Qualitative Inorganic Analysis

This study presentsa: gyrolite as adsorbent for removal of Zn2+, Cu2+ and Cd2+ ions from aqueous solutions. Adsorption reactions were found more intensive in alkaline solution (pH 10.61) because almost all (98-99%) zinc, copper and cadmium ions are adsorbed in 30 s. Ion-exchange equilibrium is reached only after 3 min in acidic (pH 5.86) medium. Alkaline solution substitution isomorphism was found typical to gyrolite because 20% of heavy metals ions participate in ion exchange reaction and other part of ions were present in gyrolite by chemosorption. At acidic solution, cation exchange mechanism proceed differs because all heavy metal ions participate only in ion exchange reaction. Crystal structure of gyrolite is stable in solutions (pH, 5.81-10.61). XRD, STA, FTIR and SEM methods characterized sorption products.

Selectivity of hydrous titanium dioxide as an ion exchanger for alkali metal and tetraalkylammonium ions, has been studied using radioactive indicators: 22 Na and ~37Cs. The equilibrium distribution of trace amounts of sodium and cesium ions between the exchanger and aqueous solutions containing macroamounts of other univalent cations was studied over the temperature range of 15 to 80 ~ The selectivity sequence in slightly acidic and neutral solutions is as follows: (CH3)4N+<Li+<Na+<K+<Rb+<Cs +, whilst in alkaline solutions it is partly reversed. From the values of selectivity coefficients and the calculated values of thermodynamic functions one can infer that whilst hydrated ions are exchanged from acidic and neutral solutions, from alkaline solutions partly dehydrated ions enter the exchanger phase. The existence of ion-sieve effects for the univalent cations studied was observed, and the presence of at least two kinds of hydroxyl functional groups of different acidities is postulated. Ion exchange reactions of alkali metal cations on hydrous titanium dioxide, as well as the selectivity sequences observed have been interpreted on the basis of EISENMAN theory.

Amberlite IR-400 was chemically modified using titan yellow as a chelating agent. Adsorption studies such as effect of concentration, pH, time and temperature on the resin has been studied. Distribution coefficient studies of metal ions in varied solvent systems have been explored. On the basis of Kd values, important binary as well as ternary separations

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Xylenol orange (XO) is one of the complexometric indicators, that can bind to metal cations at both their amino and acidic groups. In this study the protonation constants and distribution diagrams of XO were studied pH-metrically, and the corresponding six protonation constants were calculated. The complex formation between XO (L) and alkaline earth ions (M) was investigated and the formation constants of the resulting complexes ML, MHL, M 2 L and M 2 HL were determined. The stabilities of both ML and M 2 L complexes were found to vary in the order Mg 2 + \ Ca 2 + \ Sr 2 + \ Ba 2 +. Studying the complex formation between Al 3 + ion (M) and XO (L), it was observed that four complexed species with stoichiometries ML, ML 2 , MHL and MH 2 L could be formed in solution. It was also found that the Al L 2 complex can act as a chelating agent for further complexation with two cations other than Al 3 +

The ion-exchange equilibria of various divalent transition metal ion (Co 2 +, Zn 2 +, Cd 2 + andCu 2 +)/K + systems havebeen studied overthe temperature range 3D-60°C on zirconium(lV) iodophosphate (ZIP), The exchange isotherms were constructed by means of a batch technique for M(NO J)/KN03 media of 0.01 mol/kg ionic strength, where M = C0 2+, Zn 2 +, Cd 2 + or Cu 2 + , The selectivity sequence was determined as C0 2+ < Zn2+ < Cd 2 + < Cu 2 +. Thermodynamic equilibrium constants and values of ~Go, ~SO and ~Ho were evaluated for the exchange process.

In recent years, heavy metal pollution has become a worldwide problem due to their high toxic potential and tendency to accumulate in the body. In the present paper was studied the possibility of removing heavy metals using the bulk liquid membrane technique, which proved to be a useful tool in many applications of this type. The transport of a mixture of three metal cations (Mn (II), Fe (II) and Fe (III)) through the bulk liquid membrane was tested. The transport studies were carried out in the membrane system consisting of: the source phase solution of Mn (II), Fe (II) and Fe (III) in hydrochloric acid medium, the membrane solution of trioctylmethylammonium chloride (Aliquat 336) in chloroform, the receiving phase – solution of dilute hydrochloric acid. In optimal transport conditions, efficiencies of less than 10% for the removal of Mn (II), of less than 30% for Fe (II) and of about 90% for Fe (III) were obtained.

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

The separation of zinc, cadmium and lead ions by bis(2-ethylhexyl)phosphoric acid (DEHPA) dissolved in cyclohexane has been improved in the presence of aqueous N,N-bis(2-pyridylmethylidene)-1,2diiminoethane (BPIE), as a selective masking agent. The interaction between metal ions and BPIE results a shift in the extraction curve of the studied metal ions versus pH towards higher pH region. The displacement of the extraction curves varies as Zn 2+ < Pb 2+ < Cd 2+. The analysis of extraction data makes possible the evaluation of stability constant of the [M(BPIE)] 2+ complexes (M = Zn, Cd or Pb) in the aqueous phase. The influence of temperature on the extraction of studied metal ions from aqueous phase in the absence and the presence of BPIE was tested in the range 288-303 K. This investigation allows evaluating the thermodynamic parameters associated with the extraction process, and those of the complexation of cations by BPIE in the aqueous phase.

The ion-exchange equilibria of various divalent transition metal ion (Co 2 +, Zn 2 +, Cd 2 + andCu 2 +)/K + systems havebeen studied overthe temperature range 3D-60°C on zirconium(lV) iodophosphate (ZIP), The exchange isotherms were constructed by means of a batch technique for M(NO J)/KN03 media of 0.01 mol/kg ionic strength, where M = C0 2+, Zn 2 +, Cd 2 + or Cu 2 + , The selectivity sequence was determined as C0 2+ < Zn2+ < Cd 2 + < Cu 2 +. Thermodynamic equilibrium constants and values of~Go,~SO and~Ho were evaluated for the exchange process.

Polyurethane foam was chemically functionalized with β-naphthol  to adsorb metal ions (Fe3+, Cu2+, Cr3+, Co2+ and Mn2+), applying the off-line solid phase extraction procedure. The concentrations of the metals have been detemined using the flame atomic absorption spectroscopy (FAAS). Various factors including, the pH of the sample solution  and the time of extraction were examined. The interference effects of the additional ions in the solution were studied, metal ions of Na+, K+, Mg2+ and Ca2+ and anions, CO32- and SO42-. The new sorbent was examined for separation of Cu, Mn, Cr, Co and Fe ions. The adsorption of metal ions onto β-Nap-PUF was tested using the Morris-Weber equation. The straight line of the plot qt (adsorbed amounts at time t) vs t in all cases, with low R2 (0.767) in case of Mn, indicates the intra particle transport phenomena. The Lagergren equation was applied for mass action phenomenon. The plots of log(1-F) Vs t for Mn, Cr, and Cu were straight with high R2 0.9...

The [M Ϫ nH ϩ mX] (mϪn)ϩ (X ϭ alkali metal ion) are common ions in the mass spectrum of a peptide that is electrosprayed in the presence of an alkali metal salt or hydroxide. The feasibility of forming [M Ϫ nH ϩ mX] (mϪn)ϩ ions in the gas phase including those in the lens region of the mass spectrometer via ion-molecule reactions and/or reactions between components of collisionally activated adducts was investigated. The Li ϩ ion was selected for examination since its salts are computationally the least expensive among alkali metal salts. The lithium ion affinities of the [M Ϫ H] Ϫ ions of N-methylacetamide, acetic acid, and 1-propanamine were calculated by means of density functional theory (DFT) at various levels of theory, including B3LYP/6-311ϩϩG(d, p). These three compounds were selected as representatives of relevant functional groups on a peptide. The calculated lithium ion affinities, together with evaluated thermochemical data, were used to calculate the enthalpies of reactions between the model compounds and LiOH, LiCl, and Li(H 2 O) ϩ that might lead to the formation of [M Ϫ nH ϩ mX] (mϪn)ϩ. A number of these reactions were found to be exothermic or slightly endothermic (⌬HЊ Ͻ ϩ20 kcal/mol). DFT calculations on the energetics of a model reaction revealed a relatively flat potential energy hypersurface containing a well of approximately 35 kcal/mol in depth and devoid of significant barriers. These results are used to postulate the formation of [M Ϫ nH ϩ mX] (mϪn)ϩ ions in the gas phase in the ion source and/or in the lens region via collisions between an ionic peptide and neutral lithium compounds or collisional activation of lithium-peptide adducts.

The paper presents results of investigation of exchange of the clinoptilolite tuff cations with hydrogen ions from HCl solution of concentration 0.1 mmol cm −3 and ammonium ions solutions of concentrations 0.0071 to 2.6 mmol cm −3. Molal concentrations, x (mmol g −1) of cations exchanged in acid solution and in ammonium ions solutions were compared with molal concentrations of cations obtained by determination of the cation-exchange capacity of clinoptilolite tuff. The obtained results show that at ammonium ion concentrations lower than 0.1 mmol cm −3 , with regard to exchange capacity for particular ions, best exchanged are Na + ions, followed by Mg 2+ and Ca 2+ ions, while exchange of K + ions is the poorest (Na + > Mg 2+ > Ca 2+ > K +). At ammonium concentrations from 0.2 to 1 mmol cm −3 the order is Na + > Ca 2+ > Mg 2+ > K +. At concentrations higher than 1 mmol cm −3 the order is Na + > Ca 2+ > K + > Mg 2+. The results are a consequence of the uptake of hydrogen ions by zeolite samples in ammonium ions solutions at concentrations lower than 1 mmol cm −3 and indicate the importance of Mg 2+ (besides Na + ions) for the exchange between clinoptilolite cations and H + ions, in contrast to K + ions, whose participation in the reaction with H + ions is the lowest. During decationization of the clinoptilolite in acid solution, best exchanged are Na + , Mg 2+ , and Ca 2+ ions, while exchange of K + ions is the poorest. Due to poor exchange of K + and H + ions and good exchange of Na + , Mg 2+ , and Ca 2+ ions, it is to be assumed that preservation of stability of the clinoptilolite structure is caused by K + ions present in the channel C. Clinoptilolite is dissolved in the clinoptilolite A and B channels where Na + , Mg 2+ , and Ca 2+ ions are present. On the acidmodified clinoptilolite samples, exchange of ammonium ions is poorer than on natural zeolite. The longer the contact time of the zeolite and acid solution, the worse ammonium ions exchange. It can be assumed that H + ions exchanged with zeolite cations are consumed for solution of aluminum in the clinoptilolite structure; therefore the concentration of H + ions as exchangeable cations decreases. In the ammonium ion solution at a concentration of 0.0065 mmol cm −3 , from the acid-modified zeolite samples, Al 3+ ions are exchanged best, followed by Na + , Mg 2+ , Ca 2+ , and K + ions. Further to the results, it is to be assumed that exchangeable Al 3+ ions available from clinoptilolite dissolution are best exchanged with H + ions in acid solution.

The previously presented synthetic tetra-acid model compound BP10 was used to investigate the chemistry behind the formation of metal naphthenate deposits. The interactions between BP10 and the cations Ba 2þ , Ca 2þ , H þ , Mg 2þ , and Sr 2þ were investigated using potentiometric titrations, metal ion depletion by inductively coupled plasma-atomic emission spectrometry (ICP-AES), pH measurements, and elemental analysis of precipitates, in 20-600 mM NaCl ionic medium. The interactions of BP10 with the monovalent Na þ are discussed on the basis of a previous study. The data given indicate that Ca 2þ shows the strongest affinity toward BP10 and Ba 2þ , and Sr 2þ form approximately equally stable solid phases with BP10, while Mg 2þ is less tightly bound to the tetra-acid. H þ interacts more strongly than the Me 2þ ions, and Na þ shows a rather small affinity for BP10. No soluble complexes could be detected, and all products in the chemical reactions are therefore believed to be solid materials. We suggest that BP10 show the following preference of cations: H þ. Ca 2þ > Ba 2þ ≈ Sr 2þ > Mg 2þ. Na þ. This order could be due to the hydration state and size of the cations. In comparison to typical concentrations found of each in saline water, it is proposed that the dominance of Ca 2þ in naphthenate deposits is dependent upon both availability and selectivity.

