Electrokinetic Remediation of Contaminated Soils With Chromium

2018 ◽  
Author(s):  
A. Ribeiro ◽  
C. Vilarinho ◽  
J. Araújo ◽  
J. Carvalho
Keyword(s):  
Heavy Metals ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Removal Rate ◽  
Groundwater Resources ◽  
Electrokinetic Remediation ◽  
Permeable Reactive Barrier ◽  
Complexing Agent ◽  
Low Permeability ◽  
Reactive Barrier

Soil is a vital natural resource that regulates our environment sustainability and provide essential resources to humans and nature. Nowadays, with an increasingly populated and urbanized world, pollution is widely recognized as a significant challenge to soil and groundwater resources management. The most common chemicals found in soils and water plumb in a dissolved state and considered as potential pollutants are heavy metals, dyes, phenols, detergents, pesticides, polychlorinated biphenyls (PCBs), and others organic substances, such as organic matter. Unlike organic contaminants, heavy metals are not biodegradable and tend to accumulate in living organisms and many heavy metal ions are known to be toxic or carcinogenic. Toxic heavy metals of particular concern zinc, copper, nickel, mercury, cadmium, lead and chromium. Electrokinetic remediation deserves particular attention in soil treatment due to its peculiar advantages, including the capability of treating fine and low permeability materials, and achieving consolidation, dewatering and removal of salts and inorganic contaminants like heavy metals in a single stage. In this study, the remediation of artificially chromium contaminated soil by electrokinetic process, coupled with Eggshell Inorganic Fraction Powder (EGGIF) permeable reactive barrier (PRB), was investigated. An electric field of 2 V cm−1 was applied and was used an EGGIF/soil ratio of 30 g kg−1 of contaminated soil for the preparation of the permeable reactive barrier (PRB) in each test. Results proved that the study of chromium mobility revealed the predominance in its transportation through the soil towards the anode, due essentially to the existence of chromium in the form of oxyanions (chromate and dichromate), which confers a negative charge to the molecule. Chromium removal by electrokinetic remediation was faster in low levels of concentration and the utilization of citric acid as buffer and complexing agent allowed to maintain pH of soil below the precipitation limit for this element. It was obtained high removal rates of chromium in both experiments, especially near the anode. In the normalized distance to cathode of 0.8 it was achieved a maximum removal rate of chromium of 55, 59 and 60% in initial chromium concentration of 500 mg kg−1, 250 mg kg−1 and 100 mg kg−1, respectively. The viability of the new coupling technology developed (electrokinetic with EGGIF permeable reactive barrier) to treat low-permeability polluted soils was demonstrated. Based on the proved efficiency, this remediation technique has to be optimized and applied to real soils in order to validate it as a large-scale solution.

Lead (II) Removal from Contaminated Soils by Electrokinetic Remediation Coupled with Modified Eggshell Waste

2018 ◽  
Vol 777 ◽  
pp. 256-261 ◽  
Author(s):  
André Ribeiro ◽  
André Mota ◽  
Margarida Soares ◽  
Carlos Castro ◽  
Jorge Araújo ◽  
...  
Keyword(s):  
Contaminated Soil ◽  
Contaminated Soils ◽  
Removal Rate ◽  
Electrokinetic Remediation ◽  
Permeable Reactive Barrier ◽  
Inorganic Contaminants ◽  
Reactive Barrier ◽  
Eggshell Waste ◽  
Inorganic Fraction ◽  
Maximum Removal

Electrokinetic remediation deserves particular attention in soil treatment due to its peculiar advantages, including the capability of treating fine and low permeability materials, and achieving consolidation, dewatering and removal of salts and inorganic contaminants like heavy metals in a single stage. In this study, the remediation of artificially lead (II) contaminated soil by electrokinetic process, coupled with Eggshell Inorganic Fraction Powder (EGGIF) permeable reactive barrier (PRB), was investigated. An electric field of 2 V cm-1was applied and was used an EGGIF/soil ratio of 30 g kg-1 of contaminated soil for the preparation of the permeable reactive barrier (PRB) in each test. It was obtained high removal rates of lead in both experiments, especially near the cathode. In the normalized distance to cathode of 0.2 it was achieved a maximum removal rate of lead (II) of 68, 78 and 83% in initial lead (II) concentration of 500 mg-1, 200 mg-1 and 100 mg-1, respectively. EGGIF (Eggshell Inorganic Fraction) proved that can be used as permeable reactive barrier (PRB) since in all the performed tests were achieved adsorptions yields higher than 90%.

scholarly journals Effect of chemical additives on electrokinetic remediation of Cr-contaminated soil coupled with a permeable reactive barrier

2019 ◽  
Vol 6 (5) ◽  
pp. 182138 ◽  
Author(s):  
Xu Yu ◽  
Faheem Muhammad ◽  
Yujie Yan ◽  
Lin Yu ◽  
Huilin Li ◽  
...  
Keyword(s):  
Tartaric Acid ◽  
Contaminated Soil ◽  
Removal Rate ◽  
Orthogonal Experiment ◽  
Electrokinetic Remediation ◽  
Permeable Reactive Barrier ◽  
Ammonium Bromide ◽  
Voltage Gradient ◽  
Reactive Barrier ◽  
Leaching Efficiency

