Electrokinetic Technique Research Articles

Electropatterning-Contemporary developments for selective particle arrangements employing electrokinetics.

The selective positioning and arrangement of distinct types of multiscale particles can be used in numerous applications in microfluidics, including integrated circuits, sensors and biochips. Electrokinetic (EK) techniques offer an extensive range of options for label-free manipulation and patterning of colloidal particles by exploiting the intrinsic electrical properties of the target of interest. EK-based techniques have been widely implemented in many recent studies, and various methodologies and microfluidic device designs have been developed to achieve patterning two- and three-dimensional (3D) patterned structures. This review provides an overview of the progress in electropatterning research during the last 5 years in the microfluidics arena. This article discusses the advances in the electropatterning of colloids, droplets, synthetic particles, cells, and gels. Each subsection analyzes the manipulation of the particles of interest via EK techniques such as electrophoresis and dielectrophoresis. The conclusions summarize recent advances and provide an outlook on the future of electropatterning in various fields of application, especially those with 3D arrangements as their end goal.

Abstract LB082: The CytoR1: a standardized dielectrophoretic platform for label free sorting

Abstract Dielectrophoresis (DEP), a label-free electrokinetic technique, has a long history of being used to characterize and separate target subpopulations from mixed samples. A large body of literature has investigated these parameters with unique setups and limited cell varieties. The technical challenge of the technique coupled with the uncertainty in the breadth of data has limited the commercialization and widespread adoption of DEP for biological applications. The work presented here aims to evaluate a range of prior applications of DEP on a standardized platform. A variety of cell types were characterized and compared to literature values considering variables such as frequency, voltage, and flow rate. Once a cell type’s frequency response curve is generated, it is possible to design workflows to enrich that cell type from a bulk mixture, without antibody labeling. Here, we test various cell types and characteristics on a microfluidics-based, benchtop cell sorting technology, the CytoR1. First, the CytoR1 successfully facilitated the separation of ovarian cancer stem cells (CSCs) from peripheral blood mononuclear cells (PBMCs), both from mice. From a 56.2% CSCs and 43.8% PMBCs co-culture, we were able to deplete 50% of the PMBCs while retaining the original CSC population. Further work investigated the ability to sort neuron subpopulations. Live neurons can be isolated from a bulk preparation and further enriched by size and phenotype with varying voltage and frequency settings. By modulating voltage and flow rate in addition to frequency, a distinct population of small neurons can be isolated for further study. Finally, cell state can be investigated. Red blood cells were characterized in both their native and oxidatively stressed states. Curves show a distinct shift towards higher frequencies with increasing oxidative stress suggesting the ability to separate these populations from each other. Together these data suggest the versatility of a robust, DEP-based sorting platform, the CytoR1, for label free cell sorting. Citation Format: Dean E. Thomas, Katherine E. Degen, Ridi Barua, Andrea Bertke, Erin A. Henslee, Alexandra R. Hyler. The CytoR1: a standardized dielectrophoretic platform for label free sorting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB082.

Multiphase Actuation of AC Electrothermal Micropump

Electrothermal micropumps apply an AC electric field to a conductive fluid within the range of 10 kHz–1 MHz to generate fluid flow. In this frequency range, coulombic forces dominate fluid interactions over opposing dielectric forces, resulting in high flow rates (~50–100 μm/s). To date, the electrothermal effect—using asymmetrical electrodes—has been tested only with single-phase and 2-phase actuation, while dielectrophoretic micropumps have shown improved flow rates with 3- and 4-phase actuation. Simulating muti-phase signals in COMSOL Multiphysics requires additional modules and a more involved implementation to accurately represent the electrothermal effect in a micropump. Here, we report detailed simulations of the electrothermal effect under multi-phase conditions, including single-phase, 2-phase, 3-phase and 4-phase actuation patterns. These computational models indicate that 2-phase actuation leads to the highest flow rate, with 3-phase resulting in a 5% reduced flow rate and 4-phase resulting in an 11% reduced flow rate compared to 2-phase. With these modifications to the simulation, various actuation patterns can later be tested in COMSOL for a range of electrokinetic techniques.