The paper presents results of investigation of exchange of the clinoptilolite tuff cations with hydrogen ions from HCl solution of concentration 0.1 mmol cm −3 and ammonium ions solutions of concentrations 0.0071 to 2.6 mmol cm −3. Molal concentrations, x (mmol g −1) of cations exchanged in acid solution and in ammonium ions solutions were compared with molal concentrations of cations obtained by determination of the cation-exchange capacity of clinoptilolite tuff. The obtained results show that at ammonium ion concentrations lower than 0.1 mmol cm −3 , with regard to exchange capacity for particular ions, best exchanged are Na + ions, followed by Mg 2+ and Ca 2+ ions, while exchange of K + ions is the poorest (Na + > Mg 2+ > Ca 2+ > K +). At ammonium concentrations from 0.2 to 1 mmol cm −3 the order is Na + > Ca 2+ > Mg 2+ > K +. At concentrations higher than 1 mmol cm −3 the order is Na + > Ca 2+ > K + > Mg 2+. The results are a consequence of the uptake of hydrogen ions by zeolite samples in ammonium ions solutions at concentrations lower than 1 mmol cm −3 and indicate the importance of Mg 2+ (besides Na + ions) for the exchange between clinoptilolite cations and H + ions, in contrast to K + ions, whose participation in the reaction with H + ions is the lowest. During decationization of the clinoptilolite in acid solution, best exchanged are Na + , Mg 2+ , and Ca 2+ ions, while exchange of K + ions is the poorest. Due to poor exchange of K + and H + ions and good exchange of Na + , Mg 2+ , and Ca 2+ ions, it is to be assumed that preservation of stability of the clinoptilolite structure is caused by K + ions present in the channel C. Clinoptilolite is dissolved in the clinoptilolite A and B channels where Na + , Mg 2+ , and Ca 2+ ions are present. On the acidmodified clinoptilolite samples, exchange of ammonium ions is poorer than on natural zeolite. The longer the contact time of the zeolite and acid solution, the worse ammonium ions exchange. It can be assumed that H + ions exchanged with zeolite cations are consumed for solution of aluminum in the clinoptilolite structure; therefore the concentration of H + ions as exchangeable cations decreases. In the ammonium ion solution at a concentration of 0.0065 mmol cm −3 , from the acid-modified zeolite samples, Al 3+ ions are exchanged best, followed by Na + , Mg 2+ , Ca 2+ , and K + ions. Further to the results, it is to be assumed that exchangeable Al 3+ ions available from clinoptilolite dissolution are best exchanged with H + ions in acid solution.

Alkali metal ion exchange (Li+, Na+ and K+) on chromium phosphate (CrPO4) was studied potentiometrically as a function of temperature and metal ion concentration. The shift in the potentiometric titration curves corresponding to the exchange of alkali metal cations increased with increasing pH and concentration of the metal ions, while the opposite results were obtained by increasing the temperature of the system. The affinity of the exchanger for alkali metal ions was also found to be in the order Li+ &gt; Na+ &gt; K+. The data were employed to evaluate the apparent deprotonation constants of CrPO4 and the corresponding thermodynamic parameters ΔH0, ΔS0 and ΔG0.

In recent years, heavy metal pollution has become a worldwide problem due to their high toxic potential and tendency to accumulate in the body. In the present paper was studied the possibility of removing heavy metals using the bulk liquid membrane technique, which proved to be a useful tool in many applications of this type. The transport of a mixture of three metal cations (Mn (II), Fe (II) and Fe (III)) through the bulk liquid membrane was tested. The transport studies were carried out in the membrane system consisting of: the source phase solution of Mn (II), Fe (II) and Fe (III) in hydrochloric acid medium, the membrane solution of trioctylmethylammonium chloride (Aliquat 336) in chloroform, the receiving phase – solution of dilute hydrochloric acid. In optimal transport conditions, efficiencies of less than 10% for the removal of Mn (II), of less than 30% for Fe (II) and of about 90% for Fe (III) were obtained.

