Andrzej W. Trochimczuk

Supported imidazolium ionic liquid phases: A new material for solid-phase extraction

This study reports a material that is based on the concept of ionic liquid analogue: a slightly crosslinked polymer-supported imidazolium trifluoroacetate salt (IL-CF(3)COO(-)) that favorably combines the properties of ionic liquids (ILs) and the advantages of a solid support. The ionic liquid-supported material was evaluated for the first time as a solid-phase extraction (SPE) sorbent for selectively and quantitatively extracting pharmaceuticals from aqueous samples. The novel IL-CF(3)COO(-) was evaluated under reversed-phase (RP), weak anion exchange (WAX), strong anion exchange (SAX) and strong cation exchange (SCX) SPE procedures, and we found that SAX conditions are the most suitable for investigating the behaviour of the IL-CF(3)COO(-) material. Under SAX conditions, the IL-CF(3)COO(-) material was capable of selectively and quantitatively extracting a group of acidic compounds from aqueous samples, while washing basic analytes that were also present in the sample. The SPE method using IL-CF(3)COO(-) material was used to analyse 1000 ml of different aqueous samples (ultrapure, tap and river) with complete recovery of the acidic compounds studied. Moreover, the method provided clean chromatogram and high recoveries when percolating complex real samples, such as 1000 ml of river water and 250 ml of effluent wastewater from a sewage treatment plant spiked at low levels with the analytes studied.

CYPHOS IL 101 (Tetradecyl(Trihexyl)Phosphonium Chloride) Immobilized in Biopolymer Capsules for Hg(II) Recovery from HCl Solutions

Abstract A composite polymer (made of gelatin and alginate) was used for the synthesis of Cyphos IL 101-immobilized resins. These resins (with varying size and different ionic liquid (IL) content) have been tested for the recovery of mercury from concentrated HCl solutions (0.1–5 M HCl concentrations). Prior to the study of sorption performance on resins, the reactivity of Cyphos IL 101 versus mercury was tested using solvent extraction methodology. These results showed that the extraction was hardly affected by the concentration of HCl and that an ion exchange mechanism was probably involved in metal recovery (binding of HgCl4 2-). The performance of these resins for Hg(II) recovery was tested through sorption isotherms and uptake kinetics, investigating the effect of resin size, ionic liquid content, metal concentration, agitation speed, and resin state (dry state versus wet state). Sorption capacity (which was proportional to the IL content) can reached up to 150 mg Hg g−1 in 1 M HCl; this sorption capacity was decreased by increasing chloride concentration. The kinetics were described well by the pseudo-second order equation and by the intraparticle diffusion equation (the so-called Cranks equation). The intraparticle diffusion coefficient was in the range of 10−11–1.2 × 10−10 m2 min−1. The kinetic profiles were controlled by the IL content, sorbent dosage, and the sorbent particle size. Drying of the resins significantly decreased diffusion rates in the resins. The presence of competitor metals did not affect sorption capacity except when stable chloro-anionic species such as in the case of Zn(II) were formed. Mercury can be desorbed using 6 M nitric acid solutions; and the sorbent can be recycled for at least six sorption/desorption cycles without significant decrease in the sorption performance.

Highly polar polymeric sorbents: Characterization and sorptive properties towards phenol and its derivatives

Abstract Six porous copolymers of acrylonitrile (AN)/divinylbenzene (DVB) and methacrylonitrile (MAN)/DVB have been synthesised by suspension polymerization in the presence of inert diluents. They have different specific surface area (460–720 m 2 /g for AN/DVB and 560–730 m 2 /g for MAN/DVB) and contain various amounts of the strongly polar nitrile groups. Their sorptive properties have been studied using dilute (0.5 mmol) solutions of phenol and its derivatives ( o -chlorophenol, o -, m - and p -nitrophenol, 2,3- and 2,6-dimethylphenol, p -hydroxyphenol). It has been found that sorption of the most hydrophobic compounds and compounds capable of forming strong intramolecular hydrogen bonds does not depend on the polarity of the polymer surface. Sorption of phenol and m - and p -nitrophenol is stronger on sorbents having more polar groups. The influence of these groups on the sorption process is highly significant in the case of hydrophilic, water soluble sorbates such as p -hydroxyphenol. Polymeric sorbents were characterized using elemental analysis, inverse gas chromatography and their porous structure was characterized by nitrogen adsorption at 77 K.

