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Manuel A Rodrigo - One of the best experts on this subject based on the ideXlab platform.

  • removal of oxyfluorfen from spiked Soils using electrokinetic Soil Flushing with the surrounding arrangements of electrodes
    Science of The Total Environment, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, S. Rodrigo, Vicente Navarro, Humberto Rubijuarez, R Lopezvizcaino, Carlos Barreradiaz, Manuel A Rodrigo
    Abstract:

    Abstract This work reports the results of a study in which the remediation of Soil that undergoes an accidental discharge of oxyfluorfen is carried out by using electrokinetic Soil Flushing (EKSF). Two different electrode configurations were tested, consisting of several electrodes surrounding an electrode of different polarity (so-called 1A6C, one anode surrounded by six cathodes, and 1C6A, one cathode surrounded by six cathodes). A pilot plant scale was used (with a Soil volume of 175 dm 3 ) to perform the studies. During the tests, different parameters were measured daily (flowrates, pH, electrical conductivity and herbicide concentration in different sampling positions). Furthermore, at the end of the test, a complete post-mortem analysis was carried out to obtain a 3-D map of the pollution, pH and electrical conductivity in the Soil. The results demonstrate that electrode arrangement is a key factor for effective pollutant removal. In fact, the 1A6C configuration improves the removal rate by 41.3% versus the 27.0% obtained by the 1C6A configuration after a period of 35 days. Finally, a bench mark comparison of this study of Soil remediation polluted with 2,4-D allows for significant conclusions about the scale-up and full-scale application of this technology.

  • Removal of oxyfluorfen from spiked Soils using electrokinetic Soil Flushing with the surrounding arrangements of electrodes
    The Science of the total environment, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, Humberto Rubí-juárez, S. Rodrigo, R. López-vizcaíno, Carlos Barrera-díaz, Vicente Navarro, Manuel A Rodrigo
    Abstract:

    This work reports the results of a study in which the remediation of Soil that undergoes an accidental discharge of oxyfluorfen is carried out by using electrokinetic Soil Flushing (EKSF). Two different electrode configurations were tested, consisting of several electrodes surrounding an electrode of different polarity (so-called 1A6C, one anode surrounded by six cathodes, and 1C6A, one cathode surrounded by six cathodes). A pilot plant scale was used (with a Soil volume of 175dm(3)) to perform the studies. During the tests, different parameters were measured daily (flowrates, pH, electrical conductivity and herbicide concentration in different sampling positions). Furthermore, at the end of the test, a complete post-mortem analysis was carried out to obtain a 3-D map of the pollution, pH and electrical conductivity in the Soil. The results demonstrate that electrode arrangement is a key factor for effective pollutant removal. In fact, the 1A6C configuration improves the removal rate by 41.3% versus the 27.0% obtained by the 1C6A configuration after a period of 35days. Finally, a bench mark comparison of this study of Soil remediation polluted with 2,4-D allows for significant conclusions about the scale-up and full-scale application of this technology.

  • Application of electrokinetic Soil Flushing to four herbicides: A comparison.
    Chemosphere, 2016
    Co-Authors: E. Vieira Dos Santos, Pablo Cañizares, F.l. Souza, Cristina Sáez, Marcos R.v. Lanza, Carlos A. Martínez-huitle, Manuel A Rodrigo
    Abstract:

    In this work, four bench-scale plants containing Soil spiked with four herbicides (2,4-Dichlorophenoxyacetic acid (2,4-D), oxyfluorfen, chlorsulfuron and atrazine) undergo treatment consisting of an electrokinetic Soil Flushing (EKSF). Results clearly demonstrate that efficiency of EKSF depends on the chemical characteristic of the pesticide used. The amount of pesticide collected in the anode well is more significant than that collected in the cathode wells, indicating that the electromigration is much more important than drainage by electro-osmotic flux for this application. After 15 d of treatment, the 2,4-D is the pesticide most efficiently removed (95% of removal), while chlorsulfuron is the pesticide more resilient to the treatment. Additionally, volatilization was found to be a process of the major significance in the application of electrokinetic techniques to Soil polluted with herbicides and because of that it should always be taken into account in the future design of full-scale processes.

