection and removal efficiency.[36] It has been generally accepted that cost effective and inert materials should be used such
as carbon, graphite, and platinum.[37] In basic electrochemistry,
metallic anodes made of iron, for example, could be oxidized
and dissolved due to electrolysis, and this results in the introduction of corrosive products into soil mass, which can cause
contamination of unwanted metals in treated soil.[38] However,
for economic reasons it is more appropriate to use much
cheaper and reliable electrodes such as titanium, stainless
steel, and even plastic electrodes.[37a] Electrodes named dimensionally stable anodes (DSAs) have been widely used in the
wastewater treatment industry. A major advantage of these
electrodes is their long lifetime under conditions of oxygen
evolution and organic electro-oxidation.[39] RuO2 j Ti is one type
of DSA electrode that has been successfully used in the electrokinetic remediation process of soils contaminated with hydrocarbons, whereby the removal efficiency was over 90 % in
the anodic section and over 75 % in the middle and cathodic
section after 48 h treatment.[39b] Prez-Corona et al. evaluated
IrO2–Ta2O5 j Ti electrodes in the electroremediation of hydrocarbon-contaminated soil. They developed polarization curves in
three ways to obtain the density corrosion current to the standard. Their results were high compared to other
publications.[39b]
Figure 2. Estimation of the area of ineffective electric field for different electrode configurations: a) 1D parallel electrodes configuration and b) 2D centralized cathode with surrounding anodes. Adapted from Ref. [33b].
3. Applications
Zhang et al. applied both a horizontal and a vertical electrical
field in four operation modes in a bench-scale experiment for
remediation of chromium-contaminated soil. In their findings,
the 2D crossed electrical field appeared to be a promising and
practical method for the remediation of soils contaminated
with heavy metals.[34b] Kim et al. conducted a study to improve
salt removal from saline soil on pilot scale by an electrokinetic
remediation system with electrodes in a hexagonal configuration.[34a] This configuration shows that the removal efficiency is
enhanced because the inactive area of the electric field is significantly minimized, which is not the case with a 1D configuration. However, the 2D configuration may require a longer operation time, which would unfortunately lead to more energy
consumption and unexpected geochemical changes related to
changes in pH, and this could negatively affect crop production.[34a] They therefore recommend further development of an
optimal electrokinetic remediation for higher removal efficiencies while reducing electric energy consumption and promoting crop production by using pH-control mechanisms.[34a]
Another aspect of interest is the type of electrode materials
used in electrokinetic remediation. There has been much discussion about the importance of the choice of materials and
the strength and limitations of certain materials if used in electrokinetic remediation. However, the proper selection of elec 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
The application of electrokinetic remediation is further described to show the versatility of this technology in soil remediation. Electrokinetic remediation can be applied to treat polluted soils, sediments, and groundwater with inorganic species
such as lead, cadmium, chromium, mercury, zinc, iron, magnesium, and other soluble salts,[11,16f, u, 40] organic species such as
phenol,[16v, 41] and radionuclides.[42] Yeung has reported different
potential applications of electrokinetics in hazardous waste site
remediation. He stated that these applications can be applied
individually or combined with others.[12] Some researchers observed that electrokinetic remediation is often applied at the
laboratory scale and that it is rarely applied to the real field.[33c]
However, given that this technology was introduced for soil remediation in the late 1930s,[13] it has only been drawing interest over the last decade,[12, 43] and hence, much focus is on laboratory-scale trials.[40b, 43d, e] Lately, there has been slow progress
to the pilot scale. For instance, in Korea, the electrokinetic remediation technique became known in the mid-1990s.[43e] Various studies, which included enhanced electrokinetic remediation techniques, modification of electrokinetic remediation reactors/systems, hybrid electrokinetic remediation technology,
and monitoring/modeling of electrokinetic remediation processes, pilot-scaled and field application of electrokinetic remediation have been conducted in different cases to provide
higher performance and understanding of the processes used
to remove contaminants[43e] by using this technology. Among
these studies, a pH conditioning electrokinetic remediation
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field study at a shooting area was conducted to remove heavy
metals (e.g. lead and copper) from soil. In 2011, Kim et al. controlled catholyte pH by using nitric acid to enhance the mobility of heavy metals, and they implemented two types of electrokinetic remediation configuration (i.e. rectangular and hexagonal). It was intended to be scaled up in the future,[43e]
which thus suggests that the project could have yielded positive results.
Another interesting ex situ project was performed in Korea
to investigate the electrokinetic removal of salts from saline
soil.[38] One of the objectives of the project was to ensure reduced electrical energy consumption while using a pulsed current that periodically repeated on/off settings by using a DC
power supply.[38] The results of this project showed that the
pulse-powered electrokinetic remediation system reduced the
electrical energy consumption to more than one half of that of
conventional power and that the system effectively prevented
pH changes in the soil and electrode corrosion. A smaller
amount of cations was removed in the pulse power system;
however; this was beneficial for the growth of plants.[38]
4. Enhanced Electrokinetics
Every technology is expected to perform to its optimum level.
However, sometimes technologies perform below their optimum level, and electrokinetic remediation technology is no exception; it thus necessitates the use of enhancement techniques. If only water is used as the electrodes solution, the
process is known as “unenhanced electrokinetic remediation”.
If enhancement techniques are used, the process is referred to
as “enhanced electrokinetic remediation”.[44] As a remediation
technology, electrokinetic remediation is expected to ensure
complete removal of contaminants that are being removed;
however, some inefficiency in the removal of contaminants by
electrokinetic remediation has been reported.[45] Notably, the
success of electrokinetic remediation is highly dependent on
the ability of the contaminants to migrate. In that regard, it is
essential that the contaminant species are desorbed from the
soil and converted into a soluble or dissolved state.[46]
Fundamentally, soil is composed of three phases (air, water,
and soil solid particles)[47] and if soil is contaminated, it becomes a multiphase material with different chemical states.[47]
Generally, these coexisting phases and chemical states of contaminants are contaminant specific, dynamic, and reversible,
and they depend on environmental conditions, particularly the
pH of the environment. Thus, they are interrelated with the geochemical processes associated with the electrochemical remediation processes, which require proper control to enhance the
remediation process.[46a, 47] If a DC electric field is applied across
the soil through electrodes inserted in the soil profile, it results
in electrokinetic flow processes, electrochemical reactions, and,
more importantly, geochemical processes.[47] The geochemical
processes include generation of pH gradient; change in the z
potential of soil particle surfaces; change in direction of electro-osmotic flow, sorption, and desorption of contaminants
onto/from soil particle surfaces; buffer capacity of soil; complexation; redox reactions; and interactions of these process 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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es.[47] Geochemical processes may enhance or retard electrokinetic remediation processes.[47]
Yeung and Gu reported three objectives of using enhancement techniques for electrokinetic remediation to improve the
removal efficiency and guarantee an optimal performance:[46b]
1) To solubilize the adsorbed contaminants from the soil matrix
and keep them in a mobile state to facilitate their migration
toward electrodes. 2) To maintain the soil pH level within a desirable level to favor the electro-osmotic flow and/or the ionic
mobility of contaminants, depending on the soil texture. 3) To
assist degradation or transformation of contaminants simultaneously or sequentially.[46b] The last objective can also be significant in addressing regulatory constraints on injecting the selected enhancement solutions into the subsurface, high cost,
and longer treatment time and long-term stability, which are
some disadvantages of the first two objectives.[44] Enhancement strategies that have been developed and applied are
classified into three inter-related principal methodologies,
namely, 1) contaminants solubilizing methods, 2) control methods for soil pH or reservoir conditioning techniques, and
3) coupled or integrated electrochemical remediation techniques (hybridization). Yeung and Gu[46b] performed a comprehensive review of these techniques and the reader is referred
to Ref. [47] for better understanding of the accompanying geochemical processes.
