Effect of Cationic Form of a Fibrous Sulfonic Cation-Exchange Resin on Sorption of Tetramminepalladium(II) and Its Cross-Sectional Distribution

The effect of the nature of exchangeable cation (Na⁺, Mg^{2 +}, Ba^{2 +}, La^{3 +}) in FIBAN K-1 fibrous sulfonic cation-exchange resin on sorption of tetramminepalladium(II) and its cross-sectional distribution in fabrication of Pd catalysts is studied.     

Comparative Study of Water Softening with Granular and Fibrous Ion Exchangers

Comparative study of softening of model hard water with both strongly acidic fibrous FIBAN K-1 and granular KU-2 ion exchangers was carried out. The influence of the filter-bed height, packing density of fibrous ion exchangers, volume sorption capacity, and filtering rate on the efficiency of calcium removal from model hard water was analyzed.     

Activity of Palladium Catalysts Based on FIBAN K-1 Fibrous Sulfonic Cation Exchanger in Reaction of Hydrogen Oxidation

For palladium catalysts based on FIBAN K-1 fibrous sulfonic cation exchanger (Li⁺, Na⁺, Rb⁺, Cs⁺,Mg²⁺,Ca²⁺, Ba²⁺ forms) the dispersity and depth distribution of palladium metal in the fiber and the activity of the catalyst in hydrogen oxidation were studied in relation to the conditions of the synthesis and activation.     

Forward ion-exchange kinetics of heavy metal ions on the surface of carboxymethyl cellulose Sn(IV) phosphate composite nano-rod-like cation exchanger

The Nernst?CPlanck equations with some additional assumptions was used in this study to investigate the forward kinetics and ion-exchange mechanism of heavy metal ions viz. Ni²⁺?CH⁺, Cu²⁺?CH⁺, Mn²⁺?CH⁺ and Zn²⁺?CH⁺ on the surface of carboxymethyl cellulose Sn(IV) phosphate composite nano-rod-like cation-exchanger. It was observed that heavy metals' exchange processes were imparted by the particle diffusion-controlled phenomenon. Some physical parameters i.e., fractional attainment of equilibrium U(??), self-diffusion coefficients (D _o), energy of activation (E _a), and entropy of activation (??S*) were estimated. These investigations revealed that the equilibrium is attained faster at higher temperature probably because of availability of thermally enlarged matrix of carboxymethyl cellulose Sn(IV) phosphate composite nano-rod-like cation-exchange material. The physical parameters observed for this composite cation exchanger were also compared with other composite ion exchangers. The results showed that the ion-exchange phenomenon is more feasible on the surface of this composite cation exchanger as compared with the other ion exchangers which indicated the usefulness of this composite ion exchanger in various applications.     

Occlusion of transition metal ions by new adsorbents synthesized from plant polyphenols and animal fibrous proteins

Removing and collecting heavy and rare metal ions from industrial effluents and waste aqueous solutions are improtant problems. Our previous studies showed that animal fibrous proteins (AFPs) such as hen eggshell membrane, chicken feather (CF), wool, and silk were stable and insoluble proteins and had an excellent ability to bind not only hard (Mn²⁺ and Fe³⁺) but alsosoft (Ag⁺, Au⁺, Pd²⁺, Pt²⁺, and Hg²⁺) acids from aqueous solutions. In this study, we syntheszed some adsorbents for transition (Cr⁶⁺, Mn²⁺, Co²⁺, Ni²⁺, and Cu²⁺) and heavy (Cd²⁺) metalions from AFPs (gelatin, CF, and wool) and plant polyphenols (lignin and tannin) by heating a mixture of AFPs and plant polyphenols under acidic conditions. In batch experiments, pH profile, time dependency, and isotherm analysis were performed to determine binding properties of adsorbents for transition and heavy metal ions. Columnexperiments were also performed to removecopper ion from aqueous solution. The results showed that the new adsorbents were effective for collecting and removing transition and heavy metal ions from aqueous solutions.     

