Search Results (6)

The aim of this work was to develop an effective method for obtaining perrhenic acid from available ammonia waste solutions using the solvent extraction method. An ammonia waste solution was used as the test material, with Re and NH₄⁺ concentrations of 13.5 and 43.7 g/dm³, respectively. The scope of this study includes the following: the selection of an appropriate extractant for testing, and the examination of the impact of individual parameters on the efficiency and selectivity of extraction and stripping. The obtained results made it possible to determine the conditions for the production of perrhenic acid via the extraction method using organic solutions of trihexyl(tetradecyl)phosphonium chloride (Cyphos IL 101). The outcome of this study was the development of a method for obtaining perrhenic acid and the production of the acid sample with an efficiency of >90% and a Re concentration of >100 g/dm³. Full article

Six quaternary phosphonium salts (QPSs) in combination with phosphotungstic heteropolyacid, H₃PW₁₂O₄₀, were tested in the epoxidation of rapeseed oil fatty acid methyl esters with a hydrogen peroxide aqueous solution. The QPSs consisted of trihexyl(tetradecyl)phosphonium [P6], tributyl-tetradecylphosphonium [P4] or tetraoctylphosphonium [P8] cation and different anions—chloride (Cl⁻), bromide (Br⁻), tetrafluoroborate (BF₄⁻), bis(trifluoromethylsulfonyl)amide (NTf₂⁻), bis(2,4,4-trimethyl-pentyl)phosphinate (Phosf⁻). The influence of the kind of QPS and temperature on the epoxy number, iodine number, glycol content has been determined. The epoxidation was confirmed using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and elemental analysis CHO. Two QPSs with a trihexyltetradecyphosphonium cation—[P6][Fosf] and [P6][Cl]—were selected as the most effective in the studied epoxidation process. The proposed kinetic model takes into consideration the two reactions, namely, epoxidation and epoxy ring opening involving the formation of hydroxyl groups. The rate constants and activation energies for epoxidation fatty acid methyl esters were determined. Full article

A closed-cycle technology regarding the use of an exhausted Pd-based adsorbent as a photocatalyst in the degradation process of phenol is presented. Pd (II) represents a precious metal of great economic importance. Its obtained from natural sources become more difficult to achieve. Therefore, also considering the regulations of the “circular economy,” its recovery from secondary sources turn out to be a stringent issue in the last years. Pd(II) ions are removed from aqueous solution through adsorption onto Florisil (an inorganic solid support—magnesium silicate) impregnated with Cyphos IL 101 (trihexyl tetradecyl phosphonium chloride). It was observed that the presence of the ionic liquid (IL) in the adsorbent structure doubles the adsorption efficiency of the studied materials. The newly obtained Pd-based photocatalyst was exhaustively characterized and was used in the degradation process of phenol from aqueous solutions. The phenol degradation process was studied in terms of the nature of the photocatalyst used, time of photodegradation and solid: liquid ratio. It was observed that both the presence of IL and Pd lead to an increase in the efficiency of the phenol degradation process. The new Pd-based photocatalyst could be efficiently used in more cycles of phenol photodegradation processes. When is used as a photocatalyst the Florisil impregnated with IL and loaded with 2 mg/g of Pd, a degree of mineralization of 93.75% is obtained after 180 min of irradiation of a phenol solution having a concentration of 20 mg/L and using a solid:liquid ratio = 1:1. Full article

A novel and simple device that includes a polymer inclusion membrane (PIM) has been prepared and tested for the first time to detect low concentration levels of cadmium in seawater. The ionic liquid trihexyl (tetradecyl) phosphonium chloride (THTDPCl) has been shown to be an effective extractant when incorporated in a PIM that uses cellulose triacetate (CTA) as a polymer. However, it has been reported that the use of a plasticizer is mandatory to ensure an effective transport, which uses both ultrapure water and a nitric acid solution as a stripping phase. A special device incorporating a PIM made of 50% CTA, 40% nitrophenyl octyl ether (as a plasticizer), and 10% THTDPCl, effectively allows the quantitative transport and preconcentration of 10 µg L⁻¹ Cd from seawater samples to a stripping phase consisting of 0.5 M HNO₃ solution. This study shows that the efficiency of the PIM system is not affected by high salinity nor the presence of large amounts of other ions, and can thus facilitate Cd monitoring in seawater samples. Full article

Abstract: Poly(vinyl chloride) (PVC) based polymer inclusion membranes (PIMs), with different concentrations of Cyphos® IL 104 as the membrane extractant/carrier, were studied for their ability to extract Au(III) from hydrochloric acid solutions. Some of the PIMs also contained one of the following plasticizers or modifiers: 2-nitrophenyloctyl ether, dioctylphthalate, 1-dodecanol, 1-tetradecanol, or tri(2-ethylhexyl) phosphate. The best performance, in terms of extraction rate and amount of Au(III) extracted, was exhibited by a PIM consisting of 25 wt% Cyphos^® IL 104, 5 wt% 1-dodecanol, and 70 wt% PVC. An almost complete back-extraction of the Au(III) extracted from this membrane was achieved by using a 0.10 mol L⁻¹ Na₂SO₃ receiver solution at pH 8. The stoichiometry of the extracted Au(III)/Cyphos® IL 104 adduct was determined as [P]⁺ [AuCl₄]⁻ H⁺ [PO₂]⁻ where [P]⁺ and [PO₂]⁻ represent trihexyl(tetradecyl) phosphonium and bis(2,4,4-trimethylpentyl) phosphinate ions, respectively. Back-extraction of Au(III) is suggested to occur by reduction of Au(III) to Au(I), with the formation of the species [Au(SO₃)₂]³⁻ in the aqueous receiver solution. Loss of 1-dodecanol from the newly developed PIM to the aqueous solutions in contact with it was observed, which indicated that this membrane was suitable for single use in the efficient recovery of Au(III) from hydrochloric acid solutions of electronic scrap or recycled jewelry. Full article

This research determined the adsorption performance of Florisil^® impregnated with trihexyl(tetradecyl)phosphonium chloride (Cyphos IL-101) in the process of Cs⁺ removal from aqueous solutions. The obtained Florisil^® impregnated with the studied ionic liquid was characterized through energy dispersive X-ray analysis and Fourier transform infrared spectroscopy in order to verify that the impregnation with the ionic liquid had occurred. The adsorption process has been investigated as a function of pH, solid:liquid ratio, adsorbate concentration, contact time and temperature. The isotherm data was well described by a Langmuir isotherm model. The maximum adsorption capacities of the Florisil^® impregnated with the studied ionic liquid was found to be 3.086 mg Cs⁺/g of adsorbent. The results indicated that the adsorption fitted well with the pseudo-second order kinetic model. Full article