Density (near r.t.): 19.1 g cm 3 Liquid density at m.p.: 17.3 g cm 3 Melting point: K, 2070 F C

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1 3.1 Introduction Generl Properties: Nme: urnium Symbol: U Atomic number: 92 Element ctegory: ctinide Stndrd tomic weight: (3) Electron configurtion: [Rn] 5f 3 6d 1 7s 2 Electrons per shell: 2, 8, 18, 32, 21, 9, 2 Physicl Properties: Phse: solid Density (ner r.t.): 19.1 g cm 3 Liquid density t m.p.: 17.3 g cm 3 Melting point: K, 2070 F C Boiling point: 7468 F, 4131 C, 4404 K Atomic Properties: Oxidtion sttes: 6, 5, 4, 3 Electronegtivity: 1.38 (Puling scle) Atomic rdius: 156 pm Covlent rdius: 196±7 pm Vn der Wls rdius: 186 pm Crystl structure: orthorhombic Mgnetic ordering: prmgnetic Urninite, lso known s pitchblende, is the most common ore mined to extrct urnium. Urnium is nturlly occurring element tht cn be found in low levels within ll rock, soil, nd wter. Urnium is the 51st element in order of bundnce in the Erth's crust. Urnium is lso the highestnumbered element to be found nturlly in significnt quntities on erth nd is lwys found combined with other elements [1]. In nture, urnium is found s 33

2 urnium238 ( %), urnium235 ( %), nd very smll mount of urnium234 ( %) [2]. Mny contemporry uses of urnium exploit its unique nucler properties. Urnium235 hs the distinction of being the only nturlly occurring fissile isotope. Urnium238 is fissionble by fst neutrons, nd is fertile, mening it cn be trnsmuted to fissile plutonium239 in nucler rector. Another fissile isotope, urnium233, cn be produced from nturl thorium nd is lso importnt in nucler technology. While urnium 238 hs smll probbility for spontneous fission or even induced fission with fst neutrons, urnium235 nd to lesser degree urnium233 hve much higher fission crosssection for slow neutrons. In sufficient concentrtion, these isotopes mintin sustined nucler chin rection. This genertes the het in nucler power rectors, nd produces the fissile mteril for nucler wepons. Depleted urnium ( 238 U) is used in kinetic energy penetrtors nd rmor plting [3]. The importnce of urnium hs grown mny folds due to incresing ppliction of tomic energy; therefore there is n nlyticl requirement for the seprtion nd determintion of trce urnium in vrious types of smples rnging from geologicl to industril effluents. Vrious types of orgnophosphorous compounds nd mides were used to crry out seprtion of urnium. Cynex 272 hs been utilized in the seprtion of urnium from nitric cid medium [4]. The extrctive seprtion of urnium(vi) by different orgnophosphorous compounds from vrious medi hs been crried out [59]. The extrction of urnium(vi) with cynex 272 in sulphte, chloride nd nitrte medi hs been crried out [10]. Cynex 301 nd cynex 921 nd their binry mixtures hve been used to extrct urnium(vi) from nitrte nd sulphte medi [11]. Cynex 923 hs been used for the seprtion of urnium, thorium nd lnthnides in minerl cid medi using ICPAES [12]. Rre erth metls re extrcted using mixtures of secoctylphenoxy cetic cid nd bis(2,4,4 trimethylpentyl) dithiophosphinic cid [13]. Urnium(VI), Zr(IV) nd Th(IV) 34

3 by PC88A from perchlorte medi hve been crried out [14]. Liquidliquid extrction of urnium(vi) from chloride nd nitrte medium using lmine308, TBP nd cynex 302 were studied [15]. Antgonistic behviour of urnium(vi) ws studied by the binry mixture of PC88A nd benzimidzole [16]. Synergistic extrction of urnium(vi) with mixtures of PC88A nd neutrl oxodonrs like TBP, TOPO nd DOSO were reported [17]. Mechnism of urnium(iv) extrction with cynex 302 from nitrte medium in kerosene hs been studied [18]. Extrction of urnium(vi) from nitrte medium with cynex 302 in xylene hs been crried out [19]. Cynex 272 ws used for the extrction of urnium(vi) from nitrte medium in xylene by ICPAES method [20]. The literture survey revels tht no ttempts hve been mde for the seprtion of urnium(vi) from ssocited elements using cynex 272 in sodium slicylte medium. This pper describes the extrction of urnium(vi) using cynex 272 from sodium slicylte medium. The dvntges of this method over the reported methods re, tht the concentrtion of cynex 272 required for quntittive seprtion of urnium(vi) is very low nd cler cut seprtion of urnium(vi) from thorium(iv), led(ii), brium(ii), strontium(ii) nd other ssocited elements in geologicl smples hve been chieved. The method hs been extended to the nlysis of urnium(vi) in geologicl smples such s monzite snd nd syenite rock. 3.2 Experimentl Apprtus nd regents A Thermo Scientific Visible spectrophotometer (Chemito 215 D), digitl ph meter (Model LI120, Elico, Indi) with glss nd clomel electrodes nd digitl flme photometer (PI, Model no. 041, Indi) were used. A stock solution of urnium(vi) ws prepred by dissolving g of urnyl nitrte hexhydrte (Anlyticl R.grde, BDH, Poole, UK) in 100 ml distilled deionised wter nd stndrdized grvimetriclly [21]. A solution contining µg/ml of urnium(vi) ws prepred by pproprite dilution of 35

4 the stndrd stock solution. Sodium slicylte solution (1x10 1 M) ws prepred by dissolving g of sodium slicylte (FlukGrntie, puriss.p.. Switzerlnd) in distilled deionised wter nd diluted to 100 ml Generl procedure To n liquot of solution contining µg urnium(vi), sodium slicylte solution ws dded in the concentrtion rnge of 1x10 1 to 1x10 8 M in totl volume of 10 ml. The solution ws then trnsferred to seprting funnel nd ws equilibrted with 10 ml of 5x10 4 M cynex 272 in toluene s the diluent, for 5.0 minutes on wrist ction flsk shker. The two phses were llowed to settle nd seprte. Urnium(VI) ws then stripped from the orgnic phse by shking with 10 ml of 1.0 M hydrochloric cid. Urnium(VI) in the queous phse ws determined spectrophotometriclly with rsenzo (III) t 660 nm using clibrtion grph [2223]. 3.3 Results nd discussion Extrction of urnium(vi) s function of sodium slicylte concentrtion The efficiency of urnium(vi) with cynex 272 in toluene s function of sodium slicylte concentrtion is given in tble nd figure In these experiments the concentrtion of cynex 272 in the orgnic phse ws fixed t 5x10 4 M. The concentrtion of sodium slicylte ws vried from 1x10 1 to 1x10 8 M. It ws found tht there ws (quntittive) 100% extrction of urnium(vi) from 1x10 1 to1x10 6 M sodium slicylte concentrtion. With decrese in sodium slicylte concentrtion there ws decrese in extrction of urnium(vi). The subsequent extrction studies of urnium(vi) were crried out with 1x10 3 M sodium slicylte. 36

5 Tble3.3.1 Extrction of urnium(vi) s function of sodium slicylte concentrtion U(VI) µg/ml, Cynex 272 5x10 4 M, Strippnt 1.0 M HCl Concentrtion of Sodium slicylte (M) Percentge Extrction

6 Percentge Extrction Concentrtion of sodium slicylte (M) Figure Extrction of urnium(vi) s function of sodium slicylte concentrtion Effect of vrying concentrtion of cynex 272 In order to scertin the optimum concentrtion of cynex 272 required for the quntittive extrction of urnium(vi), vrious studies were conducted by vrying the concentrtion of cynex 272 in the rnge of 1x10 1 to 1x10 6 M by fixing concentrtion of sodium slicylte t 1x10 3 M. The results re shown in tble nd figure It ws found tht the extrction of urnium(vi) incresed from 5% t 1x10 1 M, to 89% t 5x 10 3 M nd ws quntittive from 1x10 3 M to 5x10 5 M. With further decrese in concentrtion of cynex 272 extrction of urnium(vi) decreses. Hence, for further extrction studies of urnium(vi) the concentrtion of cynex 272 selected ws 5x10 4 M. 38

7 Tble Effect of vrying concentrtion of cynex 272 U(VI) µg/ml, Sodium slicylte1x10 3 M, Strippnt1.0 M HCl Concentrtion of cynex 272(M) Percentge Extrction