Catalytic activity of iron hydroxides and manganese hydroxides in the deoxygenation of water

Catalysts prepared by the modification of FIBAN K-4 and FIBAN X-1 fibrous ion exchangers with the hydroxides of iron and manganese were developed and tested in a water deoxygenation process. It was established that the samples obtained by the supporting of Fe(III) hydroxide onto the FIBAN X-1 ampholyte were most effective. The conclusion that the high activity of the catalytic system is caused by the formation of a mixed phase of Fe(II) and Fe(III) hydroxides of the spinel type containing mobile (weakly bound) lattice oxygen was made. A reaction scheme was proposed to explain the reaction mechanism.     

Complexes of Di‐ and Triazacrown Ethers with Heavy Metal Ions in Water Solution

This research concerns the analysis of the metal ion binding of benzo‐ and pyridine‐azacrown ether compounds of different structures and sizes by potentiometric method. The ligands are able to form 1 : 1 complexes with heavy metal ions (Cu⁺², Pb⁺², Cd⁺², Ag⁺, Ni⁺², Zn⁺²) in water of middle or high stability. To understand the selectivity in cation binding, different factors were considered.     

2,4‐Dichlorophenyl Acrylate/8‐Quinolinyl Methacrylate Copolymers: Ion‐Exchange Study

The chelating ion‐exchange properties of the 2,4‐dichlorophenyl acrylate (2,4‐DCPA)/8‐quinolinyl methacrylate (8‐QMA) copolymers, synthesized using different monomer feed ratios, were investigated by the batch equilibrium method. Five metal ions Cu⁺², Ni⁺², Co⁺², Zn⁺², and Fe⁺³ were used to evaluate the cation‐exchanger capability of 2,4‐DCPA‐co‐8‐QMA copolymers. The ion‐exchange study was carried out for three different experimental variables viz., pH of the aqueous medium, ionic strength of electrolyte and shaking time. It was observed that due to the presence of a pendant ester‐bound quinolinyl group, the copolymers are better suited as cation exchangers.     

Radiochemical studies of the sorption behavior of strontium and barium

The sorption behavior of strontium and barium on kaolinite, bentonite and chlorite-illite mixed clay was studied by radioanalytical techniques using the batch method.⁹⁰Sr (29.1 y) and¹³³Ba (10.5 y) were used as radiotracers. Characterization of the solid matrices was done by FTIR and XRD spectrometries and specific surface area measurements. Synthetic groundwater was used as the aqueous phase. The variation of the distribution ratioR _d, as a function of metal ion loading was examined. The sorption isotherms were fitted to various isotherm models. The sorption energies were calculated to be in the range of 8–10 kJ/mol suggesting an ion exchange type of sorption mechanism. In detailed experiments, chlorite-illite mixed clay was first presaturated with K⁺, Sr²⁺, Ca²⁺ and Al³⁺ ions, respectively, prior to sorption studies with Ba²⁺ ions. The results of Ca²⁺ pretreated chlorite-illite were very similar to those of natural chlorite-illite, suggesting that the Ba²⁺ ion exchanges primarily with the Ca²⁺ ion on the clay minerals.     

Ratiometric and turn-on monitoring for heavy and transition metal ions in aqueous solution with a fluorescent peptide sensor

A novel fluorescent peptide sensor containing tryptophan (donor) and dansyl fluorophore (acceptor) was synthesized for monitoring heavy and transition metal (HTM) ions on the basis of metal ion binding motif (Cys-X-X-X-Cys). The peptide probe successfully exhibited a turn on and ratiometric response for several heavy metal ions such as Hg²⁺, Cd²⁺, Pb²⁺, Zn²⁺, and Ag⁺ in aqueous solution. The enhancements of emission intensity were achieved in the presence of the HTM ions by fluorescent resonance energy transfer (FRET) and chelation enhanced fluorescence (CHEF) effects. The detection limits of the sensor for Cd²⁺, Pb²⁺, Zn²⁺, and Ag⁺ were lower than the EPA's drinking water maximum contaminant levels (MCL). We described the fluorescent enhancement, binding affinity, and detection limit of the peptide probe for HTM ions.     

Study of Sorption Properties for Lead(II) Ions Exhibited by Anion Exchangers Synthesized on the Basis of Aromatic Hydrocarbons,Epichlorohydrin, and Polyethyleneimine

Aromatic hydrocarbons, epichlorohydrin, and polyethyleneimine were used to synthesize polyfunctional anion exchangers. IR spectroscopy and elemental analysis were used to examine their composition and structure. The method of classical polarography was employed to examine the process of extraction of lead ions and determine the dependences of the sorption of lead(II) ions in the static mode on the solution acidity, concentration of metal ions, and duration of contact between ion exchangers and a Pb(NO₃)₂ solution. It was found that the ion exchangers possess high sorption properties for lead ions.     

