Chromium leaching vs. oxidation state for a contaminated solidified/stabilized soil

Rinehart, Terry L.; Schulze, Darrell G.; Bricka, R. Mark; Bajt, Saša; Blatchley, Ernest R.

doi:10.1016/s0304-3894(96)01808-0

Cited by 38 publications

(24 citation statements)

References 5 publications

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“…The application of XAS to complex matrices in relation to environmental fate and behavior of contaminants is still relatively rare, but it has been employed in a limited number of studies of the speciation of metals in cement pastes, including chromium [9], cobalt [10], copper [11], lead [12], neodymium [13], selenium [14], tin [15], uranium [16] and zinc [17], as well as nickel [18][19][20]. Apart from Rinehart et al [9], who examined the oxidation state of chromium in a s/s contaminated soil and showed that this was not affected by S/S, and Hsaio et al [11], who indicated that S/S respeciated CuCl2 and reduced forms of copper in municipal waste incinerator air pollution control residues to Cu(OH)2, other studies have all prepared hydrated cement pastes by mixing pure solutions of soluble metal salts with cement powder.…”

Section: Introductionmentioning

confidence: 99%

“…Apart from Rinehart et al [9], who examined the oxidation state of chromium in a s/s contaminated soil and showed that this was not affected by S/S, and Hsaio et al [11], who indicated that S/S respeciated CuCl2 and reduced forms of copper in municipal waste incinerator air pollution control residues to Cu(OH)2, other studies have all prepared hydrated cement pastes by mixing pure solutions of soluble metal salts with cement powder. This contact mechanism is unrealistic, as contaminants in wastes are rarely fully dissolved, and the speciation observed in this way may not apply in cement-based systems containing real wastes.…”

Section: Introductionmentioning

confidence: 99%

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Nickel speciation in cement-stabilized/solidified metal treatment filtercakes

Roy

Stegemann

2017

Journal of Hazardous Materials

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Cement-based stabilization/solidification (S/S) is used to decrease environmental leaching of contaminants from industrial wastes. In this study, two industrial metal treatment filtercakes were characterized by X-ray diffractometry (XRD), thermogravimetric and differential thermogravimetric analysis (TG/DTG) and Fourier transform infrared (FTIR); speciation of nickel was examined by X-ray absorption (XAS) spectroscopy. Although the degree of carbonation and crystallinity of the two untreated filtercakes differed, -nickel hydroxide was identified as the primary nickel-containing phase by XRD and nickel K edge XAS. XAS showed that the speciation of nickel in the filtercake was unaltered by treatment with any of five different S/S binder systems. Nickel leaching from the untreated filtercakes and all their stabilized/solidified products, as a function of pH in the acid neutralization capacity test, was essentially complete below pH ~5, but was 3-4 orders of magnitude lower at pH 8-12. S/S does not respeciate nickel from metal treatment filtercakes and any reduction of nickel leaching by S/S is attributable to pH control and physical mechanisms only. pH-dependent leaching of Cr, Cu and Ni is similar for the wastes and s/s products, except that availability of Cr, Cu and Zn at decreased pH is reduced in matrices containing ground granulated blast furnace slag.2

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nickel speciation in cement-stabilized/solidified metal treatment filtercakes

Roy

Stegemann

2017

Journal of Hazardous Materials

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“…A review of the literature reveals some other important studies on the effective use of fly ash(lime for Cr(VI) immobilization in solid wastes (Albino et al, 1996;Rodríguez-Piñero et al, 1998). While other important research has been carried out using either cement or in addition to fly ash (Palomo and Palacios, 2003;Rinehart et al, 1997), these works focused on other applications of these agents for stabilization. The present study was intended to further the application for Cr(VI) stabilization and most important, to optimize the dose for the technique.…”

Section: Use Of Fly Ash and Lime To Stabilize Cr(vi) Contaminated Soilsmentioning

confidence: 99%

Optimum Dose Of Lime And Fly Ash For Treatment Of Hexavalent Chromium–Contaminated Soil

Kostarelos¹,

Reale²,

Dermatas

et al. 2006

Water Air Soil Pollut: Focus

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The presence of hexavalent chromium, Cr(VI), in soil is an environmental concern due to its effect on human health. The concern arises from the leaching and the seepage of Cr(VI) from soil to groundwater. In this paper, a stabilization technology to prevent this problem was simulated on an artificial soil contaminated with hexavalent chromium. The process is a physico-chemical treatment in which the toxic pollutant is physically entrapped within a solid matrix formed by the pozzolanic reactions of lime and fly ash to reduce its leachability and, therefore, its toxicity. This paper presents the optimum ratio of fly ash and lime in order to stabilize artificial soils contaminated with 0.4 wt.% of Cr (VI) in a brief term process. The degree of chromium released from the soil was evaluated using a modified Toxicity Characteristic Leaching Procedure (TCLP) by US Environmental Protection Agency (EPA). Overall, experimental results showed reduced leachability of total and hexavalent chromium from soils treated with both fly ash and quicklime, and that leachability reduction was more effective with increasing amount of fly ash and quicklime. Stabilization percentages between 97.3% and 99.7% of the initial chromium content were achieved, with Cr(VI) concentration in the TCLP leachates below the US EPA limit for chromium of 5 mg/l. Adequate treatment was obtained after 1 day of curing with just 25% fly ash and 10% quicklime.

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“…Despite its undisputed relevance, a molecular-level studies on the geochemical and microbial processes responsible for radionuclide uptake and cement degradation-including the subsequent release of contaminant into the environment-are not commonly found in the literature (e.g., Allen et al, 1997;Bonhoure et al, 2002Bonhoure et al, , 2003Rinehart et al, 1997;Rose et al, 2000Rose et al, , 2001Rose et al, , 2003Scheidegger et al, 2000;Zhao et al, 2000;Ziegler et al, 2001). In our laboratory we have successfully conducted bulk XAS studies to gain information on the interactions of radionuclides (Ni, Zn, Sr, Se, and I) with hardened cement paste (HCP) and cement phases under highly alkaline conditions (pH = 12-14, high ionic strength) (Bonhoure et al, 2002(Bonhoure et al, , 2003Scheidegger et al, 2000;Ziegler et al, 2001).…”

Section: The Complexity Of Cementitious Barrier Systemsmentioning

confidence: 99%