Hypercrosslinked Polystyrene Sorbents Research Articles

The Use of Hypercrosslinked Polystyrene Sorbents in Extraction of Valuable Components from Nitric Acid Leach Solutions of Eudialyte Concentrate

The Use of Hypercrosslinked Polystyrene Sorbents in Extraction of Valuable Components from Nitric Acid Leach Solutions of Eudialyte Concentrate

Combined Physicochemical and Energy Methods to Improve the Recovery of Rare Earth Elements from Eudialyte Concentrate

The parameters for efficient nitric acid leaching were experimentally determined, which ensured the recoveries of Zr and REEs from eudialyte concentrate up to 87.0%–91.7% and 76.0%–81.1%, respectively. The possibility was shown of intensifying the leaching process through preliminary energy treatments to ensure the intensive breakdown of mineral complexes and grains; as a result, the recovery of Zr and REEs increased by more than 10%. A process was developed for the selective recovery of up to 91.5% of zirconium and up to 71.2% of REEs in the form of carbonate compounds from the pregnant solution of nitric acid leaching by chemical precipitation as well as up to 81.1% REEs and up to 91.7% zirconium on hypercrosslinked polystyrene sorbents.

Microporous Hypercrosslinked Polystyrene Sorbents in Sorption Purification of Water-Soluble Polymers from Low-Molecular-Weight Compounds

Microporous Hypercrosslinked Polystyrene Sorbents in Sorption Purification of Water-Soluble Polymers from Low-Molecular-Weight Compounds

Capabilities of size exclusion chromatography (in off- and on-line modes) to reduce matrix effects in ICP-MS analysis of complex solutions

The analytical capabilities of frontal size exclusion chromatography are studied using neutral polystyrene sorbents. When studying the separation of mineral acids and their salts, it is shown that clear separation of the zone of thorium ions and rare-earth elements from the following acid zone is observed on the microporous hypercrosslinked polystyrene sorbents Purolite NN-381 and MN-270. However, separation of the ions of highly charged elements (Zr, Hf, Nb, Ta) from the acid on the studied Purolite sorbents failed. Peaks of significant self-concentration appear in the zone of thorium and rare-earth element release at a concentration of 0.1 – 50 μg/liter. The factors affecting concentration of the analytes were studied. The nature and concentration of the acid, as well as concentration of the analytes, affect the concentration coefficients which attain maximum values in the solutions of nitric acid compared to hydrochloric and phosphoric acids. The degree of analyte concentration depends on the structure of internal pores and dispersion of the sorbent, as well as on the rate of solution passage through the column. Macro-components of seawater are not retained or concentrated on hypercrosslinked polystyrene. Sodium and magnesium at a concentration of 0.1 wt.% do not affect the value of the concentration factor of the target analytes. After chromatographic separation, weakly acidic fractions of the solution with concentrated ions of REE and thorium can be obtained by simple passing of a portion of the test solution through the sorbent layer for 15 – 30 min. The resulting concentrate can be directly introduced into a mass spectrometer. The possibility of combining chromatographic separation and concentration of elements and on-line ICP-MS detection is studied. Optimal conditions for on-line detection have been selected; the accuracy of the developed approach is demonstrated in the determination of rare earth elements in seawater using the spiked test.

Magnetic sorbents based on hypercrosslinked copolymers of styrene and divinylbenzene with immobilized iron oxides