8 100 Percentge Extrction Concentrtion of cynex 272 (M) Figure Effect of vrying concentrtion of cynex Time of equilibrtion nd choice of stripping gents The extrction time ws optimized by performing the equilibrtion for vrious periods of time (15 min.). The results showed tht with one minute of equilibrtion there ws quntittive extrction of urnium(vi). For prcticl purpose 5 minutes equilibrtion time ws used. After extrction, bck extrction ws crried out to remove urnium(vi) from the orgnic phse, for which vrious stripping gents were used. Bck extrction of urnium(vi) ws quntittive with 0.58 M hydrochloric cid, 18 M nitric cid, 0.18 M sulphuric cid, 0.57 M hydrobromic cid, 0.58 M perchloric cid nd 38 M cetic cid. In further studies 1.0 M hydrochloric cid ws used s stripping gent. The results re shown in Tble nd Figure

9 Tble Effect of vrious stripping gents U(VI) µg/ml, Cynex 2725x10 4 M, Sodium slicylte1x10 3 M Conc. (M) Percentge Stripping of urnium(vi) HCl HNO 3 H 2 SO 4 HClO 4 HBr CH 3 COOH

10 100 Percentge Extrction HCl HNO 3 H 2 SO 4 HClO 4 HBr CH 3 COOH Concentrtion of strippnt (M) Figure Effect of vrious stripping gents Influence of diluents on the extrction of urnium(vi) In the extrction of urnium(vi) the influence of solvent is very importnt. The polrity of solvent seems to be the most decisive fctor. Urnium(VI) extrction ws crried out from 1x10 3 M sodium slicylte using 5x10 4 M cynex 272 with vrious solvents, such s nitrobenzene, ndodecne, crbon tetrchloride, chloroform, xylene, toluene, dichloroethne, tetrchloroethne s shown in Tble The phse volume rtio ws mintined t unity. From the orgnic phse urnium(vi) ws stripped with 1M hydrochloric cid. It ws observed tht there ws quntittive extrction with crbon tetrchloride, chloroform, xylene, toluene, dichloroethne while nitrobenzene, ndodecne nd tetrchloroethne were found to be inefficient diluents. Toluene ws the best diluent mong tested nd used for further study. 42

11 Tble Influence of diluents on the extrction of urnium(vi) U(VI) µg/ml, Cynex 2725x10 4 M, Sodium slicylte1x10 3 M, Strippnt1 M HCl Diluents Dielectric Percentge constnt Extrction Crbon tetrchloride Distribution rtio Chloroform Dichloroethne ndodecne Nitrobenzene Tetrchloroethne Toluene Xylene Effect of vrying concentrtion of urnium(vi) Urnium(VI) ws extrcted with 10 ml of 5x10 4 M cynex272 from 1x10 3 M sodium slicylte using toluene s diluent. The concentrtion of urnium(vi) ws vried from 1000 µg. From Tble nd Figure it ws found tht 10 ml of 5x10 4 M cynex 272 solution ws dequte to extrct urnium(vi) quntittively up to 0 µg of smple solution. 43

12 Tble Effect of vrying concentrtion of urnium(vi) Cynex 2725x10 4 M, Sodium slicylte1x10 3 M, Strippnt1.0 M HCl U(VI) (µg) Percentge Extrction Distribution rtio

13 100 Percentge Extrction Concentrtion of urnium(vi) (µg) Figure Effect of vrying concentrtion of urnium(vi) Seprtion of urnium(vi) from binry mixtures Urnium(VI) ws extrcted with 5x10 4 M cynex 272 in toluene from 1x10 3 M sodium slicylte in the presence of wide rnge of foreign ions (Tble 3.3.6). The tolernce limit ws set t the mount of foreign ions required to cuse ±2% error in the recovery of urnium(vi). Most of the sblock ctions were not extrcted. Thorium(IV) nd yttrium(iii) were coextrcted long with urnium(vi). The lkli nd lkline erth metls showed very low tolernce limit while most of the dblock ctions showed high tolernce limit. The p block ctions, nions of orgnic nd inorgnic cids showed low tolernce limit. Coextrctions of ctions were determined by spectrophotometric methods using vrious chromogenic regents. 45