Immobilization of lipase on various acrylic copolymers

Abstract Polymer carriers with various degrees of hydrophobicity, porosity, and polarity were studied for immobilization of lipase from Candida rugosa. Copolymers and terpolymers were prepared by suspension polymerization of six monomers, ethyl and butyl acrylate, acrylonitrile, methyl methacrylate, 2-hydroxypropyl methacrylate and vinyl acetate, and three crosslinking agents, divinylbenzene, ethylene glycol dimethacrylate and trimethylolpropane triacrylate, in the presence of various diluents. Immobilization of lipase was carried out via glutaraldehyde chemical binding or by adsorption. It was found that the best results were obtained for carriers of butyl acrylate, ethyl acrylate or 2-hydroxypropyl methacrylate crosslinked with ethylene glycol dimethacrylate.

Chelating resins with N-substituted diamides of malonic acid as ligands

Abstract New chelating resins with improved uptake of metal ions have been synthesized by functionalizing a vinylbenzyl chloride–divinylbenzene copolymer with a sodium salt of diethyl malonate followed by reacting modified beads with diamines (ethylenediamine, diethylenetriamine, 2-aminomethyl pyridine, 3-aminopropyl imidazol). Their chelating properties towards Cu(II), Cd(II), Ni(II) and Zn(II) from an acetate buffer of pH 3.7 and 5.6 have been studied. It was found that the sorption of the above cations on studied resins was higher than the sorption on reference ones containing respective N -substituted amides of monocarboxylic acid.

New selective resins with guanidyl groups

Abstract Conditions of reaction between nitrile groups of acrylonitrile/vinyl acetate/divinylbenzene (ANNA/DVB) copolymer and aminoguanidine bicarbonate (AGB) leading to N-substituted amides have been optimized. It has been found that the highest concentration of amino groups can be achieved carrying out aminolysis in the presence of a butanol/water mixture as solvent. Resin obtained under such conditions has 2.20 mmol/g of amino groups and 2.40 g/g water regain. Modified resins display a smaller average pore diameter (5.6 nm) than starting ANNA/DVB copolymer (11.2 nm), indicating that the pore surface is covered with amide gel. When water is used as solvent in aminolysis reaction the degree of modification is smaller and the structure of the resulting resin is similar to that of the starting copolymer. Sorption of Cu(111) on obtained resins is high and proportional to amino group concentration, whereas sorption of Au(CN)2 under alkaline conditions in the presence of excess KCN depends on the structure of the acrylic resin but not on amino group content. Resins which have been modified with AGB in the presence of a butanol/water mixture are 9-times (49.3 mg/g of dry resin) more effective in gold cyanide removal than those modified in water. Other polymers such as: methacrylic acid/trimethylolpropane trimethacrylate (TMPMA), glycidyl methacrylate/TMPMA, glycidyl methacrylate/trimethylolpropane triacrylate and vinylbenzylchloride/styrene/divinylbenzene have been investigated as matrices for aminoguanidine ligands. In the case of the latter polymer, containing 2 wt% of crosslinking agent, sorption of gold cyanide is 55.0 mg/g.

SELECTIVE RECOVERY OF GOLD FROM ACIDIC SOLUTIONS USING RESINS WITH METHYLENEDIPHOSPHONATE AND CARBOXYMETHYLPHOSPHONATE LIGANDS

The polymeric resins with methylenediphosphonate and carboxymethylphosphonate ligands in the ethyl ester form have been synthesized, characterized and used in the removal of Au(III) from hydrochloric acid solutions. It has been found that they are able to adsorb as much as 130–166 mg Au/g of the resin at high concentration of the external solutions. At low concentrations affinity of resins towards gold is very good and the obtained distribution coefficient logarithm is in the range of 4.0–4.4 for the 1×10−4 M Au(III) in 0.25–6.0 M hydrochloric acid solutions. Other metals chlorocomplexes such as Fe(III), Pd(II), Pt(II) and Ag(I) are removed to a lesser extent and the resins do not recognize Cu(II) chlorocomplexes. This allows for the use of the synthesized resins in the selective removal of Au(III) from the concentrated copper solution typically obtained in the processing of the electronic scrap. It has been possible to treat more than 1900 bed volumes of such solution (1×10−4 M Au(III) and 1×10−2 M Cu(II) in 3M HCl) obtaining sorption of 70 mg Au(III) on resin 1 with diphosphonate ligands. This resin has been effectively regenerated using 5 wt.% solution of thiourea in 0.5 M HCl.

