Diffusion and leachability index studies on stabilization of chromium contaminated soil using fly ash

Kanchinadham, Sri Bala Kameswari; Narasimman, L.M.; Pedaballe, Vihita; Chitra, K. C.

doi:10.1016/j.jhazmat.2015.04.045

Cited by 52 publications

(10 citation statements)

References 25 publications

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“…Clearly, more work is needed to demonstrate how commonplace and significant this reaction may be. Further, in view of the ease by which Cr(VI) can be adsorbed and/or reduced to Cr(III) in an aqueous environment and the many low-cost materials that have been proposed to effect this process, such as plants (Park et al, 2006;Lytle et al, 1998), various activated carbons (Zhang et al, 2010;Bishnoi et al, 2004;Selvi et al,2001), chemical and bio-materials (Dhal et al, 2013), clays and other inorganic materials (Chowdhury et al, 2012;Hu et al, 2005;Astrup et al, 2000;Griffin et al, 1977), acid-mine drainage (Kingston et al, 2005), and coal-derived fly ash (Kanchinadham, 2015;Dermatas et al, 2003;Dasmahapatra et al, 1998), it should perhaps be no surprise that fly ash does have this built-in capability to reduce its own content of Cr(VI) to Cr(III) when exposed to water.…”

Section: Resultsmentioning

confidence: 99%

On the removal of hexavalent chromium from a Class F fly ash

et al. 2016

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Coarse and fine samples of a Class F fly ash obtained from commercial combustion of Illinois bituminous coal have been exposed to two long-term leaching tests designed to simulate conditions in waste impoundments. ICP-AES analysis indicated that the coarse and fine fly ash samples contained 135 and 171mg/kg Cr, respectively. Measurements by XAFS spectroscopy showed that the ash samples originally contained 5 and 8% of the chromium, respectively, in the hexavalent oxidation state, Cr(VI). After exposure to water for more than four months, the percentage of chromium as Cr(VI) in the fly-ash decreased significantly for the coarse and fine fly-ash in both tests. Combining the XAFS data with ICP-AES data on the concentration of chromium in the leachates indicated that, after the nineteen-week-long, more aggressive, kinetic test on the coarse fly ash, approximately 60% of the Cr(VI) had been leached, 20% had been reduced to Cr(III) and retained in the ash, and 20% remained as Cr(VI) in the ash. In contrast, during the six-month-long baseline test, very little Cr was actually leached from either the coarse or the fine fly-ash (<0.1mg/kg); rather, about 66% and 20%, respectively, of the original Cr(VI) in the coarse and fine fly-ash was retained in the ash in that form, while the remainder, 34% and 80%, respectively, was reduced and retained in the ash as Cr(III). The results are interpreted as indicating that Cr(VI) present in Class F fly-ash can be reduced to Cr(III) when in contact with water and that such chemical reduction can compete with physical removal of Cr(VI) from the ash by aqueous leaching.

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Section: Resultsmentioning

confidence: 99%

On the removal of hexavalent chromium from a Class F fly ash

et al. 2016

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“…In mixtures without LFS, the encapsulation process is slower. The Cr encapsulation mechanism may be explained using the literature [6,[9][10][11]22,24,[28][29][30][31][32][33][34][35][36]. It is known that calcium sulfoaluminate hydrates play an exceptional role as Cr immobilizers.…”

Section: Hydrate Evolutionmentioning

confidence: 99%

Optimal Mixture Designs for Heavy Metal Encapsulation in Municipal Solid Waste Incineration Fly Ash

et al. 2020

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Mixing municipal solid waste incineration fly ash (MSWIFA) with industrial by-products such as ground granulated blast furnace slag (GGBFS) and ladle furnace slag (LFS) can lead to a hardened system which can encapsulate the heavy metals present in the MSWIFA. The objective of this study is to find optimal mixture designs to effectively encapsulate these heavy metals. The nature of the hydrates and the strength of the mixtures are studied to develop a sustainable and practical construction material incorporating MSWIFA. Heavy metals including Cr, Cu, Zn and Cd are safely encapsulated in several developed mixtures with leachate concentration below EPA drinking water limit. The encapsulation behavior is complex and depends on metal type, age of testing, and hydration products. In general, mixtures containing LFS have more aluminate hydrates, and show greater encapsulation capacity for most heavy metals. However, they also generally show significant Sb leaching. Mixtures which show satisfactory encapsulation for all ions and adequate strength development are identified. Three ideal mixtures, including one containing zero cement, are identified which satisfy both leaching and strength requirements.

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“…Authors showed a cost of amendments of 22.3 $ ton À1 (about 20 V ton À1 ) per ton of soil when the Pb concentration in soil ranged from 2000 to Fujiwara et al (2012) 3000 mg kg À1 . A higher cost of 130 $ ton À1 (about 118 V ton À1 ) is however provided by Kanchinadham et al (2015) investigating the S/S of Cr-contaminated soil using fly ash. Cement-based S/S process needs short periods of time, not longer than 2 days (Mallampati et al, 2015b), and consequently this results in the possibility to achieve low costs jointly with such a short remediation time that are hardly reachable by other techniques, especially if high contamination levels and/or bio processbased treatments are involved.…”

Section: Preliminary Estimation Of Costs and Comparison To Other Restmentioning

confidence: 99%

Application of a γRS index-based method and techno-economic analysis for in situ treatment of 137 Cs-contaminated soils by cement-barite based stabilisation/solidification

Falciglia

Romano

Vagliasindi

2017

Journal of Environmental Management

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Diffusion and leachability index studies on stabilization of chromium contaminated soil using fly ash

Cited by 52 publications

References 25 publications

On the removal of hexavalent chromium from a Class F fly ash

On the removal of hexavalent chromium from a Class F fly ash

Optimal Mixture Designs for Heavy Metal Encapsulation in Municipal Solid Waste Incineration Fly Ash

Application of a γRS index-based method and techno-economic analysis for in situ treatment of 137 Cs-contaminated soils by cement-barite based stabilisation/solidification

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