4.1. Contaminant-Solubilizing Methods
This methodology has been developed to solubilize contaminants during electrokinetic remediation. It includes two pillars
(ways), namely, lowering the soil pH and introducing enhancement agents. It is known that metals are more soluble in a low
pH environment.[46b, 48] During electrokinetic remediation, H +
and HO ions are generated due to the electrolysis process,
and they can migrate through the soil profile, which thus leads
to the creation of an acid/base front in the soil profile. However, the mobility of H + ions is higher than that of HO ions,
which causes the acid front to migrate faster than the base
front.[14b, 43d, 49] Thus, creating a low pH environment specifically
in low acid/base buffer capacity leads to a successful degree of
metal extractability from soil.[46b] The introduction of enhancement agents is required in soils with high acid/base buffer capacity, and hence, weak acids such as citric acid or strong
acids can be used as enhancement agents to neutralize the
excess amount of HO ions.[46b] However, the level of pH
should be maintained to a level that favors removal efficiency.[46b] If the soil pH is below the point of zero charge, the direction of electro-osmotic flow is reserved, which thus diminishes cation removal by electromigration.[47, 50] Moreover, a very
low pH environment may adversely impact the environment.[46b, 51] Different enhancement agents have been tested in
electrokinetic remediation. They include chelating agents,[52]
complexing agents,[53] surfactants or cosolvents,[54] oxidizing/reducing agents,[55] and cation solutions.[45d, 56]
The choice of enhancing agent depends on the type of contaminant present and the soil conditions[57] and is thus crucial
in achieving successful contaminant removal efficiency.
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Chelation is the formation or presence of two or more separate bonds between a bidentate or multidentate ligand (i.e.
the chelant and a single metal central atom or ion).[46b] Chelating agents desorb toxic metals from soil particle surfaces by
forming strong water-soluble complexes that can be removed
by chelant-enhanced electrochemical remediation. Ethylenediaminetetraacetic acid (EDTA), (diethylenetriamine)pentaacetic
acid (DTPA), and citric acid are the most frequently used chelating agents in electrochemical remediation.[46b] A detailed
review of the use of chelants in electrochemical remediation is
given by Yeung and Gu.[58] Citric acid was reported as one of
the most effective chelating agents for enhancement of electro-osmotic flow.[59] The use of chelating agents still presents
a challenge for treatment and disposal of the toxic used extraction fluid, as it is rich in metal–chelant complexes. The current recycling methods are also not efficient and there is a call
for more robust recycling methods for chelants that would
also increase the economic value of chelant-enhanced electrochemical remediation.[46b]
Complexing agents are chemicals that form coordination
complexes with metal ions.[46b] Complexing agents such as I ,
Cl , NH3, and HO are introduced into soil as conditioning
acids or bases during electrochemical remediation process.
Acetic acid (CH3COOH) is a complexing agent that is frequently
utilized to enhance electrochemical remediation,[46b, 53d, 60] and
although it is not as effective as HNO3, for instance, it is preferred.[46b] It can neutralize the electrolysis product at the cathode
to reduce energy consumption, and it can keep the electrolyte
pH within a certain range by its acid/base buffering capacity.
Moreover, it is relatively cheap, biodegradable, and environmentally safe.[46b] Other complexing agents include ammonium
acetate (CH3COONH4) and cyclodextrins, which are nontoxic
and biodegradable.[46b]
There are synthetic and natural surfactants or cosolvents
that may act as adhesives, flocculating agents, wetting agents,
foaming agents, detergents, de-emulsifiers, penetrants, and
dispersants.[46b] Surfactants can lower the surface tension of
a liquid to allow easier spreading, and the interfacial tension
between two liquids, or between a liquid and a solid.[46b] They
have been observed by many researchers as feasible in enhancing heavy-metal extraction from soil and sludge.[46b, 61] Factors that need to be considered in the selection of surfactants
in electrochemical remediation include: 1) efficiency and effectiveness of the surfactant in remediating the contamination;
2) biodegradability of the surfactant and degradation products;
3) toxicity of the surfactant and its degradation products to
humans, animals, plants, and the ecology; 4) its ability to be recovered, recycled, and reused; 5) public perception and regulatory restrictions; 6) functionality of the surfactant at different
pH values; 7) electrical charges, if any, carried by the surfactant; and 8) cost.[46b]
A cosolvent is a second solvent added in small quantity to
the primary solvent to form a mixture that may greatly enhance the solvent power of the primary solvent due to synergism. Cosolvents such as ethanol,[46b, 62] n-butylamine,[46b, 56, 63]
n-propanol,[46b, 64] acetone,[46b, 63a] and tetrahydrofuran[46b, 63a]
have been examined for their ability to enhance the solubiliza 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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tion of organic compounds such as polycyclic aromatic hydrocarbons and diesel oil in soil during the electrochemical remediation process.[46b]
Oxidizing or reducing agents can be injected into contaminated soil to manipulate the in situ chemistry and microbiology, to enhance extraction of contaminants, or to reduce their
toxicity through oxidation or reduction reactions.[46b] Oxidizing
agents may include air or oxygen or chemical oxidants, such as
hydrogen peroxide (H2O2), potassium permanganate (KMnO4)
or sodium permanganate (NaMnO4), ozone, chlorine, and
oxygen-releasing compounds. Contaminants are chemically or
microbially oxidized. Similarly, reducing agents such as Fe2 + ,
Fe0, calcium polysulfide, and sodium dithionite can be used to
reduce contaminants in soil.[46b]
An increase in ionic strength (electrolyte concentration) of
the soil pore fluid increases the electrical conductivity of the
soil and energy consumption of the process. Conversely, a decrease in ionic strength (electrolyte concentration) increases
the thickness of the diffuse double layer, and this leads to a decrease in the coefficient of electro-osmotic conductivity and
a reduction in the electro-osmotic flow rate and electromigration of the ions. However, the electric current flowing through
the soil is reduced, and this leads to lower energy
consumption.[46b]
4.2. Control Methods for Soil pH and Reservoir Conditioning
Techniques
This methodology is applied to eliminate the adverse impact
of electrode reactions and the result of electrolytic decomposition,[46b] The splitting of water near the anode generates H +
ions and causes the pH to decrease near the anode, which
aids heavy-metal desorption from the surface of the soil particles. Conversely, water splitting at the cathode generates HO
and causes the pH to increase near the cathode, which causes
heavy metals to precipitate and makes them very difficult to
remove with an electric field.[51a, 65] Electrode reservoir solution
conditioning is important to maintain the pH of the anolyte
and catholyte within appropriate ranges specific to the contaminants being remediated.[66] This methodology is most important in soils of low acid/base buffer capacity for which the
resistance to pH change of these soils is low. Thus, the aim of
this enhancement technique is to hinder the generation and
transport of alkaline media into the soil.[44b, 67] Two main techniques are mainly applied in this methodology, and they involve applying conditioning agents at the electrode reservoirs[66a, 68] and using ion-exchange membranes.[69]
4.3. Coupled or Integrated Electrochemical Remediation
Techniques (Hybridization)
The potential of coupling electrokinetic remediation with other
remediation techniques may provide further improvement for
contaminant removal and enhance their individual remediation
efficiencies.[44, 46b] Despite a high removal of enhancement techniques, the feasibility of such techniques is limited due to high
costs, longer treatment time, and/or constraints on injecting
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the selected enhancement solutions into the subsurface.[44]
Therefore, hybridization processes are proposed to overcome
these limitations.[44, 46b, 57] There are numerous opportunities for
hybridization processes, and they include, but not are limited
to, electrokinetic biobarriers,[27] electrokinetic (permeable) reactive barriers,[70] electrokinetic oxidation/reduction,[16k, 41a, 71] electrokinetic bioremediation,[72] electrokinetic phytoremediation,[41d, 73] electrokinetic thermal treatment,[74] and electrokinetic ultrasonication.[75] Page and Page outlined other techniques
that have been combined with electroremediation for further
improvement of contaminant removal.[57] It should be noted,
however, that these possibilities have yet to be investigated.
5. Electrokinetic Removal of Soluble Salts
Since the first application in 1936, there have been some other
applications of electrokinetic remediation in the removal of
salts (Table 1). Cho et al. effectively removed salts such as nitrate, chloride, potassium, and sodium salts from saline greenhouse soil by using electrokinetic remediation.[76] Kim et al. applied electrokinetic remediation for the removal of sodium and
chloride in tidelands soil material.[77] Their observations were
that as the operation period increased, the salinity of the tideland material decreased gradually and that the electrical current increased gradually with the operation time; this resulted
in an increase in the total energy consumption. The results
also showed complete removal of sodium and significant reduction in electrical conductivity of the tideland material to
65.5 % of the initial value, but the removal efficiency of chloride was 58.5 % after 10 days. Jia et al. successfully transported
nitrate through soil by an electrokinetic process against the hydraulic gradient. Furthermore, they concluded that coupling
electrokinetic remediation with the sludge layer brings beneficial effects of desalination (e.g. 72.2 % saline removal) in
a period of about 36–48 h of EK-S experiments.[78] Cho et al.
achieved significant nitrates removal efficiency (81.86 %) after
48 h. However, even though the electrical conductivity (EC)
was above the 2.5 dS m1 benchmark suitable for cultivating
crops, approximately 40 % of the saline soil was restored. This
was confirmed by a significant decrease in the EC with increases in operation time (i.e. 24–48 h).[40d] Similarly, Choi et al. could
not reduce the EC to the recommended value for crop growth
after 60 days though the efficiency was 80 and 60 % for top
and bottom, respectively. However, salt ions were removed significantly.[79] In their in situ experiments, they achieved 90 % reduction of nitrate, sodium, and chloride.[88] Cho et al. also achieved excellent results in their attempt to remove nitrates from
agricultural lands. They used voltage gradients of 1, 2, and
3 V cm1 applied for 48 and 96 h. The highest nitrate removal
efficiencies were 80 % at 48 h and 99 % at 96 h.[76] Jia et al. concluded that electrokinetic can effectively retain nitrates near
the anode and against gravity in sandy column.[87]
Lageman and Pool concluded that electrokinetic remediation can be used to remove sodium and chloride from saline
water, which thus allows water to meet the water-quality
standards for irrigation and drinking purposes.[29] This conclusion was drawn after they used computer simulations to
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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deploy an electric fence as a means to intercept sodium and
chloride ions at the front edge of an advancing fresh-saline
water interface.
The use of electrokinetic remediation to remove salts in contaminated soils does have challenges. For instance, Kim et al.
reported that during their study in which they were removing
sodium and chloride, they experienced the formation of complexes with magnesium and calcium such as [MgCl] + or
[CaCl] + that was associated with a lower removal of chloride.[77]
These complexes had positive charges and moved towards the
cathode by electromigration in the direction opposite to that
of chloride migration. In addition, some chlorides form a complex with sodium as dissolved NaCl. The problem is that this
complex is a noncharged species, and it cannot be migrated
by an electric field, which explains why the amount of chloride
removed is smaller than the amount of sodium removed. In
addition, a high concentration of chloride in the anolyte solution may inhibit the removal of chloride from the tideland material because of back diffusion into the soil section from the
anolyte solution.[77] Moreover, sodium is normally removed by
electromigration and electro-osmosis mechanisms, which act
in the same direction.[40d, 77] However, in the case of chloride,
the major removal mechanism is electromigration, which can
be inhibited by electro-osmotic flow.[77]
Cho et al. experienced a problem with sulfate removal,
whereby it was retarded because of precipitation with calcium
and more interaction with soil particles, even though nitrate
and chloride were removed completely.[84] The electrokinetic
remediation method still presents evident shortcomings and
some limitations. As explained in the previous section, the development of an acidic medium at the anode lowers the pH to
below 2 and an alkaline medium at the cathode increases the
pH to above 10; this results from the electrolysis process,
which is a main feature in electrokinetic remediation,[80, 89] and
it represents one of these shortcomings. Xu et al. introduced
a sludge layer on electrokinetic remediation as an enhancing
technique of saline soil remediation by using electrokinetic remediation. Through the analysis of testing results, this enhanced technology can make up the shortcoming of the late
effect on anode dehydration baking (i.e. the use of a sludge
layer in an electrokinetic system provides a longer term of
electro-osmotic flow, which moderately increases the initial
current density. However, a significant increase will lead to premature cracking of the soil beside the anode, which accelerates the corrosion process and produces too much heat at the
electrode) and polarity movements of water, which thereby
provides current density and results in 72.2 % saline removal,
which is 28.4 % or even higher than the desalination efficiency
of other enhanced electrokinetic systems (e.g. 0.0058 m EKETDA systems) under similar testing conditions.[80] In their experiments, an intermittent current is regarded as a way to improve energy efficiency and to decrease project costs of treatment.[80] However, it was concluded that further research on
the thickness, the forms of the sludge layer, and other buffer
materials instead of sludge is needed to obtain a better desalination percentage and lower costs of saline amelioration.[80] Jo
et al. investigated a process of reducing the electric energy
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In situ EK removal of nitrate nitrate
from greenhouse soil:
EK pilot test 1 (a pair of electrodes was installed horizontally in the furrows)
EK pilot test 2 (two anodes
and one cathode were
placed in the furrows and
under the ridge,
respectively)
pilot
titanium
Pt-coated Ti
graphite 7 days
[40d]
[82]
[81]
[80]
Ref.
Concentration of nitrate at anodic area
of soil was higher compared to the cathode in the EK system, whereas on adding
bacteria into the EK (EK + bio) system,
the nitrate concentration was almost
zero (100 % removal efficiency) in all the
area of soil.
Nitrate removal was > 90 % in both tests. Energy consumed for test 1 operation
[83]
EC reduced up to 87 %.
was much lower than that used in test 2.
Highest removal efficiency was achieved [76]
for nitrate: > 80 % at 48 h and > 99 % at
96 h. Chloride removal after 96 h was
substantially higher than that after 48 h.
Removal efficiency for sulfate and calcium did not change significantly between
48 and 96 h.
[72b]
72 % saline removal, 28.4 % higher than
nine enhanced EK experiments.
56 % EC reduction in DC EK.
Na + (32–81 %)
Ca2 + (8–47 %)[a]
72 % EC reduction in pulse EK.
55 % EC reduction in enhanced pulse EK. Cl (66–7 %)
SO42 ions percentage was quite different depending on the test zone and
conditions.
ESP and SAR decreased by 90 %
Compressive strength increased by 100
and 200 % in unenhanced and lime-enhanced EK, respectively.
Result
63.41–81.86 % nitrates removal efficiency
for 6 and 48 h, respectively.
50 % removal for Cl and SO4 .
40 % EC reduction.
graphite 48 and 96 h EC decrements:
At 48 h, 40.4, 46.1, and 59.3 % for 1, 2,
and 3 V cm1, respectively.
At 96 h, 48.7, 53.5, and 51.4 % for 1, 2,
and 3 V cm1, respectively.
graphite 6, 12, 24,
and 48 h
Pt-coated Ti
10–14 days
1 month
Test 1: constant Fe-pipe electrode Fe-pipe 64 days
current range
electrode
from 1 to 5 A
applied in three
steps.