Synthesis of functionalized phenylphosphinic acid resins through Michael reaction and their ion-exchange properties

Abstract Novel, functional resins, containing variously substituted phenylphosphinic acid ligands, have been obtained via the Michael reaction. Reaction has been carried out on phenylphosphinic acid resin crosslinked with 2 wt.% of divinylbenzene using the following electrophiles: methyl chloroformate, ethyl bromoacetate, ethyl 2-bromopropionate, ethyl acrylate, ethyl methacrylate, acrylonitrile and methacrylonitrile giving the desired products with 60–97% yield. Resulting resins, having carboxylic acid function in α, β and γ position in respect to the phosphinic group have been used in ion-exchange/coordination of Cu(II), Cd(II), Ni(II), Zn(II) and Eu(III) from nitric acid solutions. It has been found that resins with carboxyl groups in α and β positions display higher divalent metal uptake, when the pH of the solution is above 1.5 and ion exchange is a prevailing process. Resins with either carboxyl or nitrile group in the γ position are less effective in metal ion uptake than the parent, phenylphosphinic polymer. In experiments with Eu(III) uptake from 0.1–1.0 M nitric acid solutions, where resins are supposed to operate mostly through coordination, none of synthesized resins performs better than the phenylphosphinic one. This means that introduction of carboxyl group to the phenylphosphinic acid ligand does not give a synergistic effect in coordination of metal ions.

Influence of the structure of chelating resins with guanidyl groups on gold sorption

Abstract The chemical composition and structure of copolymers determines modification degree, concentration of ligands, their accessibility and hence capacity and selectivity of chelating resins. In order to investigate all such influences, a new series of copolymers have been obtained: one with increased polarity and hydrophilicity of polymer surface has been synthesized from vinyl benzyl chloride (VBC), methyl methacrylate (MM) and divinylbenzene (DVB) mixture, another one with toluene and hexadecane as inert diluents. As was expected copolymers synthesized in the presence of hexadecane, which is thermodynamically poor for the mixture of monomers, are porous with small pores (less than 1.8 nm radius) and with macropores (radius bigger than 17 nm). After modification with aminoguanidine bicarbonate, resins with the ligand concentration in the range 1–2 mmol/g are more hydrophilic but porosity decreases due to the elasticity of networks. The copolymers and resins obtained in the presence of toluene have a gel expanded structure. The ability of resins to remove dicyanoaurate complexes has been tested under the following conditions: an excess of potassium cyanide, 50 mg/l of dicyanoaurate concentration and ratio of aminoguanidine ligands to gold complexes 7.7:1. Under these conditions the sorption for the concentration of ligands of 1.2 mmol/g was about 23 mg/g and for 2.0 mmol/g it was 30 mg/g. Sorption of gold increases with increased ligand content. Sorption of gold at pH 7 is higher than at pH 9.5 and at 13.5 comparable to that at pH 9.5. Lowering dicyanoaurate concentration to 5 mg/l decreases the sorption of gold, but when the ligand to dicyanoaurate anions ratio is 1.1:1 the sorption reaches 30 mg of gold/g, which corresponds to a distribution coefficient of 6900. However, better sorption at low ligand to dicyanoaurate ratio is accompanied by much lower extraction degree and distribution coefficient.

Synthesis and some sorption properties of anion exchangers bearing ligands of different length with guanidyl and biguanidyl end groups

In this work the influence of ligands length with guanidyl and biguanidyl end groups on the performance of anion exchangers is presented. These anion exchangers are synthesized in a two-step reaction. Firstly, the aminolysis of chlorine in a copolymer of vinylbenzyl chloride (VBC) and 2 wt% of divinylbenzene (DVB) with hexamethylenediamine (HMDA) or diethylenetriamine (DETA) is conducted. Thus obtained amine derivatives are subsequently reacted with cyanamide, carbodiimide or sodium dicyanamide. It is found that the most convenient method of biguanidine group introduction into polymer matrix is the reaction of amino groups with sodium dicyanamide. Properties of resins are studied using Cu(II) ions as a spin probe detected by EPR method. A higher complexing ability towards Cu(II) showed by anion exchangers with DETA ligands (DETA resins) is due to chelating function of their ligands. The anion exchanger with HMDA ligands (HMDA resins) requires higher pH (about 7) to provide sufficient number of deprotonated nitrogen donors of monodentate ligands for sorption of Cu(II). The ligands length and their hydrophilicity do not change significantly sorption properties of resins towards dicyanoaurate and tetrachloroaurate.