Electrokinetic Remediation Technology Research Articles

Bioavailability enhancement of petroleum-contaminated soil by electrokinetic remediation

The Electro kinetic Remediation Technology (EKR) is recognized as the most potential remediation technology for soils with low permeability, like clay soil characteristics. Electrokinetic treatment could increase the bioavailability of contaminants in bioremediation petroleum-contaminated soil. The study, “Bioavailability enhancement of petroleum contaminated soil by electrokinetic remediation,” is experimental research in a laboratory to improve the bioavailability of petroleum hydrocarbons on clay during bioremediation with initial treatment using electrokinetic remediation techniques, finding optimum electrokinetic operating conditions of remediations, and analyzing the mechanism of remediation process in contaminated soil. Bioavailability enhancement was studied for 35 days. Polluted soil was treated with an electrokinetic box test (17cm×12cm×10cm), and DC power was used for 48 hours. Total Petroleum Hydrocarbon (TPH) concentration was determined by gravimetric methods. The results showed that the characteristics of the soil samples were dominated by 49.31% clay. The initial concentration of TPH in polluted soil is 3.7%. The electrokinetic applications during 48 hours and followed by bioremediation for 35 days those processes removed TPH up to 80.74 % (from 33780.66 mg HC (kg dry w)-1 to 6506.155176 mg HC (kg dry w)-1. There is an increase in bioavailability indicated by the rise in bacterial populations and an increase in biodegradation after electrokinetic remediation. With this approach, bioavailability has been increased by 70.18%. Bio-electrokinetic remediation is the recommended method for polluted clay soils with low bioavailability.

Effect of Charcoal and Active Carbon as Filter Media on Electrokinetic Remediated Crude Oil Contaminated Soil

Research has shown that traditional electrokinetic remediation (EKR) technology has limited efficiency against different contaminants and soils. This has led to the use of several strategies to enhance the traditional EKR for higher contaminants removal efficiency. This paper separately uses charcoal and active carbon each 1 cm thick as filter media in EKR to enhance the removal of crude oil from crude oil contaminated soil (COCS) containing 78,600 mg/kg of crude oil. The filters are placed very close to the anode compartment containing 0.01 M NaOH electrolytes. Graphite electrodes are used in a face to face configuration to pass 1 V DC/cm through the COCS. Crude oil removal efficiencies of 81.4% and 84.6% respectively are obtained from the EKR setups containing charcoal and active carbon filters after 18 days and 14 days of remediation respectively. This makes active carbon a better filter medium than charcoal for COCS. The results of the chemical oxides compositions show improvement from non-lateritic COCS to lateritic for the filter media enhanced EKR soil. Although active carbon has proven to be a better filter medium compared to charcoal for use in enhancing EKR technology for COCS. Nonetheless, with over 80% removal efficiency, charcoal or active carbon filters be used to enhance EKR remediation of COCS.

Enhanced reduction of Cr(VI) in UV/EKR system by organic acids: Focus on Cr(VI) desorption and Fe(III) catalysis

Reducing highly toxic and mobile Cr(VI) to environmentally less hazardous Cr(III) is vital research for remediating Cr-contaminated soil. In this study, a UV/EKR system, which combined electrokinetic remediation (EKR) technology with ultraviolet (UV) photoreduction, was employed to investigate the enhanced reduction of Cr(VI) in actual contaminated soil by oxalic, malic, and tartaric acids. The results demonstrated that the introduction of UV radiation resulted in the removal of 99.49% of Cr(VI) from the anolyte and further enhanced the removal efficiency of high-concentration Cr(VI) in the near-anode soil layer by 14.83% compared to traditional EKR. Among the three acids, malic acid exhibited superior performance, as it alleviated the clogging caused by precipitates, provided more photocatalyst Fe(III), and reduced the retention of the reduction product Cr(III) in the soil. This resulted in the removal rates of 90.38%, 83.82%, and 27.14% of water-soluble, weakly bound, and strongly bound Cr(VI), respectively in the near-anode soil layer. Therefore, the combination of organic acids and the UV/EKR technique shows high compatibility, offering a promising solution to the poor reduction efficiency of Cr(VI) in actual soil in the field of EKR. This approach provides new insights for the in-situ remediation of Cr-contaminated soil.