Magnetic sorbents were obtained by the immobilization of iron oxides into the pores of hypercrosslinked polystyrene sorbents via chemical precipitation. Various types of industrial Macronet and Amberlite adsorbents and the synthesized hypercrosslinked styrene-divinylbenzene copolymer were used as a porous polymer matrix. The volume fraction of the inorganic phase in the composites was 2.2–8.3 vol%. According to X-ray phase analysis and transmission electron microscopy, the inorganic phase in the sorbents was magnetite and the size of magnetite nanocrystallites was 3–16 nm. The structural studies of the composite sorbents by scanning electron microscopy/energy-dispersive X-ray spectrometry demonstrated a uniform distribution of nanodispersed iron oxides over the volume of sorbent granules. Investigation of the porous structure of magnetic sorbents by the low-temperature nitrogen sorption showed that the composites have a well-developed system of pores with a specific pore area of up to 1400 m2 g−1 and the volume of micropores (<3 nm) up to 0.6 cm3 g−1. The sorbent porosity parameters were calculated using methods based on the capillary condensation theory and the quenched solid density functional theory. Analysis of pore size distributions revealed that several specific pore “fractions” are present in the porous system of the magnetic sorbents. Micropores up to 2.5 nm in size were characteristic of all the studied sorbents; for some sorbent types, two to three additional “fractions” of mesopores up to 10 nm in size and macropores with sizes above 50 nm were detected. In the magnetic sorbents, the total pore volume was 0.4–1.0 cm3 g−1 and the mesopore volume was 0.2–0.6 cm3 g−1. It was found that the magnetic sorbents can adsorb toxic organic compounds of various classes: alcohols, ethers, and aliphatic, aromatic, and chlorine-containing hydrocarbons (from 0.4 to 1.0 mL cm−3). The obtained composite sorbents show promise for the purification of liquid, gaseous, and solid media by the magnetic separation method.

The use of hypercrosslinked polymer sorbents and composites based on them in the sorption of toxic and bad-smelling substances

The sorption of cadaverine from the air on hypercrosslinked polystyrene sorbents was investigated. An available technique for the introduction of iron oxide into the polystyrene matrix was proposed. The sorbents showed high capacity for cadaverine extraction from the air, and the iron-containing sorbent was quite universal and can be used to extract nicotine, scatol and hydrogen sulfide.

Principles and Perspective Applications of Preparative Ion Size Exclusion Chromatography on Neutral Hypercrosslinked Polystyrene Sorbents. A Selective Mini-Review

Principles and Perspective Applications of Preparative Ion Size Exclusion Chromatography on Neutral Hypercrosslinked Polystyrene Sorbents. A Selective Mini-Review

Sorption–Mass Spectrometry Determination of Platinum Metals in Basic Rocs and Ores

The results of a systematic study of sorption systems for the reversible group extraction of Ru, Rh, Pd, Ir, and Pt and their subsequent determination by inductively coupled plasma mass spectrometry are presented. The sorption system includes an sorbent, a reagent, and a desorbing solution. Purolite MN-200, НP, and Styrosorb hypercrosslinked polystyrene sorbents and Strata sorbents with immobilized nitrogen atoms were studied. Various aliphatic and aromatic amines were used as ion-pair amine reagents for the sorption extraction of PGMs. A possibility of the desorption of Ru, Rh, Pd, Ir, and Pt complexes with reagents of different nature was studied. Sorption systems were selected for the preconcentration of PGMs from solutions obtained after the decomposition of rocks. A flow-injection method for introducing high-salt and organic solutions into a mass spectrometer was proposed. Possible spectral and nonspectral effects were investigated, and the conditions for quantifying Ru, Rh, Pd, Ir, and Pt in the obtained preconcentrates were selected.

Investigation of the new sorption preconcentration systems for determination of noble metals in rocks by inductively coupled plasma–mass spectrometry

The reversible sorption preconcentration of noble metals (NMs) prior to their determination by inductively coupled plasma–mass spectrometry (ICP-MS) was investigated. Six new hypercrosslinked polystyrene sorbents were tested. The dependence of the degree of NMs sorption on the average degree of polymer network crosslinking and pore diameters was investigated. It was found that sorbents HP-100/6, HP-300/6 and HP-500/6 have low efficiency of NMs chlorocomplexes extraction. Among Stirosorb sorbents (Stirosorb-2, Stirosorb-514 and Stirosorb-584) the highest efficiency of the extraction of NMs’ chlorocomplexes has Stirosorb-514. Tributylamine (TBA), N-methylbenzylamine (MBA), N,N-dimethylbenzylamine (DMBA), N,N-dibenzylmetylamine (DBMA) were studied as the reagents for extraction of Ru, Rh, Pd, Ir, Pt and Au chlorocomplexes from hydrochloric acid solutions in the form of ion associates by reversed-phase mechanism. The reversible quantitative extraction of Ru, Pd, Pt and Au in system Stirosorb-514 – TBA – 1M HCl in ethanol as eluent was achieved. It was found that resulting eluates do not contain matrix components which may cause spectral interferences on the stage of NMs determination by ICP-MS. The found scheme of NMs reversible sorption was validated by the analysis of certified reference materials of basic and ultrabasic rocks GPt-5, GPt-6 and SARM-7. Good agreement between the measured NMs concentrations and the certified values was demonstrated. The achieved limits of detection for Ru, Pd, Pt and Au vary within 10−8–10−7wt% range.