Ion-exchange behavior of stannic selenoiodate and stannic selenosilicate: analytical application of stannic selenoiodate

Two new inorganic ion exchangers, stannic selenoiodate and stannic selenosilicate have been synthesized. The ion-exchange capacity of stannic selenoiodate and stannic selenosilicate for K⁺ was found to be 1.84 and 1.23 meq g^–1, respectively. pH titration studies reveal monofunctional and bifunctional behavior for stannic selenosilicate and stannic selenoiodate, respectively. Distribution coefficients of metal ions in dimethylformamide–HCl and formamide–HCl systems have been determined. Some important and analytically difficult quantitative binary and ternary separations, and selective separations of Ag⁺, Sn⁴⁺, Zr⁴⁺, Co²⁺, and Ni²⁺ have been achieved on stannic selenoiodate columns. The practical utility of the material has been demonstrated by analyzing the metal ion content of electroplating waste.     

Performance of anion exchangers based on aniline,epichlorohydrin, and polyamines in sorption of molybdenum(VI) ions

Polyfunctional anion exchangers based on aniline, epichlorohydrin, and some polyamines were synthesized. The composition and structure of the anion exchangers were studied by IR spectroscopy and elemental analysis. Molybdenum sorption was studied by classical polarography, and dependences of the sorption of molybdenum(VI) ions on the solution acidity, concentration of metal ions, and time of contact of the resins with the Na₂MoO₄ solution were determined in batch experiments. These ion exchangers exhibit high performance in sorption of molybdenum ions. The developed sorbents with increased sorption ability can successfully solve problems of removing molybdenum(VI) ions from process effluents in nonferrous metallurgy.     

Effect of temperature on the sorption behavior of sodium potassium fluorophlogopite with respect to the heavy metal ions Cd<Superscript>2+</Superscript>, Hg<Superscript>2+</Superscript>, and Pb<Superscript>2+</Superscript>

The effect of temperature on the sorption behavior of a synthesized gel structurally close to the fluorine mica mineral, sodium potassium fluorophologopite, was studied for the heavy metal ions Cd²⁺, Hg²⁺, and Pb²⁺. The synthesized gel was characterized by X-ray powder pattern, energy dispersive spectrometry, infrared spectroscopy, and thermogravimetric analysis and was found to have the composition Na_0.5K_0.5Mg(AlSi₃O₁₀)F₂·6H₂O. The effect of temperature on sorption was studied with respect to varying concentrations of metal ions. The overall sorption capacity of the synthesized gel was found to depend on the number of ion active groups per unit weight of the material. The data were expressed in terms of distribution coefficients (K _d). Sorption data followed Freundlich adsorption isotherms. Studies showed that sorption decreased as the concentration of metal ions increased and increased as the temperature grew, which was evidence that the process was endothermic. The text was submitted by the authors in English.     

Potentialities of fibrous ion-exchange materials in the determination of sulfate ions by color reactions of barium with organic reagents on a solid phase

The possibility of the determination of sulfate ions with the use of fibrous materials filled with ion exchangers on the basis of color reactions of barium with the organic reagents Arsenazo III, Orthanilic B, and Orthanilic K on a solid phase was examined. A polyacrylonitrile fiber filled the cation exchanger KU-2; anion exchangers AB-17, A-5, ANKF-211, and EDE-10p; and polyampholyte ANKB-50 (PANV-ANKB-50) was used as the support. The study of the different techniques of the sorption of the reaction components demonstrated the efficiency of the two systems involving PANV-ANKB-50. The determination of sulfates is possible because of the sorption of the excess barium remaining after the reaction with sulfate ions in the solution and its detection on the solid phase with a solution of Arsenazo III or the detection of the excess barium remaining after the interaction with the solution of sulfate ions on the solid phase with a solution of Orthanilic K. The calibration plots are linear in the concentration range of sulfate ions 10^?4–10^?5 M.     

