Adsorption of metal ions on activated carbon from aqueous solutions at pH 1-13

Adsorption of microgram amounts of 20 metal species on activated carbon powder from aqueous solutions of pH 1-13 was investigated. The species examined were Cs(I), Y(III), Ce(III), Ti(IV), Zr(IV), Cr(III), Cr(VI), Mn(II), Fe(III), Co(II), Ni(II), Ru(III), Cu(II), Ag(I), Zn(II), Cd(II), Al(III), Pb(II), Sb(III) and Bi(III).     

The spectrophotometric determination of vanadium after extraction as vanadium(III) ferronate by tribenzylamine

Vanadium(III) obtained by dithionite reduction of vanadium(V) can be extracted as its ferron complex with tribenzylamine in chloroform from 0.05 M sulphuric acid. Vanadium (0–5 μg ml^-1) is determined spectrophotometrically at 430 nm with a sensitivity of 0.0028 μg V cm^-2. Al(III), Co(II), Ni(II), Fe(II, III), Hg(II), Si(IV), Be(II), Mg(II), Ca(II), Sr(II), Ba(II), Cr(VI, III), W(VI), Zn(II), U(VI), Mn(II). Pb(II), Cu(II), Cd(II) and Th(IV) do not interfere; only Mo(VI), Ti(IV), Zr(IV). Bi(V) and Sn(II) interfere. A single determination takes only 7 min. The extracted complex is V^III (R-3H.TBA)₃ where R = C₉H₄O₄NSI. The method is satisfactory for the determination of vanadium in steels, alum and other samples without preliminary separations.     

Rapid and selective chelatometric titration of aluminium in non-ferrous alloys

A rapid chelatometric method for the determination of Al (4–20%) in magnesium, copper and chromium-aluminium-iron alloys is proposed. HEDTA is used as titrant and Zn solution as back-titrant, with hydrazidazol as indicator. Mn(II), Cu(II), Cd, Zn, Pb, Co(II), Ni, Hg(II), Fe(III), Bi, Cr(III), Sb(III), Ce(III), La, Sn(IV), Ti(IV), Zr and Mo(VI) do not interfere. High selectivity is achieved by a combination of group separation, masking and interference correction. The coefficient of variation varies from 0.2 to 1%.     

Potentiometric Study of Tetracycline and Oxytetracycline with some Metal Ions of Biological Interest

Abstract

The stepwise metal-ligand stability constants of tetracycline and oxytetraoycline chelates with Mg(II), Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Cu(II), Zn(II), Zr(II) and Sn(II) have been determined using the Bjerrum-Calvin titration technique as employed by Irving and Rossotti. Protonation constant of the ligand and stability constants of the respective metal complexes have been determined at constant temperature (25°C) and ionic strength (0.1 M KCl). The general order of overall stability constant values have been found to be: Zr(IV) > Fe(III) > Co(II) > Zn(II) > Mg(II) > Mn(II) > Ni(II) > Sn(II) > Tn(II) > Cr(II). The rign values of the atability constanta are attricutel to the Ligands, which are stronger as an acid and weaser as a oase.     

Organic acid solutions in the chromatography of inorganic ions VIII. Cation-exchange of Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II), Fe(III), Sc(III), Y(III), Eu(III), Dy(III), Ho(III), Yb(III), Ti(IV) and Nb(V) in malate media

Summary The cation-exchange behaviour of Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II), Fe(III), Sc(III), Y(III), Eu(III), Dy(III), Ho(III), Yb(III), Ti(IV) and Nb(V) in malate media at various concentrations and pH, was studied with Dowex 50 WX8 resin (200–400 mesh) in the ammonium form. Separation of Fe(III)/Cu(II), Fe(III)/Cu(II)/Zn(II), Fe(III)/Co(II)/Mn(II), Cu(II)/Ni(II)/Mn(II), Fe(III)/Cu(II)/Co(II)/Mn(II), Fe(III)/Cu(II)/Ni(II)/Cd(II), Yb(III)/Eu(III), Sc(III)/Y(III),Sc(III)/Yb(III)/Dy(III) and Nb(V)/Yb(III)/Ho(III) has been achieved, among others.This work was supported by C.N.R. of Italy.     