14 Tble Seprtion of U(VI) from binry mixtures U(VI) µg/ml, Cynex 2725x10 4 M, Sodium slicylte1x10 3 M, Strippnt1.0 M HCl Ion Added s Tol. Limit (mg) Ion Added s Tol. Limit (mg) Li + LiCl 0.2 Tl 3+ Tl(NO 3 ) 3.3H 2 O 0.01 N + NCl 0.1 L 3+ L(NO 3 ) 3.6H 2 O 0.01 K + KCl 0.1 Y 3+ Y(NO 3 ) 3 Coext Cs + CsCl 0.1 V 4+ VOSO 4.4H 2 O 10 Be 2+ BeSO 4.4H 2 O 0.1 Th 4+ Th(NO 3 ) 4.6H 2 O Coext Mg 2+ MgCl 2.6H 2 O 2 Mo 6+ (NH 4 ) 6 Mo 7 O 24 4H 2 O 13 C 2+ CCl Cl HCl 0.1 Sr 2+ Sr(NO 3 ) 2 2 Br HBr 0.1 B 2+ B(NO 3 ) SCN NSCN 1 Co 2+ CoCl 2.6H 2 O 0.1 ClO 4 HClO 4 8 Ni 2+ NiCl 2.6H 2 O 10 CH 3 COO CH 3 COOH 0.2 Mn 2+ MnCl 2. 4H 2 O 12 SO 4 2 H 2 SO Zn 2+ ZnCl 2 30 Trtrte Trtric cid 0.01 Cd 2+ (CH 3 COO) 2 CdH 2 O 30 EDTA EDTA 0.4 Pb 2+ Pb(NO 3 ) Oxlte Oxlic cid 0.3 Sn 2+ SnCl 2.2H 2 O 0.04 Citrte Citric cid 0.05 Fe 3+ FeCl 3.6H 2 O 0.01 Zr 4+ Zr(NO 3 ) 4.4H 2 O 0.01 Cr +6 K 2 Cr 2 O NO 3 HNO

15 3.3.7 Seprtion of urnium(vi) from multicomponent mixtures The seprtion of urnium(vi), thorium(iv) nd beryllium(ii)/ led(ii)/ nickel(ii)/ copper(ii)/ mngnese(ii)/ mgnesium(ii)/ molybdenum(vi)/ brium(ii)/ strontium(ii) ws crried out s follows. The mixture contining urnium(vi), thorium(iv) nd beryllium(ii)/ led(ii)/ nickel(ii)/ copper(ii)/ mngnese(ii)/ mgnesium(ii)/ molybdenum(vi)/ brium(ii)/ strontium(ii) in 1x10 3 M sodium slicylte ws extrcted with 5x10 4 M cynex 272 in toluene. Under this set Condition urnium(vi) nd thorium(iv)were extrcted leving Behind beryllium(ii)/ led(ii)/ nickel(ii)/ copper(ii)/ mngnese(ii)/ mgnesium(ii)/ molybdenum(vi)/ brium(ii)/ strontium(ii) in the queous phse. From the orgnic phse thorium(iv) ws first stripped with 0.02 M EDTA+3.5% ethnol while urnium(vi) remined in the orgnic phse. Finlly urnium(vi) ws stripped with 2.0 M hydrochloric cid. The seprtion of urnium(vi) from other ctions ws ccomplished by following the sme procedure. The results re shown in tble Tble Seprtion of urnium(vi) from multicomponent mixtures No. Mixture Tken µg 1 Th(IV) Found µg 49.4 *Recovery Percentge 98.9 Extrctnt Strippnt b Std. Devition (±) U(VI) M HCl Be(II) Aq. Phse Th(IV) b U(VI) M HCl Pb(II) Aq. Phse Th(IV) b U(VI) M HCl Cu(II) Aq. Phse

16 4 Th(IV) b U(VI) 100 2M HCl Ni(II) Aq. Phse Th(IV) b U(VI) M HCl Mn(II) Aq. Phse Th(IV) b U(VI) M HCl Mg(II) Aq. Phse Th(IV) b U(VI) M HCl Mo(II) Aq. Phse Th(IV) b U(VI) M HCl B(II) Aq. Phse Th(IV) b U(VI) M HCl Sr(II) Aq. Phse = Cynex 2725x10 4 M, 1x10 3 M sodium slicylte b = 0.02 M EDTA+ 3.5% Ethnol * = Averge of triplicte nlysis Anlysis of urnium(vi) in monzite snd nd syenite rock smple The method ws extended for the determintion of urnium(vi) in rel smples such s monzite snd nd syenite rock (SYII) (Cnd). The smples were brought in solution by the procedure described elsewhere [2425]. An liquot of smple solution ws extrcted with 5x10 4 M cynex 272 in toluene from 1x10 3 M sodium slicylte. Thorium nd urnium were seprted s per the procedure described in multicomponent mixture seprtion nd were 48

