Features of Cr(III) Cation-Exchange Recovery from Wash Water of Standard Chrome Plating

Features of treatment of the standard chrome plating wash water to remove Cr(III) with KU-1 cation exchanger in the H form were considered. The optimal conditions of Cr(III) recovery and ion exchanger regeneration were determined.     

Aspects of the super-equivalent sorption of glycine by cation exchanger KU-2-8

The structure formed in a sorbent during the super-equivalent sorption of glycine by cation exchanger KU-2-8 is optimized via quantum chemical simulation. The differential thermodynamic characteristics of ion exchange and super-equivalent sorption in the studied system are calculated using a thermodynamic approach that allows us to describe the simultaneous exchange and super-equivalent sorption of compounds by ion-exchangers.     

Sorption of Nickel Ions from Aqueous Solutions by Ion Exchangers

Sorption of Ni²⁺ions from aqueous solutions by ion exchangers differed in their chemical nature and structure was studied. Based on the endothermic curves of ice melting obtained by a differential scanning calorimetry, the amounts of freezing and non-freezing water present in free volumes (pores) of the studied ion exchangers were calculated. Comparison of results obtained from the kinetic curves of nickel ion sorption with data on differential scanning calorimetry indicates a role of structural factor in the sorption of nickel ions. It was found that, depending on the total amount of freezing and non-freezing water, the KU-2-8 sulfonated cationite is the most preferable ion exchanger for the sorption of nickel ions from aqueous solutions. Therefore, sorbent efficiency in this case is determined by its structure rather than by chemical nature.     

Composition,structure, and functional properties of organomineral composite sorbents KU-2×8-ZnS and KU-2×8-PbS

Organomineral composite sorbents KU-2×8-ZnS and KU-2×8-PbS were synthesized on the basis of the matrix of a strongly acidic KU-2×8 cation exchanger. Scanning electron microscopy and elemental analysis were used to study their microstructure and chemical composition. With the use of potentiometric titration, their bifunctional nature was revealed and the dissociation constants and the total exchange capacities of the ionogenic groups were determined. The sorption of copper(II), zinc, and cadmium by KU-2×8-ZnS and KU-2×8-PbS sorbents from 0.005 M solutions of their salts was examined. The total dynamic sorption capacity of the composite sorbents for the above metals, found in the study, exceeds similar values for the individual KU-2×8 cation exchanger by a factor of 1.6–2.0 and that in 0.001–0.050 M solutions of potassium and calcium chlorides, by a factor of 1.3–4.5. An explanation is suggested for the sorption process of heavy nonferrous metals on composite sorbents with an active sulfide component by the mechanism of coordination copolymerization.     

Macroporous anion exchanger purolite A-500 loaded with ferron for palladium(II) recovery

A systematic study on interaction of Pd(II) with 7-iodo-8-hydroxyquinoline-5 sulfonic acid (Ferron) and the strongly basic anion exchange resin Purolite A-500 in its chloride form was carried out. It was found that for Ferron/resin ratio ranging from 0.15 to 0.70 mmol g-1, the retention of chelating reagent on the investigated ion exchanger is practically quantitative. The sorption increase of Pd(II) on Ferron-loaded resin was observed for higher values of parameters like: pH solution, initial concentration and temperature. It was observed that the equilibrium distribution of Pd(II) between sorbent and solution could adequately be described by the Langmuir model with two parameters. The thermodynamic quantities characteristic of Pd(II) sorption process (ΔG = -18.4 kJ mol^-1; ΔH = 11.7 kJ mol^-1; ΔS = 104.4 J mol^-1 K^-1) suggest a strong affinity between Ferron-loaded resin and the tested cation.     

Ion-exchange recovery of palladium(II) from multicomponent chloride solutions

Ion-exchange sorption of palladium(II) from both concentrated aqueous hydrochloric acid solution containing Fe(III), Sn(II), Zn(II), and Cu(II) and weakly acidic concentrated aqueous ammonium chloride solution containing Zn(II) and Cu(II) was studied. The Purolite S920, Purolite S924, and Purolite S984 macroporous resins with the thiourea, thiol, and polyethylenepolyamine functional groups, respectively, were used as sorbents. Strongly basic Purolite A500 anion exchanger was also tested. The desorption of palladium(II) with aqueous ammonia, hydrochloric acid, and acidified aqueous thiourea was examined.     

Sorption behavior of gamma-irradiated silica gel

The effect of Pb(II) and non-ionic surfactants (oxyethylate alcohols OS-10 and ALM-10) on the rate of intraparticle diffusion and on to the equilibrium sorption on Purolite C 106 cation exchanger in hydrogen form was investigated. The sorption of Pb(II) cations and in free state and bonded to the surfactant was measured. The coefficients of intraparticle diffusion were also calculated.     

Kinetics of platinum(II) and platinum(IV) sorption from hydrochloric acid solutions with a complexing ion exchanger containing thiourea functional groups and with a strongly basic anion exchanger

The kinetics of platinum(II) and platinum(IV) sorption from 2 M HCl with Purolite S920 complexing ion exchanger containing thiourea functional groups and Purolite A500 strongly basic anion exchanger was studied in relation to the resin granule size, stirring intensity, and temperature.     

Sorption of mercury(II), zinc(II), and iron(III) thiocyanate complexes on AV-17 anion exchanger and KU-2 cation exchanger modified with rhodamine Zh

Sorption of anionic mercury(II), zinc(II), and iron(III) thiocyanate complexes on KU-2 cation exchanger modified with Rhodamine Zh and on AV-17-8 strongly basic anion exchanger were studied in relation to the concentration of SCN^? ions and solution pH. Optimal conditions of sorption of metal complexes from dilute solutions were found.     

