Arsenic Eh–pH diagrams at 25°C and 1 bar

Lü, Peng; Zhu, Chen

doi:10.1007/s12665-010-0652-x

Cited by 109 publications

(53 citation statements)

References 34 publications

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“…The unspiked soil had a pH value of 4.5 and Eh value of about 270 mV. According to the revised Eh-pH diagrams for the As-O-H system at 25°C and 1 bar by Lu and Zhu (2011), arsenic is expected to exist in ?5 state under these conditions in aqueous matrices. Hence, aqueous solution of Na 2 HAsO 4 Á7H 2 O was used to spike the soil.…”

Section: Soil Characterizationmentioning

confidence: 99%

Arsenic removal from soil with high iron content using a natural surfactant and phosphate

Mukhopadhyay

Hashim

Allen

et al. 2013

Int. J. Environ. Sci. Technol.

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An environment friendly arsenic removal technique from contaminated soil with high iron content has been studied. A natural surfactant extracted from soapnut fruit, phosphate solution and their mixture was used separately as extractants. The mixture was most effective in desorbing arsenic, attaining above 70 % efficiency in the pH range of 4-5. Desorption kinetics followed Elovich model. Micellar solubilization by soapnut and arsenic exchange mechanism by phosphate are the probable mechanisms behind arsenic desorption. Sequential extraction reveals that the mixed soapnut-phosphate system is effective in desorbing arsenic associated with amphoteric-Fe-oxide forms. No chemical change to the wash solutions was observed by Fourier transform-infrared spectra. Soil:solution ratio, surfactant and phosphate concentrations were found to affect the arsenic desorption process. Addition of phosphate boosted the performance of soapnut solution considerably. Response surface methodology approach predicted up to 80 % desorption of arsenic from soil when treated with a mixture of &1.5 % soapnut, &100 mM phosphate at a soil:solution ratio of 1:30.

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Section: Soil Characterizationmentioning

confidence: 99%

Arsenic removal from soil with high iron content using a natural surfactant and phosphate

Mukhopadhyay

Hashim

Allen

et al. 2013

Int. J. Environ. Sci. Technol.

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“…Arsenic species equilibria constants were updated based on the most recent literature, as reported in Tables 1 and 2 of Lu and Zhu [35]. Predominant As species in the As-Fe-S-O-H system were predicted over the range of total As, Fe and S concentrations measured in the BCR influent, effluent, lysimeter and borehole pore water (Tables S1-S3 in the Supplemental Information).…”

Section: Geochemical Modelingmentioning

confidence: 99%

Mineralogical Study of a Biologically-Based Treatment System That Removes Arsenic, Zinc and Copper from Landfill Leachate

2013

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Mineralogical characterization by X-ray diffraction (XRD) and a high throughput automated quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) was conducted on samples from a sulphate-reducing biochemical reactor (BCR) treating high concentrations of metals (As, Zn, Cu) in smelter waste landfill seepage. The samples were also subjected to energy dispersive X-ray (EDX) analysis of specific particles. The bulk analysis results revealed that the samples consisted mainly of silicate and carbonate minerals. More detailed phase analysis indicated four different classes: zinc-arsenic sulphosalts/sulphates, zinc-arsenic oxides, zinc phosphates and zinc-lead sulphosalts/sulphates. This suggests that sulphates and sulphides are the predominant types of Zn and As minerals formed in the BCR. Sphalerite (ZnS) was a common mineral observed in many of the samples. In addition, X-ray point analysis showed evidence of As and Zn coating around feldspar and amphibole particles. The presence of arsenic-zinc-iron, with or without cadmium particles, indicated arsenopyrite minerals. Copper-iron-sulphide particles suggested chalcopyrite (CuFeS 2 ) and tennantite (Cu,Fe) 12 As 4 S 13 . Microbial communities found in each sample were correlated with metal content to describe taxonomic groups associated with high-metal samples. The research results highlight mineral grains that were present or formed at the site that might be the predominant forms of immobilized arsenic, zinc and copper.

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“…In this study, when injected CO 2 leaked into the shallow potable groundwater aquifer, the dissolution of leaked CO 2 induced the acidification of the ambient groundwater to 4 < pH < 6 [11], where H 3 AsO 3 0 and H 2 AsO 4 − were dominant under reducing and oxidizing conditions, respectively [33,39]. Here, the shallow aquifer was considered to be under the reducing condition, and thus, H 3 AsO 3 0 was chosen as the most dominant species.…”

Section: Behavior Of Arsenic In Subsurface Environmentmentioning

confidence: 89%

“…Arsenic in natural water typically originates from arsenicbearing minerals that frequently possess sulfur, oxygen, and iron [33]. Figure 1, arsenic species can be present in several valence states (−3, 0, +3, and +5), but in natural groundwater, it is mostly found in oxyanions of trivalent arsenite (As(III)) or pentavalent arsenate (As(V)), depending on reducing or oxidizing conditions, respectively.…”

Section: Behavior Of Arsenic In Subsurface Environmentmentioning

confidence: 99%

CO₂ Leakage-Induced Contamination in Shallow Potable Aquifer and Associated Health Risk Assessment

et al. 2018

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Leakage of stored CO 2 from a designated deep reservoir could contaminate overlying shallow potable aquifers by dissolution of arsenic-bearing minerals. To elucidate CO 2 leakage-induced arsenic contamination, 2D multispecies reactive transport models were developed and CO 2 leakage processes were simulated in the shallow groundwater aquifer. Throughout a series of numerical simulations, it was revealed that the movement of leaked CO 2 was primarily governed by local flow fields within the shallow potable aquifer. The induced low-pH plume caused dissolution of aquifer minerals and sequentially increased permeabilities of the aquifer; in particular, the most drastic increase in permeability appeared at the rear margin of CO 2 plume where two different types of groundwater mixed. The distribution of total arsenic (∑As) plume was similar to the one for the arsenopyrite dissolution. The breakthrough curve of ∑As monitored at the municipal well was utilized to quantify the human health risk. In addition, sensitivity studies were conducted with different sorption rates of arsenic species, CO 2 leakage rates, and horizontal permeability in the aquifer. In conclusion, the human health risk was influenced by the shape of ∑As plume, which was, in turn, affected by the characteristics of CO 2 plume behavior such as horizontal permeability and CO 2 leakage rate.

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Arsenic Eh–pH diagrams at 25°C and 1 bar

Cited by 109 publications

References 34 publications

Arsenic removal from soil with high iron content using a natural surfactant and phosphate

Arsenic removal from soil with high iron content using a natural surfactant and phosphate

Mineralogical Study of a Biologically-Based Treatment System That Removes Arsenic, Zinc and Copper from Landfill Leachate

CO₂ Leakage-Induced Contamination in Shallow Potable Aquifer and Associated Health Risk Assessment

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Arsenic Eh–pH diagrams at 25°C and 1 bar

Cited by 109 publications

References 34 publications

Arsenic removal from soil with high iron content using a natural surfactant and phosphate

Arsenic removal from soil with high iron content using a natural surfactant and phosphate

Mineralogical Study of a Biologically-Based Treatment System That Removes Arsenic, Zinc and Copper from Landfill Leachate

CO2 Leakage-Induced Contamination in Shallow Potable Aquifer and Associated Health Risk Assessment

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CO₂ Leakage-Induced Contamination in Shallow Potable Aquifer and Associated Health Risk Assessment