Test 2: constant
current 1 A.
laboratory 20 V
Combined electro-biokinetics technology on nitrate
removal
nitrate
laboratory 1, 2, and
3 V cm1
EK restoration of saline agri- Na + , Cl ,
cultural lands
Ca2 + , K + ,
SO4 , NO3
Removal of salts in greenhouse soil by using EK
process
exchangeable laboratory 0.5 V cm1
sodium percentage (ESP)
sodium absorption ratio
(SAR)
laboratory 1 V cm1
Na + , Cl ,
Ca2 + , K + ,
SO4 , NO3
Modification of salt affected
properties by using EK
treatments
Fe
120 h
mild
steel
laboratory 1.5–3.0 mA cm2
Na + , Cl ,
2.0–3.3 V cm1
Ca2 + , Mg2 +
+
2+
30 V
EK0, EK2 (DC):
Na , Cl ,Ca , pilot
SO4
high silicon-cast
iron (HSCI), Fe
EK2, EK4 (pulse):
HSCI, Fe
Enhanced EK remediation of
saline soil by sludge layer
In situ pulse power EK remediation: DC EK regime, pulse
power EK regime
Duration
mild steel
Target
Model
contaminants scale
Description
Current = voltage Electrode material
applied
anode
cathode
Table 1. The efficiency and feasibility of the electrokinetic (EK) technique for restoring salt-accumulated soils.
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REVIEWS
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1112
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Na + , Cl , K + ,
NO3 , Ca2 + ,
Mg2 + , SO4
Na + , Cl , K + ,
NO3 , Ca2 + ,
Mg2 + , SO4
EK salts removal of greenhouse in field test
Pulse-enhanced EK restoration of sulfate-containing
saline greenhouse soil
laboratory 1 V cm1
field test
Cl , K + , Ca2 + , pilot
Mg2 + , NO3 ,
SO4
Ex situ pilot scale EK restoration of saline soil by using
pulsed current
Pt6 days
coated Ti
14 days
Duration
Pt-coated Ti
2 months
9 weeks
Pt28 days
coated Ti 14 days for
the pulse
power tests
(cumulative
time length)
Fe plate
stainless
steel
dimensionally
graphite 14 days
stable anode
(DSA),Ti/
(IrO2+RuO2),
Pt,Si/BDD (borondoped diamond),
and Fe
graphite
1 V cm1
stainless steel
the system with
pulsed current
was on/off periodically every
15 min
0.8 V cm1
high silicon cast
iron (HSCI) rod
Na + , Cl , SO4 laboratory 4 V cm1
Effect of electrode material
on EK reduction of soil
salinity
Electrode configuration for
Cl , K + , Ca2 + , laboratory 1 and 2 V cm1
EK restoration of greenhouse Mg2 + , NO3 ,
saline soil (one anode in the SO4
center of the EK cell and
two cathodes at the end of
the cell)
stainless
steel
1 V cm1
Cl , K + , Ca2 + , pilot
Mg2 + , NO3 ,
SO4
Hexagonal 2D EK system
stainless steel
Current = voltage Electrode material
applied
anode
cathode
Target
Model
contaminants scale
Description
Table 1. (Continued)
90 % removal effectively for Na + , Cl ,
NO3 .
Ca2 + , Mg2 + , SO4 were not removed
from the soil effectively.
73–83 % EC reduction efficiency in top
soil on the average.
62 % EC reduction efficiency in all
pulsed-power tests, which is similar to
normal power tests.
Nitrate removal was higher than chloride
removal.
Sulfate removal was uniform across all
layers.
Mg2 + was higher after treatment.
30 % removal efficiency for K + and Ca2 + .
19 % average reduction in EC
NO3 and Cl were removed completely.
Removal of anions under 2 V cm1 was
slightly higher than removal of ions
under 1 V cm1.
SO4 removal was very low.
50 % of K + was removed.
Ca2 + and Mg2 + showed similar movement patterns.
In all tests Na + and Cl were easily removed from the soil (> 97 %).
EC was reduced 64–74 % in the tests
with DSA, Pt, and BDD anodes.
Fe anode tests showed higher reduction
of SO4 concentration and resulted in
higher electrical conductivity reduction
( 90 %) than the other anode tests.
Slightly less removal efficiency in the
pulse power system compared with conventional DC power system.
Result
[84]
[34a]
[79]
[38]
The pulsed EK process lowered the elec- [86]
trical-energy consumption to 50 % of
that of the conventional process, while
producing a similar decrease in salinity.
Frequency of on/off switching did not influence the total reduction in salinity,
but the amounts of sulfate and Ca removed were correlated with the on/off
frequency positively and negatively, respectively.
Energy consumption was
980 kW h m3, which was higher than
the laboratory-scale experiment.
The pulse power system lowered the
electrical energy consumption to 64 %
and effectively prevented pH changes
and electrode corrosion compared with
conventional DC power system.
Results demonstrated that the Fe anode [85]
is more suitable for restoration of SO4rich saline soil than other insoluble
anodes.
A voltage gradient of 1 V cm1 is more
efficient if taking into account both removal and energy.
The higher voltage gradient showed removal efficiency similar to that of the
lower voltage gradient.
Overall removal efficiency was not sufficiently high, because of the relatively
short operating time.
Ref.
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ChemElectroChem 2014, 1, 1104 – 1117
1113
[87]
[31]
An increase in pH near the cathode was
seen in all soils.
Water content for sandy soil was higher
at the bottom of the column and lower
at the top of the column, but for loamy
and clay soils, the lowest water content
was found above the cathode near the
bottom of the column.
EK process effectively concentrated and
retained nitrates close to the anode.
www.chemelectrochem.org
consumption in electrokinetic restoration of saline soil by applying on/off power pulsing regime. The results stated that
pulse-enhanced electrokinetic restoration of saline soil can decrease energy consumption to 50 % of that of the conventional
process, while producing a similar decrease in salinity.[86]
6. Conclusions and Outlook
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
[a] The minus sign means the final content was over its initial value.
Electromigration of nitrate in Na + ,NO3
sandy soil
laboratory 1.5, 3, 5, 10 mA
(closed & 30–90 V
open
system)
carbon, copper,
and stainless
steel
carbon,
copper,
and
stainless
steel
5–24 h in
closed
system
12 h in
open
system
Nitrate retained near the anode against
gravity in sandy soil.
In clay soil, the EK effect on ion movement decreased.
Loamy soil showed a slight increase in nitrate concentration near the anode but
the clay soil showed no change.
Sandy soil required the highest electrical
potential difference to obtain the desired
current level; loamy and clay soils required less.
In closed systems: 60 % nitrate removal
was achieved at the cathode, whereas
only 20 % removal was achieved within
the middle portion.
Significant clean-up of Na + .
9h
stainless
steel
stainless steel
NO3
Nitrate control by EK in different soils
laboratory 0.5 mA cm2
(vertical
column)
Target
Model
contaminants scale
Description
Table 1. (Continued)
Current = voltage Electrode material
applied
anode
cathode
Duration
Result
Ref.
CHEMELECTROCHEM
REVIEWS
This Review shows that electrokinetic remediation can be applied in various situations and under different conditions. The
varying observations, which are based on the experience of
different researchers and mainly laboratory based, could be
proof enough that there is a need to begin formulating
a knowledge base about the categories of materials, efficiencies, and limitations, as well as their related applications. This
would help to shape trends in the use of specific materials in
specific applications and would, thus, allow thorough analysis
of the suitability (i.e. acceptance or rejection/isolation of materials), efficiency, and enhancement needs of those materials.