Test Determination of Cu(II), Ni(II), and Cr(VI) in a Single Sample

It was shown that Cr(VI), Ni(II), and Cu(II) can be simultaneously adsorbed on a solid phase consisting of two filled fibrous disks and then determined visually using organic reagents. One sorbent disk, a fibrous material filled with an AB-17 anion exchanger, was used to determine chromium by its reaction with 1,5-diphenylcarbazide. Another disk filled with an KU-2 cation exchanger was used for the simultaneous sorption of copper and nickel followed by the consecutive determination of nickel with dimethylglyoxime and copper with sodium diethyldithiocarbamate. The conditions were optimized for the determination of nickel in the presence of copper and of copper in the presence of nickel after decomposing its dimethylglyoxime complex with 1 M HCl. The detection limits were 0.02, 0.1, and 0.05 mg/L for Cr, Ni, and Cu, respectively. The time of analysis was no longer that 20 min.     

Dynamics of Copper(II), Nickel(II), and Iron(III) Ion Exchange

The degree of utilization of the static exchange capacity of KU-2×8×12 cation exchanger with respect to copper(II), nickel(II), and iron(III) cations was considered as a function of the solution flow velocity through the column cross section.     

Complexation of vanadium(IV) with organic reagents on the solid phase of fibrous ion exchangers according to diffuse reflectance and EPR data

Diffuse reflectance and EPR spectroscopic data are reported for the formation of vanadium complexes with the organic reagents (ORs) sulfochlorophenol S (SCP) and pyridylazoresorcinol (PAR) on the solid phase of polyacrylonitrile fiber filled with the cation exchanger KU-2 or the anion exchanger AV-17 or A-5. The effects of the order of sorption of the reaction components, sorption conditions, and the V: OR ratio on the complexation process are discussed. The characteristics of the complexes obtained on the solid phase and in solution are compares. Both M : OR = 1 : 1 and M : OR = 2 : 1 SCP complexes can form on the solid phase without involving any croups of the matrix. PAR forma a 1 : 1 complex involving groups of the A-5 matrix.     

Ion exchange extraction of platinum(IV) and palladium(II) from hydrochloric acid solutions

Sorption concentration of platinum(II, IV) and palladium(II) from freshly prepared and aged two-yearold hydrochloric acid solutions by a series of anion exchangers with different functional groups and of different physical structure of Purolite and CYBBER grades was studied. The high sorption ability of the ion exchangers in relation to the extracted chlorocomplexes of noble metals is shown. It was demonstrated that palladium(II) from all tested ion exchangers can be completely desorbed with thiourea solutions acidified with hydrochloric acid, while complete desorption of platinum is achieved only from Purolite S 985 anion exchanger of the complexforming type and Purolite A 111 weak base anion exchanger.     

Sorption-spectroscopy determination of zirconium on a PANV-KU-2 fibrous ion exchanger using Arsenazo III

The sorption and complexation of zirconium with Arsenazo III have been studied on a polyacry-lonitrile fibrous material filled with strongly acidic KU-2 cation exchanger in strongly acidic media. The optimal conditions have been chosen for the sorption-spectrophotometric and test determination of zirconium by diffuse reflection spectroscopy or visual testing. The limit of zirconium detection is 0.02 ??g/mL. The procedure was tested in the analysis of model solutions of ammonium molybdate and vanadate and copper chloride using the standard addition method.     

Interpretation of hypsochromic and bathochromic shifts of vibrational frequencies of a cation exchanger

Structures of a representative fragment of a sulfocation exchanger in the form of alkali metal salts were optimized using the Gaussian-03 program package. Frequencies of stretching vibrations of the sulfo group were calculated for structures of the contact ion and hydrate-separated ion pairs. A comparison of the calculated and experimental values of hypsochromic (bathochromic) shifts of the frequencies of stretching vibrations of the sulfo group due to the cation field suggests that the ion pair in the studied systems dissociates. The calculated IR spectra of the representative fragment of the sulfocation exchanger can be used as calculated benchmarks in analyzing substances using expert systems.     

Computer simulation of the hydration of sulfocation exchanger containing imino acid

The mechanism of formation of hydrate structures in the system sulfo exchanger-imino acid was suggested. The mutual position of fixed ion, imino acid, and water molecules was determined in cation exchanger. The conclusion was made on the presence of water molecule between the functional group of sorbent and counterion of imino acid. It was demonstrated that the mechanism of sorption of proline and hydroxyproline is performed by the break of bond between water molecules and protonation of carboxylic group of imino acid.     

Hydration of purolite S950 ion exchanger in deprotonated forms

A quantitative evaluation of the degree of hydration, including the ratios of water with different energies in the phase of the aminophosphonic exchanger Purolite S950 in sodium, copper, and nickel forms is conducted. The changes in the Gibbs free energy and enthalpies of hydration and dehydration are determined. It is found that the amount of bound water decreases upon the transition from nickel to copper, especially to the sodium forms of the ion exchanger, and that changes in the Gibbs energy and enthalpy are greatest upon the hydration of the sodium form of polyampholytes.     

Structural analysis of a sulfo cation exchanger in the form of glycine

A quantum chemical and molecular dynamics simulation of a fragment of the sulfo cation exchanger in the form of glycine is performed. It is found that in the system studied an ionic pair dissociates.     

Influence of Humus Acids on Physicochemical Features of KU-2×8 Cation Exchangers

In prolonged industrial desalination of natural water with KU-2×8 cation exchanger, humic and fulvic acids are accumulated on the resin, which deteriorates its sorption characteristics, desalination efficiency.