Cation-Exchange Study on a Crystalline and Thermally Stable Phase of Antimony Silicate. Effect of Irradiation on Ion-Exchange Behavior and Separation of Cd(II) from Zn(II) and Mn(II) and of Mg(II) from Ba(II), Ca(II), and Sr(II)

Varshney, K. G.; Sharma, Uma; Rani, Sima; Premadas, A.

doi:10.1080/01496398209438471

Cited by 18 publications

(7 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sandia octahedral molecular sieves (SOMS) also seem efficient under acidic and alkaline conditions (24), but their selectivity for strontium is dramatically reduced even with the presence of low Na ϩ concentrations (24). Sb silicate (SbSi) is the only inorganic adsorbent highly selective for strontium in pH as low as 1 (8), but its ability to be efficient at pH Ն 14 (pH of many nuclear waste types) is questionable because of its appreciable dissolution at pH Ն 13 (25).…”

Section: Resultsmentioning

confidence: 99%

Layered metal sulfides: Exceptionally selective agents for radioactive strontium removal

Manos

Ding

Kanatzidis

2008

Proc. Natl. Acad. Sci. U.S.A.

252

180

View full text Add to dashboard Cite

In this article, we report the family of robust layered sulfides K 2xMnxSn3-xS6 (x ‫؍‬ 0.5-0.95) (KMS-1). These materials feature hexagonal 2x؊ slabs of the CdI2 type and contain highly mobile K ؉ ions in their interlayer space that are easily exchangeable with other cations and particularly strontium. KMS-1 display outstanding preference for strontium ions in highly alkaline solutions containing extremely large excess of sodium cations as well as in acidic environment where most alternative adsorbents with oxygen ligands are nearly inactive. The implication of these results is that simple layered sulfides should be considered for the efficient remediation of certain nuclear wastes.chalcogenide ͉ environmental remediation ͉ ion exchange ͉ layered materials ͉ nuclear waste C urrent growing interest in nuclear power as a potential solution for global energy may also raise serious environmental and health concerns due to highly radioactive nuclear waste.90 Sr is one of the major heat producers and biohazards in nuclear wastes. The removal of radioactive strontium is essential to reducing the risk of human exposure to radiation and for the considerable cost savings due to minimization of the storage space requirements for the nuclear waste (1, 2). There is a long-standing and continuous research effort to develop highly selective strontium adsorbents for application in a variety of wastes. Inorganic ion exchangers possess a number of advantages as Sr 2ϩ adsorbents over the conventional organic ion-exchange resins, such as superior chemical, thermal, and radiation stability (3). The naturally abundant ion exchangers such as clays (3, 4) and zeolites (3) are not effective as strontium adsorbents in nuclear waste solutions with extreme pH values because of their immediate decomposition (i.e., dissolution of their aluminum). Commercial inorganic adsorbents capable for Sr 2ϩ adsorption in highly alkaline solutions with extremely high salt concentrations [i.e., conditions present in many nuclear waste types (1)] are mainly limited to titanates and silicotitanates (3,5,6). These materials, however, are not effective for Sr 2ϩ capture even at mildly acidic conditions (pH Ͻ 4-5) because protons inhibit ion exchange (7). Only doped antimony silicates represent Sr 2ϩ ion exchangers efficient in strongly acidic environment (pH Յ 1) (8). Finally, solvent extraction and extraction chromatography methods have proven promising for strontium decontamination of acidic and alkaline nuclear wastes (9-11).We show here that layered sulfide compounds with ionexchangeable interlayer cations are not inhibited by protons and can be very efficient Sr 2ϩ -ion-removers over a wide pH range. Layered chalcogenides with ion-exchange properties are relatively few (12-16) and are mainly limited to alkali intercalated early transition metal dichalcogenides A x MQ 2 (A ϭ alkali ion; M ϭ early transition metal from groups 4,5 and 6; Q ϭ S, Se, Te) (13-16). Such materials, however, are not suitable for practical applications because of their hydrolytic...

show abstract

Section: Resultsmentioning

confidence: 99%

Layered metal sulfides: Exceptionally selective agents for radioactive strontium removal

Manos

Ding

Kanatzidis

2008

Proc. Natl. Acad. Sci. U.S.A.

252

180

View full text Add to dashboard Cite

show abstract

“…The mixture was heated at 60 ‡C overnight. 16 (2) An amorphous material (code: KSbSi) formed when KSb(OH) 6 , dissolved in distilled water, was mixed with Si(OC 2 H 5 ) 4 (TEOS, 98%) in ethanol (Sb : Si molar ratio 1 : 1). The pH was set below 1 with concentrated HNO 3 .…”

Section: Syntheses Of the Materialsmentioning

confidence: 99%

“…The crystalline one was given a tentative molecular formula of [Sb 2 O 5 (H 2 SiO 3 ) 6 ]?nH 2 O. 16 These materials showed high selectivity for strontium in acidic solutions, but the selectivity for caesium and cobalt was low. Thus an attempt was made to increase the selectivity of antimony silicates for Cs z and Co 2z by adding a metal dopant.…”

Section: Introductionmentioning

confidence: 99%

“…14 A fine review of the oxide pyrochlores was given by Subramanian et al in 1983. 15 More recently, antimony silicates 16,17 have attracted some interest as ion exchangers for strontium separations. When silicon is added to antimonic acid in low temperature reactions it does not necessarily change the pyrochlore structure, but affects the ion exchange properties by creating vacancies.…”

Section: Introductionmentioning

confidence: 99%

“…When silicon is added to antimonic acid in low temperature reactions it does not necessarily change the pyrochlore structure, but affects the ion exchange properties by creating vacancies. 18,19 In this work, antimony silicate materials have been prepared using two different procedures 16,20 that lead to two products: an amorphous and a crystalline product with a pyrochlore structure. The crystalline one was given a tentative molecular formula of [Sb 2 O 5 (H 2 SiO 3 ) 6 ]?nH 2 O.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations