IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (2) 2011 Separation and Extraction Micro Amount of Cadmium (II) and Mercury (II) with Liquid Anion Exchange Method S. K. Jawad , S. M. Hameed Department of Chemistry , College of Education for Girls ,Kufa University Received in :13 December 2010 Accepted in : 12 April 2011 Abstract For extraction chloro anion complexes of Cd 2+ and Hg 2+ used many organic agents as extractant according to liquid ion exchange method such as α-Naphthyl amine (α-NA), 4-Amino benzoic acid (4-ABA), 2-[(4-Carboxy methyl phenyl) azo]-4,5-diphenyl imidazole (4- CMePADPI) and Cryptand (C222). This study includes definition hydrochloric acid concentration in aqueous phase and shaking with organic phase necessary for extraction as well as shaking time, organic solvent effect, interferences and alkaline salt effect. Thermodynamic showed the ion exchange reaction was exothermic for α-NA, C222 and endothermic for 4-ABA, 4-CMePADPI for extraction CdCl4 =, but for extraction HgCl4 = was exothermic with 4-ABA, 4- CMePADPI and C222 but endothermic with α-NA. In addition stoichiometry showed the ion pair complex extracted was 1:1:1 Cation: Ligand: Anion. Key word: Liquid ion exchange, Cadmium, Mercury, Solvent extraction. Introduction Zn2+ was extracted from chloride ion media with (TPP) and the definition of all parameters effect on extraction method[1], Au3+ was extracted from hydrochloric acid media with amine alamine304 [R3N + H,Cl - ] in Xylene, and calculate distribution ratio for complex R3N + H,AuCl4 - [2]. Different new liquid ion exchange [Ethylene bis (trioctyl phosphonium)](EBTOP) used for extraction of Pb2+, Cu2+, Cd2+, Zn2+ as well as Fe3+ and In3+[3]. Hg2+ was separated from 0.5M acetic acid by Aliquat 336S as liquid ion exchange, and extracted species was [2R4N + ; Hg(OAC)4 = ], this method suitable for separation from Zn, Cd, Ni, Co, Cu, Bi, Mn [4]. Zn, Cd and Hg were extracted from chloride and sulphate media by solvation and liquid ion exchange methods and studied the extracted species [5]. Hg2+ extracted as chloro complexes anion by different high molecular weight amines and tetra ammonium salts with distribution the effective parameters and extracted species[6], Cd2+ extracted from sulphate media by di(2-ethyl hexyl)phosphoric acid (D2EHPA) dissolved in Toluene, at pH=5-6 and 0.1M of reagent in Toluene [7]. IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (2) 2011 The present study was undertaken to investigate the effect of various extraction parameters on the extraction of Cd(II) and Hg(II) as chloro complex from hydrochloric acid media by (α- NA),(4-ABA), (4-CMePADPI) and (C222) parameters studied include the effect of hydrochloric acid concentration, metal concentration, foreign ion and temperature of extraction, organic solvent. Experimental Apparatus For absorbance measurements shimadzu UV-1700 spectrophotometer is used with 1cm quartz cells (Japan), pH- measurements were carried out using WTW, listed 8F93(Germany), for shaking used HY-4 vibrator with AD just about speed multiple(Italy). Reagents A standard stock solutions 1mg/mL for Cd2+ and Hg2+ was prepared by dissolving drier (0.1631 gm) of CdCl2 and (0.1354 gm) of HgCl2 [Fluka] in 100mL distilled water contain 1mL HCl concentration in volumetric flask, other working solutions prepared by appropriate dilution of the stock solution with distilled water. Stock solution of dithiazone (1×10 -2 M) was prepared by dissolving (0.0256 gm) in 10mL carbontetrachloride in volumetric flask, working solution (1×10 -4 M) was prepared instantaneously by dilution with CCl4. Standard solutions of different ligand prepared by dissolving weighed quantities of each one in chloroform. General extraction procedure Shaking fixed volume of ligand solution with HCl solution at optimum concentration in order to conversion ligand to liquid anion exchanger, as well aqueous phase contains suitable concentration of HCl to formation chloro anion complex for metal ion, after that shaking organic phase with aqueous phase to exchange small anion Cl - in liquid anion exchanger with chloro complex in aqueous phase as in the equilibria below:- nLorg. + H+ aq. + Cl - aq. H + LnCl - org. H+LnCl -org. +X -aq. H+LnX - org. + Cl -aq. L= -NA, 4-ABA, 4-CMePADPI, C222 X -= CdCl4 =, HCdCl4 -,HgCl4 =, HgCl3 -,HHgCl4 - ... ........ ....(1) .. ........ .....(2) Afterwards determined reminder quantity of metal ion in aqueous solution and transferred quantity to organic solution at later calculate distribution ratio (D), according to dithiazone method [8]. Results and Discussion Effect of HCl Concentration in Aqueous Solutions The concentration of HCl in aqueous solutions at range (0.1-3.0M), the concentration of HCl shaked with ligand solution was 1M to forming liquid anion exchanger, the obtained results, reported in figure (3). IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (2) 2011 Effect of HCl Concentration on liquid ion pair formation At optimum concentration of HCl for each ion in aqueous phase and organic phase of each ligand shaking with HCl solution in different concentrations (0.1-3.0M), the obtained results in figure (4). Effect of Metal ion Concentration Organic phase of ligand shaking with HCl optimum concentration, this organic phase shaking once again with aqueous solutions contain Cd 2+ (5-100μg) and Hg 2+ (5-150μg) at optimum HCl concentration, the results as in table (2) and figure (5). Study about shaking time necessary for extraction, taken different times for shaking (2- 20min), the obtained results, reported in table (3). The stoichiometry of the probable extracted species was determined on the basis of slope analysis method by plotting logD versus log[L] graph and giving strait line relation with slope value demonstrate the stoichiometry of ion pair complex extracted was 1:1:1 [HL +]HCdCl4 -, [HL + ]HHgCl4 - , [HL + ]HgCl3 - , the results as in table (4). Organic solvent effect on extraction method illustrates there is not any linear relation between dielectric constant (ε) of organic solvents and distribution ratio (D), obtain table (5). Effect of electrolyte salt on distribution ratio investigated by use KCl and NaCl salts at different concentrations, the results show there is optimum