Changes in chromium distribution during the electrodialytic remediation of a Cr (VI)-contaminated soil

Castillo, Ana M. Nieto; Soriano, Juan José Sánchez; García-Delgado, R. A.

doi:10.1007/s10653-008-9137-1

Cited by 16 publications

(5 citation statements)

References 8 publications

(8 reference statements)

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“…Nieto Castillo et al (2008) treated a Cr(VI) contaminated soil (not suspension but static state) using a three-compartment electrodialytic cell under constant-voltage conditions for 7-14 days, and the results showed that over 90% of the Cr removed was found in the anolyte and less than 10% in the catholyte. The migration of Cr towards the catholyte was suggested to be associated with the reduction of Cr(VI) in the soil by reducing agents (e.g.…”

Section: Three Compartment Cell Setup-cmentioning

confidence: 99%

Electrodialytic extraction of Cr from water-washed MSWI fly ash by changing pH and redox conditions

et al. 2018

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Electrodialytic process offers a range of possibilities to waste management by electrodialytic separation (EDS) of heavy metals, depending on how the process is designed. Using three EDS cell setups (two two-compartment and one three-compartment) and their combinations, the extraction of Cr from municipal solid waste incineration fly ash by changing pH and redox conditions was investigated in the present work. The experiments were designed into single, two and three steps, based on the number of setups (by changing EDS cells) or effective setups (by shifting working electrode pairs) used. Prior to EDS the ash studied went through pretreatments such as water-washing and dry-sieving with a 50 µm sieve. The results showed that Cr was strongly bound in the ash, and the major fraction remained bound after the different treatments. Two/three-step treatment, which obtained the maximum Cr extraction rate of 27.5%, is an improvement on the single-step that extracted maximum 3.1%. The highest extraction was obtained due to the combined extraction of Cr(III) under low pH (accompanied with high redox) conditions and Cr(VI) under high pH (low redox) conditions subsequently. The Cr leaching from the treated ashes with acidic pH was lower than from those with alkaline pH; after the three-step treatment, Cr leaching was much lower from the coarse fraction (> 50 µm), as compared to the fine (≤ 50 µm) or the unsieved ash. As for the coarse fraction, two/three-step treatment reduced the leaching of Cr compared to the single-step in the same pH range (either acidic or alkaline).

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Section: Three Compartment Cell Setup-cmentioning

confidence: 99%

Electrodialytic extraction of Cr from water-washed MSWI fly ash by changing pH and redox conditions

et al. 2018

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“…F in solution is found in the form of fluoride (F − ) [29], and Cr(VI) is an oxyanion that can be found as HCrO 4 − , CrO 4 2− , and Cr 2 O 7 2− depending on the pH [30]. Low As(V) sorption efficiency can be related to the solution pH.…”

Section: Data Analysesmentioning

confidence: 99%

Wheat Straw as a Bio-Sorbent for Arsenate, Chromate, Fluoride, and Nickel

Romar-Gasalla

Coelho

Nóvoa-Muñoz

et al. 2017

Water

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Abstract:Batch-type experiments were used to study As(V), Cr(VI), F − , and Ni 2+ sorption/desorption on wheat straw. For the lowest concentration added (0.5 mmol·L −1 ), the sorption sequence was F − > Ni 2+ > Cr(VI) >> As(V) (93%, 61%, 29%, 0.3%), but changed to Ni 2+ > F − > Cr(VI) >> As(V) when 3.0 and 6.0 mmol·L −1 were added (with 65%, 54%, 25%, 0%, and 68%, 52%, 27%, 0% sorption, respectively). Overall, As(V) showed the lowest sorption, whereas it was 25-37% for Cr(VI), 61-68% for Ni 2+ , and 52-93% for F − . For As(V), pH in the equilibrium solution was always above the pH of the point of zero charge (pH PZC ) for wheat straw, decreasing sorption efficiency. For Cr(VI), pH was below pH PZC , but not enough to reach high sorption. For F − , pH in the equilibrium was above pH PZC , which could reduce sorption. For Ni 2+ , pH in the equilibrium was always below pH PZC , which made sorption difficult. The satisfactory fitting of Cr(VI), F − , and Ni 2+ data to the Freundlich model suggests multilayer-type adsorption. Desorption was high for F − , whereas Ni 2+ showed the lowest desorption. This research could be especially relevant when focusing on the use of wheat straw as a bio-sorbent, and in cases where straw mulching is used.

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“…This process also occurred after EK remediation in the FA experiment, but only a small amount of chromium in the residue fraction converted to other fractions. As we know, species of chromium in soil and sludge can convert during the EK remediation process [17,20,[23][24][25], and metal complexes or precipitates can be partially solubilized in acidic soil conditions near the anode, allowing for migration to occur under a DC electric field [17,20]. The low soil pH and high field intensity conditions during the EK remediation process in the AAs experiment favored desorption and dissolution of chromium from the soil, therefore the inversion of chromium in the residue fraction to other fractions was more significant.…”

Section: Chromium Fractionationmentioning

confidence: 99%

Enhanced electrokinetic remediation of chromium-contaminated soil using approaching anodes

et al. 2012

Front. Environ. Sci. Eng.

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As a new technology used for the cleaning of chromium-contaminated soil, worldwide interest in eletrokinetic (EK) remediation has grown considerably in recent times. However, owing to the fact that chromium exists as both cationic and anionic species in the soil, it is not an efficient method. This paper reports upon a study in which a process using approaching anodes (AAs) was used to enhance the removal efficiency of chromium by eletrokinetics. Two bench-scale experiments to remove chromium from contaminated soil were performed, one using a fixed anode (FA) and the other using AAs. In the AAs experiment, the anode moved toward the cathode by 7 cm every three days. After remediation, soil pH, total chromium, and fractionation of chromium in the soil were determined. The average removal efficiency of total chromium was 11.32% and 18.96% in the FA and AAs experiments, respectively. After remediation, acidic soil conditions throughout the soil were generated through the use of AAs, while 80% of the soil remained neutral or alkalic when using the FA approach. The acidic soil environment and high field intensity in the AAs experiment might have favored chromium desorption, dissolution and dissociation from the soil, plus the mobility of chromium in the soil was also enhanced. The results demonstrate that AAs used in the process of EK remediation can enhance the efficiency of chromium removal from soil.

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Changes in chromium distribution during the electrodialytic remediation of a Cr (VI)-contaminated soil

Cited by 16 publications

References 8 publications

Electrodialytic extraction of Cr from water-washed MSWI fly ash by changing pH and redox conditions

Electrodialytic extraction of Cr from water-washed MSWI fly ash by changing pH and redox conditions

Wheat Straw as a Bio-Sorbent for Arsenate, Chromate, Fluoride, and Nickel

Enhanced electrokinetic remediation of chromium-contaminated soil using approaching anodes

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