  • remediation of Soils polluted with 2 4 d by electrokinetic Soil Flushing with facing rows of electrodes a case study in a pilot plant
    Chemical Engineering Journal, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, Vicente Navarro, R Lopezvizcaino, Ángel Yustres, Manuel A Rodrigo
    Abstract:

    Abstract This study focuses on evaluating the application of electrokinetic Soil Flushing (EKSF) technologies to remediate Soil polluted with 2,4-dichlorophenoxyacetic acid (2,4-D). This compound was selected as an example of polar herbicides that may cause Soil percolation and groundwater contamination due to its high water solubility, lifetime and mobility. To evaluate this technology, a 40-day test was conducted on a bench-scale set-up (175 dm3 of capacity) that was fully automated and operating under potentiostatic mode (1 V cm−1). The electrical current, temperature, pH, humidity and pollutant concentration in the electrolyte wells were monitored daily, and at the end of the tests, a post-analysis characterization of the Soil section was performed to obtain 3-D plots of the changes in each parameter. Simultaneously, a blank test was carried out (without applying an electric field) to determine spreading of the pollutant in the Soil that did not experience an electric field. The results indicate that the 2,4-D is transported to the anode wells by electromigration (the primary species is an anion under the treatment pH) and the cathode wells by electroosmotic drag, even though a lower concentration is obtained because a large volume of water is mobilized. After 40 days of the EKSF treatment, 50% of the initial 2,4-D leaked into the Soil was eliminated, 25% remained in the Soil, and the remaining 25% was volatilized.

  • Removal of oxyfluorfen from spiked Soils using electrokinetic Soil Flushing with linear rows of electrodes
    Chemical Engineering Journal, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, S. Rodrigo, Vicente Navarro, R. López Vizcaíno, Ángel Yustres, Manuel A Rodrigo
    Abstract:

    Abstract This study focuses on the evaluation of the electrokinetic Soil Flushing (EKSF) strategy to remediate Soil following a simulated spill of the herbicide oxyfluorfen. EKSF is attained by placing (in the Soil mockup) two rows of electrodes of different polarity facing each other. The results are compared with those obtained in a reference experiment in which the same spill was simulated and no remediation actions were taken. In addition to the daily monitoring of the most important parameters in the flows, after the remediation test, a post-mortem analysis was performed to obtain a 3-D map of the pollutant distribution. Those results demonstrate that despite the hydrophobic character of oxyfluorfen, it can be efficiently transported by EKSF. Hence, after 34 days of treatment, a 26.8% improvement in the removal of oxyfluorfen was achieved (explained in terms of the effect of the electric field on the pollutant) compared with the reference experiment in which only volatilization can explain the removal of the herbicide. Comparison of the removal of oxyfluorfen by EKSF with that of 2,4-D (studied in a previous study) demonstrates that comparable dragging to the cathode and volatilization are obtained. However, the lower efficiency of the transport of oxyfluorfen by gravity fluxes and electromigration (explained because it is contained as micelles) yielded worse performance of EKSF for this water-insoluble pesticide and hence less efficient remediation. This contradictory result reveals the importance of tests at large-scale facilities such as that used in this work to predict the performance of real systems in future full-scale applications.

Pablo Cañizares - One of the best experts on this subject based on the ideXlab platform.

  • removal of oxyfluorfen from spiked Soils using electrokinetic Soil Flushing with the surrounding arrangements of electrodes
    Science of The Total Environment, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, S. Rodrigo, Vicente Navarro, Humberto Rubijuarez, R Lopezvizcaino, Carlos Barreradiaz, Manuel A Rodrigo
    Abstract:

    Abstract This work reports the results of a study in which the remediation of Soil that undergoes an accidental discharge of oxyfluorfen is carried out by using electrokinetic Soil Flushing (EKSF). Two different electrode configurations were tested, consisting of several electrodes surrounding an electrode of different polarity (so-called 1A6C, one anode surrounded by six cathodes, and 1C6A, one cathode surrounded by six cathodes). A pilot plant scale was used (with a Soil volume of 175 dm 3 ) to perform the studies. During the tests, different parameters were measured daily (flowrates, pH, electrical conductivity and herbicide concentration in different sampling positions). Furthermore, at the end of the test, a complete post-mortem analysis was carried out to obtain a 3-D map of the pollution, pH and electrical conductivity in the Soil. The results demonstrate that electrode arrangement is a key factor for effective pollutant removal. In fact, the 1A6C configuration improves the removal rate by 41.3% versus the 27.0% obtained by the 1C6A configuration after a period of 35 days. Finally, a bench mark comparison of this study of Soil remediation polluted with 2,4-D allows for significant conclusions about the scale-up and full-scale application of this technology.

  • Removal of oxyfluorfen from spiked Soils using electrokinetic Soil Flushing with the surrounding arrangements of electrodes
    The Science of the total environment, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, Humberto Rubí-juárez, S. Rodrigo, R. López-vizcaíno, Carlos Barrera-díaz, Vicente Navarro, Manuel A Rodrigo
    Abstract:

    This work reports the results of a study in which the remediation of Soil that undergoes an accidental discharge of oxyfluorfen is carried out by using electrokinetic Soil Flushing (EKSF). Two different electrode configurations were tested, consisting of several electrodes surrounding an electrode of different polarity (so-called 1A6C, one anode surrounded by six cathodes, and 1C6A, one cathode surrounded by six cathodes). A pilot plant scale was used (with a Soil volume of 175dm(3)) to perform the studies. During the tests, different parameters were measured daily (flowrates, pH, electrical conductivity and herbicide concentration in different sampling positions). Furthermore, at the end of the test, a complete post-mortem analysis was carried out to obtain a 3-D map of the pollution, pH and electrical conductivity in the Soil. The results demonstrate that electrode arrangement is a key factor for effective pollutant removal. In fact, the 1A6C configuration improves the removal rate by 41.3% versus the 27.0% obtained by the 1C6A configuration after a period of 35days. Finally, a bench mark comparison of this study of Soil remediation polluted with 2,4-D allows for significant conclusions about the scale-up and full-scale application of this technology.

  • Application of electrokinetic Soil Flushing to four herbicides: A comparison.
    Chemosphere, 2016
    Co-Authors: E. Vieira Dos Santos, Pablo Cañizares, F.l. Souza, Cristina Sáez, Marcos R.v. Lanza, Carlos A. Martínez-huitle, Manuel A Rodrigo
    Abstract:

    In this work, four bench-scale plants containing Soil spiked with four herbicides (2,4-Dichlorophenoxyacetic acid (2,4-D), oxyfluorfen, chlorsulfuron and atrazine) undergo treatment consisting of an electrokinetic Soil Flushing (EKSF). Results clearly demonstrate that efficiency of EKSF depends on the chemical characteristic of the pesticide used. The amount of pesticide collected in the anode well is more significant than that collected in the cathode wells, indicating that the electromigration is much more important than drainage by electro-osmotic flux for this application. After 15 d of treatment, the 2,4-D is the pesticide most efficiently removed (95% of removal), while chlorsulfuron is the pesticide more resilient to the treatment. Additionally, volatilization was found to be a process of the major significance in the application of electrokinetic techniques to Soil polluted with herbicides and because of that it should always be taken into account in the future design of full-scale processes.

