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In this work, aqueous biphasic systems (ABSs) formed by copolymers, ionic liquids (ILs) and natural deep eutectic solvents (NADES) have been demonstrated to be effective separation platforms for the extraction of hydrophobic pharmaceutical ingredients such as parthenolide (PAR). This work addresses the determination of the liquid–liquid equilibrium of ABS composed of choline lactate IL or choline chloride – lactic acid NADES and two different block copolymers Pluronic (PL17R4 and PL10R5), and their influence on the ABS formation and extraction efficiency of PAR. The ability of Pluronics to form ABS is compared to widely used polypropylene glycol polymer (PPG400). Comparing the effect of the ionic liquid and NADES on the ABS formation, it is shown that both salting-our reagents successfully form ABS and do not affect the extraction efficiency of PAR. The main influence on the high parthenolide extraction efficiency (>96%) is governed by the hydrophobic interactions between Pluronic and investigated compound, regardless on the applied salting-out reagent. Due to a high extraction efficiency achieved in PL-rich phase and promissing medical features of PAR, obtained results showed that this phase could be used as biocompatible drug delivery system. Avoiding commercially available organic solvents, elevated temperatures and pressure, the proposed method is greener alternative for PAR extraction.

Although sample preparation, as an unavoidable step of the analytical process should be simple, it is very often identified as a bottleneck. Simplicity of sample preparation based on cost-effective and non-hazardous materials is mandatory for any sustainable and environmental friendly approach. Aqueous biphasic systems (ABS), based on functionalized ionic liquids (FILs) are acceptable alternatives to classical extraction procedures, due to the replacement of organic solvent with diluted aqueous-soluble ionic liquids. In this work, two water soluble FILs based on 2-mercaptobenzothiazolate anion, [mbt]: 1-butyl-3-methylimidazolium [mbt] ([bmim][mbt]) and 1-ethyl-3-methylimidazolium [mbt] ([emim][mbt]), were designed and synthesized in order to selectively extract Cd(II) and Pb(II) from the river sediment. It was found that [mbt]– anion acts as the ligand and forms complexes with Cd(II) and Pb(II) which are responsible for their efficient extraction, while cation is more responsible for the formation of ABS. Partition coefficients of 408 and 180 for Cd(II) and Pb(II), respectively, were obtained using ABS based on [bmim][mbt]. Direct extraction of Cd(II) and Pb(II) from the river sediment has been investigated and obtained optimal conditions are: 60 min direct contact of the aqueous solution of [bmim][mbt] and the sediment sample at 90 °C, followed by formation of ABS upon addition of potassium citrate. Using AGRE and AGREEprep tools greenness of the proposed method for direct extraction of Cd(II) and Pb(II) from the sediment are calculated. Obtained values of 0.69 and 0.71 for Cd(II) and Pb(II) extraction, respectively, showed a high level of the greenness of the proposed method.

Development of cost-effective, bi-functional carbon electrocatalysts via direct carbonization of ionic liquids (bis(cholinium) tetrachlorocobaltate(II) ([Ch]2[CoCl4]) and bis(1-butyl-3-methylimidazolium) tetrachlorocobaltate(II) ([Bmim]2[CoCl4])) is reported herein for the first time. Carbon electrocatalysts, dual-doped with cobalt and nitrogen, were tested for oxygen reduction (ORR) and oxygen evolution (OER) reactions. Both materials show high bi-functional catalytic activity and excellent stability due to synergistic effects arising from the presence of nitrogen and cobalt. Electrocatalyst prepared by carbonization of [Ch]2[CoCl4] show exceptional activity and selectivity toward ORR. Conversely, electrocatalyst prepared from [Bmim]2[CoCl4] showed a slightly better OER performance indicating that different catalytic sites are responsible for O2 reduction and H2O oxidation. Parent CoO particles with graphitic nitrogen boost activity for ORR, while elemental Co supported by nitrogen atoms is responsible for OER activity. Finally, energy consumption during electrolytic oxygen production was calculated revealing energy saving when using two materials as anode electrocatalysts.