Chloroform extraction of metal ethyl xanthates from hydrochloric acid media

The chloroform extraction of 32 elements (Fe, Co, Ni, Zn, Cd, Ge, Sn, Pb, V, As, Sb, Bi, Cu, Ag, Au, Mn, Re, Ga, In, Tl, Ce, Se, Te, Cr, Mo, U, Pt, Pd, Rh, Ir, Ru and Os) from O.1-10M hydrochloric acid media in the presence of potassium ethyl xanthate has been studied. The oxidation states in which some elements react, and potential analytical separations, are discussed. Pd(II), As(III) and Se(IV) are completely extracted as ethyl xanthate complexes, Te(IV) is almost completely extracted, and Au(III) is largely extracted over the range of acid concentration investigated. Mn(II), Zn, Rh(III), Ir(IV), Ru(III), Os(IV), Cr(III), Cr(VI), Ce(III) and Ce(IV) are not extracted. Ge is partly extracted from 6-10M media as the chloro-complex. Depending on the acid concentration, the remaining elements are all partially extracted as xanthate complexes.     

Preparation, characterization and metal sorption studies of a Chrome-Azurol-S-loaded anion-exchange resin

Chrome Azurol S (CS) was mobilized on an strongly basic anion-exchange resin (Dowex 2 x 4, in Cl(-) form) by batch equilibration. The modified resin was stable in acetate buffer solution and in 0.1 M HCl and H(2)SO(4), but it was readily degraded with 2-6 M HCl and HNO(3). Retention of Ba(II), Sr(II), Ca(II), Mg(II), Al(III), Cr(III), Zn(II), Fe(III), Ti(IV), Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) was studied using the batch equilibration method. The uptake and recovery yields were determined by using inductively-coupled plasma atomic emission spectroscopy (for Mg, Al, Cr, Ti, Fe, Mn, Ni, Zn, Cu, Cd and Pb) and atomic absorption spectrophotometry (for Ba, Sr, Ca and Co). The optimum pH value was established for performing a selective separation of Al(III) from the other metal ions. The sorption capacities of the CS-loaded resing for Al(III), Cr(III), Mg(II) (at pH 6), Fe(III) (at pH 5) and Ti(IV) (at pH 4) were 14, 2.9, 0.3, 3 and 3.9 mumoles g(-1) respectively. On this basis a method for separating Al(III) from other cations was established.     

Distribution coefficients for twelve elements in oxalic acid medium on a strong anion-exchange resin

The distribution coefficients were determined for twelve elements, namely As(III), Ce(III), Cr(III), Co(II), Cu(II), In(III), Lu(III), Mn(II), Hg(II), Mo(VI), Sc(III) and Zn(II), on a strong base anion exchanger in pure oxalic acid solutions. The K_D curves are given. A scheme was developed for the chromatographic separation of five elements, namely As(III), Mn(II), Co(II), Zn(II) and Cu(II). Ce(III) can be separated from Lu(III).     

Fractional sublimation of some metal chelates of thenoyltrifluoroacetone

Studies on the fractional sublimation of various metal β-diketone chelates have been extended to include the chelates of thenoyltrifluoroacetone (TTA). Many of the common metal chelates were found to be stable, to sublime readily, and to form well-defined zones in the vacuum fractional sublimator. Of the 17 chelates reported only those of manganese (II) and iron(II) were not volatile. The chelates of UO₂(II), Zr(IV), Pb(II), and Cr(III) partially decomposed during sublimation and their recovery was incomplete. The recovery of the sublimed chelates of Ni(II), Mg(II), Al(III), Pd(II), Co(II), Cu(II). Fe(III), Tl(III), Zn(II) and Be(II) ranged from 87 to 100%, with most recoveries being quantitative. The sublimation recrystallization zone temperatures of the various chelates are compared to those of the metal acetylacetonates and the benzoyltrifluoroacetonates; in general, the metal chelates of TTA sublime more readily than those of benzoyltrifluoroacetone but are potentially less useful for fractional sublimation separations than the corresponding metal acetylacetonates. Even so, a quantitative separation of iron(III) from Ni(II), Al(III), Mn(II), and Fe(II) is proposed that depends upon the fractional sublimation of the TTA chelates.     

Rapid coprecipitation technique using yttrium hydroxide for the preconcentration and separation of trace elements in saline water prior to their ICP-AES determination.

Yttrium hydroxide quantitatively coprecipitated Be(II), Ti(IV), Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) at pH 9.6 - 10.0 for seawater and pH 10.5 - 11.4 for a table-salt solution. The coprecipitated elements could be determined by inductively coupled plasma atomic emission spectrometry; yttrium was used as an internal standard element. The detection limits ranged from 0.001(6) microg (Mn(II)) to 0.22 microg (Zn(II)) in 100 mL of sample solutions. The operation time required to separate 11 elements was approximately 30 min.     