Study of the interaction of mono-, di-, and trisubstituted sodium orthophosphates with thermally activated dolomite

Interaction of dolomite thermally treated at 800°C with solutions of mono-, di-, and trisubstituted sodium phosphate was studied. It was shown that thermally treated dolomite binds 0.75 to 3.0 mmol g^–1 of phosphorus, depending on the nature of a phosphating reagent, and the interaction mostly occurs with magnesium oxide, which enables use of this kind of dolomite as a sorbent of phosphate ions. It was found that the nature of the phosphating reagent affects the chemical and phase composition of the materials obtained, as well as their sorption properties with respect to heavy metal ions. The products formed in acid-free phosphation of dolomite have high sorption capacity, from 1.5 to 6.8 mmol g^–1 for Pb²⁺, Zn²⁺, Cu²⁺, Cd²⁺, Ni²⁺, Sr²⁺, and Co²⁺ ions, which enables their use as effective sorbents for heavy metal ions.urning.     

Synthesis and metal extraction behavior of pyridine and 1,2,4-triazole substituted calix[4]arenes

Three series of heterocycle substituted calixarenes, derivatized at lower and upper rim, were synthesized and successfully evaluated for metal extraction towards alkali, alkaline, transition and heavy metal ions. The presence and placement of sulfur, heterocycle functionality at upper/lower rim played a crucial role toward the extractability and selectivity of metal ions. The lower rim substituted calixarenes have shown high extractability and poor selectivity. In contrast to this, upper rim substituted calixarenes exhibited good selectivity. Moreover, sulfur functionalized calixarenes have shown better selectivity for heavy metal ions than alkali and alkaline metal ions. Among upper rim substituted calixarenes, 17 and 18 were found to be suitable for Na⁺, K⁺ and Ag⁺, 19,13 for heavy metal ions i.e., Pb²⁺, Hg⁺, Hg²⁺ and Ag⁺, and 11,12 for Pb²⁺ and Ag⁺ only.     

Study of the structure of chelate fibrous ionites by IR spectroscopy

Structure of fibrous chelate ion exchangers FIBAN X-1 and FIBAN X-2 prepared by a two-step synthesis was studied by IR Fourier spectroscopy. The first step of the ion exchanger preparation consists in the production of an aminated fiber (AF). The process can be carried out in different phases: either vapor, or aqueous. It is found that conditions of the synthesis of AF affect differently the ion exchanger structure. For the ion exchanger FIBAN X-1 it does not a matter in which phase is AF synthesized, and the FIBAN X-1 sorbent has amidoamine structure. The structure of chelate ion exchanger FIBAN X-2 depends on the conditions of the synthesis of AF. When the process is carried out in aqueous medium the FIBAN X-2 has amidoamine structure, while amination in the vapor phase leads to formation of the FIBAN X-2 ion exchanger mainly containing in its structure imidazoline rings.     

Determination of orders of relative alkali metal ion affinities of crown ethers and acyclic analogs by the kinetic method

Ladders of relative alkali ion affinities of crown ethers and acyclic analogs were constructed by using the kinetic method. The adducts consisting of two different ethers bound by an alkali metal ion, (M₁ + Cat + M₂)⁺, were formed by using fast atom bombardment ionization to desorb the crown ethers and alkali metal ions, then collisionally activated to induce dissociation to (M₁ + Cat)⁺ and (M₂ + Cat)⁺ ions. Based on the relative abundances of the cationized ethers formed, orders of relative alkali ion affinities were assigned. The crown ethers showed higher affinities for specific sizes of metal ions, and this was attributed in part to the optimal spatial fit concept. Size selectivities were more pronounced for the smaller alkali metal ions such as Li⁺, Na⁺, and K⁺ than the larger ions such as Cs⁺ and Rb⁺. In general, the cyclic ethers exhibited greater alkali metal ion affinities than the corresponding acyclic analogs, although these effects were less dramatic as the size of the alkali metal ion increased.     

New tetrapyrazolic macrocycle. Synthesis and preliminary use in metal ion extraction

A new macrocycle containing two bipyrazolic units, with a side-arm bearing an attached donor-group is reported. The complexing properties of this compound towards heavy metal ions (Hg²⁺, Cd²⁺, Pb²⁺) and alkaline metal ions (Ca²⁺, Cs⁺, K⁺, Na⁺, Li⁺) was studied by a liquid-liquid extraction process and the extracted cation percentage was determined by atomic absorption measurements and UV spectroscopy.