Biological Oxidation of Arsenite in Strong Acid Water

Nakazawa, Hiroshi; Hareyama, Wataru

doi:10.4144/rpsj.54.182

Cited by 9 publications

(7 citation statements)

References 11 publications

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“…However, oxidation of As(III) in the simulated stomach (pH 1.8 under anoxic conditions) would be unlikely given the duration of our study, i.e., 2 hr. Nakazawa and Hareyama noticed no observable As(III) oxidation in aqueous media at pH 1.8 after 5 days(35). Observed maximum bound values for As binding to ferrihydrite in the simulated intestine were 0.335 mol/kg and 0.266 mol/kg for As(III) and As(V), respectively (Figure 3).…”

Section: Resultsmentioning

confidence: 99%

In Vitro Evaluation of Ferrihydrite as an Enterosorbent for Arsenic from Contaminated Drinking Water

Taylor

Robinson

Johnson

et al. 2009

Environ. Sci. Technol.

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Arsenic (As) is a toxic trace element found in groundwater due to natural and industrial processes. Exposure has been linked to cancers of the bladder, lungs, skin, kidneys, nasal passages, liver, and the prostate. Arsenic in drinking water is a problem in many countries, notably Bangladesh and Taiwan. The purpose of this research was to utilize binding isotherms, a simulated gastrointestinal (GI) model, and the adult Hydra bioassay to evaluate ferrihydrite's potential to bind As and serve as a potential enterosorbent for As found in drinking water. A variety of clay minerals and synthesized iron oxides including ferrihydrite were screened for their ability to bind As(III), as sodium arsenite, and As(V), as sodium arsenate. After ferrihydrite was demonstrated to be the most effective sorbent for both As species, adsorption isotherms were performed. All isotherm data were fit to the Langmuir equation to determine adsorption capacity (Q max ). Ferrihydrite bound 96% of As(III) and 97% of As (V) in the screening studies and had a Q max of 1.288 mol/kg for As(III) and 0.744 mol/kg for As(V). Using a simulated GI model, ferrihydrite was found to effectively adsorb As(V) and As(III) in the stomach and intestine. Ferrihydrite (0.25% w/w) protected adult hydra at levels up to 200 times the minimal effective concentration (MEC) for As(III) and up to 2.5 times the MEC for As(V). These experiments confirm that ferrihydrite is a high capacity sorbent of As, and that it is effective at removing As in a simulated GI model. These results suggest that ferrihydrite could be used as a potential enterosorbent for As found in drinking water. Future work will focus on verifying ferrihydrite's safety and efficacy in vivo.

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Section: Resultsmentioning

confidence: 99%

In Vitro Evaluation of Ferrihydrite as an Enterosorbent for Arsenic from Contaminated Drinking Water

Taylor

Robinson

Johnson

et al. 2009

Environ. Sci. Technol.

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“…Among those autotrophic and heterotrophic As-oxidizers reported so far, the majority are neutrophilic bacteria with a few studies on acid-tolerant species such as Thiomonas spp. (Cavalca et al 2013) and unknown acidophilic strains (Nakazawa and Hareyama 2007). Nonetheless, to our knowledge, there is yet no detailed study available on extremelyacidophilic As-oxidizers with moderately-thermophilic or mesophilic growth temperatures, which exhibit robust As(III) oxidation at the concentration of several millimolar.…”

Section: Introductionmentioning

confidence: 99%

Bioremediation of highly toxic arsenic via carbon-fiber-assisted indirect As(III) oxidation by moderately-thermophilic, acidophilic Fe-oxidizing bacteria

Okibe

Fukano

2019

Biotechnol Lett

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Objective To enable removal of highly toxic As(III) from acidic waters by inducing indirect microbial As(III) oxidation by Fe-oxidizing bacteria via carbon-assisted redox-coupling between As(III) oxidation and Fe 3+ reduction.Results Carbon-fiber (CF) was shown to function as an electron-mediator to catalyze chemical (abiotic) redox-coupling between As(III) oxidation and Fe 3+ reduction. Accordingly, by taking advantage of Fe 3+ regeneration by Fe-oxidizing bacteria, it was possible to promote oxidative removal of As(III) as ferric arsenate at moderate temperature. This reaction can be of use under the situation where a high-temperature treatment is not immediately available. Arsenic once concentrated as ferric arsenate on carbon-fibers can be collected to undergo phase-transformation to crystalline scorodite as the next re-solubilization/re-crystallization step at a higher temperature (70°C).Conclusions While extremely acidophilic Fe-oxidizing bacteria are widely found in nature, the As-oxidizing counterparts, especially those grown on moderately-thermophilic and mesophilic temperatures, are hardly known. In this regard, the finding of this study could make a possible introduction of the semi-passive, low-temperature As-treatment using readily available Feoxidizing bacteria.

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“…Therefore, the treatment of arsenic (As) in AMD is required. 8,9) Currently, the AMD that includes Fe(II) and As(III) is treated at the Matsuo neutralization plant by oxidation using iron-oxidizing bacteria and neutralization using CaCO 3 . [10][11][12] This method can easily remove As from the solution because As(V) ions that are oxidized from As(III) ions by the bacteria are easily adsorbed on the Fe(OH) 3 precipitates and removed from the solution.…”

Section: Introductionmentioning

confidence: 99%

Removal of arsenious acid from sulfuric acidic solution using ultrasound oxidation and goethite

Okawa

Yoshikawa

Hosokawa

et al. 2015

Jpn. J. Appl. Phys.

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We investigated the properties of synthetic goethite for the adsorption of As from strongly acidic solutions in ambient atmosphere under ultrasound irradiation. The goethite was successfully synthesized from iron-containing sulfuric acidic solution (1271 ppm) using an autoclave apparatus for 1 h at 0.12 MPa and 121 °C. The ratio of the iron eluted from the synthetic goethite to the acidic solution was only 0.58% at pH 2.1. Ultrasound irradiation (200 kHz, 200 W) was applied to oxidize 10 ppm of As(III) to As(V) at pH 2.2 for 60 min under various atmospheric conditions. Remarkably, the oxidation ratio of As(III) to As(V) is quite high (89.7%) at pH 2.2 in ambient atmosphere and is close to those obtained for Ar (95.3%) and O2 (95.9%) atmospheres. The As(III) removal ratio reached 94.5% after 60 min of irradiation. Therefore, goethite is a promising material for As adsorption using ultrasound oxidation in the acidic region in ambient atmosphere.

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Biological Oxidation of Arsenite in Strong Acid Water

Cited by 9 publications

References 11 publications

In Vitro Evaluation of Ferrihydrite as an Enterosorbent for Arsenic from Contaminated Drinking Water

In Vitro Evaluation of Ferrihydrite as an Enterosorbent for Arsenic from Contaminated Drinking Water

Bioremediation of highly toxic arsenic via carbon-fiber-assisted indirect As(III) oxidation by moderately-thermophilic, acidophilic Fe-oxidizing bacteria

Removal of arsenious acid from sulfuric acidic solution using ultrasound oxidation and goethite

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