The 226 Ra 2+ selectivity of the ionizable (thia)calix[4]crowns 1-4 was determined in the presence of a large excess of the most common alkali and alkaline earth cations. Selective 226 Ra 2+ (2.9 × 10-8 M) extraction occurs even at extremely high M n+ / 226 Ra 2+ ratios of 3.5 × 10 7 [M n+) Na + , K + , Rb + , Cs + , Mg 2+ , Ca 2+ , and Sr 2+ (1 M)] and an ionophore concentration of 10-4 M. The selectivity coefficients log(K Ra ex /K M ex) are ∼3.5 for Mg 2+ , Ca 2+ , and Sr 2+. In the presence of Ba 2+ , which has very similar chemical properties, only the thiacalix[4]crown-6 derivative 4 showed a selectivity for 226 Ra 2+. In addition to the remarkable 226 Ra 2+ selectivities, the effective pH range (pH 8-13) of the thiacalix[4]crown dicarboxylic acids (3 and 4) allows for full regeneration of the ionophores at lower pH values (pH <6).

The objective of this work is the use of dicalcium phosphate dihydrate CaHPO 4 , 2H 2 O (SAP) for the decontamination of aqueous solutions charged in divalent metal ions Cu 2+ , Zn 2+ and Cd 2+. After realization of a reliable experimental protocol giving reproducible results, the metals of aqueous solutions are analyzed by flame atomic absorption spectroscopy. The Mass balance before and after extraction makes possible the determination of the rate of metal retention R of the apatitic support. The obtained results show that the R values are closely related to the concentration of metal and the imposed pH in the supernatant solution. Indeed, at low concentrations of Cu 2+ ions (10-4 M) the R value is close to 0.08. The increase of the pH favours the fixation of the Cu 2+ ions on SAP (R passes from 0.058 to 0.085, respectively for pH= 3.5 and 6.5). The kinetic study shows that the mechanism of fixation of the Cu 2+ ions by SAP is controlled by a cation exchange: Ca 2+ (SAP) /Cu 2+ (Solution). The application of SAP to the treatment of metal mixtures of ions leads to a selective extraction: Cd > Zn > Cu.

A new selective Zn 2+ fluorescent chemosensor, o-vanillin-4-ethoxybenzoylhydrazone (1), was designed and prepared. Free 1 mainly displayed very weak fluorescence at 480 nm upon excitation at 403 nm. It displayed high selectivity for Zn 2+ and had a 518fold fluorescent enhancement upon binding of Zn 2+ , while the other cation ions had only little influence on the fluorescence of 1. Mechanism of enhancement of 1's fluorescence by Zn 2+ was briefly discussed.

This study presentsa: gyrolite as adsorbent for removal of Zn2+, Cu2+ and Cd2+ ions from aqueous solutions. Adsorption reactions were found more intensive in alkaline solution (pH 10.61) because almost all (98-99%) zinc, copper and cadmium ions are adsorbed in 30 s. Ion-exchange equilibrium is reached only after 3 min in acidic (pH 5.86) medium. Alkaline solution substitution isomorphism was found typical to gyrolite because 20% of heavy metals ions participate in ion exchange reaction and other part of ions were present in gyrolite by chemosorption. At acidic solution, cation exchange mechanism proceed differs because all heavy metal ions participate only in ion exchange reaction. Crystal structure of gyrolite is stable in solutions (pH, 5.81-10.61). XRD, STA, FTIR and SEM methods characterized sorption products.