Consequently, this would contribute towards achieving a costeffective application of electrokinetic remediation.
Furthermore, recent advances in electrokinetic remediation,
especially upscaling, could suggest that much information has
been accumulated on the application of electrokinetic remediation in certain areas, and therefore, it is time to begin applying this technology in the real field to gain more insight, with
regard to electrokinetic remediation, into those specific applications and further research in other areas (e.g. salt removal
and addressing seawater intrusion).
It can be seen that electrokinetic remediation can be applied
in different settings to remediate contaminated soils and that
it is capable, based on the various configurations, to address
diverse remediation challenges. However, there are some
areas, such as salt removal from contaminated soils, for which
this technology has not been extensively explored. Given the
current global challenge and impact of soil salinity, it is tempting to suggest that the research community should apply this
technology to generate in-depth knowledge about the efficiency of electrokinetic remediation in determining the feasibility and efficiency of electrokinetic remediation in salt removal,
particularly in addressing sea-water intrusion, which is slowly
creating growing challenges in freshwater supplies and security, mainly in coastal and arid regions in light of growing populations, economic and industrial growth, as well as climate
change.
Keywords: electrochemistry · electrokinetic remediation ·
environmental chemistry · salts removal · seawater intrusion
[1] P. Rengasamy, J. Exp. Bot. 2006, 57, 1017 – 1023.
[2] L. S. Sonon, U. Saha, D. E. Kissel, Soil Salinity, Testing, Data Interpretation
and Recommendations, The University of Georgia, Cooperative Extension, College of Agricultural and Environmental Sciences, 2012, Circular
No. 1019.
[3] a) C. Podmore, Irrigation Salinity – Causes and Impacts, New South
Wales Department of Primary Industries, http://www.dpi.nsw.gov.au/
_data/assets/pdf-file/0018/310365/Irrigation-salinity-causes-and-impacts.
pdf, accessed on 06 December 2013; b) Salinity, The Commonwealth
ChemElectroChem 2014, 1, 1104 – 1117
1114
CHEMELECTROCHEM
REVIEWS
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
Scientific and Industrial Research Organisation Land and Water (CSIRO),
The Commonwealth Scientific and Industrial Research Organisation
Land and Water (CSIRO), 2008.
F. Ghassemi, A. J. Jakeman, H. A. Nix, Salinization of Land and Water Resources: Human Causes, Extent, Management and Case Studies, Cab International, Wallingford, 1995.
a) M. El Moujabber, B. Bou Samra, T. Darwish, T. Atallah, Water Resour.
Manage. Ser. 2006, 20, 161 – 180; b) K. Nicholas, P. Charalambos, Journal
of Water Reuse and Desalination. 2013, 3, 392 – 401.
A. D. Werner, M. Bakker, V. E. A. Post, A. Vandenbohede, C. H. Lu, B.
Ataie-Ashtiani, C. T. Simmons, D. A. Barry, Adv. Water Resour. 2013, 51,
3 – 26.
A. Vengosh, Treatise Geochem. 2003, 9, 333 – 365.
I. Szabolcs, Acta Agron. Hung. 1987, 36, 159 – 172.
R. K. Gupta, I. Abrol in Advances in Soil Science (Ed.: B. A. Stewart),
Springer, New York, 1990, pp. 223 – 288.
World Soil Resources Reports No. 104, The Food and Agriculture Organization of the United Nations, Rome, 2009.
G. I. Metternicht, J. A. Zinck, Remote Sens. Environ. 2003, 85, 1 – 20.
A. T. Yeung, Sep Purif Technol 2011, 79, 124 – 132.
A. N. Puri, B. Anand, Soil Sci. 1936, 42, 23 – 28.
a) Y. B. Acar, Geotech. Spec. Publ. 1992, 30, 1420 – 1432; b) Y. B. Acar,
A. N. Alshawabkeh, Environ. Sci. Technol. 1993, 27, 2638.
a) K. R. Reddy, C. Y. Xu, S. Chinthamreddy, J. Hazard. Mater. 2001, 84,
279 – 296; b) C. Mulligan, R. Yong, B. Gibbs, Eng. Geol. 2001, 60, 193 –
207.
a) A. P. Shapiro, R. F. Probstein, Environ. Sci. Technol. 1993, 27, 283 – 291;
b) S. Banerjee, J. Horng, J. Ferguson, P. Nelson, Unpublished report presented to US EPA, Land Pollution Control Division, RREL, CR 1990,
pp. 811762 – 811701; c) Y. B. Acar, R. J. Gale, US Patents, 1992, 5137608,
Commissioner of Patents and Trademarks, Washington, DC; d) K. R.
Reddy, S. Chinthamreddy, Adv. Environ. Res. 2003, 7, 353 – 365; e) J. K.
Wittle, S. Pamukcu, Electrokinetic Treatment of Contaminated Soils, Sludges and Lagoons, 65IL: Argonne National Laboratories. DOE/CH-9206, No.
02112406; f) T. Suzuki, M. Moribe, Y. Okabe, M. Niinae, J. Hazard. Mater.
2013, 254 – 255, 310 – 317; g) K. R. Reddy, K. Maturi, C. Cameselle, J. Environ. Eng. 2009, 135, 989 – 998; h) T. Suzuki, M. Niinae, T. Koga, T. Akita,
M. Ohta, T. Choso, Colloids Surf. A. 2014, 440, 145 – 150;i) S. V. Ho, C.
Athmer, J. M. Brackin, M. A. Heitkamp, P. W. Sheridan, D. Weber, P. H.
Brodsky in Bioremediation: Principles and Practices Vol. 3 (Eds.: S. K.
Sikdar, R. L. Irvine), Lancaster, PA: Technomic Publishing, 1998, pp. 393 –
417; j) C. Weng, C. Huang, Practice Periodical of Hazardous, Toxic, and
Radioactive Waste Management 2004, 8, 67 – 72; k) S.-S. Kim, J.-H. Kim,
S.-J. Han, J. Hazard. Mater. 2005, 118, 121 – 131; l) A. N. Alshawabkeh,
R. M. Bricka, Environ. Sci. Pollut. Cont. Ser. 2000, 95 – 112; m) D. D. Runnells, J. L. Larson, Ground Water Monit. Rem. 1986, 6, 85 – 91; n) P. Renauld, R. Probstein, PCH PhysicoChem. Hydrodyn. 1987, 9, 345 – 360;
o) D. D. Runnells, C. Wahli, Ground Water Monit. Rem. 1993, 13, 121 –
129; p) R. F. Probstein, R. E. Hicks, Science 1993, 260, 498 – 503; q) S. Pamukcu, J. K. Wittle, Environ. Prog. 1992, 11, 241 – 250; r) R. Lageman, W.
Pool, G. Seffinga in Forum on Innovative Hazardous Waste Treatment
Technologies 1989, pp. 19 – 21; s) E. D. Mattson, E. R. Lindgren in Proceedings of the 8th National Outdoor Action Conference and Exposition,
Minneapolis, MN, 1994, pp. 235 – 245; t) C. J. Bruell, B. A. Segall, M. T.
Walsh, J. Environ. Eng. 1992, 118, 68 – 83; u) J. Hamed, Y. B. Acar, R. J.
Gale, J. Geotech. Eng. 1991, 117, 241 – 271; v) Y. B. Acar, H. Li, R. J. Gale, J.
Geotech. Eng. 1992, 118, 1837 – 1852; w) Y. Acar, J. Hamed, A. Alshawabkeh, R. Gale, Geotechnique 1994, 44, 239 – 254; x) Y. B. Acar, A. N. Alshawabkeh, R. J. Gale in Proceedings of the Mediterranean Conference on Environmental Geotechnology, CRC Press, Cesme, Turkey, 1992, pp. 321 –
330.