Impact of variable density on electrokinetic transport and mixing in porous media

Electrokinetic (EK) techniques can effectively mobilize amendments and contaminants in porous media and therefore have a great potential for in situ subsurface remediation of a wide variety of organic and inorganic contaminants. However, the fundamental mechanisms governing EK applications in porous media are complex and entail coupling between different flow, transport, electrostatic and geochemical processes. In this study we investigate the interactions between density driven effects and electrokinetic transport in permeable porous media and we compare the observed dynamics with the outcomes of analogous scenarios in which advection and dispersion are the only transport mechanisms. We perform a series of multidimensional experiments and we demonstrate the strong interplay between Coulombic interactions among charged species in pore water and density-driven effects during electrokinetics. Our study illuminates non-trivial interactions between the pore water composition and the macroscopic behavior of variable density dye tracer plumes, showing different sinking and floating patterns, distinct plume shapes and spreading, as well as different extent of mixing depending on the chemical composition of the pore water. A numerical model, based on the Nernst-Planck-Poisson formulation and on the coupling with the geochemical code PHREEQC, was developed to simulate variable density flow and transport and to update the density of the aqueous solution resulting from mixing and electrostatic interactions between all chemical species in the injected plume and in the surrounding pore water electrolyte. The model allowed us to interpret the experiments and to visualize the impact of small density gradients and Coulombic effects on the macroscopic transport of the dye tracer. The outcomes of this study highlight the importance of density-driven flow also during EK transport, where the electrostatic interactions not only influence the concentration of charged species but can also affect the density and result in complex flow patterns, plume shapes and mixing behavior, radically different from the ones generated during advective-dispersive transport.

Copper metal elimination from polluted soil by electro-kinetic technique.

The electro kinetic method is one of the common methods in the process of pollutants removal. In this paper, the process of removing copper from contaminated soil has been studied. Some improved conditions were used in this process; the pH of the solution was changed for each experiment during the first three experiments. SDS (sodium dodecyl sulfate) has been used as an activator to improve the removal process by washing the soil with it. Date palm fibers (DPF) were also used as an adsorbent material to counteract the reverse flow that occurred during the removal process, thus increasing the removal value. Various experiments were performed, where it was observed that by decreasing the pH, the removal capacity was increased. The removal capacity in the three different experiments were 70% at pH 4, 57% at pH 7, and 45% at pH 10. The use of SDS as a solution in the process increased the dissolution and absorption of copper from the soil surface and then increased the removal capacity (74%). The use of DPF to counter the osmosis flow has been successful in adsorbing the pollutants (copper) returning from this flow, and thus this material can be considered good from an economic and environmental aspect when compared to other commercial adsorbents.

Evaluating the Effect of the Approaching Electrode On the Migration for Metal Ions through the Electro-Kinetic Technique for Contaminated Soil

Evaluating the Effect of the Approaching Electrode On the Migration for Metal Ions through the Electro-Kinetic Technique for Contaminated Soil

Electrical surface properties of nanoporous alumina membranes: influence of nanochannels' curvature, roughness and composition studied via electrokinetic experiments.

Among classical nanoporous oxide membranes, anodic aluminum oxide (AAO) membranes, made of non-connected, parallel and ordered nanochannels, are very interesting nanoporous model systems widely used for multiple applications. Since most of these applications involve local phenomena at the nanochannel surface, the fine description of the electrical surface behavior in aqueous solution is thus of primordial interest. Here, we use an original experimental approach combining several electrokinetic techniques (tangential and transverse streaming potential as well as electrophoretic mobility experiments) to measure the ζ-potential and determine the surface isoelectric points (IEPs) of several AAOs having different characteristic sizes and compositions. Using such an approach, all the different surfaces available in AAOs can be probed: outer surfaces (top and bottom planes), pore wall surfaces (i.e., inner surfaces) and surfaces created by the grinding of the AAOs. We find clear IEP differences between the outer, pore wall and ground surfaces and discuss these in terms of nanochannel and surface morphology (curvature and roughness) and of modifications of the chemical environment of the surface hydroxyl groups. These results highlight the heterogeneities between the different surfaces of these AAO membranes and emphasize the necessity to combine complementary electrokinetic techniques to properly understand the material, an approach which can be extended to many nanoporous systems.