Chromium (Cr) contamination in soil, especially Cr(VI), is a serious threat to the environment and human health. The electrokinetic remediation (EKR) is a promising technology to remediate the Cr(VI). Therefore, in this study, EKR coupled with a permeable reactive barrier (PRB) was used to treat the Cr(VI)-contaminated soil. The CTMAB-Z, a modified zeolite (prepared with cetyltrimethyl ammonium bromide) alone and a mixture of CTMAB-Z and Fe(0) were used as PRB-1 and PRB-2 reactive media, respectively. The effect of chemical enhancers/additives, i.e. DL-tartaric acid and Tween 80 on EKR of Cr(VI) was also analysed in the contrasting experiments. While the effects of repair time, voltage gradient and DL-tartaric acid concentration on Cr(VI) remediation were investigated by using the multifactor orthogonal experiment which was based on contrasting experiments. The contrasting experiment results showed that the highest Cr(VI) removal rate (66.27%) and leaching efficiency (71.29%) were observed in the experimental group which had DL-tartaric acid and PRB-2. Furthermore, the multifactor orthogonal experiment results had depicted that the highest Cr(VI) removal rate (80.92%) and leaching efficiency (85.25%) were achieved after treating the samples at a voltage gradient of 2.5 V cm −1 for 8 days in the presence of 0.15 M concentration of DL-tartaric acid. This study demonstrated that Cr(VI) remediation through EKR process could be significantly enhanced by the use of PRB and additives.

scholarly journals The Remediation Characteristics of Heavy Metals (Copper and Lead) on Applying Recycled Food Waste Ash and Electrokinetic Remediation Techniques

2021 ◽  
Vol 11 (16) ◽  
pp. 7437
Author(s):  
Sounghyun Lee ◽  
Jung-Mann Yun ◽  
Jong-Young Lee ◽  
Gigwon Hong ◽  
Ji-Sun Kim ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Acetic Acid ◽  
Food Waste ◽  
Removal Rate ◽  
Electrokinetic Remediation ◽  
Permeable Reactive Barrier ◽  
Lead Removal ◽  
Polluted Soils ◽  
Reactive Barrier

Most food waste is incinerated and reclaimed in Korea. Due to the development of industry, soil and groundwater pollution are serious. The purpose of this study was to study recycled materials and eco-friendly remediation methods to prevent secondary pollution after remediation. In this study, recycled food waste ash was filled in a permeable reactive barrier (PRB) and used as a heavy metal adsorption material. In situ remediation electrokinetic techniques (EK) and acetic acid were used. Electrokinetic remediation is a technology that can remove various polluted soils and pollutants, and is an economical and highly useful remediation technique. Thereafter, the current density increased constantly over time, and it was confirmed that it increased after electrode exchange and then decreased. Based on this result, the acetic acid was constantly injected and it was reconfirmed through the water content after the end of the experiment. In the case of both heavy metals, the removal efficiency was good after 10 days of operation and 8 days after electrode exchange, but, in the case of lead, it was confirmed that experiments are needed by increasing the operation date before electrode exchange. It was confirmed that the copper removal rate was about 74% to 87%, and the lead removal rate was about 11% to 43%. After the end of the experiment, a low pH was confirmed at x/L = 0.9, and it was also confirmed that there was no precipitation of heavy metals and there was a smooth movement by the enhancer and electrolysis after electrode exchange.

Decontamination of Heavy Metals From Municipal Sewage Sludge (MSS) by Electrokinetic Remediation

2019 ◽  
Author(s):  
A. Ribeiro ◽  
J. Araújo ◽  
A. Mota ◽  
R. Campos ◽  
C. Vilarinho ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Operation Time ◽  
Electrokinetic Remediation ◽  
Permeable Reactive Barrier ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Reactive Barrier

Abstract A large quantity of sludges resulting from the treatment of MWWTP (Municipal Wastewater Treatment Plant) effluent is generated annually following the increase of population density and acceleration of urbanization. Sludge production in Europe has been predicted by around 12 million tons in 2020. As a solid waste, appropriate disposal of Municipal Sewage Sludge (MSS) has been taken seriously due to its larger volume and toxic substances such as heavy metals. Electrokinetic remediation has more advantages in heavy metals uptake compared to other technologies, due to the ability to treat soils in-situ and to remove heavy metals from soils. In this work, it was studied the remediation of MSS by the electrokinetic remediation coupled with activated carbon (AC) as a permeable reactive barrier (PRB). It was applied an electric current of 3 V cm−1 and it was used an AC/sludge ratio of 30 g kg−1 of contaminated sludge for the preparation of the PRB. In each trial, the evolution of cadmium (Cd), lead (Pb), copper (Cu), chromium (Cr), nickel (Ni) and zinc (Zn) removal from the sludge were evaluated. Results proved that this process is perfectly suited for the removal of chromium, nickel and zinc metals from the sludge. At the end of the operation time, it was achieved a maximum removal rate of 56% for chromium, 73% for nickel and 99% for zinc, with initial concentrations of 2790 mg kg−1, 2840 mg kg−1, and 94200 mg kg−1, respectively. Based on these results, it was proved the technical viability of the proposed technology (electrokinetic with AC as a permeable reactive barrier) to treat municipal sewage sludges.