Filter media enhanced electrokinetic remediated crude oil contaminated soil: investigation of its engineering properties and its suitability for road construction

Research have shown how electrokinetic remediation (EKR) technology attempts to tackle the challenge of soil contamination by crude oil. However, the suitability of the resulting remediated soils for use in road construction have not been well reported. This work investigates the engineering properties of filter media enhanced electrokinetic remediated crude oil contaminated soil (COCS) with a view to ascertain its suitability for use in road construction by comparing the performance of charcoal and active carbon as filter materials. COCS collected at a depth of 1m from the Nigerian Pipeline and Storage Company, Kaduna was remediated by using graphite electrodes to pass 1V DC/cm across EKR setups enhanced by incorporating a 1cm thick charcoal and active carbon separately as filter materials across the setups. Average removal efficiencies of 81.4% and 84.6% were obtained against the 78,600 mg/kg oil content of the COCS from charcoal and active carbon filter media enhancements respectively. This showed that active carbon, with higher removal efficiency, is a better filter medium for COCS than charcoal. The compaction and California bearing ratio (CBR) properties of the COCS also improved with the filter media enhanced EKR. However, the CBR values for the filter media enhanced EKR soils only meet the 20% minimum requirements for Type 2 sub-base course materials specified for light trafficked Nigeria roads. As such, charcoal or active carbon filter media enhanced EKR technology can be adopted for remediating COCS for light trafficked Nigeria road construction in areas not subjected to flooding.

Effect of Ethanol and Acetone Cosolvents in Enhancing Electrokinetic Remediation of Crude Oil Contaminated Soil Obtained from a Pipeline and Storage Company, Kaduna Nigeria

A lot of work has shown that despite the effectiveness of the traditional electrokinetic remediation (EKR) technology in decontaminating soils with different types and amounts of contaminants, it can be enhanced by a number of strategies for extra effective performance. This work presents the effect of ethanol and acetone cosolvents in enhancing EKR of crude oil contaminated soil (COCS), collected at a depth of 1 m from a petroleum pipeline and storage company, Kaduna Nigeria using graphite electrodes to pass 1 V DC/cm across EKR setups enhanced by incorporating 20% ethanol and 20% acetone separately as cosolvents in the anode compartments of the setups. The total petroleum hydrocarbon results showed that the crude oil content of 78,600 mg/kg present in the COCS exceeds permissible limits for soils. Average removal efficiencies of 74.61% and 67.79% obtained from 20% ethanol and 20% acetone cosolvents enhancements respectively showed that 20% ethanol, with higher removal efficiency, is a better cosolvents for COCS than 20% acetone. Although 20% ethanol has been shown to be a better cosolvents compared to 20% acetone, either of them can be incorporated into EKR technology for enhancing the remediation of COCS.

Simultaneous electrokinetic removal and in situ electrochemical degradation of a high nitrogen accumulated greenhouse soil

High nitrogen (N) concentration in farmland soil can easily cause the eutrophication of water bodies and a decline in soil fertility. As a new technology for quick in-situ nitrate restoration strategy, electrokinetic remediation has high efficiency, reliability, and competitive economic feasibility. However, the traditional electrokinetic remediation configuration will cause excessive acidification and alkalization of soil. The treatment of produced nitrogenous waste liquid was also necessary. In this study, the optimal design by the cation exchange membrane was adopted to solve the problems of soil over-acidification (pH<4) and over-alkalization (pH>10) caused by traditional electrokinetic remediation technology. Adding NaCl to the electrolyte, the anodic oxidation of ammonium was promoted, and the concentration of N in the electrolyte was reduced. Citric acid was added to stabilize pH and promote the conversion of NO3−-N. The removal efficiency of NO3−-N in the soil could reach 90%, 93%, and 97%, respectively, after 5, 10, and 15 days of electrokinetic treatment. The NO3−-N concentration in the processing solution was below 4 mg/L, the NH4+-N concentration was less than the method detection line, the total nitrogen concentration was not more than 8 mg/L, and the N in the waste liquid did not need secondary treatment. This study revealed the electrochemical behavior of nitrate on stainless steel electrodes, indicating that active chlorine can promote the anodic oxidation process of NH4+. At the same time, it was found that citric acid positively affected nitrate transformation. Based on the clarification of the transport and transformation mechanism, this study inspired optimizing our existing electric remediation technology to solve the problem of high N-accumulation in soils.

