Silicate Hindering In Situ Formed Ferric Hydroxide Precipitation: Inhibiting Arsenic Removal from Water

Our effort for decontamination of radioactive cesium scattered widely by nuclear accident in March 2011 in Fukushima, Japan has been described. Radioactive cesium scattered widely in Japan has been accumulating in arc or plasma molten-solidified ash in waste incinerating facilities up to 90,000 Bq/kg of the radioactive waste. Water rinsing of the ash resulted in dissolution of cesium ions together with high concentrations of potassium and sodium ions. Although potassium inhibits the adsorption of cesium on zeolite, we succeeded to precipitate cesium by in-situ formation of ferric ferrocyanide and iron rust in the radioactive filtrate after rinsing of the radioactive ash with water. Because the regulation of no preservation of any kind of cyanide substances, cesium was separated from the precipitate consisting of cesium-captured ferric ferrocyanide and ferric hydroxide in diluted NaOH solution and subsequent filtration gave rise to the potassium-free radioactive filtrate. Cesium was captured by zeolite from the potassium-free radioactive filtrate. The amount of this final radioactive waste of zeolite was significantly lower than that of the arc-molten-solidified ash.

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Double-pathway arsenic removal and immobilization from high arsenic-bearing wastewater by using nature pyrite as in situ Fe and S donator

Chemical Engineering Journal ◽

10.1016/j.cej.2020.128303 ◽

2021 ◽

Vol 410 ◽

pp. 128303

Author(s):

Yongkui Li ◽

Xianjin Qi ◽

Guohua Li ◽

Hua Wang

Keyword(s):

Arsenic Removal ◽

High Arsenic

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Arsenic removal from industrial effluent: In-situ ferric sulfate production and arsenic partitioning in the residues

Minerals Engineering ◽

10.1016/j.mineng.2021.106945 ◽

2021 ◽

Vol 169 ◽

pp. 106945

Author(s):

H.L. Mendes ◽

C.L. Caldeira ◽

V.S.T. Ciminelli

Keyword(s):

Arsenic Removal ◽

Industrial Effluent ◽

Ferric Sulfate ◽

Sulfate Production

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Arsenic removal from groundwater through iron oxyhydroxide coated waste productsA paper submitted to the Journal of Environmental Engineering and Science.

Canadian Journal of Civil Engineering ◽

10.1139/s08-059 ◽

2009 ◽

Vol 36 (5) ◽

pp. 881-888 ◽

Cited By ~ 9

Author(s):

Elsadig A.M. Abdallah ◽

Graham A. Gagnon

Keyword(s):

Ferric Oxide ◽

Arsenic Removal ◽

Ferric Hydroxide ◽

Structure Surface ◽

Seafood Industry ◽

Isotherm Adsorption ◽

Scallop Shells ◽

Glass Recycling ◽

By Products ◽

Better Than

The goal of this research was to remove arsenic from groundwater supplies via adsorption into media obtained from waste material generated as by-products from glass recycling programs and the seafood industry such as crushed glass and scallop shells. During the course of this research four new adsorbents were developed: ferric hydroxide coated crushed glass (FHCCG); ferric oxide coated crushed glass (FOCCG); ferric hydroxide coated scallop shells (FHCSS); and ferric oxide coated scallop shells (FOCSS). The adsorbents were characterized through evaluation of their structure, surface area, chemical composition, iron content, and coating stability. Efficiency of the adsorbents to remove arsenic from water was examined through batch kinetic and isotherm adsorption experiments. The adsorption capacity of the adsorbents was also evaluated by performing column experiments using real ground waters and a synthetic water. Arsenic removal to a concentration less than 10 μg/L was achieved with the FHCSS and more than 9000 bed volumes of water were treated before the breakthrough point was reached. The research results revealed that scallop shells coated with ferric hydroxideperformed better than crushed glass coated with ferric hydroxide. Both FOCCG and FOCSS had poor arsenic removal compared with FHCSS and granular ferric hydroxide (GFH). Ferric hydroxide coated scallop shells performed similarly to GFH.

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Arsenic removal from groundwater by Anjili tree sawdust impregnated with ferric hydroxide and activated alumina

Water Science & Technology Water Supply ◽

10.2166/ws.2015.119 ◽

2015 ◽

Vol 16 (1) ◽

pp. 115-127 ◽

Cited By ~ 4

Author(s):

P. Dhanasekaran ◽

P. M. Satya Sai ◽

C. Anand Babu ◽

R. Krishna Prabhu ◽

K. K. Rajan

Keyword(s):