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

2020 ◽  
Vol 1013 ◽  
pp. 81-90
Author(s):  
André Ribeiro ◽  
André Mota ◽  
Jorge Araújo ◽  
Cândida Vilarinho ◽  
Joana Carvalho
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Operation Time ◽  
Electrokinetic Remediation ◽  
Permeable Reactive Barrier ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Reactive Barrier ◽  
Study Results ◽  
Mussel Shells

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.

scholarly journals Fractionation of Heavy Metals in Multi-Contaminated Soil Treated with Biochar Using the Sequential Extraction Procedure

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 448
Author(s):  
Mahrous Awad ◽  
Zhongzhen Liu ◽  
Milan Skalicky ◽  
Eldessoky S. Dessoky ◽  
Marian Brestic ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Ph ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Extraction Procedure ◽  
Sequential Fractionation ◽  
Relationship Of ◽  
The Relationship

Heavy metals (HMs) toxicity represents a global problem depending on the soil environment’s geochemical forms. Biochar addition safely reduces HMs mobile forms, thus, reducing their toxicity to plants. While several studies have shown that biochar could significantly stabilize HMs in contaminated soils, the study of the relationship of soil properties to potential mechanisms still needs further clarification; hence the importance of assessing a naturally contaminated soil amended, in this case with Paulownia biochar (PB) and Bamboo biochar (BB) to fractionate Pb, Cd, Zn, and Cu using short sequential fractionation plans. The relationship of soil pH and organic matter and its effect on the redistribution of these metals were estimated. The results indicated that the acid-soluble metals decreased while the fraction bound to organic matter increased compared to untreated pots. The increase in the organic matter metal-bound was mostly at the expense of the decrease in the acid extractable and Fe/Mn bound ones. The highest application of PB increased the organically bound fraction of Pb, Cd, Zn, and Cu (62, 61, 34, and 61%, respectively), while the BB increased them (61, 49, 42, and 22%, respectively) over the control. Meanwhile, Fe/Mn oxides bound represents the large portion associated with zinc and copper. Concerning soil organic matter (SOM) and soil pH, as potential tools to reduce the risk of the target metals, a significant positive correlation was observed with acid-soluble extractable metal, while a negative correlation was obtained with organic matter-bound metal. The principal component analysis (PCA) shows that the total variance represents 89.7% for the TCPL-extractable and HMs forms and their relation to pH and SOM, which confirms the positive effect of the pH and SOM under PB and BB treatments on reducing the risk of the studied metals. The mobility and bioavailability of these metals and their geochemical forms widely varied according to pH, soil organic matter, biochar types, and application rates. As an environmentally friendly and economical material, biochar emphasizes its importance as a tool that makes the soil more suitable for safe cultivation in the short term and its long-term sustainability. This study proves that it reduces the mobility of HMs, their environmental risks and contributes to food safety. It also confirms that performing more controlled experiments, such as a pot, is a disciplined and effective way to assess the suitability of different types of biochar as soil modifications to restore HMs contaminated soil via controlling the mobilization of these minerals.

scholarly journals Enhanced Electrokinetic Remediation for the Removal of Heavy Metals from Contaminated Soils

2021 ◽  
Vol 11 (4) ◽  
pp. 1799
Author(s):  
Claudio Cameselle ◽  
Susana Gouveia ◽  
Adrian Cabo
Keyword(s):  
Heavy Metals ◽  
Citric Acid ◽  
Organic Acids ◽  
Contaminated Soils ◽  
Electrokinetic Remediation ◽  
Deionized Water ◽  
Soil Specimen ◽  
Removal Of Heavy Metals ◽  
Ph Conditions ◽  
Neutral Metal

The electrokinetic remediation of an agricultural soil contaminated with heavy metals was studied using organic acids as facilitating agents. The unenhanced electrokinetic treatment using deionized water as processing fluid did not show any significant mobilization and removal of heavy metals due to the low solubilization of metals and precipitation at high pH conditions close to the cathode. EDTA and citric acid 0.1 M were used as facilitating agents to favor the dissolution and transportation of metals. The organic acids were added to the catholyte and penetrated into the soil specimen by electromigration. EDTA formed negatively charged complexes. Citric acid formed neutral metal complexes in the soil pH conditions (pH = 2–4). Citric acid was much more effective in the dissolution and transportation out of the soil specimen of complexed metals. In order to enhance the removal of metals, the concentration of citric acid was increased up to 0.5 M, resulting in the removal of 78.7% of Cd, 78.6% of Co, 72.5% of Cu, 73.3% of Zn, 11.8% of Cr and 9.8% of Pb.

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