Surfactant combined with PASP enhance electrokinetic remediation removal heavy metal and hydrocarbon from contaminated soil

ABSTRACT In this work, a new electrokinetic remediation technology was used to remove heavy metal and hydrocarbon from contaminated soil. The surfactant combined with PASP (Polyaspartic acid) was used to enhance heavy metal and hydrocarbon removing from contaminated soil. Electric current, soil pH, electroosmotic flow, water content variation, heavy metal removal efficiency and residual content distribution, heavy metal speciation, removal of TPH (total petroleum hydrocarbons), group composition of oil, mechanism of enhance electrokinetic remediation were investigated during the electrokinetic remediation process. Results indicated that Rhamnolipid, PASP, Tween 80 and SDS (sodium dodecyl sulphate) can reduce the heavy metal precipitation during the electrokinetic remediation process. Also, it can promote EOF (electroosmotic flow) and electrolyte evaporation during the EK remediation. The rhamnolipid (3.0 g.L−1) combined with PASP (3.0 g.L−1) can significantly improve Cu, Cr, Ni, Pb and hydrocarbon mobility and solubility during the EK remediations. Cu, Cr, Ni and Pb obtained the dominant removal efficiencies, which were 66.0 ± 3.45%, 61.2 ± 4.35%, 67.1 ± 3.21%, 61.8 ± 4.22%, respectively. Also, the TPH has attained a dominant removal efficiency of 80.2 ± 4.36% after the enhanced electrokinetic remediation. This research provides a novel in-situ remediation approach for reducing heavy metals and hydrocarbon from contaminated soil in an environmentally friendly way.

Tandem Electrokinetic/Electrocatalytic Remediation of Pfas in Soils

Per-/polyfluorinated species (PFAS) are a class of widely used, highly stable chemicals that do not readily break down in the environment or human body. As a result of their widespread use and persistence in the environment, PFAS can be found in soil, air, and water at numerous sites across the United States. Recent work has linked exposure to some types of PFAS found in the environment to adverse health effects in humans. The bio-accumulative nature of PFAS along with the potential adverse health effects has provided strong motivation for active remediation of these emerging contaminants at environmental sites. Development of energy- and cost-efficient technologies for the in-situ treatment of PFAS-contaminated soils would greatly facilitate efforts to remediate these contaminated sites and alleviate the public health threat they represent.This talk will discuss recent efforts to develop a tandem electrokinetic/electrocatalytic technology for energy-efficient concentration and destruction of PFAS in contaminated soils. In this approach (Figure A), electrokinetic soil remediation technology is used to drive the PFAS contaminants to a localized area around the electrokinetic anode and electrocatalysis reactors situated near this electrokinetic anode degrade and destroy the concentrated PFAS species. Data will be presented describing the electrokinetic transport observed for various C4-C12 linear-chain PFAS in a Dayton, OH till soil on the bench scale (see Figure B). Experimental results to date suggest that larger PFAS species (above ~C6) experience sufficiently strong physicochemical attraction to the soil particles that electrokinetic transport is mostly or completely suppressed. Based on these results, current work is identifying ways to improve electrokinetic PFAS remediation by disrupting these PFAS-soil interactions in a fashion that is economically and environmentally favorable. Results demonstrating the ability to enhance electrocatalytic PFAS destruction through the use of pulsed-waveforms (relative to traditional direct current methods) will also be presented.Figure Caption. (A) Mechanism of tandem electrokinetic/electrocatalytic PFAS destruction. (B) Bench-scale apparatus for soil electrokinetics tests. Figure 1

Enhanced electrokinetic remediation of heterogeneous aquifer co-contaminated with Cr(VI) and nitrate by rhamnolipids

Electrokinetic remediation is an in situ remediation technique that is gaining increasing attention in the field of groundwater contaminant removal. Aquifers co-contaminated with hexavalent chromium (Cr(VI)) and nitrate are becoming more common and research on the remediation of this pollutant is attracting worldwide attention owing to the considerable human health hazards of Cr(VI) and nitrate, including carcinogenicity, genotoxicity, and cytotoxicity. Electrokinetic remediation technology has significant advantages for the treatment of heterogeneous aquifers. This is the first study on the electrokinetic remediation of an aquifer co-contaminated with toxic heavy metals and inorganic salts. This study investigated the feasibility of electrokinetic remediation for layered heterogeneous aquifers co-contaminated with Cr(VI) and nitrate in the presence of groundwater flow, and it also assessed the ability of the anionic biosurfactant rhamnolipid to enhance the remediation effect. Changes in the pH, electrical conductivity, Cr(VI), nitrate, electric current, and the distribution of energy consumption and the voltage contour were analyzed through seven sets of experiments. The highest removal rates of Cr(VI) and nitrate were 97.30% and 87.08%, respectively. Rhamnolipids greatly enhanced the electrokinetic remediation process, especially in medium with moderately low permeability: 1) rhamnolipids improved Cr(VI) removal(from 1.62% of EK3 to 85.57% of EK6 and from 48.42% of EK4 to 94.18% of EK7) through migration and reduction; and 2) rhamnolipids improved nitrate removal (from 13.03% of EK3 to 71.72% of EK6 and from 23.69% of EK4 to 78.43% of EK7) through enhanced migration.