  • remediation of Soils polluted with 2 4 d by electrokinetic Soil Flushing with facing rows of electrodes a case study in a pilot plant
    Chemical Engineering Journal, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, Vicente Navarro, R Lopezvizcaino, Ángel Yustres, Manuel A Rodrigo
    Abstract:

    Abstract This study focuses on evaluating the application of electrokinetic Soil Flushing (EKSF) technologies to remediate Soil polluted with 2,4-dichlorophenoxyacetic acid (2,4-D). This compound was selected as an example of polar herbicides that may cause Soil percolation and groundwater contamination due to its high water solubility, lifetime and mobility. To evaluate this technology, a 40-day test was conducted on a bench-scale set-up (175 dm3 of capacity) that was fully automated and operating under potentiostatic mode (1 V cm−1). The electrical current, temperature, pH, humidity and pollutant concentration in the electrolyte wells were monitored daily, and at the end of the tests, a post-analysis characterization of the Soil section was performed to obtain 3-D plots of the changes in each parameter. Simultaneously, a blank test was carried out (without applying an electric field) to determine spreading of the pollutant in the Soil that did not experience an electric field. The results indicate that the 2,4-D is transported to the anode wells by electromigration (the primary species is an anion under the treatment pH) and the cathode wells by electroosmotic drag, even though a lower concentration is obtained because a large volume of water is mobilized. After 40 days of the EKSF treatment, 50% of the initial 2,4-D leaked into the Soil was eliminated, 25% remained in the Soil, and the remaining 25% was volatilized.

  • Removal of oxyfluorfen from spiked Soils using electrokinetic Soil Flushing with linear rows of electrodes
    Chemical Engineering Journal, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, S. Rodrigo, Vicente Navarro, R. López Vizcaíno, Ángel Yustres, Manuel A Rodrigo
    Abstract:

    Abstract This study focuses on the evaluation of the electrokinetic Soil Flushing (EKSF) strategy to remediate Soil following a simulated spill of the herbicide oxyfluorfen. EKSF is attained by placing (in the Soil mockup) two rows of electrodes of different polarity facing each other. The results are compared with those obtained in a reference experiment in which the same spill was simulated and no remediation actions were taken. In addition to the daily monitoring of the most important parameters in the flows, after the remediation test, a post-mortem analysis was performed to obtain a 3-D map of the pollutant distribution. Those results demonstrate that despite the hydrophobic character of oxyfluorfen, it can be efficiently transported by EKSF. Hence, after 34 days of treatment, a 26.8% improvement in the removal of oxyfluorfen was achieved (explained in terms of the effect of the electric field on the pollutant) compared with the reference experiment in which only volatilization can explain the removal of the herbicide. Comparison of the removal of oxyfluorfen by EKSF with that of 2,4-D (studied in a previous study) demonstrates that comparable dragging to the cathode and volatilization are obtained. However, the lower efficiency of the transport of oxyfluorfen by gravity fluxes and electromigration (explained because it is contained as micelles) yielded worse performance of EKSF for this water-insoluble pesticide and hence less efficient remediation. This contradictory result reveals the importance of tests at large-scale facilities such as that used in this work to predict the performance of real systems in future full-scale applications.

Cristina Sáez - One of the best experts on this subject based on the ideXlab platform.

  • removal of oxyfluorfen from spiked Soils using electrokinetic Soil Flushing with the surrounding arrangements of electrodes
    Science of The Total Environment, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, S. Rodrigo, Vicente Navarro, Humberto Rubijuarez, R Lopezvizcaino, Carlos Barreradiaz, Manuel A Rodrigo
    Abstract:

    Abstract This work reports the results of a study in which the remediation of Soil that undergoes an accidental discharge of oxyfluorfen is carried out by using electrokinetic Soil Flushing (EKSF). Two different electrode configurations were tested, consisting of several electrodes surrounding an electrode of different polarity (so-called 1A6C, one anode surrounded by six cathodes, and 1C6A, one cathode surrounded by six cathodes). A pilot plant scale was used (with a Soil volume of 175 dm 3 ) to perform the studies. During the tests, different parameters were measured daily (flowrates, pH, electrical conductivity and herbicide concentration in different sampling positions). Furthermore, at the end of the test, a complete post-mortem analysis was carried out to obtain a 3-D map of the pollution, pH and electrical conductivity in the Soil. The results demonstrate that electrode arrangement is a key factor for effective pollutant removal. In fact, the 1A6C configuration improves the removal rate by 41.3% versus the 27.0% obtained by the 1C6A configuration after a period of 35 days. Finally, a bench mark comparison of this study of Soil remediation polluted with 2,4-D allows for significant conclusions about the scale-up and full-scale application of this technology.

  • Removal of oxyfluorfen from spiked Soils using electrokinetic Soil Flushing with the surrounding arrangements of electrodes
    The Science of the total environment, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, Humberto Rubí-juárez, S. Rodrigo, R. López-vizcaíno, Carlos Barrera-díaz, Vicente Navarro, Manuel A Rodrigo
    Abstract:

    This work reports the results of a study in which the remediation of Soil that undergoes an accidental discharge of oxyfluorfen is carried out by using electrokinetic Soil Flushing (EKSF). Two different electrode configurations were tested, consisting of several electrodes surrounding an electrode of different polarity (so-called 1A6C, one anode surrounded by six cathodes, and 1C6A, one cathode surrounded by six cathodes). A pilot plant scale was used (with a Soil volume of 175dm(3)) to perform the studies. During the tests, different parameters were measured daily (flowrates, pH, electrical conductivity and herbicide concentration in different sampling positions). Furthermore, at the end of the test, a complete post-mortem analysis was carried out to obtain a 3-D map of the pollution, pH and electrical conductivity in the Soil. The results demonstrate that electrode arrangement is a key factor for effective pollutant removal. In fact, the 1A6C configuration improves the removal rate by 41.3% versus the 27.0% obtained by the 1C6A configuration after a period of 35days. Finally, a bench mark comparison of this study of Soil remediation polluted with 2,4-D allows for significant conclusions about the scale-up and full-scale application of this technology.

  • Application of electrokinetic Soil Flushing to four herbicides: A comparison.
    Chemosphere, 2016
    Co-Authors: E. Vieira Dos Santos, Pablo Cañizares, F.l. Souza, Cristina Sáez, Marcos R.v. Lanza, Carlos A. Martínez-huitle, Manuel A Rodrigo
    Abstract:

    In this work, four bench-scale plants containing Soil spiked with four herbicides (2,4-Dichlorophenoxyacetic acid (2,4-D), oxyfluorfen, chlorsulfuron and atrazine) undergo treatment consisting of an electrokinetic Soil Flushing (EKSF). Results clearly demonstrate that efficiency of EKSF depends on the chemical characteristic of the pesticide used. The amount of pesticide collected in the anode well is more significant than that collected in the cathode wells, indicating that the electromigration is much more important than drainage by electro-osmotic flux for this application. After 15 d of treatment, the 2,4-D is the pesticide most efficiently removed (95% of removal), while chlorsulfuron is the pesticide more resilient to the treatment. Additionally, volatilization was found to be a process of the major significance in the application of electrokinetic techniques to Soil polluted with herbicides and because of that it should always be taken into account in the future design of full-scale processes.

