A review of the arsenic cycle in natural waters

Ferguson, John F.; Gavis, Jerome

doi:10.1016/0043-1354(72)90052-8

Cited by 914 publications

(454 citation statements)

References 36 publications

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“…All chemicals were analytical-grade and were purchased from Beijing Chemical Co. (Beijing, China). The As(III) and As(V) stock solutions were prepared with deionized water using NaAsO 2 11 Batch Sorption Experiments. Adsorption experiments were performed at an ionic strength of 0.01 M NaNO 3 .…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Respective Role of Fe and Mn Oxide Contents for Arsenic Sorption in Iron and Manganese Binary Oxide: An X-ray Absorption Spectroscopy Investigation

Zhang

Liu

et al. 2014

Environ. Sci. Technol.

213

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ABSTRACT:In our previous studies, a synthesized Fe−Mn binary oxide was found to be very effective for both As(V) and As(III) removal in aqueous phase, because As(III) could be easily oxidized to As(V). As(III) oxidation and As(V) sorption by the Fe−Mn binary oxide may also play an important role in the natural cycling of As, because of its common occurrence in the environment. In the present study, the respective role of Fe and Mn contents present in the Fe−Mn binary oxide on As(III) removal was investigated via a direct in situ determination of arsenic speciation using X-ray absorption spectroscopy. X-ray absorption near edge structure results indicate that Mn atoms exist in a mixed valence state of +3 and +4 and further confirm that MnO x (1.5 < x < 2) content is mainly responsible for oxidizing As(III) to As(V) through a two-step pathway [reduction of Mn(IV) to Mn(III) and subsequent Mn(III) to Mn(II)] and FeOOH content is dominant for adsorbing the formed As(V). No significant As(III) oxidation by pure FeOOH had been observed during its sorption, when the system was exposed to air. The extended X-ray absorption fine structure results reveal that the As surface complex on both the As(V)-and As(III)-treated sample surfaces is an inner-sphere bidentate binuclear corner-sharing complex with an As−M (M = Fe or Mn) interatomic distance of 3.22−3.24 Å. In addition, the MnO x and FeOOH contents exist only as a mixture, and no solid solution is formed. Because of its high effectiveness, low cost, and environmental friendliness, the Fe−Mn binary oxide would play a beneficial role as both an efficient oxidant of As(III) and a sorbent for As(V) in drinking water treatment and environmental remediation. ■ INTRODUCTIONArsenic, a ubiquitous trace element in the aquatic environment, is introduced from both natural processes and anthropogenic sources. 1 In natural water, arsenic is mostly found in two inorganic forms, namely, arsenate and arsenite. In welloxygenated water, As(V) is the major arsenic species, while As(III) is dominant in reduced groundwater. As(III) is more toxic, soluble, and mobile than As(V). 2,3 A high level of arsenic in groundwater and surface waters is a major concern worldwide, because of its high toxicity and carcinogenicity. To minimize the possible health risks, the World Health Organization (WHO) has set a stringent limit of 10 μg L −1 As for drinking water. 4 The adsorption reactions between arsenic and minerals (particularly metal oxides) play a very important role in its mobility and potential bioavailability because arsenic can be strongly adsorbed onto the surface of metal oxides, such as iron (hydr)oxides, alumina, and manganese oxides, which commonly occur in the aquatic environment. 5,6 Adsorption is also regarded as a promising method for the removal of arsenic from water, owing to its simple operation, high efficiency, and cost effectiveness. Numerous investigations have focused on arsenic immobilization by natural and synthetic Fe (hydr)oxides and Fe-containing materials. 7−10 Recently,...

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Respective Role of Fe and Mn Oxide Contents for Arsenic Sorption in Iron and Manganese Binary Oxide: An X-ray Absorption Spectroscopy Investigation

Zhang

Liu

et al. 2014

Environ. Sci. Technol.

213

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“…Inorganic arsenic is predominantly present in natural waters. Arsenate [As(V)] and arsenite [As(III)] are primary forms of arsenic in soils and natural waters (Ferguson and Gavis, 1972). As(III) is more mobile in groundwater and 25-60 times more toxic than As(V).…”

Section: Introductionmentioning

confidence: 99%

“…Under low pH and mildly reducing conditions (>100 mV), As(III) is thermodynamically stable and exists as arsenious acid (H 3 AsO 0 3 , H 2 AsO À 3 , HAsO 2À 3 and AsO 3À 3 ). Under oxidizing conditions, the predominant species is As(V) which exists as arsenic acid (H 3 AsO 4 , H 2 AsO À 4 , HAsO 2À 4 and AsO 3À 4 ) (Ferguson and Gavis, 1972).…”

Section: Introductionmentioning

confidence: 99%

Removal of arsenic from water by electrocoagulation

et al. 2004

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“…As(V) is the major arsenic species in well-oxygenated water (Ferguson and Gavis, 1972), whereas As(III) is the dominant arsenic in groundwater (Smedley and Kinniburgh, 2002). As(III) is much more toxic (Ferguson and Gavis, 1972), more soluble, and more mobile than As(V).…”

Section: Introductionmentioning

confidence: 99%

Preparation and evaluation of a novel Fe–Mn binary oxide adsorbent for effective arsenite removal

et al. 2007

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Adsorbent OxidationArsenite Removal a b s t r a c t Arsenite (As(III)) is more toxic and more difficult to remove from water than arsenate (As(V)).As there is no simple treatment for the efficient removal of As(III), an oxidation step is always necessary to achieve higher removal. However, this leads to a complicated operation and is not cost-effective. To overcome these disadvantage, a novel Fe-Mn binary oxide material which combined the oxidation property of manganese dioxide and the high adsorption features to As(V) of iron oxides, were developed from low cost materials using a simultaneous oxidation and coprecipitation method. The adsorbent was characterized by BET surface areas measurement, powder XRD, SEM, and XPS. The results showed that prepared Fe-Mn binary oxide with a high surface area ð265 m 2 g À1 Þ was amorphous. Iron and manganese existed mainly in the oxidation state þIII and IV, respectively. Laboratory experiments were carried out to investigate adsorption kinetics, adsorption capacity of the adsorbent and the effect of solution pH values on arsenic removal. Batch experimental results showed that the adsorbent could completely oxidize As(III) to As(V) and was effective for both As(V) and As(III) removal, particularly the As(III). The maximal adsorption capacities of As(V) and As(III) were 0:93 mmol g À1 and 1:77 mmol g À1 , respectively. The results compare favorably with those obtained using other adsorbent. The effects of anions such as SO 2À 4 , PO 3À 4 , SiO and humic acid (HA), which possibly exist in natural water, on As(III) removal were also investigated. The results indicated that phosphate was the greatest competitor with arsenic for adsorptive sites on the adsorbent. The presence of sulfate and HA had no significant effect on arsenic removal. The high uptake capability of the Fe-Mn binary oxide makes it potentially attractive adsorbent for the removal of As(III) from aqueous solution.

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A review of the arsenic cycle in natural waters

Cited by 914 publications

References 36 publications

Respective Role of Fe and Mn Oxide Contents for Arsenic Sorption in Iron and Manganese Binary Oxide: An X-ray Absorption Spectroscopy Investigation

Respective Role of Fe and Mn Oxide Contents for Arsenic Sorption in Iron and Manganese Binary Oxide: An X-ray Absorption Spectroscopy Investigation

Removal of arsenic from water by electrocoagulation

Preparation and evaluation of a novel Fe–Mn binary oxide adsorbent for effective arsenite removal

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