Roles of oxidant, activator, and surfactant on enhanced electrokinetic remediation of PAHs historically contaminated soil.

Electrokinetic (EK) remediation technology can enhance the migration of reagents to soil and is especially suitable for in situ remediation of low permeability contaminated soil. Due to the long aging time and strong hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) from historically polluted soil, some enhanced reagents (oxidant, activator, and surfactant) were used to increase the mobility of PAHs, and remove and degrade PAHs in soil. However, under the electrical field, there are few reports on the roles and combined effect of oxidant, activator, and surfactant for remediation of PAHs historically contaminated soil. In the present study, sodium persulfate (PS, oxidant, 100 g L-1) or/and Tween 80 (TW80, surfactant, 50 g L-1) were added to the anolyte, and citric acid chelated iron(II) (CA-Fe(II), activator, 0.10 mol L-1) was added to catholyte to explore the roles and contribution of enhanced reagents and combined effect on PAHs removal in soil. A constant voltage of 20 V was applied and the total experiment duration was 10 days. The results showed that the removal rate of PAHs in each treatment was PS + CA-Fe(II) (21.3%) > PS + TW80 + CA-Fe(II) (19.9%) > PS (17.4%) > PS + TW80 (11.4%) > TW80 (8.1%) > CK (7.5%). The combination of PS and CA-Fe(II) had the highest removal efficiency of PAHs, and CA-Fe(II) in the catholyte could be transported toward anode via electromigration. The addition of TW80 reduced the electroosmotic flow and inhibited the transport of PS from anolyte to the soil, which decreased the removal of PAHs (from 17.4 to 11.4% with PS, from 21.3 to 19.9% with PS+CA-Fe(II)). The calculation of contribution rates showed that PS was the strongest enhancer (3.3~9.9%), followed by CA-Fe(II) (3.9~8.5%) (with PS), and the contribution of TW80 was small and even negative (-1.4~0.6%). The above results indicated that the combined application of oxidant and activator was conducive to the removal of PAHs, while the addition of surfactant reduced the EOF and the migration of oxidant and further reduced the PAHs removal efficiency. The present study will help to further understand the role of enhanced reagents (especially surfactant) during enhanced EK remediation of PAHs historically contaminated soil.

Environmental Footprint Analysis Tools of Electrokinetic Remediation (EKR): A Bibliometric View of The Literature

Electrokinetic remediation (EKR) technology has been applied in both lab and pilot scales to actual size since 1993. Recently, sustainable measures for EKR have been relatively considered a form of minimizing resource use during land restoration. This study aims to identify the environmental footprint assessment tools that arise during the EKR process according to the scale of the application. 284 scientific literature indexed by Scopus and the Web of Science during 2011-2021 was analyzed using the Systematic Literature Review (SLR) method, and the results were visualized using the VOSviewer application. The investigated parameters included the amount of scientific literature, year of publication, topics of scientific literature, authors of literature and their country of origin, names of reputable journals, and a number of citations. Research results from 43 scientific literature studies show that different environmental footprint analyses in EKR have been applied in various parts of the world. Most of environmental footprint assessment tools used by researchers include life cycle assessment (LCA) and green and sustainable remediation (GSR) tools. A recommendation is given to the GSR tools developed by the US EPA because known to have the simplest analytical method compared to other methods.

Insights into the development of electrokinetic remediation technology: A bibliometric analysis

Electrokinetic remediation (EKR) is a powerful technique aimed at pollutant removal in soil, sludge, mine tailings, and so on. In the current work, we performed a bibliometric analysis of the research on EKR for the period of 1900–2018 on the basis of the core database of the Science Citation Index Expanded. In addition to a basic analysis of the research characteristics, keywords were analysed for four major participants: USA, China, Spain, and South Korea. The periods of 1990–2001, 2002–2008, and 2009–2018 were studied using the keyword analysis method to gain insights into the development of EKR and predict its future trends. The results revealed that the related research field in the USA was broad during the study periods. Meanwhile, China was interested in fluorine pollution and contamination in red soil. Spain paid close attention to pollution due to agricultural contamination. South Korea focused on radioactive element pollution. The number of papers published over a period of 28 years increased steadily and continued to rise after 2008. The combined techniques of EKR + phytoremediation and EKR + bioremediation were successively utilised by scholars over time, and the latter is expected to demonstrate vitality in the future.