  • remediation of Soils polluted with 2 4 d by electrokinetic Soil Flushing with facing rows of electrodes a case study in a pilot plant
    Chemical Engineering Journal, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, Vicente Navarro, R Lopezvizcaino, Ángel Yustres, Manuel A Rodrigo
    Abstract:

    Abstract This study focuses on evaluating the application of electrokinetic Soil Flushing (EKSF) technologies to remediate Soil polluted with 2,4-dichlorophenoxyacetic acid (2,4-D). This compound was selected as an example of polar herbicides that may cause Soil percolation and groundwater contamination due to its high water solubility, lifetime and mobility. To evaluate this technology, a 40-day test was conducted on a bench-scale set-up (175 dm3 of capacity) that was fully automated and operating under potentiostatic mode (1 V cm−1). The electrical current, temperature, pH, humidity and pollutant concentration in the electrolyte wells were monitored daily, and at the end of the tests, a post-analysis characterization of the Soil section was performed to obtain 3-D plots of the changes in each parameter. Simultaneously, a blank test was carried out (without applying an electric field) to determine spreading of the pollutant in the Soil that did not experience an electric field. The results indicate that the 2,4-D is transported to the anode wells by electromigration (the primary species is an anion under the treatment pH) and the cathode wells by electroosmotic drag, even though a lower concentration is obtained because a large volume of water is mobilized. After 40 days of the EKSF treatment, 50% of the initial 2,4-D leaked into the Soil was eliminated, 25% remained in the Soil, and the remaining 25% was volatilized.

  • Removal of oxyfluorfen from spiked Soils using electrokinetic Soil Flushing with linear rows of electrodes
    Chemical Engineering Journal, 2016
    Co-Authors: C. Risco, Pablo Cañizares, Cristina Sáez, S. Rodrigo, Vicente Navarro, R. López Vizcaíno, Ángel Yustres, Manuel A Rodrigo
    Abstract:

    Abstract This study focuses on the evaluation of the electrokinetic Soil Flushing (EKSF) strategy to remediate Soil following a simulated spill of the herbicide oxyfluorfen. EKSF is attained by placing (in the Soil mockup) two rows of electrodes of different polarity facing each other. The results are compared with those obtained in a reference experiment in which the same spill was simulated and no remediation actions were taken. In addition to the daily monitoring of the most important parameters in the flows, after the remediation test, a post-mortem analysis was performed to obtain a 3-D map of the pollutant distribution. Those results demonstrate that despite the hydrophobic character of oxyfluorfen, it can be efficiently transported by EKSF. Hence, after 34 days of treatment, a 26.8% improvement in the removal of oxyfluorfen was achieved (explained in terms of the effect of the electric field on the pollutant) compared with the reference experiment in which only volatilization can explain the removal of the herbicide. Comparison of the removal of oxyfluorfen by EKSF with that of 2,4-D (studied in a previous study) demonstrates that comparable dragging to the cathode and volatilization are obtained. However, the lower efficiency of the transport of oxyfluorfen by gravity fluxes and electromigration (explained because it is contained as micelles) yielded worse performance of EKSF for this water-insoluble pesticide and hence less efficient remediation. This contradictory result reveals the importance of tests at large-scale facilities such as that used in this work to predict the performance of real systems in future full-scale applications.

Soon-jae Lee - One of the best experts on this subject based on the ideXlab platform.

  • application of an in situ Soil sampler for assessing subsurface biogeochemical dynamics in a diesel contaminated coastal site during Soil Flushing operations
    Journal of Environmental Management, 2018
    Co-Authors: Man Jae Kwon, Baknoon Ham, Yun Ho Hwang, Moojoon Shim, Edward J Oloughlin, Soon-jae Lee
    Abstract:

    Subsurface biogeochemistry and contaminant dynamics during the remediation of diesel-contamination by in-situ Soil Flushing were investigated at a site located in a coastal region. An in-situ sampler containing diesel-contaminated Soils separated into two size fractions (<0.063- and <2-mm) was utilized in two monitoring wells: DH1 (located close to the injection and extraction wells for in-situ Soil Flushing) and DH2 (located beyond sheet piles placed to block the transport of leaked diesel). Total petroleum hydrocarbon (TPH) concentrations and biogeochemical properties were monitored both in Soil and groundwater for six months. A shift occurred in the groundwater type from Ca-HCO3 to Na-Cl due to seawater intrusion during intense pumping, while the concentrations of Ni, Cu, Co, V, Cr, and Se increased substantially following surfactant (TWEEN 80) injection. The in-situ sampler with fine particles was more sensitive to variations in conditions during the remedial Soil Flushing process. In both wells, Soil TPH concentrations in the <0.063-mm fraction were much higher than those in the <2-mm fraction. Increases in Soil TPH in DH1 were consistent with the expected outcomes following well pumping and surfactant injection used to enhance TPH extraction. However, the number of diesel-degrading microorganisms decreased after surfactant injection. 16S-rRNA gene-based analysis also showed that the community composition and diversity depended on both particle size and diesel contamination. The multidisciplinary approach to the contaminated site assessments showed that Soil Flushing with surfactant enhanced diesel extraction, but negatively impacted in-situ diesel biodegradation as well as groundwater quality. The results also suggest that the in-situ sampler can be an effective monitoring tool for subsurface biogeochemistry as well as contaminant dynamics.

  • Application of an in-situ Soil sampler for assessing subsurface biogeochemical dynamics in a diesel-contaminated coastal site during Soil Flushing operations.
    Journal of Environmental Management, 2017
    Co-Authors: Man Jae Kwon, Edward J. O’loughlin, Baknoon Ham, Yun Ho Hwang, Moojoon Shim, Soon-jae Lee
    Abstract:

    Subsurface biogeochemistry and contaminant dynamics during the remediation of diesel-contamination by in-situ Soil Flushing were investigated at a site located in a coastal region. An in-situ sampler containing diesel-contaminated Soils separated into two size fractions (

Tsun-kuo Chang - One of the best experts on this subject based on the ideXlab platform.

  • Application of Waste Lemon Extract to Toxic Metal Removal through Gravitational Soil Flushing and Composting Stabilization
    Sustainability, 2020
    Co-Authors: Pei-wen Zhang, Ya-zhen Huang, Chihhao Fan, Tsun-kuo Chang
    Abstract:

    The present study aims to investigate the treatment efficiency of Soil Flushing using waste lemon extract for samples collected from contaminated farmland, in which the copper concentration was measured as 2487 ± 139 mg/kg. The Flushing solution, containing 9.9 g/L citric acid, was prepared from the waste lemon extraction process. The Soil-Flushing treatment using a solution containing commercial citric acids of 10 g/L was also conducted for comparison. Additionally, the collected Soil was mixed with crushed waste lemons and the mixture was subjected to a composting process for subsequent stabilization study. After 120-min batch experiments, the desorbed copper concentration for waste lemon-extract experiment was 36.9 mg/L, which was higher than that (28.6 mg/L) for commercial citric solution experiment. The reduction in Soil copper concentration (1504 mg/kg) treated by waste lemon-extract Flushing was more than that treated by commercial citric solution (1256 mg/kg) at the comparable citric acid concentration. More metals were removed by waste lemon-extract Flushing. This is because the waste lemon-extract solution contains additional co-dissolved organic substances with a longer Flushing time, which allows more exchange reactions between adsorbed metals and Flushing solution. For the treatment with waste lemon extract, the Soil pH values were 4.56, 5.70 and 6.29 before, after Flushing and after compost treatment, respectively. The observed variation in Soil pH also showed that waste lemon extract might be a better Flushing agent, while Flushing with commercial citric solution decreased the pH in the Soil environment. The plant copper availability dropped from 677 mg/kg to 156 mg/kg after waste lemon-extract Flushing and stabilization with composted waste lemon. Therefore, the use of waste lemon extract for Soil Flushing not only removed toxic metals from the Soil but also prevented the occurrence of Soil acidification, an often-observed phenomenon using an acidic solution in conventional Soil Flushing. After Soil Flushing, the application of composted waste lemon could stabilize the toxic metals and increase the pH to a range suitable for plant growth.