S. Martin, W. Griswold, Center for Hazardous Substance Research,
Kansas State University, Manhattan, http://www.engg.ksu.edu/chsr/outreach/resources/docs/15HumanHealthEffectsofHeavyMetals.pdf, 2009.
S. Khan, Q. Cao, Y. M. Zheng, Y. Z. Huang, Y. G. Zhu, Environ. Pollut.
Manage. 2008, 152, 686 – 692.
a) R. Lageman, R. L. Clarke, W. Pool, Eng. Geol. 2005, 77, 191 – 201; b) V.
Korolev, Moscow University Geology Bulletin 2008, 63, 2008, 63, 11 – 18;
c) J. P. Collopy, Process for the improvement and reclamation of soils,
1958, US Patent 2831304; d) J. E. Slater, D. R. Lankard, P. J. Moreland,
Mater Performance 1976, 15, 21 – 26; e) R. Hamnett, A Study of the Pro-
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemelectrochem.org
[20]
[21]
[22]
[23]
[24]
[25]
[26]
[27]
[28]
[29]
[30]
[31]
[32]
[33]
[34]
[35]
[36]
[37]
[38]
[39]
[40]
[41]
cesses Involved in the Electro-reclamation of Contaminated Soils, University of Manchester, Manchester, 1980; f) R. Lageman, W. Pool, G. Seffinga,
Land, Water en Milieutechniek (mei) 1988, 5; g) W. Pool, European Patent
EP0312174 A1, 1989.
a) R. Lageman, W. Pool in Electrochemical Remediation Technologies for
Polluted Soils, Sediments and Groundwater (Eds.: K. R. Reddy, C. Cameselle), Wiley, Hoboken, NJ, 2009, pp. 697 – 717; b) R. J. Lynch, A. Muntoni, R. Ruggeri, K. C. Winfield, Electrochim. Acta 2007, 52, 3432 – 3440.
A. Shapiro, P. Renaud, R. F. Probstein, PCH PhysicoChem. Hydrodyn. 1989,
11, 785 – 802.
R. Lageman, W. Pool, Proceedings of the 3rd Symposium and Status
Report on Electrokinetic Remediation (EREM 2001), Karlsruhe, 2001, 1,
1 – 17.
R. Lageman, Environ. Sci. Technol. 1993, 27, 2648 – 2650.
R. Lageman, W. Pool, G. Seffinga, EPA/540/2 – 89/056, 1989.
A. Yeung, J. Mitchell, Geotechnique 1993, 43, 121 – 134.
J. K. Mitchell, A. T. Yeung, “Electrokinetic Flow Barriers in Compacted
Clay”, Transportation Research Record No. 1288: Soils, Geology and Foundations, Transportation Research Board, Washington, D.C., 1990, pp. 1 –
9.
M. Godschalk, R. Lageman, Eng. Geol. 2005, 77, 225 – 231.
R. Lynch in Electrochemical Remediation Technologies for Polluted Soils,
Sediments and Groundwater (Eds.: K. R. Reddy, C. Cameselle), Wiley,
Hoboken, NJ, 2009, pp. 333 – 356.
R. Lageman, W. Pool, H2O—Tijdschrift voor watervoorziening en waterbeheer 2011, 44, 45 – 47.
B. Narasimhan, R. Sri Ranjan, J. Contam. Hydrol. 2000, 42, 1 – 17.
N. Eid, W. Elshorbagy, D. Larson, D. Slack, J. Hazard. Mater. 2000, 79,
133 – 149.
N. Eid, D. Larson, D. Slack, P. Kiousis, J. Irrig. Drain. Div. Am. Soc. Civ. Eng.
1999, 125, 7 – 11.
a) A. N. Alshawabkeh, A. T. Yeung, M. R. Bricka, J. Environ. Eng. 1999,
125, 27 – 35; b) A. N. Alshawabkeh, R. J. Gale, E. Ozsu-Acar, R. M. Bricka,
J. Soil Contam. 1999, 8, 617 – 635; c) W.-S. Kim, G.-Y. Park, D.-H. Kim, H.B. Jung, S.-H. Ko, K. Baek, Electrochim. Acta 2012, 86, 89 – 95.
a) D.-H. Kim, S.-U. Jo, J.-H. Choi, J.-S. Yang, K. Baek, Chem. Eng. J. 2012,
198, 110 – 121; b) P. Zhang, C. Jin, Z. Zhao, G. Tian, J. Hazard. Mater.
2010, 177, 1126 – 1133.
E. Mndez, E. Bustos, R. Feria, G. Garca, M. Teutli, in Electrochemical
Cells—New Advances in Fundamental Researches and Applications (Ed.: Y.
Shao), InTech, 2012, pp. 219-239..
E. Mndez, M. Prez, O. Romero, E. Beltrn, S. Castro, J. Corona, A.
Corona, M. Cuevas, E. Bustos, Electrochim. Acta 2012, 86, 148 – 156.
a) J. Virkutyte, M. Sillanp, P. Latostenmaa, Sci. Total Environ. 2002, 289,
97 – 121; b) A. T. Yeung, T. B. Scott, S. Gopinath, R. M. Menon, C. Hsu,
Geotech. Test J. 1997, 20, 199 – 210.
D.-H. Kim, S.-U. Jo, J.-C. Yoo, K. Baek, Sep Purif Technol 2013, 120, 282 –
288.
a) L. Ouattara, S. Fierro, O. Frey, M. Koudelka, C. Comninellis, J Appl Electrochem 2009, 39, 1361 – 1367; b) M. Prez-Corona, A. Corona, E. D.
Beltrn, J. Crdenas, E. Bustos, Sustainable Environ. Res. 2013, 23, 279 –
284.
a) D. Leštan, C.-l. Luo, X.-d. Li, Environ. Pollut. 2008, 153, 3 – 13; b) D.-H.
Kim, J.-M. Cho, K. Baek, J. Soils Sediments 2011, 11, 947 – 958; c) W. Pool,
US Patents US5589056, 1996; d) J.-M. Cho, K.-J. Kim, K.-Y. Chung, S.
Hyun, K. Baek, Sep. Sci. Technol. 2009, 44, 2371 – 2384; e) J. Wang, X.
Feng, C. W. N. Anderson, Y. Xing, L. Shang, J. Hazard. Mater. 2012, 221 –
222, 1 – 18; f) R. Anderson, Resource guide for electrokinetics laboratory
and field processes applicable to radioactive and hazardous mixed wastes
in soil and groundwater from 1992 to 1997, Report No. EPA 402-R-97006, US Environmental Protection Agency-Office of Air and Radiation,
1997.
a) G. C. Yang, Y.-W. Long, J. Hazard. Mater. 1999, 69, 259 – 271; b) P.
Thepsithar, E. P. Roberts, Environ. Sci. Technol. 2006, 40, 6098 – 6103;
c) A. T. Lima, L. M. Ottosen, K. Heister, J. P. G. Loch, Sci. Total Environ.
2012, 435 – 436, 1 – 6; d) H. I. Gomes, C. Dias-Ferreira, A. B. Ribeiro, Chemosphere 2012, 87, 1077 – 1090; e) A. M. Polcaro, A. Vacca, M. Mascia, S.
Palmas, J. Hazard. Mater. 2007, 148, 505 – 512; f) R. Lpez-Vizcano, J.
Alonso, P. CaÇizares, M. J. Len, V. Navarro, M. A. Rodrigo, C. Sez, J.