Green chromatographic techniques: separation and purification of organic and inorganic analytes

Saving Solvents in Chromatographic Purifications: The Counter-current Chromatography Technique.- Ion Size Exclusion Chromatography on Hypercrosslinked Polystyrene Sorbents as a Green Technology of Separating Mineral Electrolytes.- Supercritical Fluid Chromatography: A Green Approach for Separation and Purification of Organic and Inorganic Analytes.- High Performance Thin-layer Chromatography.- Green Techniques in Gas Chromatography.- Preparation and Purification of Garlic-Derived Organosulfur Compound Allicin by Green Methodologies.- Green Sample Preparation Focusing on Organic Analytes in Complex Matrices.- Studies Regarding the Optimization of the Solvent Consumption in the Determination of Organochlorine Pesticides from Complex Fodder.- Size Exclusion Chromatography- A Useful Technique for Speciation Analysis of Polydimethylsiloxanes.

Selectivity in preparative separations of inorganic electrolytes by size-exclusion chromatography on hypercrosslinked polystyrene and microporous carbons

Preparative-scale separation of concentrated solutions of simplest mineral electrolytes by size-exclusion chromatography was performed on three samples of commercially available microporous hypercrosslinked polystyrene sorbents “Macronet Hypersol” and two experimental samples of activated carbons. Selectivity of separation of a pair of electrolytes was found to be determined by the largest ions in each pair. Fortunately, selectivity rises at higher concentrations of electrolytes, which was explained by exclusion of smaller species from the concentrated solution, i.e., mobile phase, into small pores of the column packing that are inaccessible to large species. The separation of concentrated mixtures revealed another remarkable advantage of the new process – self-concentrating of each of two separated components in the corresponding fractions. Self-concentration is more pronounced for the minor component that occupied less space in the initial mixture. The new method may prove productive in processing pickle bath solutions.

A study of the adsorption properties of the hypercross-linked polystyrene sorbents Styrosorb by gas chromatography. Effect of the conditioning temperature

The effect of the conditioning temperature of the hypercross-linked polystyrene sorbents Styrosorb on the retention ofn-hexane, benzene. and acetone was studied by gas chromatography. The rigid but mobile structure of 100% cross-linked polymers with a specific surface area of 300–500 m2 g−1 prepared in cyclohexane slightly shrinks by conditioning above 200 °C. This results in a significant increase in the specific retention volumes of the adsorbates. The commercial hypercross-linked sorbents MN-100 and MN-200 with specific surface areas of −1000 m2 g−1 retain their structure up to 250 °C.

Sorption of organic compounds from aqueous media by hypercrosslinked polystyrene sorbents ‘Styrosorbrs

Sorption experiments with a variety of organic compounds dissolved or suspended in water and a new hypercrosslinked polystyrene-type sorption material ‘Styrosorb’ (‘Macronet-Hypersol’) showed superiority of the latter to other chemically related adsorbents

Use of the hyper-crosslinked polystyrene sorbents ?Styrosorb? for solid phase extraction of phenols from water

The analytical HPLC procedure for the quantitation of trace amounts of phenol and chlorophenols in aqueous media has been supplemented with the on-line preconcentration of phenols in a sorption cartridge packed with microporous hyper-crosslinked polystyrene. The cartridge is coupled in succession with a reversed-phase analytical column, which is operated isocratically in an aqueous acetonitrile eluent (1:1, v/v). Phenol concentrations down to 0.5 μg/l can be detected using a simple 254 nm UV detector.