Arsenic mobilization from iron oxides in the presence of oxalic acid under hydrodynamic conditions

Inorganic deposits formed during operation and intermediate storage contain radionuclides, whose removal during the chemical decontamination of spent ion-exchange resins used in filters for special water purification at nuclear power plants has proved to be a challenge. In such deposits, radionuclides of the corrosion group (58.60Co, 54Mn, 51Cr) are typically located in the crystal lattice of poorly soluble iron oxides. The present work discusses the possibility of using mechanochemical activation in the decontamination of spent ion-exchange resins polluted with deposits of activated corrosion products from structural materials. Samples of natural and synthesised on the surface of the KU-2-8 cation exchanger in the presence of the 57Co label magnetites were used as model deposits. It was shown that an increase in the duration of mechanochemical activation leads to an increase in the dissolution rate of magnetite in model decontamination solutions based on еthylenediaminetetraacetic acid disodium salt (Trilon B) and nitric acid. It was shown that, when using Trilon B, magnetite dissolves more efficiently, which is explained by the interaction between the oxide surface and organic complexing agents. It can be assumed that solid-phase reactions occur during the mechanochemical activation of magnetite in the presence of dry reagents (Trilon B, oxalic, ascorbic and citric acids). Therefore, a poorly soluble shell formed on the oxide surface hinders the dissolution at a low magnetite/solution ratio. Unlike the reagent-free activation, for magnetite activated in the presence of oxalic acid, an increase in the solution/magnetite ratio promotes the dissolution of iron oxides. Using the example of a model cation exchanger, it was shown that the rate and efficiency of decontamination of spent ion-exchange resins polluted with deposits containing activated corrosion products increase significantly after mechanochemical activation in the presence of oxalic acid.

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Oxalic Acid-Induced Photodissolution of Ferrihydrite and the Fate of Loaded As(V): Kinetics and Mechanism

Nanomaterials ◽

10.3390/nano9081143 ◽

2019 ◽

Vol 9 (8) ◽

pp. 1143 ◽

Cited By ~ 1

Author(s):

Hai-Tao Ren ◽

Jing Han ◽

Ting-Ting Li ◽

Qi Lin ◽

Jia-Horng Lin ◽

...

Keyword(s):

Oxalic Acid ◽

Iron Oxides ◽

Uv Light ◽

Water Environment ◽

Light Irradiation ◽

Aquatic Environments ◽

Light Illumination ◽

Acidic Water ◽

Uv Illumination ◽

Uv Light Irradiation

The fate of arsenic in the water environment is of great concern. Here, the influences of oxalic acid and UV light illumination on the dissolution of naked ferrihydrite (Fhy), Fhy loaded with As(V) [Fhy*-As(V)], as well as the fate of As(V) at pH 3.0 were studied. With the assistance of oxalic acid, complexes of Fe(III)-oxalic acid produced on Fhy/Fhy*-As(V) were reduced to Fe(II)-oxalic acid by photo-induced electrons under UV light irradiation. UV light has nearly no impact on the release of As(V) in the system of Fhy*-As(V) without the assistance of oxalic acid. Nevertheless, in the existence of oxalic acid, UV light illumination resulted in the contents of liberated As(V) decreased by 775–1300% compared to that without light. Considering the coexistence of As(V), oxalic acid as well as iron oxides in aquatic environments, the present study revealed that UV illumination could enhance the retention of As(V) on Fhy in the acidic water environment containing oxalic acid.

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Blanqueo de caolín por medio de lixiviación en pilas con ácido oxálico

Respuestas ◽

10.22463/0122820x.638 ◽

2016 ◽

Vol 21 (1) ◽

pp. 65 ◽

Cited By ~ 3

Author(s):

Manuel Julián Barros-Daza ◽

Pablo Bustamante-Baena ◽

Moisés Oswaldo Bustamante-Rúa

Keyword(s):

Scale Development ◽

Oxalic Acid ◽

Iron Oxides ◽

Iron Content ◽

Experimental Results ◽

Whiteness Index ◽

Palabras Clave

Se estudiaron los resultados experimentales de lixiviación en pilas para el blanqueo del caolín a escala de laboratorio basados en un desarrollo teórico. El objetivo principal fue evaluar la remoción de óxidos de hierro sobre la superficie del caolín, Método con el uso de diferentes concentraciones de ácido oxálico en un tiempo de 48 días. Resultado. El índice de blancura del caolín de alimento fue del 52.1%, con porcentajes de hierro del 0.19%. A partir de los ensayos experimentales, Conclusión los resultados mostraron que para las concentraciones de 0.15M, 0.015M y 0.95M, las remociones de hierro fueron alrededor del 72.2%, 26.7%, 90.8% y los índices de blancura obtenidos fueron de 90.2%, 83.8% y 97% respectivamente.Abstract The experimental results of leaching were studied in batteries for bleaching kaolin scale The experimental results of leaching were studied in batteries for bleaching kaolin scale development based on a theoretical laboratory. The main objective was to evaluate the removal of iron oxides on the surface of kaolin, Methods: the use of different concentrations of oxalic acid drip for 48 days in each heap. Results: The whiteness index of feed Kaolin is 52.1%, with an iron content of 0.19%. Conclusions: The results showed that for acidic concentrations 0.15M, 0.015M and 0.95M, the iron removed was approximately 72.2%, 26.7%, 90.8% and the whiteness index rose to 90.23%, 83.8%, and 97% respectively. Palabras clave: Acido Oxálico, Blanqueo de Caolín, Hidrometalurgia, Lixiviación en pilas, Óxidos de hierro

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