Use of an Eletrokinetic Remediated Soil as a Road Subgrade Material

The soil investigated for suitability checks, as a subgrade material in this study, was a crude oil contaminated (COC) soil treated using an electrokinetic technique. The index properties and compaction characteristics of the electrokinetic remediated (EKR) soil are natural moisture content was 10.97%; The Atterberg limit test showed liquid limit, plastic limit, plasticity index and linear shrinkage of 36.50%, 22.05%,14.45 %, and 4.30%, respectively. The percentage of 62.80% passes 0.075mm sieve with a maximum dry density (MDD) of 1.77 Mg/m3, and the moisture content decreased from 13.2% to 11.81%. The soil is classified as A-6 according to AASHTO classification system and belong to clay of low plasticity CL or OL group according to the Unified Soil Classification System. The unconfined compression strength, (UCS), durability, and California bearing ratio (CBR) of the electrokinetic remediated soil improved marginally from 46.63kN/m2 to 92.64kN/m2; from 18% to 23%; and from 2.55% to 4.05% respectively. However, these results obtained, do not meet the minimum requirement of the Nigerian General Specification. As a result, it is advised for further research, that an EKR soil be stabilized using cement stabilization to achieve the desired subgrade strength.

Incidence of Electric Field and Sulfuric Acid Concentration in Electrokinetic Remediation of Cobalt, Copper, and Nickel in Fresh Copper Mine Tailings

In the present study, the assessment of heavy metal contaminant migration from fresh mine tailings was conducted using the electrokinetic remediation technique (EKR). In this sense, a pilot EKR cell was designed to evaluate the recovery potential of copper, nickel, and cobalt species. In particular, the focus was on the impacts of electric field intensity and pH in initial mixture and testing their interaction in copper, nickel, and cobalt migration. Experiments were made using a 22 factorial experimental design with a central point, using DC electric fields from 1.0 to 2.0 V cm−1 and H2SO4 pretreatment solutions from 1.0 to 2.0 mol L−1, along with an ANOVA test with error reduction. The metal removal rates were approximately 7% for cobalt, neglectable for copper, and 6% for nickel. In the best cases, the highest concentrations by migration at the cathodic zone were 11%, 31%, and 30%, respectively. According to ANOVA tests, factor interaction was proven for each metal in the half cell near the cathode and the closest zone from the cathode specifically. Both factors affected metal concentrations, which indicates that when the goal aims for species accumulation in a narrower section, each factor has a significant effect, and their interaction makes a proven enhancement. Thus, using 2.0 V cm−1 and 2.0 mol L−1 showed a high improvement in metal concentration in the cathodic zone.

Using the electrokinetic remediation (EKR) technique for the soil remediation from the contaminants

ABSTRACT Nowadays, soil pollution caused by petroleum extraction has received much attention due to its negative environmental impact. Hence, the present study aims to propose the optimal solution to confront the environmental damage of contaminated soil. The major novelty of this work lies in the accuracy of the electrokinetic technique used in the study. The electrokinetic remediation (EKR) technique is considered for soil remediation, and seven tests are conducted, among which only four tests present efficient results. Notably, Kaolinite is the soil considered in this study, and the soil is contaminated with diesel fuel. The experiments are performed in 3 and 10 days with 20 and 30 V. The initial pollutant contents are 10% and 20%, based on which the results are analyzed. The obtained results represent the remarkable capability of the EKR method for soil remediation and highlight the most optimal condition for each test. The contributions of this study are considered beneficial for those environmental managers aiming to tackle soil pollution with the best approach.

Free-flow biomolecular concentration and separation of proteins and nucleic acids using teíchophoresis

The ability to preconcentrate, separate, and purify biomolecules, such as proteins and nucleic acids, is an important requirement for the next generation of portable diagnostic tools for environmental monitoring and disease detection. Traditionally, such pretreatment has been accomplished using large, centralized liquid- or solid-phase extraction equipment, which can be time-consuming and requires many processing steps. Here, we present a newly developed electrokinetic concentration technique, teíchophoresis (TPE), to concentrate and separate proteins, and to concentrate nucleic acids. In TPE, a free-flowing sample is exposed to a perpendicular electric field in the vicinity of a mass-impermeable conductive wall and a conductive terminating electrolyte (TE), which creates a high electric field strength zone between the lower mobility sample and the no-flux barrier. Unlike a similar electrokinetic concentration method, isotachophoresis (ITP), TPE does not require a leading electrolyte (LE), yet still enables a continuous field-driven electrophoretic ion migration across the channel and a free-flowing biomolecular concentration at the conductive wall. Here, we demonstrate the use of free-flow TPE (FFTPE) to manipulate biomolecular samples containing proteins or nucleic acids. We first use TPE to drive a 6.6-fold concentration increase of avidin-FITC, and also demonstrate protein separation and stacking between ovalbumin-fluorescein and BSA-AlexaFluor 555, both without the use of a conventional LE. Further, we utilize TPE to perform a 21-fold concentration increase of nucleic acids. Our results show that TPE is biocompatible with both proteins and nucleic acids, requires only 10 V DC, produces no significant sample pH changes during operation, and demonstrates that this method can be used as an effective sample pretreatment to prepare biological samples for downstream analysis in a continuous free-flowing microfluidic channel.