17 determined spectrophotometriclly. The mount of urnium(vi) found (triplicte nlysis) in monzite snd ws % s ginst the stndrd vlue of 0.30 %. In syenite rock it ws 278 ppm. s ginst the reported vlue of 280 ppm. [26]. 3.4 Conclusion A simple method hs been developed for the extrction seprtion nd determintion of urnium(vi) using cynex 272 from sodium slicylte medium. The method permits the seprtion of urnium(vi) from other elements such s thorium(iv), beryllium(ii), led(ii), nickel(ii), copper(ii), mngnese(ii), mgnesium(ii), molybdenum(vi), brium(ii), strontium(ii). The method ws extended for the nlysis of urnium in monzite snd nd syenite rock. The method is simple, rpid nd selective with good reproducibility (pproximtely ±2%). 49

18 References 1. Hmmond C. R., The Elements, in Hndbook of Chemistry nd Physics 81st edition. CRC press. ISBN , (2000). 2. Urnium Isotopes, retrieved 14 Mrch Emsley 2001, p Dogmne S. D., Singh R.K., Bjpi D.D., Mthur J.N., J. Rdionl. Nucl. Chem., 253, (2002). 5. Bisws S., Hreendrn K.N., Singh D.K., Shrm J.N., Roy S.B., J. Rdionl. Nucl. Chem., 283, (2010). 6. Bisws S., Singh D.K., Hreendrn K.N., Shrm J.N., Roy S.B., J. Rdionl. Nucl. Chem. 284, (2010). 7. Guoxin S., Yu C., Yexin L., Zhenwei Z., Sixiu S., J Rdionl. Nucl. Chem. 264, (2005). 8. Kumr J. R., Kim J.S., Lee J.Y., Yoon H.S., J. Rdionl. Nucl. Chem. 285, (2010). 9. Tn X.F., Wng Y.S., Tn T.Z., Zhou G.F., Bo B.R., J. Rdionl. Nucl. Chem. 242, (1999). 10. Ali AMI, Ahmd I.M., Doud J.A., Arb J. Nucl. Sci. Appl., 38(3), 2944 (2005). 11. Awwd N.S., Afifi E.M., El Reefy S.A., Arb J. Nucl. Sci. Appl. 38(3), (2005). 12. Gupt B., Mlik P., Deep A., J. Rdionl. Nucl. Chem. 251, (2002). 13. Ji Q., Tong S., Li Z., Zhou W., Li H., Meng S., Sepn. Purif. Technol., 64, 3453 (2009). 14. Singh R.K., Dhdke P.M., J. Rdionl. Nucl. Chem., 254, (2002). 15. Senol A., J. Rdionl. Nucl. Chem. 258, (2003). 16. Mukherjee A., Kmil S., Chkrvortty V., J. Rdionl. Nucl. Chem., 242, (1999).

19 17. Bisws S., Pthk P.N., Singh D.K., Roy S.B., Mnchnd V.K., J. Rdionl. Nucl. Chem., 284, 1319 (2010). 18. Rhmn N.A., Doud J.A., Aly H.F., J. Rdionl. Nucl. Chem. 25(3), (2003). 19. Krve M., Gur C., J. Rdionl. Nucl. Chem., 273, (2007). 20. Rjeswri B., Dhwle B.A., Bngi T.R., Mthur J.N., Pge A.G., J. Rdionl. Nucl. Chem., 254, (2002). 21. Vogel A.I., A Textbook of Quntittive Inorgnic Anlysis, 3 rd edn. Longmns, p 540 (1975). 22. Mohite B.S., Khopkr S.M., Tlnt 32,565 (1985). 23. Mohite B.S., Ptil J.M., Zmbre D.N., J. Rdionl. Nucl. Chem. 170, 215 (1993). 24. Oliveir J.M., Crvlho F.P., Czech. J. Phys. 56: p. Suppl. D545 (2006). 25. Glindo C., Mougin L., Nourreddine A., Appl. Rdit. Isotopes., 65, 9 (2007). 26. Mohite B.S., Mne S.G., Swnt S.M., J. Rdionl. Nucl. Chem. 249(3), (2001). 51

When, Ti(IV)-Fe(III) and Ti(IV)-Zr(IV) binary mixtures were passed through the column at ph

When, Ti(IV)-Fe(III) and Ti(IV)-Zr(IV) binary mixtures were passed through the column at ph Electronic Supplementry Mteril (ESI) for RSC Advnces. This journl is The Royl Society of Chemistry 2014 Supplementry dt: The distribution co-efficient (K d ) t different ph hs been computed (eq. 2) nd