concentration of electrolyte salt solution giving higher distribution ratio (D) as in Figure (7,8). Extraction of CdCl4 = and HgCl4 = according to liquid anion exchange by C222 and 4- CMePADPI in foundation of cations appear interferences with hydrogen ions, these study and results shown the cations Na+ , K + , Mg 2+ and Ca 2+ restrict the chloro complex anion CdCl4 = and HgCl4 = and decline distribution ratio by using C222 and transition metal cations Cu2+, Ni2+ could not give stable coordination complex cation with 4-CMePADPI in acidic media because the protonation of 4-CMePADPI in acidic media decrease the chance of binding with Cu2+ , Ni 2+ ions. The study about temperature effect shows the reaction of anion exchange was endothermic for CdCl4 = with 4-ABA and 4-CMePADPI but exothermic with α-NA and C222, and the extraction of HgCl4 = was endothermic with α-NA but exothermic with 4-ABA, 4-CMePADPI, C222. Obtained results in table (6) and figure (8).And thermodynamic data for extraction demonstrate in table (7). Kex = D [HMCl4 -]aq. [L]org. ......... .......(3) Slope= -Hex 2.303 R ........ .......(4) ΔGex= -RT ln Kex …………….. (5) ΔGex= ΔHex – T ΔSex …………… (6) IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (2) 2011 References 11-- Ababa, A. and Adekola, F.A., (2008) Extraction of Zinc (II) by Triphenyl phosphate hydrochloric acid: kinetics and Mechanism, International Journal of physical sciences, 3 (4): 104-111. 22-- Alguacil ,F.J. (2003) Solvent extraction of Au (III) by the chloride salt of the amine alamine 304 and its application to a solid supported liquid membrane system, Solvent Extraction and ion exchange, 21, Issue.6: 841-852. 33-- Akira, O.; Kunihiko, D.and Makoto T. (2009) Novel liquid anion-exchange extractant, ethy lene bis (Tri octyl phosphonium) salt, Bearing two cation centers adjacently in a molecule", Journal of the pharmaceutical Society of Japan, 25(4): 181-187. 44-- Shivade M.R., Shinde V.M., (1981) Liquid anion exchange studies and separation of mercury", Analytical Letters, 14, Issue.(3): 155-161. 55-- Rice, N.M .and Smith, M.R. (2007) Recovery of Zinc, Cadmium and Mercury (II) from chloride and sulfate media by solvent extraction , Journal of Applied Chemistry and Biotechnology,.25Issue (5): 379-402. 66-- Singh, O.V. and Tandon, S,N. (2003) Extraction of Mercury (II) as chloride by high molecular weight amines and quaternary ammonium salts, Journal of Inorganic and Nuclear Chemistry, 36 Issue(2): 439-443. 77-- Asrafi, F.; Feyzbakhsh, A.and entezari, N. H. (2009) Solvent extraction of Cadmium (II) from sulfate medium by Bis (2-ethy l hexyl) phosphoric acid in toluene, International Journal of Chem. Tech. Research, 1(3): 420-425. 