Consecutive thin-layer chromatographic separation of Au(III), Pt(IV), Pd(II) and large amounts of associated base metals

Summary The TLC system composed of ECTEOLA-cellulose and 2.5 mol/l HCl–2.5 mol/l NaCl–0.6% (w/v) H₂O₂ solution allows consecutive separations of Au(III), Pt(IV), Pd(II) and a number of associated base metals such as Cr(III), Mn(II), Fe(III), Co(II) Ni(II), Cu(II), Mg, Ca, Ba, Al, Bi(III), Pb(II), Zn(II) and Ag(I) coexisting in an extremely wide range of amounts and ratios, to be conducted completely in a single run. The effectiveness of the present system is verified by applying it to various synthesized samples containing the three noble metals and one of the base metals, Pt-metal powder and two kinds of Au-alloys.     

Preparation, characterization and application of an cellulose ion-exchanger with acetoacetamide functional groups

Summary A method is described for functionalizing acetoacetamide chelating groups onto microcrystalline cellulose (Cell-AcAc). This material shows a significant affinity for Fe(III), Cu(II) and U(VI) and no or very less affinity for the M(I) ions (M=Na, K), M(II) ions (M= Mg, Ca; Fe, Co, Ni, Zn), La(III) and Y(III) including Th(IV). The obtained K _d values offer a column separation method for U(VI) ions from the rest of above-mentioned metal ions except Fe(III). Cell-AcAc and its Cu(II) complexes are characterized by means of FT-IR spectra.

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Darstellung, Charakterisierung und Anwendung von Ionenaustauschmaterial aus Cellulose mit chemisch gebundener Acetoacetamid-Gruppe

Zusammenfassung Die Darstellung von immobilisiertem Acetoacetamid auf mikrokristallinem Cellulosepulver (Cell-AcAc) wird beschrieben. Der Ionenaustauscher Cell-AcAc hat eine ausgeprägte Affinität für Fe(III), Cu(II) and U(VI), aber nahezu keine für die M(I)-Ionen (M=Na, K) M(II)-Ionen (M=Mg, Ca; Fe, Co, Ni, Zn), La(III), Y(III) sowie Th(IV). Die erhaltenen K _d-Werte ermöglichen für U(VI)-Ionen eine quantitative säulen-chromatographische Trennung von den anderen genannten Kationen mit Ausnahme von Fe(III). Das Ionenaustauschmaterial Cell-AcAc und sein Cu(II)-Komplex wurden durch FT-IR-Spektren charakterisiert.

     

Syntheses,spectroscopic, and magnetic properties of polystyrene-anchored coordination compounds of tridentate ONO donor Schiff base

The crosslinked chloromethylated polystyrene (PSCH₂–Cl) reacts with the Schiff base, derived from condensation of PSCH₂–Cl with 3-formylsalicylic acid and salicylhydrazide to form a polystyrene-anchored Schiff base, PSCH₂–LH₃ (1). Compound 1 reacts with a number of metal ions to form polystyrene-anchored coordination compounds, PSCH₂–LHM?·?DMF (where M?=?Cu, Zn, Cd, UO₂, and MoO₂), PSCH₂–LHM′?·?3DMF (where M′?=?Mn, Co, and Ni), PSCH₂–LHFeCl?·?2DMF, and PSCH₂–LHZr(OH)₂?·?2DMF. The polystyrene-anchored coordination compounds have been characterized by elemental analyses, spectra (infrared, reflectance, and electron spin resonance) and magnetic susceptibility measurements. The polystyrene-anchored compounds are magnetically dilute. Shifts in band positions of the groups involved in coordination have been utilized to find tridentate ONO donor behavior of 1. The polystyrene-anchored Zn(II), Cd(II), Zr(IV), MoO₂(VI), and UO₂(VI) compounds are diamagnetic, while Mn(II), Co(II), Ni(II), Cu(II), and Fe(III) compounds are paramagnetic. The polystyrene-anchored Cu(II) compound is square planar; Zn(II) and Cd(II) compounds are tetrahedral; Co(II), Ni(II), Mn(II), Fe(III), MoO₂(VI), and UO₂(VI) compounds are octahedral; and Zr(IV) compound is pentagonal bipyramidal.     

The extraction of various metals as their anionic complexes with edta by solutions of aliquat-336 chloride in 1.2-dichloroethane

The extraction of anionic complexes of EDTA with Ca. Mg, V(IV), V(V), Cr(III), Mn(II), Mn(III), Fe(III), Co(II), Co(III), Ni, Cu(II), Zn, Cd, Hg(II), Pd(II), Pb and Bi by solutions of Aliquat-336 chloride in 1,2-dichloroethane has been studied as a function of the pH of the aqueous phase. The order and extent of the extractability varies greatly with the pH and provides a number of new possibilities for separation procedures. Thus iron(III) can be separated from many other metals in strongly alkaline solution while the extraction of V(V), V(IV), Hg(II) and Pd(II) exceeds 99% over wide pH ranges. The complex of Mn(III) with EDTA which is very unstable in aqueous solution can be preserved for up to 5 h when extracted by Aliquat-336.One of us (R. H. A1-J.) wishes to thank the Ministry of Oil of the Republic of Iraq for financial support.     

