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Electrochemical remediation for contaminated soils, sediments and groundwater
Published in Katalin Gruiz, Tamás Meggyes, Éva Fenyvesi, Engineering Tools for Environmental Risk Management – 4, 2019
Electrokinetic remediation is a powerful technology that can be used for the remediation of contaminated soils, sludge, sediments, wastes and other porous matrices. It is also called electrokinetics, electroremediation, or electroreclamation in literature. Electrokinetic technology is based on a low intensity electric field applied to the contaminated soil (Acar, 1993). The electric field mobilizes the contaminant chemical species that migrate under the effect of the electric field towards one of the electrodes. The key transport processes are electromigration (the movement of ions towards the opposite electrode) , electroosmosis (the net flux of water in the interstitial fluid induced by the electric field), and electrophoresis (the movement of charged particles towards the opposite electrode). Diffusion (the movement of chemical species due to a concentration gradient) is usually insignificant compared to other transport mechanisms.
Phytoremediation Potential of Some Bioenergy Crops
Published in S Rangabhashiyam, V Ponnusami, Pardeep Singh, Biotechnological Approaches in Waste Management, 2023
V. Anbuganesan, R. Vishnupradeep, A. S. Archana, S. Soundarya, L. Benedict Bruno, M. Rajkumar
HM have been claimed to be removed using a wide range of physical processes, involving detoxifying the polluted system by using metals’ physicochemical properties. The physical method of remediation includes soil replacement (Yao et al., 2012), soil washing (Abumaizar and Smith, 1999), soil isolation (Zheng and Wang, 2002), soil adsorption (Muharrem and Olcay, 2017), electrokinetic method (Sivapullaiah et al., 2015), membrane filtration (Khulbe and Matsuura, 2018), granular activated carbon (Sani et al., 2017), vitrification (Mallampati et al., 2015) and photocatalysis (Tahir et al., 2019). Earlier soil replacement, washing and isolation approaches successfully isolate polluted soil and ecosystem, reducing environmental impact. These processes dilute the concentration of HM in the soil and render increased potential in soil functionality. Despite its advantages, because of the significant labour requirements, these techniques are only suitable for extremely contaminated soils with a limited space as well in case agricultural fields there exist a high risk of losing soil fertility. The process of soil vitrification includes the involvement of high temperature in the HM-contaminated soil site in order to encourage the formation of materials for preventing the movement of HM across the contaminated soil site. The tons of Zn- and Pb-rich ceramic wastes were cleaned up by using in-field Joule heating vitrification at about 1850 oC (Dellisanti et al. 2016). Solar technology was used by Navarro et al. (2013) to vitrify waste from Ag–Pb mines in Spain. They discovered that vitrification rendered Zn, Mn, Fe and Cu immobile in the contaminated soil itself. The thermal treatment at high temperature (1350°C) immobilized the HM (Zn, Ni, Mn and Cu) and restricted the leaching out from the soil, thereby reducing the environmental risk. Soil electrokinetic remediation works on the basis of establishing an appropriate electric field gradient on two sides of an electrolytic tank holding saturated contaminated soil. The usage of ideal nanomaterials such as nano-photocatalyst could improve the remediation of HM in the soil. These photocatalysts have many specific properties with high adsorption ability for HM, and the ability to convert high toxic elements into low toxic effluents at lower costs (Tahir et al., 2019).
Basics and Applications of Electrokinetic Remediation
Published in Donald L. Wise, Debra J. Trantolo, Edward J. Cichon, Hilary I. Inyang, Ulrich Stottmeister, Remediation Engineering of Contaminated Soils, 2000
Akram N. Alshawabkeh, Ray Mark Bricka
Electrokinetic remediation may also effective for the removal of organic pollutants such as phenol, gasoline hydrocarbons, and TCE from contaminated soils. Successful application of the process has been demonstrated for extraction of the BTEX (benzene, toluene, ethylene, and m-xylene) compounds and trichloroethylene from kaolinite specimens at concentrations below the solubility limit of these compounds (42,43). High degrees of removal of phenol and acetic acid (up to 94% ) were also achieved by the process (44,45). Acar et al. (39) reported removal of phenol from saturated kaolinite by the technique. Two pore volumes were sufficient to remove 85-95% of phenol at an energy expenditure of 19-39kWh/m3. Wittle and Pamukcu (29) investigated the feasibility of removal of organics from different synthetic soil types. Tests were conducted on kaolinite, Na-montmorillonite, and sand samples mixed with different organics. Their results showed the transport and migration of acetic acid and acetone toward the cathode. Samples mixed with hexachlorobenzene and phenol are reported to show accumulation at the center of each samples. The results of some of these experiments were inconclusive, either because contaminant concentrations were below detection limits or because the samples were processed for only 24h, which might not be sufficient to demonstrate feasibility in electrokinetic soil remediation. Recently, the U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), Monsanto, General Electric, and Dupont have also applied electric fields for electroosmotic extraction using layered horizontal electrodes in what is called the "Lasagna TM," process.