Remediation of High Concentration Chromium Contaminated Soil by Enhanced Electrodynamic Method

High concentration of chromium salt has caused serious pollution to the environment since its production. The long-standing chromium residue has polluted the soil, and the total chromium concentration of some polluted soil has reached 30000 mg / kg. For the remediation of chromium contaminated soil, the enhanced electrodynamic method was proposed. In order to improve the efficiency of electrokinetic remediation of chromium contaminated soil, two enhanced electrokinetic remediation technologies were proposed: Electrokinetic oxidation enhanced remediation technology and electrokinetic enhanced remediation technology. (III) in soil was polluted by oxidant chromium oxide to increase the content of dissolved (VI),so as to improve the efficiency of electric repair, in order to find a suitable PRB medium as a breakthrough to improve the repair efficiency. The experimental results show that compared with the traditional electrodynamic technology, the enhanced electrodynamic method can effectively improve the removal rate of total chromium in the soil, and provide technical support for the enhanced electrodynamic remediation of chromium contaminated soil. The pH control system makes the pH of anode and cathode electrolyte always maintain acidic, and the H+ migration speed is faster than that of OH-, and the pH of soil near the anode is lower than that near the cathode.

Electrokinetic remediation technology of heavy metal contaminated soil based on improving soil electrical conductivity

Electrokinetic remediation technology of heavy metal contaminated soil based on improving soil electrical conductivity

Effect of Mussel Shells as a Permeable Reactive Barrier in Municipal Sewage Sludge Treatment by Electrokinetic Remediation

IIn this work, it was evaluate the utilization of mussel shells (raw and calcinated) as a permeable reactive barrier (PRB) for the treatment of municipal sewage sludge (MSS) contaminated with heavy metals, creating a novel combined system, which integrates two technologies: electrokinetic remediation technology, and adsorption by the utilization of mussel shells adsorbents. Regarding the adsorption process into the mussel shells adsorbents, it was also aimed to study the influence of aragonite and calcite on the adsorption of lead (Pb), copper (Cu), chromium (Cr), and zinc (Zn). For the preparation of the PRB, it was used three adsorbents: MEXMT (raw mussel shells); MEXMT 600 (mussel shells calcinated at 600°C) and finally, a commercial calcium carbonate (CCCom). It was applied an electric current of 1 V cm-1 and it was used an adsorbent/sludge ratio of 30 g kg-1 of contaminated sludge for the preparation of the PRB. Results proved that this process is perfectly suited for the removal of the heavy metals understudy from the sludge, especially with MEXMT (raw mussel shells) adsorbent. With this adsorbent, at the end of the 92 hours of operation time, it was obtained high removal rates for each metal in study. Results demonstrate that higher removals rates were achieved in lead (92%), followed by zinc (82%), copper (76%), and finally chromium with 72%. Based on these results, it was proved the technical viability of the proposed technology (electrokinetic remediation with raw mussel shells as a permeable reactive barrier) to treat municipal sewage sludges.

Emerging organic contaminants in soil irrigated with effluent: electrochemical technology as a remediation strategy

The effluent reuse for soil irrigation is foreseen as a possible strategy to mitigate the pressure on water resources. However, there is the risk of potential accumulation in soil of emerging organic contaminants (EOCs).In the present work the electrokinetic remediation (EKR) technology, use of direct current, was applied for the removal of EOCs from a soil irrigated with effluent. For this, a soil collected from a rice field (located in Portugal) was mixed with spiked effluent to simulate flood irrigation in one time-period. The experiments were carried out for 6 days applying a low current intensity of 2.5 mA. Different current strategies were tested: continuous mode, reversed electrode polarization (REP), On/Off time periods, and the combination of the last two. The target EOCs comprises a list of six pharmaceuticals and personal care products widely detected in treated wastewater.This study showed that once introduced in soil through effluent irrigation, 20–100% of the EOCs were still present in the soil after 6 days. EKR enhanced up to 20% of the EOCs removal when comparing with control (without current). The EOC removals showed to be related to the microcosm location (anode, central or cathode sections) and dependent of EOCs characteristics. Soil characteristics did not change when On/Off system was combined with REP as a current strategy, and a more homogenous removal of the studied EOCs was achieved in the tested conditions. EKR showed to be a promising technology to be applied in EOCs contaminated soils, not only for removal purposes, but also to avoid possible dispersion in the environment.