88-- Marczenko Z., (1976) Separation and Spectrophotometric determination of elements, Ellis - Horwood- Limited John Wiley and Sons, 2nd ed, PP:178-179,352-353. Table (1): Sandyl Sensitivity Cd Hg Ligand α-NA 4-ABA 4-CMePADPI C222 α-NA 4-ABA 4- CMePADPI C222 S µg/mL 0.065 0.18 0.2 0.81 0.055 0.043 0.15 0.21 IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (2) 2011 Table(2):Effect of Metal ion concentration on distribution ratio (D) μμgg ((CCdd22++,,HHgg22++)) DD CCdd DD HHgg αα--NNAA 44-- AABBAA 44-- CCMMeePPAADDPPII CC222222 αα--NNAA 44--AABBAA 44-- CCMMeePPAADDPPII CC222222 5 No.Ex. 0.78 0.56 2.12 No.Ex. No.Ex. No.Ex. No.Ex. 10 0.42 2.12 1.27 4.55 No.Ex. No.Ex. No.Ex. 0.47 20 1.17 3.76 2.56 9.52 0.29 0.06 0.53 1.85 30 1.77 5.81 4 14 0.82 0.54 1.34 2.94 40 2.57 7.69 4.71 18.04 1.22 1.02 2.12 4.31 50 4.55 11.5 7.92 49 1.45 1.47 3.23 6.14 60 3.83 9.34 5.26 25.08 1.97 1.88 3.61 6.87 70 2.5 4.38 4.88 21.74 2.3 2.27 4.3 7.25 80 1.7 3.12 4.37 19.05 2.47 2.66 4.88 8.3 90 1.36 1.5 4.06 16.29 2.54 3.16 5.92 8.58 100 1.22 1.22 3.84 14.12 3.03 2.62 6.63 9.99 110 - - - - 3.1 - 7.2 12.41 120 - - - - 3.51 - 7.69 12.95 130 - - - - 3.85 - 8.92 10.76 140 - - - - 4.26 - 8.58 9.42 150 - - - - 4.1 - 8.37 7.39 Table (3):Effect of shaking time on distribution ratio (D) DD HHgg DD CCdd Time (min.) CC222222 44-- CCMMee PPAADDPPII 44-- AABBAA αα-- NNAA CC222222 44-- CCMMee PPAADDPPII 44-- AABBAA αα-- NNAA 11.76 8.02 3.01 3.82 10.36 4.55 4.81 0.82 2 14.78 8.55 3.12 4.07 20.01 5.09 5.94 1.52 5 12.95 8.92 3.16 4.26 49 7.92 11.5 4.55 10 11.5 8.28 3.78 4 26.77 5.57 2.78 2.67 15 10.76 7.9 3.63 3.72 9.41 3.71 1.68 1.74 20 IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (2) 2011 Table (4): Effect of ligand concentration on distribution ratio (D) Table (5): Effect of organic solvents on distribution ratio (D) OOrrggaanniicc SSoollvveennttss εε DD CCdd DD HHgg αα--NNAA 44--AABBAA 44--CCMMeePPAADDPPII CC222222 αα--NNAA 44--AABBAA 44--CCMMeePPAADDPPII CC222222 Nitrobenzene 35.74 2.33 3.54 7.92 11.5 5.66 2.78 9.48 15.21 1,2-Dichloroethane 10.65 5.94 2.37 9 26.77 5.08 4.35 8.7 16.64 Dichloromethane 9.08 2.47 1.97 5.09 24 5.25 4.05 9.83 15.9 Chlorobenzene 5.708 2.42 8.61 6.81 21.72 5.08 3.83 8.15 16.14 Chloroform 4.806 4.55 11.5 7.92 49 4.26 3.78 8.92 14.78 Benzene 2.804 1.65 1.68 4.68 22.8 5.48 3.16 7.66 15.66 Toluene 2.438 3.46 1.84 8.61 19.83 4.93 3.45 8.42 14.58 Carbontetrachloride 2.38 1.68 2.52 9.41 12.15 5.14 5 8.28 11 DD HHgg DD CCdd CCoonncc.. OOff [[LL]] CC222222 44-- CCMMeePPAADDPPII 44--AABBAA αα--NNAA CC222222 44-- CCMMeePPAADDPPII 44--AABBAA αα--NNAA SSlloopp ee DD SSlloopp ee DD SSlloopp ee DD SSlloopp ee DD SSlloopp ee DD SSlloopp ee DD SSlloopp ee DD SSlloopp ee DD 0 .0 6 5 20.0 3 0 .0 9 7 13.9 3 0 .0 5 7 5.08 0 .0 8 5 6.21 0 .6 0 2 832. 3 0 .3 31.6 3 0 .3 49.1 6 0 .0 6 2 6.14 1x10-2 19.0 9 12.6 6 4.84 5.79 682. 4 22.5 9 37.8 2 5.94 5x10-3 17.2 1 10.8 1 4.35 5.14 251. 4 15.5 2 24.6 8 5.41 1x10-3 16.1 3 10.2 4.17 4.78 154. 6 11.5 3 17.5 3 5.09 5x10-4 14.7 8 8.92 3.78 4.26 49 7.92 11.5 4.55 1x10-4 13.9 3 8.54 3.68 3.96 30.8 5 6.56 9.14 4.43 5x10-5 12.7 9 7.27 3.36 3.45 11.8 4.36 5.99 3.8 1x10-5 12.3 8 6.82 3.2 3.21 7.57 3.1 5.25 3.62 5x10-6 10.9 7 5.7 2.98 2.84 3.31 2.03 3.08 3.46 1x10-6 IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (2) 2011 Table (6): Effect of Temperature on distribution ratio (D) TT°°CC CCdd HHgg αα--NNAA 44--AABBAA 44--CCMMeePPAADDPPII CC222222 αα--NNAA 44--AABBAA 44--CCMMeePPAADDPPII CC222222 DD KKeexx ××110099 DD KKeexx ××110099 DD KKeexx ××110099 DD KKeexx ××110099 DD KKeexx ××110099 DD KKeexx ××110099 DD KKeexx ××110099 DD KKeexx ××110099 5 6.57 0.74 8.77 0.99 5.94 0.67 124 14.09 3.24 2.31 4.69 0.52 12.26 9.5 16.61 13.84 10 5.94 0.67 9.41 1.07 6.35 0.72 99 11.25 3.4 2.43 4.48 0.5 11.74 9.1 16 13.33 15 5.41 0.61 10 1.13 6.93 0.78 82.33 9.35 3.6 2.57 4.17 0.46 10.6 8.22 15.54 12.95 20 4.95 0.56 10.4 1.18 7.33 0.83 61.5 6.98 3.92 2.8 4 0.44 9.65 7.48 15.29 12.74 25 4.55 0.51 11.5 1.3 7.92 0.9 49 5.56 4.26 3.04 3.78 0.42 8.92 6.91 14.78 12.32 30 4.31 0.49 12.2 1.38 8.25 0.93 40.66 4.62 4.46 3.19 3.63 0.4 8.42 6.52 14.45 12.04 40 3.71 0.42 13.7 1.55 9.41 1.07 30.25 3.43 4.98 3.55 3.41 0.38 7.55 5.85 13.88 11.57 50 3.31 0.37 14.6 1.66 10.36 1.17 19.83 2.25 5.42 3.87 3.12 0.35 6.83 5.29 13.28 11.07 60 3.03 0.34 15.7 1.78 11.5 1.3 15.66 1.78 6 4.28 2.98 0.33 6.47 5.01 12.55 10.46 Table (7): Thermodynamic data Ligand Cd Hg ΔHex (KJ.mole-1) ΔGex (KJ.mole-1) ΔSex (J.mole-1 .K- 1) ΔHex (KJ.mole-1) ΔGex (KJ.mole-1) ΔSex (J.mole-1 .K-1) α-NA -0.0107 -46.15 165.96 0.0085 -53.80 161.58 4-ABA 0.0083 -57.66 173.17 -0.0063 -45.38 163.21 4-CMePADPI 0.0091 -56.81 170.62 -0.0085 -46.72 168.02 C222 -0.0028 -52.81 190.06 -0.0041 -47.57 171.12 IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (2) 2011 Fig. (1):Calibration curve of Cd(II) Fig. (2):Calibration curve of Hg(II) Fig.(3): Effect of HCl concentration in aqueous solutions on distribution ratio (D) - [Cd 2+ ]aq., [Hg 2+ ]aq.=50μg/5mL, [Ligand]=1x10 - 4M in CHCl3 Fig. (4): Effect of HCl concentration on liquid ion exchanger formation-[Cd2+]aq., [Hg 2+ ]aq.=50μg/5mL, [Ligand]=1x10 -4 M in CHCl3 IBN AL- HAITHAM J. FOR PURE & APPL. SCI. VOL.24 (2) 2011 Fig. (5): Effect of Cd(II), Hg(II) ions concentration Fig. (6): Effect of KCl concentration on extraction of Cd(II), Hg(II). Fig. (7): Effect of NaCl concentration on extraction of Fig.(8): Temperature effect on the extraction method of Cd(II), Hg(II). 2011) 1( 24المجلد والتطبیقیة الصرفة للعلوم الهیثم ابن مجلة (II)الزئبق و (II)فصل واستخالص الكمیات المایكرویة من الكادمیوم طة طریقة التبادل االیوني السائلابوس صفا مجید حمید، شوكت كاظم جواد جامعة الكوفة ،كلیة التربیة للبنات ،قسم الكیمیاء 2010كانون األول 13: استلم البحث في 2011 نیسان 12: في البحث قبل الخالصة كلورو السالبة للكادمیوم مواد مستخلصة بوصفھا عضویة ات كواشفلمعاست(II) و الزئبق، (II)الستخالص معقدات ال و ،Amino benzoic acid (4-ABA)-4و ، α-Naphthyl amine (α-NA)مثل ،وفق تقنیة التبادل االیوني السائلعلى 2-[(4-Carboxy methyl phenyl) azo]-4,5-diphenyl imidazole (4-CMePADPI) ،و Cryptand )C222 .( ھذه الدراسة شملت تحدید تركیز حامض الھیدروكلوریك في الوسط المائي والتركیز المناسب للرج مع الطور العضوي والالزم الجانب الثرمودینامیكي . تأثیر األمالح القلویة والتداخالت،وتأثیر المذیب العضوي، وزمن الرج، فضال عن ص لعملیة االستخال رة اوماص C222و α-NAلكل من exothermicللحرارة اوضح إن تفاعل التبادل االیوني كان باعث endothermic للحرا CdCl4عند استخالص CMePADPI-4و ، ABA-4لكل من HgCl4أما عند استخالص = للحرارة افكان التفاعل باعث = exothermic 4مع كل من-ABA 4و-CMePADPI وC222 للحرارة اوماص endothermic معα-NA . فضال عن .Cation: Ligand: Anion 1:1:1دراسة تركیب معقد الترابط االیوني المستخلص أثبتت انھ .االیوني السائل، الكادمیوم، الزئبق، االستخالص بالمذیبالتبادل : الكلمات المفتاحیة