To determine the nature and origin of the unconsolidated bottom sediments, as well as to demonstrate and quantify the presence of Presumably Contaminating Elements (PCE) in the Serbian Danube River, as a novelty, the mass fractions on nine major elements as oxides—SiO2, TiO2, Al2O3, FeO, MnO, MgO, CaO, Na2O, and K2O, as well as Sc, V, Cr, Co, Ni, Cu, Zn, As, Rb, Sr, Zr, Sb, Cs, Ba, La, Hf, Ta, W, Th, and U were determined by Instrumental Neutron Activation Analysis (INAA) in 13 sediment samples collected between Belgrade and Iron Gate 2 dam. INAA was chosen for its ability to perform elemental analysis without any preliminary sample treatment that could introduce systematic errors. The distribution of major elements was relatively uniform, with the sampling locations having less influence. Concerning the trace elements, excepting the PCE Cr, Ni, Cu, Zn, As, and Sb, their distributions presented the same remarkable similarity to the Upper Continental Crust (UCC), North American Shale Composite (NASC), Average Bottom Load (ABL), and Average Dobrogea Loess (AVL), and were in good concordance with the location of the Serbian Danube River in the Pannonian Plain. In the case of considered PCE, both Enrichment Factor and Pollution Load Index showed values higher than the pollution threshold, which pointed towards a significant anthropogenic contamination, and rising concern to what extent the water quality and biota could be affected.

Recent studies show that lanthanides (Ln) are becoming emerging pollutants due to their wide application in new technologies, but their environmental fate, transport, and possible accumulation are still relatively unknown. This study aims to determine major and trace elements including Ln in the Danube River sediment which either belong or close to the Iron Gate Reservoir. The Iron Gate Reservoir is characterized by accumulation of sediments as an effect of building hydropower dam Iron Gate I. The surface sediments were collected on the Danube River—1141 to 864 km and three tributaries along this waterway. Two samples of deep sediments were used for comparison. The results indicate the significant upward enrichment of Zn, Sb, Cr, Nd, and Dy in sediments belongs to the Iron Gate Reservoir. The sample 4-Smed is labelled as a hot spot of contamination with Zn, Cr, As, Sb, Nd, and Dy. Also, a trend of increasing concentration in the time period from 1995 to 2016 was found for elements Zn, Cr, and Ni in sediment samples in the Iron Gate Reservoir. Chemometric analysis shows the grouping of sample sites into clusters characterized by the following properties: (i) increased concentration of all measured elements (samples within the Iron Gate Reservoir); (ii) increased Cu concentration (11-Pek); and (iii) lower concentrations of the measured elements (deep sediments). The data presented hereby contribute to the monitoring of pollution of the River Danube sediments and give the first view of Ln profile in the studied sediments.

Besides the evident harmful impact to human health, black carbon (BC) is considered as second important contributor to climate change due to its sunlight absorption and warming effects. It is a major component of fine atmospheric particulate matter emitted during the incomplete combustion of fossil fuels and biomass burning emissions from both natural and anthropogenic sources. Atmospheric carbon was recognized in forms of soot, black carbon, elemental carbon, inorganic carbon, organic carbon, brown carbon, etc, depending on the origin and absorption characteristics. Measurement methodologies for BC analysis in aerosol samples are mostly based on optical and thermal properties of carbon species. Here are presented results of the application of the optical analytical technique which relies on the multi-wavelenght light attenuation by black carbon component of fine particulate matter deposited on filter media. For that purpose, standard polytetrafluoroethylene (PTFE), quartz and carbon nanotube filters with different qualitative features and pore diameters were exposed to fine aerosol fraction at urban background monitoring site in heating and non heating seasons, using low-volume air samplers with 2.3 m3/h air flow. A multi wavelength absorption black carbon instrument (MABI) with 405 nm, 465 nm, 525 nm, 639 nm, 870 nm, 940 nm and 1050 nm LEDs was used for blank and exposed filters analysis and black carbon evaluation. Differences in obtained BC values are discussed in relation to various absorption potential of different filter media, taking into account absorption coefficients dependence on the wavelength and density. Main advantage of this method is simplicity and complementarity with nondestructive nuclear analytical techniques (EDXRF, PIXE) for elemental analysis of fine aerosol fraction on specific filter media. Differentiation between black carbon coming from fossil fuels combustion and from biomass burning sources would be additional information valuable for