Arsenic Removal ◽

Heart Diseases ◽

Ferric Hydroxide ◽

Sorption Kinetics ◽

Activated Alumina ◽

Maximum Sorption Capacity ◽

Maximum Sorption ◽

Freundlich Adsorption Isotherm ◽

Pseudo Second Order ◽

Removal Of Arsenic

Arsenic is a toxic element found naturally in groundwater. Due to its carcinogenicity, risk for heart diseases and diabetes, arsenic needs to be removed from groundwater for potable application. ‘Anjili’ tree sawdust was chemically modified with ferric hydroxide and activated alumina (SFAA) and used as an adsorbent for the removal of arsenic from groundwater. The adsorbent was characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) to study the pore structure and surface functional groups. Effect of contact time, initial concentration, pH, particle size and temperature was studied. Arsenic adsorbed by SFAA followed Freundlich adsorption isotherm. Maximum sorption of arsenic by SFAA adsorbent occurred at pH 6.5. Arsenic sorption kinetics followed a pseudo-second-order model. The maximum sorption capacity at 303 K was found to be 54.32 mg/g for As(III) and 77.60 mg/g for As(V). Interference of other ions on the adsorption was in the order of PO43− > SO42− > HCO3− > NO3−.

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Arsenic removal by ferric-chloride coagulation – effect of phosphate, bicarbonate and silicate

Water Science & Technology ◽

10.2166/wst.2011.419 ◽

2011 ◽

Vol 64 (5) ◽

pp. 1046-1055 ◽

Cited By ~ 11

Author(s):

Dóra Laky ◽

István Licskó

Keyword(s):

Adverse Effect ◽

Arsenic Removal ◽

Linear Regression Analysis ◽

Arsenic Concentration ◽

Ferric Hydroxide ◽

Multiple Linear Regression Analysis ◽

Ph Values ◽

Robust Model ◽

Coagulant Dosage ◽

Negative Effect

Jar tests with synthetic water were carried out in order to investigate the effect of phosphate, bicarbonate and silicate on arsenic removal efficiency by in-situ formed ferric hydroxide. Above 12 mg C/L inorganic carbon concentration, the adverse effect of bicarbonate was definite, and resulted in higher remaining arsenic concentration. At all pH values (7.5–7.8) and coagulant dosages (0.84–3.00 mg/L Fe) tested, the negative effect of phosphate on arsenic removal was also evident. In the presence of silicate small ferric-hydroxide colloids were formed, which were able to go through the 0.45 μm pore-size membrane. Compared to silicate-free systems, 2.5–3.5 times higher coagulant dose was needed to achieve the target arsenic concentration in the presence of 14–23 mg/L Si. At higher pH values the adverse effect of silicate was even more significant. All data were merged and multiple linear regression analysis was carried out in order to build up a robust model to predict the residual arsenic concentration if the raw water contains 50–60 μg/L initial arsenic concentration. The estimation was based on the following variables: PO4-P concentration, final pH, Si concentration, Fe(III) dose. The most important influencing factors proved to be the silicate concentration and applied coagulant dosage.

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Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface

Minerals ◽

10.3390/min10070583 ◽

2020 ◽

Vol 10 (7) ◽

pp. 583

Author(s):

Dongdong He ◽

Yuming Xiong ◽

Li Wang ◽

Wei Sun ◽

Runqing Liu ◽

...

Keyword(s):

Red Mud ◽

Arsenic Removal ◽

Ferric Hydroxide ◽

Morphological Properties ◽

Molar Ratio ◽

Inorganic Pollutants ◽

High Concentration ◽

Initial Concentration ◽

X Ray ◽

Alkaline Agent

Arsenic (As) is considered one of the most serious inorganic pollutants, and the wastewater produced in some smelters contains a high concentration of arsenic. In this paper, we purified the high-concentration arsenic solution with red mud and Fe3+ synergistically. In this system, arsenite anions reacted with Fe(III) ions to form ferric arsenite, which attached on the surface of red mud particles. The generated red mud/Fe1−x(As)x(OH)3 showed a better sedimentation performance than the pure ferric arsenite, which is beneficial to the separation of arsenic from the solution. The red mud not only served as the carrier, but also as the alkaline agent and adsorbent for arsenic treatment. The effects of red mud dosage, dosing order, pH, and molar ratio of Fe/As on arsenic removal were investigated. The efficiency of arsenic removal increased from a pH of 2 to 6 and reached equilibrium at a pH of 7. At the Fe/As molar ratio of 3, the removal efficiency of arsenic ions with an initial concentration of 500 mg/L reached 98%. In addition, the crystal structure, chemical composition, and morphological properties of red mud and arsenic removal residues (red mud/Fe1−x(As)x(OH)3) were characterized by XRD, XPS, X-ray fluorescence (XRF), SEM-EDS, and Raman spectroscopy to study the mechanism of arsenic removal. The results indicated that most of the arsenic was removed from the solution by forming Fe1−x(As)x(OH)3 precipitates on the red mud surface, while the remaining arsenic was adsorbed by the red mud and ferric hydroxide.

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