Modeling and optimizing by the response surface methodology of the Pb(II)-removing effectiveness from a soil by electrokinetic remediation
Published in Soil and Sediment Contamination: An International Journal, 2023
K. Kada, A. Abdi, Z. Bekkar Djelloul Sayah, D. E. Akretche, S. Rafai, H. Lahmar, M. Benamira
Heavy metal pollution is one of the major environmental concerns in the world because of their toxic properties and the adverse effects they can cause to the environment and human health, besides their low solubility and long persistence. Owing to the high toxicity level of the heavy metal-polluted soils (Reddy and Cameselle 2009; Zhang et al. 2014), several remediation technologies are already available, such as thermal desorption, excavation to involve digging up and transport of contaminated soil to hazardous waste sites for landfilling (Khan et al. 2011), solidification and leaching, which in many cases require significant technical and financial resources (Baraud et al. 1997). Many researchers (Acar and Alshawabkeh 1993; Alcántara et al. 2012) have successfully applied the electrochemical process of electrokinetic remediation (EKR) for decontaminating polluted soils containing toxic species, such as chromium (Liu et al. 2012), cadmium (Chen et al. 2006; Torabi et al. 2021), mercury (Asce, Chaparro, and Saichek 2003) and arsenic (Ryu, Jeon, and Baek 2016). The distinctiveness of the EKR process is the simplicity of implementation, as well as its quite interesting decontamination efficiency. It is one of the most promising and effective methods for removing metals and organic pollutants from soils or industrial sludge, through application of an electric field between two electrodes immersed in anodic and cathodic compartments (Cang et al. 2013).
Environmental remediation using metals and inorganic and organic materials: a review
Published in Journal of Environmental Science and Health, Part C, 2022
Haragobinda Srichandan, Puneet Kumar Singh, Pankaj Kumar Parhi, Pratikhya Mohanty, Tapan Kumar Adhya, Ritesh Pattnaik, Snehasish Mishra, Pranab Kumar Hota
Strategies for soil remediation include chemical fixation, chemical oxidation, chemical leaching and electrokinetic approaches. FeSO4 solution as a chemical fixation agent is used to remove As from soil wherein insoluble phases like FeAsSO4 or FeAsSO4.2H2O formed thereby preventing As from ecological risk.15,17 Along with primarily chemical oxidation employed to remediate polycyclic aromatic hydrocarbons (PAHs) in soil, the use of ozone, permanganate, persulphate and peroxides as oxidants for PAHs removal are reported.16 Use of chemical reagents like diluted sulfuric, nitric, hydrochloric and phosphoric acids, bio-generated Fe3+ and sulfuric acid, and supercritical CO2 for chemical leaching of toxic metals (As, Pb, Cd, Zn, Ni, V, etc.) and organic pollutants are well established.15,18–20 Solubilized metals in leachate can be further recovered suitably through solvent extraction, selective precipitation, etc. In electrokinetic remediation, an external electric field is applied by maintaining anode and cathode around the soil. The negatively charged particles/pollutants migrate toward anode while the positive toward the cathode.21 As this needs maintaining the soil pH, suitable buffer solution may be needed.22
Electrokinetic remediation of Pb near the e-waste dismantle site with Fe(NO3)3 as cathode electrolyte
Published in Environmental Technology, 2021
Zichao Zhang, Wentao Ren, Jing Zhang, Fang Zhu
Among all of the technologies of soil remediation, electrokinetic remediation (EK) is a promising technology for removing contaminants from soil. It has been applied to remediate organic and heavy metal pollutants in the soil [8–11]. Compared with the chemical methods and biological treatments, EK has the advantages of low cost, simple operation, and flexibility [12-15].