Oximidobenzotetronic acid as a reagent for the separation and gravimetric determination of palladium and cobalt

Oximidobenzotetronic acid is recommended for the separation and gravimetric determination of palladium and cobalt An ethanolic solution of the reagent quantitatively precipitates palladium(II) from solutions which are 0.75 N in acid up to pH 5.1, the complex is weighed as Pd(C₉H₅NO₄)₂. Cobalt(II) can be determined in the filtrate after the precipitation of palladium. With 0.5 N acid solutions, no interference was found from Pt(IV), Ir(IV), Rh(III), Ru(III), Os(IV), Au(III), Ag(I), Cu(II), Fe(III), Ni(II), Hg(II). Pb(II), Bi(III), Cd(II), As(V), Se(VI), Te(IV), Mo(VI), Sb(III), Al(III), Cr(III), Zn(II), Ti(IV), Zr(IV). acetate, oxalate, citrate, tartrate, phosphate and fluoride.     

Chloroform extraction of ethyl xanthate complexes from sulphuric acid media

The chloroform extraction of 30 elements (Fe, Co, Ni, Zn, Cd, Ge, Sn, V, As, Sb, Bi, Cu, Ag, Au, Mn, Re, Ga, In, Tl, Se, Te, Cr, Mo, U, Pt, Pd, Rh, Ir, Ru and Ce) from 0.1-8M sulphuric acid in the presence of potassium ethyl xanthate has been studied. Pd(II), Bi, As(III), Sb(III), Se(IV) and Te(IV) are completely extracted and Au(III) is largely extracted over the range of acid concentration investigated. Fe(II), Tl(I), Rh(III) and Cr(VI) are only slightly extracted and Se(VI), Te(VI), Ru(III), Cr(III), Mn(II), Zn, Ce(IV), Ir(IV) and Ge(IV) are not extracted at all. Depending on the acid concentration, the remaining elements are all partly extracted. Results are compared with those obtained in an earlier study of the extraction of xanthate complexes from hydrochloric acid media. The processes involved in the formation of some xanthate complexes and potential analytical separations are discussed.     

Spectroscopic investigations and physico-chemical characterization of newly synthesized mixed-ligand complexes of 2-methylbenzimidazole with metal ions

Some mixed ligand complexes containing 2-methylbenzimidazole and thiocyanate ion were synthesized. Free ligands and their metal complexes were characterized using elemental analysis, determination of metal, magnetic susceptibility, molar conductivity, infrared, UV-VIS, and (¹H, ¹³C) NMR spectra, and X-ray structure analysis. The results suggest that the Ag(I) complex has linear geometry, Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) have tetrahedral geometry, Pd(II) complex has square planar geometry, VO(IV) square pyramidal geometry, Pb(II) irregular tetrahedral geometry, and that the Cr(III) and Mn(II) complexes have octahedral geometry. The following general formulae were proposed for the prepared complexes: [AgBX], [CrB₃X₃], (HB)₂[MnB₂X₄] · 2B and [MB₂X₂], where B = 2-methylbenzimidazole, HB = 2-methylbenzimidazolium, X = thiocyanate ion, and M = VO(IV), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Cd(II), and Pb(II). Molar conductance of a 10⁻³ M solution in N,N-dimethyl formamide (DMF) indicates that all the complexes are non-electrolytes except the Mn(II) complex which is an electrolyte because the molar conductivity of its solution in DMF is high.     

Luminol-K2S2O8体系中金属离子化学发光行为的研究

报导了在自行设计的流动注射式化学发光分析仪上,对Luminal-K2S2O8体系中32种金属离子的化学发光行为的系统研究.确定了对金属离子的最优测定条件以及大多数金属离子的检出极限和线性范围.     

Synthesis of new ionic β-cyclodextrin polymers and characterization of their heavy metals retention

In this study, a new aqueous insoluble ionic β-cyclodextrin polymer (PYR), synthesized by reaction of β-cyclodextrin with pyromellitic anhydride [1], is characterized by IR spectroscopy, showing typical cyclodextrin and carboxylic absorptions. pH-metric titrations of the acidic functions with standard NaOH solutions followed by a refinement of protonation constants, with specific software for equilibrium in solution, have been performed. Through this approach, the pK _a values of the functional groups have been calculated. The complexation capabilities of PYR towards metal ions [Al(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Cd(II), Pt(IV), Tl(I), and U(IV)] have been evaluated in aqueous solution (pH 3–5). The retention is mainly pH dependent and higher than 70% for Al(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Cd(II) and U(IV). For Tl(I) and Pt(IV) the retention is about 60% and 40% respectively.