Polyurethane foam was chemically functionalized with β-naphthol  to adsorb metal ions (Fe3+, Cu2+, Cr3+, Co2+ and Mn2+), applying the off-line solid phase extraction procedure. The concentrations of the metals have been detemined using the flame atomic absorption spectroscopy (FAAS). Various factors including, the pH of the sample solution  and the time of extraction were examined. The interference effects of the additional ions in the solution were studied, metal ions of Na+, K+, Mg2+ and Ca2+ and anions, CO32- and SO42-. The new sorbent was examined for separation of Cu, Mn, Cr, Co and Fe ions. The adsorption of metal ions onto β-Nap-PUF was tested using the Morris-Weber equation. The straight line of the plot qt (adsorbed amounts at time t) vs t in all cases, with low R2 (0.767) in case of Mn, indicates the intra particle transport phenomena. The Lagergren equation was applied for mass action phenomenon. The plots of log(1-F) Vs t for Mn, Cr, and Cu were straight with high R2 0.9...

Hydrated Mn/Al-SO 4-A (A = Li, Na or K) layered double hydroxides with M +2 :M +3 molar ratio close to 1:1 were synthesized by co-precipitation with increasing pH. All phases presented solvated alkali metals and sulfate as intercalated species. In the exchange reactions, when sulfate solutions of alkali metals were used, sodium could be partially replaced by potassium, and the same was true for the potassium phase, where potassium could be partially replaced by Na and Li, without removing the intercalated sulfate anions. This class of compounds, considered to be anion exchanger, can also exchange cations, which opens new perspectives for applications.

Poly(ethyl eugenyl oxyacetate) (PEEOA) had been synthesized for separating heavy metals like Fe(III), Cr(III), Cu(II), Ni(II), Co(II), and Pb(II) by liquid membrane transport method. The effects of pH, ion carrier volume, stripping concentration, transport time, and metal ion concentration were investigated to obtain optimum conditions. Experimental results showed that optimum pH occurred at pH 4 for Fe(III) ions and pH 5 for others. Carrier volumes were optimum at 8.5 mL for Fe(III) and Pb(II) ions but 7.5 mL for others. The optimum concentrations of the stripping phase were 2 M for Fe(III) and Cu(II) ions, 1 M for Cr(III), Ni(II), Co(II) ions, and 0.5 M for Pb(II) ion. Transport times were optimum at 36 h for Fe(III) and Co(II) ions and 48 h for others. The optimum metal ion concentrations were 0.25 mM for Fe(III) and Cr(III) ions, while other ions were 0.1 mM. The response of PEEOA to Fe(III) ion was the best with selectivity order, Fe(III) &gt; Cr(III) &gt; Pb(II) &gt; Cu(II) &g...

The sorption of Zn2+, Ni2+, Cd2+, Ca2+ and Mg2+ ions on to a mixed oxide of iron and silicon was found to increase with increasing temperature, concentration and pH of the system. The selectivity of this mixed oxide was Cd2+ ≥ Zn2+ ≥ Ni2+ &gt; Ca2+ &gt; Mg2+, indicating that the mixed oxide was more selective as an exchanger towards Cd2+ ions relative to its components, SiO2 and Fe(OH)3. The sorption data fitted the linear forms of the Kurbatov and Langmuir adsorption equations. The sorption of metal cations was accompanied by the release of H+ ions to the bulk phase. On average 1 mol H+ was released for every cation sorbed. The values of the binding constants were used to estimate the apparent thermodynamic parameters, ΔH and ΔS. The phenomenon of enthalpy/entropy compensation showed that the adsorption of metal ions by the mixed oxide occurred typically through a cation-exchange mechanism.

Selectivity of hydrous titanium dioxide as an ion exchanger for alkali metal and tetraalkylammonium ions, has been studied using radioactive indicators: 22 Na and ~37Cs. The equilibrium distribution of trace amounts of sodium and cesium ions between the exchanger and aqueous solutions containing macroamounts of other univalent cations was studied over the temperature range of 15 to 80 ~ The selectivity sequence in slightly acidic and neutral solutions is as follows: (CH3)4N+<Li+<Na+<K+<Rb+<Cs +, whilst in alkaline solutions it is partly reversed. From the values of selectivity coefficients and the calculated values of thermodynamic functions one can infer that whilst hydrated ions are exchanged from acidic and neutral solutions, from alkaline solutions partly dehydrated ions enter the exchanger phase. The existence of ion-sieve effects for the univalent cations studied was observed, and the presence of at least two kinds of hydroxyl functional groups of different acidities is postulated. Ion exchange reactions of alkali metal cations on hydrous titanium dioxide, as well as the selectivity sequences observed have been interpreted on the basis of EISENMAN theory.

