Aqueous chemistry of airborne hexavalent chromium during sampling

Torkmahalleh, Mehdi Amouei; Karibayev, Mirat; Konakbayeva, Dinara; Fyrillas, Marios M.; Rule, Ana M.

doi:10.1007/s11869-018-0607-z

Cited by 13 publications

(10 citation statements)

References 24 publications

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“…2− as the most stable form of Cr(VI) at the prevalent pH, along with possible reduction of Cr(VI) to Cr(III) due to presence of reducing agents like Fe(II). 49,50 The presence of Cr in groundwater could be attributed to leaching from COPR dump due to either dissolution of some Cr-bearing solid phases 7,24 or desorption of Cr(VI) present in the COPR. 31 Calculated saturation indices for many groundwater samples indicate Cr(VI) and Cr(III) phases, Cr(VI)jarosite (s) , BaCrO 4(s) , Cr(OH) 3(s) , and Cr 2 O 3(s) , as either supersaturated or at-saturation (Figure 4).…”

Section: Resultsmentioning

confidence: 99%

“…Precipitation of BaCrO 4(s) , along with other Cr(VI) phases in the vicinal water surrounding airborne particles was also suggested by the simulation-based study cited in the previous paragraph. 50 Further investigation toward the presence of such potential Cr-bearing solid phases in the groundwater was carried out for samples where filtration caused a decrease of more than 50% in total Cr concentrations (Table S4). Presence of colloidal Crcontaining phases could explain this decrease.…”

Section: Resultsmentioning

confidence: 99%

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Processes Governing Chromium Contamination of Groundwater and Soil from a Chromium Waste Source

Bhattacharya

Shriwastav

Bhole

et al. 2019

ACS Earth Space Chem.

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Chromium (Cr) contamination of natural resources from unregulated disposal of pretanning industrial waste, chromite ore processing residue (COPR), is a serious environmental concern, especially in developing countries. Although there have been studies on COPR characterization, the fate and transport of chromium emanating from COPR remains poorly understood. In this study, processes governing Cr contamination in groundwater and soil near known COPR disposal sites were investigated. Field sampling of groundwater, irrigated soil, and COPR was conducted near Kanpur (India) to identify the extent and forms of chromium contamination. Both dissolved and suspended fractions of groundwater were analyzed to evaluate the presence of any Cr-containing colloids. At certain locations with elevated Cr levels, the saturation state of sampled groundwater was evaluated to be near equilibrium with respect to BaCrO 4(s) through speciation modeling of wet chemical data. Colloidal forms of Cr, such as BaCrO 4(s) or as Cr adsorbed on other non-Cr containing phases, were suggested through measured differences in total and dissolved Cr concentrations and SEM-EDS evidence of Ba and Cr on filtrate residues. As BaCrO 4(s) was not detected in COPR, the presence of these colloids in groundwater could be indicative of secondary precipitation of Cr upon interaction with Ba present in the subsurface. Rapid formation of colloidal BaCrO 4(s) was also supported through controlled batch experiments with Cr(VI)-and Ba-spiked ultrapure water and groundwater. These results indicate the importance of secondary precipitation of colloidal BaCrO 4(s) in determining eventual Cr(VI) solubility in aquifers impacted by Cr originating from COPR dissolution.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Processes Governing Chromium Contamination of Groundwater and Soil from a Chromium Waste Source

Bhattacharya

Shriwastav

Bhole

et al. 2019

ACS Earth Space Chem.

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“…We recommend the following articles [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ] to interested readers. There is a wide range of applications of such molecular & materials modeling methods, at different scales, to study drug design, biological processes, wastewater treatment, enhanced oil recovery, concrete admixtures, rational design of carbon nano-sheets, lithium-ion batteries, and fuel cells, to name a few [ 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 ].…”