Hazard. Mater. 2014, 265, 142 – 150; g) A. B. Ribeiro, J. M. RodrguezMaroto, E. P. Mateus, H. Gomes, Chemosphere 2005, 59, 1229 – 1239;
ChemElectroChem 2014, 1, 1104 – 1117
1115
CHEMELECTROCHEM
REVIEWS
[42]
[43]
[44]
[45]
[46]
[47]
[48]
[49]
[50]
[51]
[52]
[53]
[54]
[55]
[56]
[57]
h) A. B. Ribeiro, E. P. Mateus, J.-M. Rodrguez-Maroto, Sep. Purif. Technol.
2011, 79, 193 – 203; i) R. Lpez-Vizcano, C. Sez, P. CaÇizares, M. A. Rodrigo, Sep. Purif. Technol. 2012, 88, 46 – 51.
a) G.-N. Kim, D.-B. Shon, H.-M. Park, K.-W. Lee, U.-S. Chung, Sep Purif
Technol 2011, 80, 67 – 72; b) K. Agnew, A. B. Cundy, L. Hopkinson, I. W.
Croudace, P. E. Warwick, P. Purdie, J. Hazard. Mater. 2011, 186, 1405 –
1414; c) W. Kovalick, In Situ Remediation Technology: Electrokinetics,
Report No. EPA542-K-94-007, U.S. Environmental Protection Agency,
Washington, D.C., 1995; d) K.-H. Kim, S.-O. Kim, C.-W. Lee, M.-H. Lee, K.W. Kim, Sep. Sci. Technol. 2003, 38, 2137 – 2163.
a) Z. Shen, B. Ju, X. Chen, W.-h. Wang, Soil Res. 2008, 46, 485 – 491; b) M.
Gillen, 2006; c) C.-H. Weng, T. Lin, S.-H. Chu, C. Yuan, Pract. Period.
Hazard., Toxic, Radioact. Waste Manage. 2006, 10, 171 – 178; d) C.-H.
Weng, H.-W. Tsai, J. Environ. Eng. Manage. 2009, 19, 379 – 387; e) B.-K.
Kim, K. Baek, S.-H. Ko, J.-W. Yang, Sep. Purif. Technol. 2011, 79, 116 – 123.
K. R. Reddy, C. Cameselle, Electrochemical Remediation Technologies for
Polluted Soils, Sediments and Groundwater, Wiley, Hoboken, NJ, 2009,
pp. 1 – 28.
a) A. Karagunduz in Electrochemical Remediation Technologies for Polluted Soils, Sediments and Groundwater (Eds.: K. R. Reddy, C. Cameselle)
Wiley, Hoboken, NJ, 2009, pp. 235 – 248; b) B. Mukhopadhyay, J. Sundquist, R. J. Schmitz, J. Environ. Manage. 2007, 82, 66 – 76; c) G. De Gioannis, A. Muntoni, A. Polettini, R. Pomi, J. Environ. Sci. Health Part A 2008,
43, 852 – 865; d) K. Reddy, S. Chinthamreddy, J. Environ. Eng. 2004, 130,
442 – 455; e) A. Colacicco, G. De Gioannis, A. Muntoni, E. Pettinao, A.
Polettini, R. Pomi, Chemosphere 2010, 81, 46 – 56.
a) A. T. Yeung, Environ. Eng. Sci. 2006, 23, 202 – 224; b) A. T. Yeung, Y.-Y.
Gu, J. Hazard. Mater. 2011, 195, 11 – 29.
A. T. Yeung in Electrochemical Remediation Technologies for Polluted
Soils, Sediments and Groundwater (Eds.: K. R. Reddy, C. Cameselle), Wiley,
Hoboken, NJ, 2009, pp. 65 – 94.
a) M. C. F. Magalhaes, ChemInform 2003, 13, DOI: 10.1002/
chin.200313209; b) M. C. Chuan, G. Y. Shu, J. C. Liu, Water Air Soil Pollut.
1996, 90, 543 – 556; c) K. J. Reddy, L. Wang, S. P. Gloss, Plant Soil 1995,
171, 53 – 58.
a) Y. Acar, A. Alshawabkeh, J. Geotech. Eng. 1996, 122, 173 – 185; b) K. R.
Reddy, Coupled Phenom. Environ. Geotech. 2013, 131; c) A. Z. AlHamdan, K. R. Reddy, Chemosphere 2008, 71, 860 – 871.
a) A. Asadi, B. B. Huat, M. Hassim, T. A. Mohamed, M. Hanafi, N. Shariatmadari, Am. J. Environ. Sci. 2009, 5, 310; b) K. Ahmad, K. A. Kassim, M.
Taha, Malaysain J. Civil Eng. 2006, 18, 74 – 88.
a) J. Almeira O. , C.-S. Peng, A. Abou-Shady, Desalination 2012, 300, 1 –
11; b) H. F. Wang, N. Takematsu, S. Ambe, Appl. Radiat. Isot. 2000, 52,
803 – 811; c) B. Marschner, A. D. Noble, Soil Biol. Biochem. 2000, 32, 805 –
813; d) P. K. Sahoo, P. Bhattacharyya, S. Tripathy, S. M. Equeenuddin,
M. K. Panigrahi, J. Hazard. Mater. 2010, 179, 966 – 975.
a) Y.-Y. Gu, A. T. Yeung, A. Koenig, H.-J. Li, Sep. Sci. Technol. 2009, 44,
2203 – 2222; b) A. Yeung, C. Hsu, R. Menon, J. Geotech. Eng. 1996, 122,
666 – 673; c) I. Popov Konstantin, G. Yachmenev Val, A. Barinov in Biogeochemistry of Chelating Agents Vol. 910 (Eds.: B. Nowack, J. M. VanBriesen), American Chemical Society, Washington, D.C., 2005, pp. 398 – 420.
a) C. D. Cox, M. A. Shoesmith, M. M. Ghosh, Environ. Sci. Technol. 1996,
30, 1933 – 1938; b) K. R. Reddy, C. Chaparro, R. E. Saichek, J. Environ. Sci.
Health Part A 2003, 38, 307 – 338; c) P. Sur, T. Lifvergren, J. Environ. Eng.
2003, 129, 441 – 446; d) . Hanay, H. Hasar, N. N. KoÅer, O. Ozdemir, Environ. Technol. 2009, 30, 1177 – 1185; e) J. Chen, J. Iyengar, L. Subramanian, B. Ford in Proceedings of the ACM SIGMETRICS Joint International
Conference on Measurement and Modeling of Computer Systems, ACM,
San Jose, CA, 2011, pp. 157 – 158.
a) C.-H. Weng, C. Yuan, Environ. Geochem. Health 2001, 23, 281 – 285;
b) P.-W. Chang, Y.-C. Tan, I. S. Wang, Irrig. Drain. Pap. 2008, 57, 187 – 201;
c) A. Giannis, E. Gidarakos, A. Skouta, Desalination 2007, 211, 249 – 260;
d) K. Reddy, C. Cameselle, P. Ala, J. Appl. Electrochem. 2010, 40, 1269 –
1279.
a) S. Pamukcu, A. Weeks, J. K. Wittle, Environ. Sci. Technol. 2004, 38,
1236 – 1241; b) Y. Yukselen-Aksoy, K. Reddy, J. Geotech. Geoenviron. Eng.
2013, 139, 175 – 184.
T. Coletta, C. Bruell, D. Ryan, H. Inyang, J. Environ. Eng. 1997, 123, 1227 –
1233.
M. M. Page, C. L. Page, J. Environ. Eng. 2002, 128, 208 – 219.
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemelectrochem.org
[58] A. Yeung, Y. Gu in Chelating Agents for Land Decontamination Technologies (Eds.: D. C. W. Tsang, I. M. C Lo, R. Y. Surampalli), American Society
of Civil Engineers, Reston, VA, 2012, pp. 212 – 280.