A new chemosensor (L 1) is synthesized and its spectral response was screened with most alkali, alkaline earth, transition and lanthanide metal ions in THF-water (2:3, v/v, pH 7.2, 20 mM HEPES buffer) medium. This is found to bind four different transition metal ions such as Hg 2+ , Cu 2+ , Ag + and Ni 2+ in mixed aqueous solution at pH 7.2; while binding affinity towards the Hg 2+ is found to be an order of magnitude higher as compared to other three cations mentioned. Experimental results reveal that the L 1 could be used for colorimetric detection of Hg 2+ , present in the lower organism like Pseudomonas putida.

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

The equilibrium exchange of Li + and K + ions with the hydrogen form of tin(IV) and iron(lll) antimonates was investigated in MC1 HC1 media at 25, 45 and 60°C. The exchange isotherms were measured for both the forward and reverse reactions at a solution ionic strength of 0.1 by the batch technique. Enthalpy and entropy changes accompanying the Li + H + and K + H + exchanges were determined by the temperature variation method. The Li + Hand K+-H + exchanges are enthalpy directed, the enthalpy change determining the selectivity of the alkali metal ions over hydrogen ion. ~© 1998 Elsevier Science B.V.

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

The sorption of Zn2+, Ni2+, Cd2+, Ca2+ and Mg2+ ions on to a mixed oxide of iron and silicon was found to increase with increasing temperature, concentration and pH of the system. The selectivity of this mixed oxide was Cd2+ ≥ Zn2+ ≥ Ni2+ &gt; Ca2+ &gt; Mg2+, indicating that the mixed oxide was more selective as an exchanger towards Cd2+ ions relative to its components, SiO2 and Fe(OH)3. The sorption data fitted the linear forms of the Kurbatov and Langmuir adsorption equations. The sorption of metal cations was accompanied by the release of H+ ions to the bulk phase. On average 1 mol H+ was released for every cation sorbed. The values of the binding constants were used to estimate the apparent thermodynamic parameters, ΔH and ΔS. The phenomenon of enthalpy/entropy compensation showed that the adsorption of metal ions by the mixed oxide occurred typically through a cation-exchange mechanism.

Grafted rubberwood fibre was converted to polyamidoxime ion-exchange resin in order to remove heavy metal ions from aqueous solution. The cation-exchange resin existed predominantly in the syn-hydroxyamino form. The water uptake by the resin was ca. 31 g/g dry resin while its hydrogen ion capacity was 3.6 mmol/g. The adsorption capacity of the resin towards different metal ions from wastewater was determined at different pH values within the range 1–6. The prepared chelating ion-exchanger exhibited the highest adsorption capacity towards Cu2+ ions (3.83 mmol/g), followed by Cd2+, Fe3+, Pb2+, Ni2+ and Co3+ ions, respectively. The results showed that the adsorption capacity depended on the solution pH. Polyamidoxime ion-exchange resin was also used to separate Co3+ and Ni2+ ions from Cu2+ ions using a column technique. On passing Cu2+/Ni2+ and Cu2+/Co3+ ion mixtures through the resin at pH 3, Cu2+ ions were adsorbed by the resin but no sorption of Ni2+ or Co3+ ions was detected. Appro...

Purpose of this book on qualitative inorganic analysis, is to provide the students with the necessary guidelines for solving confidently an unknown inorganic sample, within the duration of a practical
examination. It insists on acquiring the basic knowledge about the classical chemistry associated with detecting the cations and anions as well as the dissolution aspects in bringing them in solution. They
enable a student to modify the detection procedures carefully according to the composition of the sample, without losing the logical aspects. Dry/preliminary tests for the cations and anions, treatment
of the Na2CO3 extract as well as that of its residue, form the foundation of the present semi-micro analytical procedures.
Keywords: Detection of cations and anions in solution; different dissolution procedures; treatment of “rare” metal salts; importance of the Na2CO3 extract and its residue.
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