Fluoride and uranium removal

REVERSE OSMOSIS FOR ARSENIC, FLUORIDE AND URANIUM REMOVAL FROM WATER... 

Removal of Toxic Trace Elements with Emphasis on Arsenic, Fluoride and Uranium... 

MEMBRANE TECHNOLOGIES FOR WATER TREATMENT REMOVAL OF TOXIC TRACE ELEMENTS WITH EMPHASIS ON ARSENIC, FLUORIDE AND URANIUM... 

Title Membrane technologies for water treatment removal of toxic trace elements with emphasis on arsenic, fluoride and uranium / editors, Alberto Figoli, Institute of Membrane Technology, ITM-CNR, Rende (CS), Italy, Jan Hoinkis, Karlsruhe University of Applied Sciences, Institute of Applied Research, Karlsruhe, Germany, Jochen Bundschuh, Deputy Vice Chancellor s Office (Research and Innovation) Faculty of Health, Engineering and Sciences, Toowoomba, Queensland, Australia Royal Institute of Technology (KTH), Stockholm, Sweden. 

The use of reverse osmosis (RO) for removal of arsenic, fluoride and uranium from drinking water... 

Fluoride, arsenic and uranium removal from water using adsorbent materials and integrated membrane systems... 

Membrane Technologies for Water Treatment Removal of Toxic Trace Elements with Emphasis on Arsenic, Fluoride and Uranium Editors Alberto Figoli, Jan Hoinkis Jochen Bundschuh... 

Other applications that have been reported are the removal of fluoride and aluminum (Kettunen and Keskitalo, 2000 Pervov et al., 2000) and uranium removal from natural waters (Raff and WUken, 1999). 

The vendor claims that the following metals have been successfully treated to parts per biUion (ppb) and detection limit levels aluminum, arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, molybdenum, nickel, selenium, silver, tin, uranium, vanadium, and zinc. The system is also able to remove ammonia, nitrates, phosphates, potassium, fluorides, and sodium. Studies have also been performed using Aqua-Fix to remove radionuchdes such as uranium from waste streams. 

Calcium serves as a reductant for such reactive metals as zirconium, thorium, vanadium, and uranium. In zirconium reduction, zirconium fluoride is reacted with culcium metal. The high heat of the reaction melts the zirconium. The zirconium ingot resulting is remelted undet vacuum for purilicatinn. Thorium and uranium oxides are reduced with an excess of calcium in reactors or trays under an atmosphere of argon. The resulting tnetals are leached with acetic acid tu remove the lime. 

Uranium Z, also thought to be a product of uranium X, was discovered by Hahn in 1921, who isolated it in the following manner. The mother-liquors from repeated fractional crj stallisations of uranous nitrate, containing uranium X and uranium Z, w ere treated with ferric chloride solution, and the iron precipitated by means of ammonia and ammonium carbonate. The precipitate, which contained both the uranium Xj and uranium Z, was treated with a solution of tantalum in hydrofluoric acid, lanthanum nitrate added, and the mixture digested on a water-bath with dilute hydrofluoric and sulphuric acids. Lanthanum fluoride was precipitated, and carried do%vn with it uranium The filtrate was evaporated to dryness and the residue ignited. The tantalum was thus rendered insoluble, whilst the iron could be removed by means of concentrated hydrochloric acid. The uranium Z remained with the tantalum. By this means Hahn obtained specimens of uranium Z which were 99-5 per cent, radioactively pure. 

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