[59] a) G. Li, S. Guo, S. Li, L. Zhang, S. Wang, Chem. Eng. J. 2012, 203, 231 –
238; b) M. Pazos, A. Plaza, M. Martn, M. C. Lobo, Chem. Eng. J. 2012,
183, 231 – 237; c) R. Bassi, S. O. Prasher, B. K. Simpson, Environ. Prog.
2000, 19, 275 – 282.
[60] a) G.-N. Kim, Y.-H. Jung, J.-J. Lee, J.-K. Moon, C.-H. Jung, Sep Purif Technol
2008, 63, 116 – 121; b) L. M. Rajic, B. D. Dalmacija, J. S. Trickovic, M. B.
Dalmacija, D. M. Krcmar, J. Environ. Sci. Health Part A 2010, 45, 1134 –
1143.
[61] R.-a. Doong, Y.-W. Wu, W.-g. Lei, Water Sci. Technol. 1998, 37, 65 – 71.
[62] a) R. E. Saichek, K. R. Reddy, Environ. Technol. 2003, 24, 503 – 515; b) J.
Wan, S. Yuan, J. Chen, T. Li, L. Lin, X. Lu, J. Hazard. Mater. 2009, 166,
221 – 226.
[63] a) A. Li, K. Cheung, K. Reddy, J. Environ. Eng. 2000, 126, 527 – 533; b) K.
Maturi, K. Reddy, Water Air Soil Pollut. 2008, 189, 199 – 211.
[64] H. Han, Y.-J. Lee, S.-H. Kim, J.-W. Yang, Sep. Sci. Technol. 2009, 44, 2437 –
2454.
[65] R. E. Hicks, S. Tondorf, Environ. Sci. Technol. 1994, 28, 2203 – 2210.
[66] a) D.-M. Zhou, C.-F. Deng, L. Cang, A. N. Alshawabkeh, Chemosphere
2005, 61, 519 – 527; b) D.-H. Kim, C.-S. Jeon, K. Baek, S.-H. Ko, J.-S. Yang,
J. Hazard. Mater. 2009, 161, 565 – 569.
[67] S. K. Puppala, A. N. Alshawabkeh, Y. B. Acar, R. J. Gale, M. Bricka, J.
Hazard. Mater. 1997, 55, 203 – 220.
[68] E. Gidarakos, A. Giannis, Water Air Soil Pollut. 2006, 172, 295 – 312.
[69] a) W.-S. Kim, S.-O. Kim, K.-W. Kim, J. Hazard. Mater. 2005, 118, 93 – 102;
b) Z. Shen, X. Chen, J. Jia, L. Qu, W. Wang, Environ. Pollut. 2007, 150,
193 – 199.
[70] a) H. I. Chung, M. Lee, Electrochim. Acta 2007, 52, 3427 – 3431; b) C. J.
Athmer, S. V. Ho in Electrochemical Remediation Technologies for Polluted
Soils, Sediments and Groundwater (Eds.: K. R. Reddy, C. Cameselle), Wiley,
Hoboken, NJ, 2009, pp. 625 – 646; c) C.-H. Weng in Electrochemical Remediation Technologies for Polluted Soils, Sediments and Groundwater
(Eds.: K. R. Reddy, C. Cameselle), Wiley, Hoboken, NJ, 2009, pp. 483 –
503.
[71] a) M. Pazos, O. Iglesias, J. Gmez, E. Rosales, M. A. Sanromn, J. Ind. Eng.
Chem. 2013, 19, 932 – 937.
[72] a) S.-J. Kim, J.-Y. Park, Y.-J. Lee, J.-Y. Lee, J.-W. Yang, J. Hazard. Mater.
2005, 118, 171 – 176; b) J.-H. Choi, S. Maruthamuthu, H.-G. Lee, T.-H. Ha,
J.-H. Bae, J. Hazard. Mater. 2009, 168, 1208 – 1216; c) W. Xu, C. Wang, H.
Liu, Z. Zhang, H. Sun, J. Hazard. Mater. 2010, 184, 798 – 804.
[73] a) L. Cang, Q. Y. Wang, D. M. Zhou, H. Xu, Sep. Purif. Technol. 2011, 79,
246 – 253; b) L. Cang, D.-M. Zhou, Q.-Y. Wang, G.-P. Fan, Electrochim.
Acta 2012, 86, 41 – 48; c) C. Cameselle, R. A. Chirakkara, K. R. Reddy, Chemosphere 2013, 93, 626 – 636.
[74] G. J. Smith in Electrochemical Remediation Technologies for Polluted Soils,
Sediments and Groundwater (Eds.: K. R. Reddy, C. Cameselle), Wiley,
Hoboken, NJ, 2009, pp. 505 – 535.
[75] a) T. D. Pham, R. A. Shrestha, J. Virkutyte, M. Sillanp, Electrochim. Acta
2009, 54, 1403 – 1407; b) T. D. Pham, R. A. Shrestha, M. Sillanp, Sep.
Sci. Technol. 2009, 44, 2410 – 2420.
[76] J.-M. Cho, S.-Y. Park, K. Baek, J. Appl. Electrochem. 2010, 40, 1085 – 1093.
[77] K. J. Kim, J. M. Cho, K. Baek, J. S. Yang, S. H. Ko, J. Appl. Electrochem.
2010, 40, 1139 – 1144.
[78] X. Jia, D. Larson, D. Slack, J. Walworth, Eng. Geol. 2005, 77, 273 – 283.
[79] J.-H. Choi, Y.-J. Lee, H.-G. Lee, T.-H. Ha, J.-H. Bae, Electrochim. Acta 2012,
86, 63 – 71.
[80] H. Xu, W. Chen, C. Wang, B. Chen, J. Yang, J. Food Agric. Environ. 2012,
10, 709 – 713.
[81] Y.-J. Lee, J.-H. Choi, H.-G. Lee, T.-H. Ha, Environ. Eng. Sci. 2013, 30, 133 –
141.
[82] S. Jayasekera, S. Hall, Geotech. Geol. Eng. 2007, 25, 1 – 10.
[83] Y.-J. Lee, J.-H. Choi, H.-G. Lee, T.-H. Ha, J.-H. Bae, Sep. Purif. Technol.
2011, 79, 254 – 263.
[84] J. M. Cho, D. H. Kim, J. S. Yang, K. Baek, Sep. Sci. Technol. 2012, 47,
1677 – 1681.
[85] Y.-J. Lee, J.-H. Choi, H.-G. Lee, T.-H. Ha, J.-H. Bae, Sep. Sci. Technol. 2012,
47, 22 – 29.
[86] S.-U. Jo, D.-H. Kim, J.-S. Yang, K. Baek, Electrochim. Acta 2012, 86, 57 –
62.
ChemElectroChem 2014, 1, 1104 – 1117
1116
CHEMELECTROCHEM
REVIEWS
[87] X. Jia, D. L. Larson, W. S. Zimmt, J. L. Walworth, Trans. ASAE 2005, 48,
1343 – 1352.
[88] J.-H. Choi, Y.-J. Lee, H.-G. Lee, T.-H. Ha, J.-H. Bae, Electrochim. Acta 2012,
86, 63 – 71.
www.chemelectrochem.org
[89] a) B. Kornilovich, N. Mishchuk, K. Abbruzzese, G. Pshinko, R. Klishchenko,
Colloids Surf. A 2005, 265, 114 – 123; b) M. Qadir, A. Ghafoor, G. Murtaza,
Land Degrad. Develop. 2000, 11, 501 – 521.
Received: March 26, 2014
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemElectroChem 2014, 1, 1104 – 1117
1117