Vortex-assisted ionic liquid based liquid-liquid microextraction of selected pesticides from a manufacturing wastewater sample

The ionic liquid based vortex-assisted liquid-liquid microextraction (IL-VALLME) procedure was developed and validated for determination of four pesticides in a manufacturing wastewater sample: acetamiprid, imidacloprid, linuron and tebufenozide. The following ILs were tested as extractants: 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-hexyl-3-methylimidazolium hexafluorophosphate, and 1-methyl-3-octylimidazolium hexafluorophosphate. The extraction efficiency and the enrichment factor dependencies on the type and amount of ionic liquids, extraction and centrifugation time, volume, pH and the ionic strength of the sample, were investigated. The concentration of pesticides in the aqueous and IL phases was determined by HPLC-DAD. The optimal conditions for extraction of the pesticides were determined: the aqueous sample volume of 10 mL with the addition of 0.58 g NaCl, 40 A mu L of the 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide as extractant, 2 min extraction under vigorous mixing applying the vortex agitator, and separation of the phases by centrifugation for 2 min at 1000 rpm. The calibration curves of the pesticides showed good linear relationship (r(2) a parts per thousand yen 0.9996) in the concentration range from 0.005 to 1.00 mg L-1. Determined LOD values are 1.8, 2.3, 4.8 and 8.6 A mu g L-1 for Tebf, Linr, Acet and Imid, respectively. The optimized IL-VALLME was applied for determination of the pesticides in the pesticide manufacturing wastewater

Phase diagram ofthe selected aqueous twophase systems based on ionic liquids

Liquid-liquid equilibrium data have been reported for aqueous two-phase systems formed by imidazolium-based ionic liquids, 1-hexyl-3-methylimidazolium chloride, and 1-butyl-3-methylimidazolium dicyanamide, with inorganic salts,K2HPO4 and K3PO4. The binodal curves were fitted to a three parameter equation and the tie line length was calculated.PHYSICAL CHEMISTRY 2014: 12th International Conference on Fundamental and Applied Aspects of Physical Chemistry;Belgrade (Serbia),22-26 September, 201

Voltammetric determination of lutetium

Half wave potential of lutetium was determined by anodic stripping voltammetry using various electrolyte solutions at the mercury electrode. The influence of electrolyte pH on the value of peak current was also observed. The results show that the choice of the supporting electrolyte and the electrolyte pH strongly influence the voltammetric behaviour of lutetium.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Determination of copper and nickel by ion chromatography and voltammetry

Simultaneous determination of copper(II) and nickel(II) by ion chromatography (IC) has been optimized and the detection limits of the new method were compared to stripping voltammetry. The best eluent enabling fast end efficient separation of Cu(II) and Ni(II) is a mixture of 8 mM citric and 0.3 mM oxalic acid using a Metrosep C2 (Metrohm) IC column. The detection limits are significantly lower using stripping voltammetry, while IC is considerably faster.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

The effect of boron doping on the structure and properties of carbonized hydrothermal carbon

Structural and surface characterization of pristine and boron doped carbonized hydrothermal carbons (CHTC) is reported. Boron was introduced into glucose precursor solution with concentration of 0.2% and 1%. Following hydrothermal treatment, samples were carbonized to 1000oC and examined by Raman spectroscopy and temperature programmed desorption. Characterization of obtained samples as material for carbon paste electrode was performed by cyclic voltammetry measurements of the Fe (CN)6 3-/4- redox couple. Structural analysis showed that lower boron content in precursor solution induced structure ordering, while higher amount of boron caused structural disorder of CHTC sample. Boron presence in CHTC samples reduced number of surface active sites for oxygen adsorption and consequently improved their electrochemical response as electrode material for carbon paste electrode

Indirect determination of lutetium by differential pulse anodic stripping voltammetry at a hanging mercury drop electrode