On-chip dielectrophoretic recovery and detection of a lactate sensing probiotic from model human saliva.

Early detection has led to increased survival for multiple cancers; however, the 5-year survival rate of oral carcinoma (OC) has remained at 40% for the last several decades. Screening for OC is routinely done via visual examinations, followed by tissue biopsy and laboratory testing. Point-of-care testing would be a more convenient and widely available alternative for at-risk individuals. Increased lactate production is a hallmark of many head-and-neck tumors, due to the Warburg Effect, where tumor cells favor glycolysis in the place of oxidative phosphorylation. To detect excess lactate, we have modified the commensal bacterium Escherichia coli Nissle 1917 to express fluorescent reporter genes in response to extracellular lactate. Administering this commensal as a mouth wash and subsequently collecting saliva for the detection of the reporter may allow for noninvasive, early detection of cancerous lesions in at-risk individuals. Furthermore, we demonstrate a new on-chip electrokinetic technique to recover these probiotic probes from model saliva fluid to improve the detection of reporter gene activation.

Analysis of Alkali-Induced Soil Heaving in Non-Expansive Soil Using Electrokinetic Model

An attempt has been made in this paper to conduct an Electrokinetic (EK) enhanced large-scale model study to analyze the heaving phenomena observed in fields. The application of the EK technique on fields to study alkali-induced heaving has been simulated in the laboratory using a rectangular and circular model. The EK technique was mainly employed to facilitate alkali soil interaction. Analysis of the geometry of the model boundary on the various physiochemical as well as geotechnical properties of the soil was conducted. Before that, a simple heaving analysis was also performed in an oedometer without the EK technique. Compare to the maximum heaving of 5.55% observed in the oedometer the soil in EK-equipped circular and rectangular models showed the heaving of 5.42% and 4.21% respectively. The heaving pressure recorded for the oedometer was 67.5 t.m-2 while for the circular and rectangular models these values were 37.7 t.m-2 and 18.8 t.m-2 respectively. Further, the value of unconfined compressive strength of soil decreases from 141 kPa to 80 kPa after interaction with alkali and the decrease was more prominent in the circular EK model. However, there was an increase in the friction angle and a decrease in cohesion value after alkali interaction. The structural alteration due to alkali solution was examined by SEM and XRD analysis.

An investigation into the efficiency of electrokinetic and electrokinetic coupled with calcium peroxide permeable reactive barriers techniques for soil remediation using a statistical analysis.

The current study emphasizes onthe applicability of combining the electrokinetic (EK) and permeable reactive barriers (PRB) techniques compared to the simple EK technique. For this purpose, a statistical analysis is conducted using the Fractional Factorial Design statistical method. Also, General Linear Model and Two-sample T-Test analyzes are considered to clarify which type of soil remediation technique represents the highest efficiency. Calcium peroxide, an affordable material with easy capability for cultivation, is utilized in the PRB process to eliminate the soil from diesel contamination. The experiments were performed for 3 days and 10 days, according to which the initial contamination rates of 10 and 20% were selected, and the applied voltages were 20 V and 30 V. Using the innovative remediation technique, the experiments were conducted for 10 days with 20% initial pollution content and the applied voltage of 30 V, the initial gasoil content was about 190.5 mg/g, and after applying the proposed technique, the average final pollution content throughout soil reached approximately 37 mg/g. This experiment was also conducted for the approximately initial gasoil content of 185, 206, and 191 mg/g, which led to the removal efficiency of 79.59%, 78.93%, and 79.15%, respectively. The main novelty of this paper is attributed to the use of calcium peroxide in the EK-PRB technique and the statistical analysis conducted in this study that indicates the remarkable efficiency of the proposed approach. It was also revealed that the efficiency of the proposed technique is on par with the other state-of-art ones presented in the literature and even sometimes outperforms them.

