Mechanisms of Arsenic Uptake from Aqueous Solution by Interaction with Goethite, Lepidocrocite, Mackinawite, and Pyrite:  An X-ray Absorption Spectroscopy Study

Farquhar, Morag L.; Charnock, John; Livens, Francis R.; Vaughan, David J.

doi:10.1021/es010216g

Cited by 427 publications

(404 citation statements)

References 19 publications

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“…Bacterium, such as Desulfotomaculum auripigmentum, was reported to induce precipitation of As 2 S 3 by its reduction of As(V) to As(III) and S(VI) to S(−II) under anoxic conditions with excessive S (Figure 3b) (Newman et al 1997). And in the environment with high Fe (II) or FeS, FeAsS may be formed by coprecipitation of As with Fe and S (Farquhar et al 2002). Furthermore, higher soil pH, resulted by As addition and excessive S supply (Figure 3b), may promote the formation of these indiscerptible compounds.…”

Section: Discussionmentioning

confidence: 99%

Excessive sulfur supply reduces arsenic accumulation in brown rice

Fan¹,

Xia²,

Hu³

et al. 2013

Plant Soil Environ.

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Arsenic (As), an extremely toxic metalloid pollutant, is distributed in soil through anthropogenic activities, such as pesticide and herbicide application, mining, or irrigation with contaminated groundwater . Rice grown on As-contaminated paddy soil can accumulate high levels of As, approximately 10-fold larger than other cereals (Lombi et al. 2009). Thus, As uptake by rice plants is recognized as a major route of As transfer into food chain which has the potential to become a new disaster for population in Southeast Asia (Heikens et al. 2007). Therefore, it is crucial to understand the mechanism of As uptake by rice and to find strategies for reducing As accumulation in grain for enhanced food safety.Paddy rice (Oryza sativa L.) oxygenates its rhizosphere, resulting in the formation of an iron oxyhydroxide plaque (Hansel et al. 2001 ABSTRACTThe objective of this study was to investigate the influence of excessive sulfur (S) supply on iron plaque formation and arsenic (As) accumulation in rice plants. A combined soil-sand pot experiment was conducted by using two As levels (0, 20 mg/kg) combined with three S concentrations (0, 60, 120 mg/kg). The results showed that excessive S supply significantly decreased As concentration in brown rice, but As concentration in root increased with increasing rate of S supply. Moreover, bioconcentration factors for leaves and stems were 8-35 fold of that for brown rice, indicating that As was mainly accumulated in rice leaves and stems instead of brown rice. Furthermore, excessive S supply significantly decreased translocation factor of As compared to treatment without S supply. These results indicated that excessive S may reduce As translocation from soils and roots to grain. The mechanism could be ascribed to excessive S that induced the decrease of As availability, the increase of iron plaque formation under As stress, and the increase of glutathione in rice leaves and roots. Therefore, excessive S can reduce As accumulation in brown rice exposed to As contaminated soils though it may result in loss of rice yield.

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Section: Discussionmentioning

confidence: 99%

Excessive sulfur supply reduces arsenic accumulation in brown rice

Fan¹,

Xia²,

Hu³

et al. 2013

Plant Soil Environ.

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“…The products formed on pyrite surfaces are complicated. The formation of As 2 S 3 or As 4 S 4 surface phases has been demonstrated in the uptake of As(III) and As(V) by synthetic pyrite [5], and the formation of outer-sphere surface complexes between As(V)/As(III) and mackinawite and pyrite is also reported [6]. Additionally, pH impacts the species of products formed between As(III) and nano-FeS m and the removal efficiency of As (III) thereafter [7].…”

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confidence: 89%

Treatment of strongly acidic wastewater with high arsenic concentrations by ferrous sulfide (FeS): Inhibitive effects of S(0)-enriched surfaces

Liu

Yang

et al. 2016

Chemical Engineering Journal

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h i g h l i g h t sFeS shows higher removal efficiency towards As(III) than As(V). In acidic solution FeS dissolve to S(-II) for As(V) reduction and As 2 S 3 formation. S(-II) react with As(V) to form S(0)-rich surface on FeS and inhibit As removal. S(II)-rich surface inhibit FeS dissolution and arsenic removal. As(V) reduction to As(III) by dosing Na 2 S prior to FeS improve As(V) removal. The utilization of arsenopyrite (FeAsS), the As ore mineral, produces strongly acidic wastewater with extremely high arsenic (As) concentrations. This study investigates the feasibility of using ferrous sulfide (FeS) as a sulfide [S(-II)] source to treat strongly acidic wastewater with high concentrations of arsenite [As(III)] and arsenate [As(V)]. The removal of As(III) by FeS was nearly 30% higher than that of As(V), and higher acidity and elevated FeS doses benefited their removal. At extremely high acidity of above 7 mol/L as H 2 SO 4 , the consumption of S(-II) by H 2 SO 4 inhibited As removal. At lower acidity of below 2 mol/L as H 2 SO 4 , elevated FeS doses up to 4 times the theoretical dose could achieve good As removal. SEM/EDS and XPS analysis indicated the formation of As 2 S 3 precipitates, and sulfur [S(0)] also formed in the As(V)-removing system. The tiny and negatively-charged S(0) particles tend to coat the FeS surface. The S(0)-enriched surface acts as a barrier to inhibit S(-II) detachment and As(V) penetration and inhibits As(V) removal thereafter. The reduction of As(V) to As(III) by Na 2 S, prior to dosing with FeS, is preferred to achieve rapid and favorable As(V) removal. The low-cost FeS provides available Fe(II) and S(-II) for As removal, and is practically valuable to treat acidic high-As wastewater.

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“…Arsenic contamination in the environment is one of the most important public health problems in the world; high arsenic concentrations have been reported in China, Bangladesh, Nicaragua, Vietnam, Brazil, France, the USA, and several other countries (McClintock et al 2012). Water contaminated with As requires special attention because of its high toxicity, even in low concentrations (Celik et al 2008), and the mobility of this element in the environment (Farquhar et al 2002).…”

Section: Introductionmentioning

confidence: 99%