Despite a large collection of publications dealing with the characterization of ionic liquid-based aqueous biphasic systems (IL-ABS), a gap still exists regarding the impact of functionalized alkyl side branches and IL positional isomers on phase equilibria. Therefore, this work addresses the investigation of the ability of different methyl substituted pyridinium based ILs on the formation of ABSs with K3PO4. We evaluated the impact of (i) functional groups (hydroxyl or ether) embed in side alkyl chains of pyridinium cations, (ii) positional isomerism of methyl group (ortho, meta and para) and (iii) the IL cation core. Ternary phase diagrams of the ABSs formed by these ILs and K3PO4 and the appropriate tie lines were determined and presented. It is shown that the presence of functionalized alkyl chain largely affects the salting-in behavior of ILs (ILs with the oxygen groups are more difficult to form ABS) while more subtle differences were observed among positional isomers. Based on the obtained results it is concluded that change of biphasic area of ABS is the manifestation of the altered affinity of ILs for water as a consequence of cation structure. Moreover, aiming at gathering a broader picture of the relationship between ILs structure and ABS properties, molecular simulations were performed, and it was showed that the obtained results are consistent with the experimental results. © 2020 Elsevier B.V.

Expired energy drinks are rich in bioactive value-added compounds that can be recovered and reused in order to valorize food waste within a circular economy perspective. However, to accomplish such requirements, it is necessary to develop sustainable extraction and recovery processes, which must consist of decreasing the number of steps required or developing integrated strategies. In this work, novel aqueous biphasic systems (ABS) composed of ionic liquids (ILs) and a biocompatible polymer polypropylene glycol (400 g.mol(-1), PPG 400) were studied for the simultaneous extraction and recovery of three value-added compounds, namely, caffeine, taurine, and niacin, from expired energy drinks. ILs were designed and synthesized in order to have similar anions to the target compounds, thus allowing enhanced selectivity and biological activity, while avoiding an extra step of separation of these high-value compounds from the IL-rich phase. To this end, cholinium-based ILs comprising the anions lactate, pyruvate, taurate, and nicotinate were synthesized, and their cytotoxicity and ecotoxicity credentials were evaluated. Overall, taurine and niacin are majorly enriched in the IL-rich phase, while caffeine preferentially migrates in the majority of the cases toward the PPG-rich phase. However, caffeine also partitions to the IL-rich phase in the ABS formed by cholinium pyruvate or cholinium nicotinate. The ABS formed by cholinium nicotinate and PPG 400 is the best system identified, allowing the almost complete recovery (recovery efficiencies > 82%) of all target compounds into the IL-rich phase in one step. Furthermore, cholinium nicotinate exhibits marginal cytotoxic potential and is harmless from an ecotoxicological point of view. This system is thus a promising platform to simultaneously extract, recover, and reuse value-added compounds from expired energy drinks without the need of removing the IL or recovering the target compounds from the IL-rich phase, thus contributi

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.

