title: Removal of strontium (Sr2+) from aqueous solutions with titanosilicates obtained by the sol-gel method.
abstract: Titanosilicates (TiSis) were synthesized from pure and technical precursors by the sol-gel method. X-ray diffraction (XRD) studies of TiSi identified amorphous phases. The Brunauer, Emmett and Teller (BET) surface area of TiSis obtained from pure and technical precursors measured using the low-temperature nitrogen adsorption/desorption technique were 270.3 and 158.7 m(2) g(-1), respectively. Micro-mesopore and micro- meso- macropore structures were attributed to TiSi prepared from pure and technical precursors, correspondingly. TiSis mass, solution pH, contact time, initial Sr(2+) concentration, temperature and background solution were investigated for their effect on sorption properties. TiSis were observed to have a high affinity for strontium in the pH range of 4-12. Strontium adsorption isotherms were established and fitted to the Langmuir, Freundlich, Redlich-Peterson, Sips and Toth models. Pseudo-first and pseudo-second models were used to describe experimental kinetic data. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) data for TiSis were collected before and after adsorption. Heterophase was observed on the surfaces of both types of TiSi material after Sr(2+) uptake. The mechanism of Sr(2+) sorption on titanosilicates was suggested.
authors.affiliation: Institute of Sorption and Problems of Endoecology NAS of Ukraine, 13 General Naumov str., Kyiv 03164, Ukraine; Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, Mikkeli 50130, Finland. Electronic address: ovalexis@gmail.com.
authors.forename: Olga
authors.initials: O
authors.lastname: Oleksiienko
authors.affiliation: Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, Mikkeli 50130, Finland.
authors.forename: Irina
authors.initials: I
authors.lastname: Levchuk
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Al. Mickiewicza 30, 30-059 Kraków, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Sitarz
authors.affiliation: Institute of Sorption and Problems of Endoecology NAS of Ukraine, 13 General Naumov str., Kyiv 03164, Ukraine.
authors.forename: Svitlana
authors.initials: S
authors.lastname: Meleshevych
authors.affiliation: Institute of Sorption and Problems of Endoecology NAS of Ukraine, 13 General Naumov str., Kyiv 03164, Ukraine.
authors.forename: Volodymyr
authors.initials: V
authors.lastname: Strelko
authors.affiliation: Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, Mikkeli 50130, Finland.
authors.forename: Mika
authors.initials: M
authors.lastname: Sillanpää
mesh_terms: D005782:Gels; D019904:Polymethyl Methacrylate; D017640:Silicates / Q000737:chemistry*; D012996:Solutions; D013324:Strontium / Q000737:chemistry / Q000302:isolation & purification*; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D005782:Gels; D017640:Silicates; D012996:Solutions; D014867:Water; D019904:Polymethyl Methacrylate; D014025:Titanium; D013324:Strontium
keywords: Adsorption; Kinetic study; Porous structure; Sol–gel synthesis; Titanosilicate