title: Silica with immobilized phosphinic acid-derivative for uranium extraction.
abstract: A novel adsorbent benzoimidazol-2-yl-phenylphosphinic acid/aminosilica adsorbent (BImPhP(O)(OH)/SiO2NH2) was prepared by carbonyldiimidazole-mediated coupling of aminosilica with 1-carboxymethylbenzoimidazol-2-yl-phenylphosphinic acid. It was obtained through direct phosphorylation of 1-cyanomethylbenzoimidazole by phenylphosphonic dichloride followed by basic hydrolysis of the nitrile. The obtained sorbent was well characterized by physicochemical methods, such as differential scanning calorimetry-mass spectrometry (DSC-MS), surface area and pore distribution analysis (ASAP), scanning electron microscopy (SEM), X-ray photoelectron (XPS) and Fourier transform infrared (FTIR) spectroscopies. The adsorption behavior of the sorbent and initial silica gel as well as aminosilica gel with respect to uranium(VI) from the aqueous media has been studied under varying operating conditions of pH, concentration of uranium(VI), contact time, and desorption in different media. The synthesized material was found to show an increase in adsorption activity with respect to uranyl ions in comparison with the initial compounds. In particular, the highest adsorption capacity for the obtained modified silica was found at the neutral pH, where one gram of the adsorbent can extract 176mg of uranium. Under the same conditions the aminosilica extracts 166mg/g, and the silica - 144mg/g of uranium. In the acidic medium, which is common for uranium nuclear wastes, the synthesized adsorbent extracts 27mg/g, the aminosilica - 16mg/g, and the silica - 14mg/g of uranium. It was found that 15% of uranium ions leached from the prepared material in acidic solutions, while 4% of uranium can be removed in a phosphate solution.
authors.affiliation: Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 17 General Naumov Str., 03164 Kyiv, Ukraine. Electronic address: tetyanabudnyak@yahoo.com.
authors.forename: Tetyana M
authors.initials: TM
authors.lastname: Budnyak
authors.affiliation: Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Street, 01601 Kyiv, Ukraine.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Strizhak
authors.affiliation: Maria Curie Skłodowska University, 2 M. Curie Skłodowska Sq., 20-031 Lublin, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Gładysz-Płaska
authors.affiliation: Maria Curie Skłodowska University, 2 M. Curie Skłodowska Sq., 20-031 Lublin, Poland.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Sternik
authors.affiliation: Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Street, 01601 Kyiv, Ukraine.
authors.forename: Igor V
authors.initials: IV
authors.lastname: Komarov
authors.affiliation: Maria Curie Skłodowska University, 2 M. Curie Skłodowska Sq., 20-031 Lublin, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Kołodyńska
authors.affiliation: Maria Curie Skłodowska University, 2 M. Curie Skłodowska Sq., 20-031 Lublin, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Majdan
authors.affiliation: Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 17 General Naumov Str., 03164 Kyiv, Ukraine.
authors.forename: Valentin А
authors.initials: VА
authors.lastname: Tertykh
keywords: Adsorption; Phosphinic acid; Silica; Sorbent; Uranium