Synthesis of nanoporous zirconium oxophosphate and application for removal of U(VI)

• Published in: Water research (Oxford) 2007-08, Vol.41 (15), p.3217-3226
• Main Authors: Um, Wooyong, Mattigod, Shas, Jeffrey Serne, R., Fryxell, Glen E., Kim, Do Heui, Troyer, Lyndsay D.
• Format: Article
• Language: English
• Subjects: absorbents; ADSORBENTS; ADSORPTION; ADSORPTION ISOTHERMS; Applied sciences; BEARINGS; Carbaryl; CARBONATES; chemical concentration; Distribution coefficient; environmental impact; Exact sciences and technology; groundwater contamination; Hanford Site; hazardous waste; ionic strength; ISOTHERMS; kinetics; MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; mathematical models; Nanoporous materials; nanoporous zirconium oxophosphate; Other industrial wastes. Sewage sludge; PHOSPHATES; Pollution; Porosity; RADIOACTIVE WASTE DISPOSAL; Radionuclide; reduction; REMOVAL; simulation models; speciation; STABILITY; streams; SYNTHESIS; thermal stability; Uranium; Uranium - chemistry; Uranium, Nanoporous materials; Waste Disposal, Fluid - methods; WASTES; Water Pollutants, Radioactive - chemistry; Water Purification - methods; Water treatment and pollution; YUCCA MOUNTAIN; ZIRCONIUM; Zirconium - chemistry
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2007.05.030

Uniformly arrayed zirconium-phosphate nanoporous material was synthesized, characterized, and used as an adsorbent for removal of U(VI) in a NaNO 3 solution with varying background conditions including pH, ionic strength, U(VI) concentrations, and carbonate concentrations. Batch U(VI) adsorption results showed that U(VI) adsorption reached steady-state condition within 48 h, and all the dissolved U(VI) (10 −6 M) was removed by this material at neutral pH and closed conditions to atmospheric CO 2(g). The U(VI) adsorption followed a traditional Langmuir adsorption isotherm, and the distribution coefficient ( K d) calculated from the linear region of the Langmuir isotherm was 105,000 mL g −1. Because this phosphate-bearing nanoporous material exhibits high thermal stability and has a very high K d value, it can be applied as an efficient adsorbent for removing U(VI) from various contaminated waste streams, such as those present at the US Department of Energy defense sites and the proposed geologic radioactive waste disposal facility at Yucca Mountain in Nevada.