Investigation of the effect of surfactant on the electrokinetic treatment of PFOA contaminated soil

Perfluorooctanoic acid (PFOA) is a persistent, nonbiodegradable environmental pollutant progressively becoming more problematic. Due to its ubiquitous use, PFOA is one of the PFAS chemicals frequently detected in the environment. This study assessed electrokinetic (EK) technology as an in-situ remediation procedure to remove PFOA from kaolinite as a model soil. In this study, a 100 mg/kg of PFOA/kaolinite mixture was used, and the effectiveness of the unenhanced EK was compared with the surfactant-enhanced EK experiments with SDS, NaC, and Tween80. 5% (w/w) surfactants were added to the cathode in the EK experiments of one and two weeks long. The study evaluated the impacts of processing time and electric current on the EK performance. Electroosmosis and electromigration mechanisms affected PFOA transport in soil, causing PFOA to accumulate in the middle of the soil. However, the minimal accumulation of PFOA in the cathode region suggests that electromigration was the main transport mechanism. In a one-week EK experiment, the PFOA removal efficiency in the unenhanced EK process was 14.49% at 10 mA and 19.00% at 20 mA, while in surfactant enhanced EK, it was 17.67% at 10 mA and reached 32.66% at 20 mA. The PFOA removal in surfactant enhanced EK reached 75.58% in the two weeks EK experiments carried out at 20 mA. The NaC-EK experiment exhibited the highest PFOA removal, followed by the SDS-EK experiment and TW80-EK experiment. The outcomes show the feasibility of removing PFAS from contaminated soil using the surfactant-enhanced EK technique. • Enhanced EK for the removal of PFOA from kaolinite soil using three types of surfactants. • PFOA removal from kaolinite doubled by increasing the EK duration from 1 to 2 weeks. • PFOA removal is in the following order EK-NaC > EK-SDS > EK > EK-TW80. • NaC-EK tests achieved 75% PFOA removal, the highest among all surfactant-EK tests.

Continuous Molecular Concentration and Separation Using Pulsed-Field Conductive-Wall Single-Buffer Teı́chophoresis

We present an experimental study of a novel continuous electrokinetic molecular concentration and separation technique termed teı́chophoresis (TPE). We demonstrate here that TPE can serve as a potential alternative to the electrokinetic method isotachophoresis (ITP). In ITP, an electric field serves to focus charged species between a low-mobility terminating electrolyte (TE) and a high-mobility leading electrolyte (LE). Similarly, TPE serves to focus charged species between a low-mobility TE; however, the LE is conveniently replaced with a no-flux boundary generated by a conductive wall. The electric field can still penetrate this no-flux region due to the wall's finite conductivity, but ion migration is impeded due to the physicality of the wall. We perform detailed concentration and separation experiments across varying electric potentials, flow rates, and TE concentrations. We also show that TPE can achieve a 60,000-fold concentration factor continuously without an LE, using only 10 V DC. In comparison with conventional batch-driven ITP, continuous free-flow wall TPE (FFTPE) has the potential to serve as a simplified alternative method. FFTPE offers a high concentration power at a fraction of the required voltage, does not require an LE, and has the increased throughput potential of a continuous process.

A modeling approach for electrokinetic transport in double-porosity media

Electrokinetic techniques have attracted considerable attention due to their competitive advantage in enhancing transport phenomena and remediation of low permeability soils. However, many types of low-permeability porous media, such as active clays like bentonite, present a double porosity structure that strongly affects mass transfer processes. In this work, we develop a modeling approach to simulate electrokinetic transport in double porosity media. The proposed model is based on the previously released code M4EKR and explicitly considers the transport due to electromigration as well the effects of the electrical diffuse layer in charged porous media. For this purpose, two modeling levels have been established: one associated with the soil macrostructure (bulk water) and the other with the microstructure (diffuse layer). At the latter level, the effect of the electrostatic interactions imposed by the negative charge of the clay particles is modeled with a Donnan approach. The comparison of the results between synthetic cases in single and double porosity systems shows the fundamental role of the microstructural modeling level. High enrichment of cations and, therefore, high cationic fluxes are produced in such microstructural level. These mechanisms significantly modify the extent of cation transport by electromigration and, thus, directly influence the transport of other species determined by the electrostatic interactions.

