Journal ArticleDOI
Competitive Sorption of Arsenate and Phosphate on Different Clay Minerals and Soils
Antonio Violante,Massimo Pigna +1 more
TLDR
In this article, the competitive sorption of PO 4 and AsO 4 on selected phyllosilicates, metal oxides, synthetic organo-mineral complexes, and soil samples as affected by pH (4.0-8.0), ligands concentration, surface coverage of the oxyanions on the samples and the residence time.Abstract:
Sorption and desorption of AsO 4 on or from different soil components may have a dominant role in regulating As mobility in soils. The objectives of this work were to provide information on the factors that influence the competitive sorption of AsO 4 and PO 4 in soil. We studied the competitive sorption of PO 4 and AsO 4 on selected phyllosilicates, metal oxides, synthetic organo-mineral complexes, and soil samples as affected by pH (4.0-8.0), ligands concentration, surface coverage of the oxyanions on the samples and the residence time. We found that Mn, Fe, and Ti oxides and phyllosilicates particularly rich in Fe (nontronite, ferruginous smectites) were more effective in sorbing AsO 4 than PO 4 . In fact, by adding AsO 4 and PO 4 as a mixture (AsO 4 /PO 4 molar ratio of 1) more AsO 4 , than PO 4 was usually sorbed on birnessite, pyrolusite, goethite, nontronite, and ferruginous smectite, but more PO 4 than AsO 4 was sorbed on noncrystalline Al precipitation products, gibbsite, boehmite, allophane, and kaolinite. For example, at pH 5.0 the sorbed AsO 4 /sorbed PO 4 molar ratio (rf) was 1.81 for bimessite, 1.05 for nontronite, but was only 0.45 for kaolinite and 0.14 for allophane. For montmorillonite, illite, and vermiculite the rf values were slightly <1. For soil samples, particularly rich in kaolinite, halloysite, allophane, and containing relatively large amounts of organic C, the rf values were usually much <1. For all the samples, the rf values increased by decreasing the pH and with the residence time of the oxyanions. The sorption of AsO 4 (or PO 4 ) on goethite and gibbsite decreased by increasing the initial PO 4 /AsO 4 (or ASO 4 / PO 4 molar ratio) up to 2.0. However, PO 4 inhibited AsO 4 sorption more on gibbsite than on goethite, whereas AsO 4 prevented PO 4 sorption more on goethite than on gibbsite. The data reported in this paper suggest that the mobility, the bioavailability, and the toxicity of As in soil environments may be greatly affected by the nature of soil components, pH, presence of anions (PO 4 ), and residence time.read more
Citations
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Journal ArticleDOI
Characterization of As-polluted soils by laboratory X-ray-based techniques coupled with sequential extractions and electron microscopy: the case of Crocette gold mine in the Monte Rosa mining district (Italy)
Ignazio Allegretta,Carlo Porfido,Maria Martin,Elisabetta Barberis,Roberto Terzano,Matteo Spagnuolo +5 more
TL;DR: The proposed combination of laboratory X-ray techniques could be successfully employed to unravel environmental issues related to metal(loid) pollution in soil and sediments.
Journal ArticleDOI
Effective stabilization of antimony in Waste-to-Energy fly ash with recycled laboratory iron–rich residuals
TL;DR: In this article, two laboratory iron-rich residuals (LIR-1 and LIR-2) were collected and their effectiveness for stabilizing Sb in WtE fly ash were evaluated by toxicity characteristic leaching procedure (TCLP) and continuous acid leaching tests.
Journal ArticleDOI
Micron-scale distribution controls metal(loid) release during simulated weathering of a Pennsylvanian coal shale
David M. Singer,Elizabeth Herndon,Kortney Cole,Michael F Burkey,Sarah Morisson,Michael Cahill,Matthew A. Bartucci +6 more
TL;DR: In this paper, a combination of electron microscopy and synchrotron-based X-ray microprobe analyses was used to determine how the micron and sub-micron scale mineralogy, morphology, and texture of metal-bearing phases in a coal-shale control the rate and release of metal(loid)s during subsequent weathering.
Journal ArticleDOI
Phosphate has a differential influence on arsenate adsorption by soils with different properties
TL;DR: In this article, the adverse effect of P application on As (V) adsorption by the six soils were observed to be variable and the results indicated that the adsorbed As contents all increased as a function of the As(V) content in equilibrium.
Journal ArticleDOI
A gel probe equilibrium sampler for measuring arsenic porewater profiles and sorption gradients in sediments: I. Laboratory development.
TL;DR: In this study, clear and HFO-doped gels were tested under laboratory conditions to constrain the gel behavior prior to field deployment and provide a basis for interpreting results obtained by deploying the gel probe in the field and elucidating the mechanisms controlling As partitioning between solid and dissolved phases in the environment.
References
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Journal ArticleDOI
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TL;DR: In this paper, the authors compared the adsorption behavior of arsenite and arsenate on ferrihydrite, under carefully controlled conditions, with regard to adaption kinetics and the influence of pH.
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Journal ArticleDOI
Arsenic contamination of groundwater and drinking water in Vietnam: a human health threat.
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Journal ArticleDOI
Arsenate and Chromate Retention Mechanisms on Goethite. 1. Surface Structure
TL;DR: In this paper, the authors used Extended X-ray absorption fine structure (EXAFS) spectroscopy to deduce the local coordination environment of two environmental contaminants, arsenate and chromate, on the mineral goethite (α-FeOOH).