Lutetium has been determined by differential pulse anodic stripping voltammetry in an acidic solution containing Zn-EDTA. Lutetium (III) ions liberated zinc (II), which was preconcentrated on a hanging mercury drop electrode and stripped anodically, resulting in peak current linearly dependent on lutetium (III) concentration. Less than 0.4 ng mL(-1) lutetium could be detected after a 2 min deposition

Aqueous biphasic systems comprising copolymers and cholinium-based salts or ionic liquids: insights on the mechanisms responsible for their creation

Aqueous biphasic systems (ABS) formed by copolymers and ionic liquids (ILs) have demonstrated to be effective separation platforms, but there is still a gap on the complete understanding of the molecular-level mechanisms ruling the two-phase formation for this type of systems. This work addresses the determination of the liquid-liquid equilibrium of ABS composed of cholinium-based salts or cholinium-based ILs and the triblock copolymer Pluronic PE6200 (PL6200). It is demonstrated that PL6200 can form ABS with all investigated cholinium-based salts or ILs, contrarily to most poly(ethylene)glycol polymers, which is due to the presence of hydrophobic propylene oxide (PO) blocks. From the phase diagrams behavior and IL/salt anions properties, it is shown that the formation of ABS with cholinium-based salts is ruled by the anions polar surface and ability to be hydrated, whereas in systems comprising ILs van der Waals interactions between the copolymer and the IL cannot be discarded. The partition of a series of alkaloids in these systems, namely caffeine, nicotine, theophylline, and theobromine, was additionally appraised. It is shown that caffeine, theophylline, and theobromine preferentially migrate to the more hydrophobic PL6200-rich phase, and that their partition depends on the water content in the respective phase, being ruled by the phases’ hydrophobicity. On the other hand, nicotine, with the most prominent hydrophobic character amongst the studied alkaloids, preferentially migrates to the salt- or IL-rich phase, in which interactions occurring between this alkaloid and the IL/salt cannot be discarded. The ABS formed by cholinium dihydrogenphosphate is the most selective system identified to separate nicotine from the remaining alkaloids, giving some insights into their investigation as separation platforms for alkaloids from natural extracts.publishe

Liquid-phase microextraction in a single hollow fibre - determination of mass transfer coefficient

In this study, the mass transfer coefficient of two local anesthetics in liquid-phase microextraction (LPME), which is performed in a single hollow fibre, was investigated. Previously developed mathematical model has been applied for the determination of the overall mass transfer coefficient based on the acceptor phase, KA, in an unsteady-state LPMEPhysical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Pyrophyllite as a Sustainable Material for Purification of Mine-Waste Water

Wastewater from mines poses a significant problem as it often contains high concentrations of metals, which are discharged into river systems, thereby contributing to environmental pollution. Pyrophyllite is a natural hydrous aluminum silicate clay mineral (Al2Si4(OH) 10(OH) 2) with a high melting point, stable chemical properties, and low cost. The elementary sheet of pyrophyllite is composed of an aluminum-oxygen/hydroxyl octahedral layer between two tetrahedral layers of silicon-oxygen. The layered silicate structure of pyrophyllite crystals has natural adsorption activity. Mechanochemical activation (MCA) is a simple method for modification of solid materials that causes structural disorder, amorphization and increased chemical reactivity. MCA, usually performed by grinding, is an environmentally friendly process because of low energy consumption, processing temperatures and cost. This study investigates the adsorption kinetics of the divalent metal ions (Cd, Ni, Cu, Zn, and Pb) from aqueous solutions using pyrophyllite as an adsorbent. It was found that the removal depends on the mechanochemical treatment of pyrophyllite, contact time with the aqueous solution, and the mutual competition of ions. The conditions were optimized for maximum removal of metal ions from synthesized aqueous solutions. Subsequently, pyrophyllite was applied under optimal conditions for removing Zn (II) from the wastewater of the closed Red Hill mine on mountain Avala. Based on the obtained results, it can be concluded that pyrophyllite completely removes zinc from mine water in a very short time (10 minutes) and thus has great potential for applicationPublished in Bulletin of the Chemists and Technologistsof Bosnia and Herzegovina as Special Issue (2024)