Enhanced remediation of surface-bound hexavalent chromium in soils using the acidic and alkaline fronts of electrokinetic technology

In the subsurface environment, highly toxic hexavalent chromium (Cr(VI)) control and remediation are essential to avoid further ecological impacts and reduce environmental risks. This paper investigated the enhanced Cr(VI) electrokinetic removal in the soil through the approaching cathode method. Besides, a novel four-step sequential fractionation method was used to reflect the strength of Cr(VI) binding to the soil. The approaching cathode enhanced the electrokinetic delivery of surface-bound Cr(VI) by advancing the alkaline front for Cr(VI) desorption and improving the electric potential flattening of the soil layers. Desorption of Cr(VI) by the alkaline front involved converting the inner-sphere complexes form of Cr(VI) to a weakly adsorbed form susceptible to ionic strength. In addition, the acidic front provided a favorable environment for the photochemical reduction of Cr(VI) by soil species or the added citrate as the electron donors. Improving the potential distribution could regulate the energy consumption of individual soil layers and efficiently operate the electrokinetic transfer of pollutants. The work results have significant scientific and practical significance for applying the in-situ electrokinetic technique in subsurface pollution control.

Electrokinetic Preconcentration and Label-Free Electrical Detection of Sars-Cov-2 RNA at a Packed Bed of Bioconjugated Microspheres

In diagnostics, point-of-care (POC) devices, such as lateral flow assays, play an important role due to their ease of use, practical application, and fast response. However, one of the major limitations of POC devices is low sensitivity. To address this limitation, electrokinetic techniques have been utilized to enrich the target analyte prior to detection. In one such technique, ion concentration polarization (ICP), an ion depleted zone (IDZ) is formed near an ion permselective membrane or electrode following the application of an external electric field. The low conductivity of the IDZ supports the formation of an extended electric field gradient. Enrichment arises from focusing of a charged analyte along this electric field gradient in the presence of opposing fluid flow. ICP focusing is a reliable technique for the enrichment and mobility-based separation of charged species, such as DNA, RNA, or proteins. However, ICP focusing is negatively impacted by electroconvective vortices that drive unwanted mixing.We utilize an out-of-plane faradaic ion concentration polarization (fICP) technique that employs a 3D porous electrode and an adjacent packed bed of insulating microbeads to improve the stability of the enriched plug. In this work, we exhibit the detection of SARS-CoV-2 RNA, extracted from lysed virus, at subpicomolar concentrations in this microfluidic device. Here, the insulating beads are bioconjugated with an uncharged peptide nucleic acid (PNA) oligoprobe that hybridizes with the target RNA. The resulting increase in negative charge on the bead surface leads to a shift in a current-voltage curve between the 3D electrode and a driving electrode at the microchannel inlet. This shift in conductivity serves as a non-optical sensing mechanism for detection of the hybridized SARS-CoV-2 RNA. Most notably, this enrichment and sensing scheme utilizes off-the-shelf streptavidin-modified beads, making it highly versatile, while the reagent-free approach and low driving voltage render it amenable to POC implementation.This work is supported by a grant from the Roy J. Carver Charitable Trust.

Remediation alternatives for an abandoned gold mine contaminated with mercury in Brazil / Alternativas para descontaminação de mina de ouro abandonada contaminada com mercúrio no Brasil

Heavy metal contamination of soils has generated two major problems, namely, loss of land value and health risk for people near contaminated sites. Studies on soil remediation are typically conducted on a pilot scale under very controlled conditions. This is a misleading approach, once the complexity of the actual biogeochemical soil conditions may causes inefficiency in full scale real-world application. In addition, environmental impacts of remediation practices themselves are often ignored, which may make them unfeasible. In 2002, an occurrence of mercury in an abandoned old gold mine was detected in a rural area of Descoberto, Brazil. In 2014, the State Public Prosecutor required from the responsible State Environment Agency, a remediation project to the area. This study compares alternatives for remediation of the contaminated area. Also a historical approach on mercury amalgamation in gold mining in the region, in order to estimate the amount of mercury remaining in the site. The geochemical characterization of the contaminated area was performed to describe the contamination process. The results were compared with the remediation proposal advocated by the Brazilian Ministry Public, and some alternatives for decontamination of the area were studied. The electrokinetic method has displayed the lowest overall unit cost, between US$ 120.00/t and US$ 260.00/t. The residual Hg concentration after four cycles of the electrokinetic technique was estimated at 1.28 mg (Hg)/kg (soil), slightly higher than the intervention value for agricultural soil, which is 1.20 mg (Hg)/kg (soil).