Section: Introductionmentioning

confidence: 99%

Molecular Modeling in Anion Exchange Membrane Research: A Brief Review of Recent Applications

et al. 2022

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Anion Exchange Membrane (AEM) fuel cells have attracted growing interest, due to their encouraging advantages, including high power density and relatively low cost. AEM is a polymer matrix, which conducts hydroxide (OH−) ions, prevents physical contact of electrodes, and has positively charged head groups (mainly quaternary ammonium (QA) groups), covalently bound to the polymer backbone. The chemical instability of the quaternary ammonium (QA)-based head groups, at alkaline pH and elevated temperature, is a significant threshold in AEMFC technology. This review work aims to introduce recent studies on the chemical stability of various QA-based head groups and transportation of OH− ions in AEMFC, via modeling and simulation techniques, at different scales. It starts by introducing the fundamental theories behind AEM-based fuel-cell technology. In the main body of this review, we present selected computational studies that deal with the effects of various parameters on AEMs, via a variety of multi-length and multi-time-scale modeling and simulation methods. Such methods include electronic structure calculations via the quantum Density Functional Theory (DFT), ab initio, classical all-atom Molecular Dynamics (MD) simulations, and coarse-grained MD simulations. The explored processing and structural parameters include temperature, hydration levels, several QA-based head groups, various types of QA-based head groups and backbones, etc. Nowadays, many methods and software packages for molecular and materials modeling are available. Applications of such methods may help to understand the transportation mechanisms of OH− ions, the chemical stability of functional head groups, and many other relevant properties, leading to a performance-based molecular and structure design as well as, ultimately, improved AEM-based fuel cell performances. This contribution aims to introduce those molecular modeling methods and their recent applications to the AEM-based fuel cells research community.

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“…While the prior studies conducted on Cr speciation considered groundwater conditions and were centralized on the presence of reductants or oxidants available in the aqueous medium, our understanding of chromium reactions with volatile organic compounds in particulate matter under atmospheric conditions is limited. Recently, Amouei Torkmahalleh et al 21 developed a computer model by utilizing the earlier concept of Seigneur and Constantinou 4 . They implemented field data collected in New Jersey, US, to understand the chemistry and speciation of soluble, and insoluble chromium at pH ~ 9.…”

mentioning

confidence: 99%

“…The reduction rate of Cr(VI) to Cr(III) was observed to be higher than the oxidation rate of Cr(III) to Cr(VI). The use of a basic pH solution was found to retard the conversion of Cr(VI) in the presence of Fe(II) and As(III) and though it facilitated the precipitation of Cr(III) 21 . Although dissolved gases such as O 3 , O 2 , HO 2 , and HO 3 were employed in their model, possible reaction of VOCs were not included to understand Cr chemistry under typical atmospheric conditions.…”

mentioning

confidence: 99%

Impact of volatile organic compounds on chromium containing atmospheric particulate: insights from molecular dynamics simulations

Shah

Karibayev

Adotey

et al. 2020

Sci Rep

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The effect of volatile organic compounds (VOCs) on chromium-containing atmospheric particles remains obscured because of difficulties in experimental measurements. Moreover, several ambiguities exist in the literature related to accurate measurements of atmospheric chromium concentration to evaluate its toxicity. We investigated the interaction energies and diffusivity for several VOCs in chromium (III)-containing atmospheric particles using classical molecular dynamics simulations. We analyzed xylene, toluene, ascorbic acid, carbon tetrachloride, styrene, methyl ethyl ketone, naphthalene, and anthracene in Cr(III) solutions, with and without air, to compare their effects on solution chemistry. The interaction energy between Cr(III) and water changed from 48 to 180% for different VOCs, with the highest change with anthracene and the lowest change with naphthalene. The results revealed no direct interactions between Cr(III) particles and the analyzed volatile organic compounds, except ascorbic acid. Interactions of Cr(III) and ascorbic acid differ significantly between the solution phase and the particulate phase. The diffusion of Cr(III) and all the VOCs also were observed in a similar order of magnitude (~ 10−5 cm2/s). The results can further assist in exploring the variation in chromium chemistry and reaction rates in the atmospheric particles in the presence of VOCs.

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Aqueous chemistry of airborne hexavalent chromium during sampling

Cited by 13 publications

References 24 publications

Processes Governing Chromium Contamination of Groundwater and Soil from a Chromium Waste Source

Processes Governing Chromium Contamination of Groundwater and Soil from a Chromium Waste Source

Molecular Modeling in Anion Exchange Membrane Research: A Brief Review of Recent Applications

Impact of volatile organic compounds on chromium containing atmospheric particulate: insights from molecular dynamics simulations

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