Electrokinetic-Fenton for the remediation low hydraulic conductivity soil contaminated with petroleum

The use of electrokinetic Fenton (EK Fenton) process, as promising soil remediation approach, was investigated by using an iron electrode with different supporting electrolytes (tap water, H2O2, and citric acid) to depollute soil spiked with petroleum where kaolin was selected as low hydraulic conductivity. The results clearly confirm that, the combination of electrokinetic remediation (EK) and Fenton technologies, is an efficient oxidizing approach for removing hydrocarbons from this kind of soil. In fact, the electrokinetic Fenton reactions and the control of the soil pH conditions by adding citric acid enhanced the oxidation process because the addition of the H2O2 with iron electrode resulted in higher removal efficiencies (89%) for total petroleum hydrocarbons (TPHs). These figures allowed to confirm that EK Fenton process with pH control contributed for the transport of H2O2 and Fe2+ ions in the soil by electromigration and eletro-osmotic phenomena. Conversely, no control of pH conditions when only EK was applied, achieved lower hydrocarbons removal (27%) after 15 d of treatment due to the precipitation of iron ions. Finally, the efficiency of the EK Fenton remediation prevented the generation of secondary effluent with higher organic content, avoiding its treatment by other advanced oxidation process.

Research progress of in-situ remediation of polluted soil and groundwater by electrokinetic and permeable reaction barrier

The combination of electrokinetic remediation and permeable reactive barrier (EK-PRB combined remediation technology) is a new green technology for in-situ removal of soil and groundwater pollutants. This technology combines the advantages of electrokinetic remediation and permeable reactive barrier technology, and can deal with different types of organic and inorganic pollutants. It has the characteristics of convenient installation, simple operation, no secondary pollution, etc., and has broad development and application prospect. This paper introduces the technical principle of EK-PRB, summarizes the latest research results on the remediation of heavy metal, organic matter and nitrate contaminated soil and groundwater by the electrokinetic remediation and PRB. Finally,the technical problems of combinated remediation were pointed out, and development and application direction of this technology was noted.

Charge interactions, reaction kinetics and dimensionality effects on electrokinetic remediation: A model-based analysis

The potential of electrokinetic remediation technologies (EKR) for the removal of different contaminants from subsurface porous media has been increasingly recognized. Despite electrokinetic applications have shown promising results, quantitative understanding of such systems is still challenging due to the complex interplay between physical transport processes, electrostatic interactions, and geochemical reactions.In this study, we perform a model-based analysis of electrokinetic transport in saturated porous media. We investigate the effects of: (i) Coulombic interactions between ions in the system mobilized by electromigration, (ii) reaction kinetics on the overall removal efficiency of a non-charged organic contaminant, and (iii) dimensionality and different electrode configurations. The results show that such effects play a major role on the performance of electrokinetic systems. The simulations illuminate the importance of microscopic processes, such as electrostatic interactions and ion-specific diffusivities, and their non-intuitive macroscopic impact on the delivery of charged amendments and on the efficiency of contaminant removal. The insights of this study are valuable to improve and optimize the design and the operational strategies of electrokinetic remediation systems.

Analysis of mobilization of inorganic ions in soil by electrokinetic remediation

Saline soil has imposed a serious threat on many expressway engineering and agricultural areas. This paper describes the performance of saline soil treatment using electrokinetic remediation technology. Comparison study involving sample soil and in situ soil is carried out. Two different electric fields, i.e., uniform and non-uniform are utilized to promote the migration of inorganic ions contained in the soil toward the electrode area. The effects of different electric field types and potential gradient ion migration rate in soil are investigated. The test result reveals that a uniform electric field of a constant potential gradient of 1 V/cm drives the Cl− through the sample soil at a rate of 1.36 cm/h. Moreover, larger potential gradients could make ions migrate faster, but more electrical energy is consumed in such a way. Compared with uniform electric field, the non-uniform process maintains the soil pH values more effectively and consumes less electrical energy. A desirable result of removing Na+ in soil is expected using electrokinetic remediation technology under four-times scaling up of soil volume.