This work addresses use of a set of 2-hydroxypropylammonium based protic ionic liquids (PILs) as adjuvants in the aqueous biphasic system (ABS) composed of polyethylene glycol, with molecular weight 2000 g/mol (PEG 2000) and potassium carbonate. The phase diagrams were determined at 25 °C for ABS without and with the addition of 5 wt% of PIL. Comparative analysis of solubility curves indicates that PILs influence liquid-liquid equilibria of PEG 2000-K2CO3 ABS by heightening the hydrophilicity of a PEG-rich phase in various degrees. The compositions of the phases (tie lines) were determined for the selected ABS mixture composition, 26 wt% of PEG 2000 + 10 wt% of K2CO3, without and with 5 wt% of PILs, that is further used for the separation studies. The distribution of PILs between two phases is mainly dependent on specific PEG-PIL interactions and on the PIL content in ABS mixture. The experimental results are supported by molecular simulations that contributed to a broader picture of underlying effects of PILs as adjuvants on ABS formation. The partition of four dye compounds, Remazol Brilliant Blue R (RBBR), Orange II (OII), Rhodamine B (RB) and Congo Red (CR), as probe molecules with different intrinsic properties, was investigated. Obtained results show that the addition of PILs can improve the extraction of hydrophilic and charged compounds as OII, RBBR and CR in PEG-rich phase. On the other hand, it promotes the extraction of hydrophobic and neutral solutes as RB in salt-rich phase. By the addition of the most hydrophilic 3-chloropropanoate based PIL in the PEG 2000-K2CO3 ABS 12 times higher separation factor for OII and RB was achieved. © 2020 Elsevier B.V.

The novel aqueous biphasic systems based on symmetric imidazolium ionic liquids (IL-ABSs)for the extraction of toxic and resistive dyes from water was studied. The cation symmetricity of ILs strongly influence the outstanding ability of 1,3-dibutylimidazolium dicyanamide, [bbim][dca], to generate ABS with the exceptionally low amount of eco-friendly citrate salt. A remarkable potential of [bbim][dca]/citrate based ABS to remove Orange II from wastewater with concentration up to 1000 fold and efficiency above 99.4% in a single step was achieved. The improved safety of proposed method nominates it as promising future strategy for pollution prevention. © 2019 The Korean Society of Industrial and Engineering Chemistry

The authors regret errors in the above mentioned article in the equation (2)as well as in the Fig. 10a. In the equation (2)the number 2 was accidently omitted, whereas the values for the x-axis of Fig. 10a were doubled by accident. The authors would like to apologise for any inconvenience caused. The corrected equation (2)and Fig. 10 are shown below. [Formula presented][Figure presented]Fig. 10. a)Galvanostatic charge-discharge curves for Carb-IL at different current densities in 6 M KOH and b)dependence of the discharge specific capacitance of Carb-IL on the number of cycles, at 5 A g −1 . © 2018 Elsevier Ltd

This work shows the potential application of carbon materials prepared by three different ionic liquid-based methods, using 1-butyl-3-methylimidazolium methanesulfonate [bmim][MeSO3], for electrochemical supercapacitors. The effects of [bmim][MeSO3] on morphology, texture and surface chemistry of prepared materials has been explored by SEM/TEM, N2/CO2 adsorption measurements and XPS. The results indicate the possibility of synthesis of carbon materials with tunable physicochemical properties using ionic liquid based methods. The charge storage behavior of all materials was studied in three different pH aqueous electrolytes. The pseudocapacitive and double layer contributions were estimated and discussed from the aspect of the textural changes and the changes of the chemical composition of surface functional groups containing heteroatoms. C[dbnd]O type functional groups, with the contribution of COOH groups, were found to be responsible for a different amount of charge, which could be stored in alkaline and acidic electrolytic solution. The material prepared by direct carbonization of [bmim][MeSO3], showed the best electrochemical performance in alkaline electrolyte with a capacitance of 187 F g−1 at 5 mV s−1 (or 148 F g−1 at 1 A g−1), due to the contribution of both electric-double layer capacitance and pseudocapacitance which arises from oxygen, nitrogen and sulfur functional groups. © 2018 Elsevier Ltd

Carbon materials, prepared by using different methods with ionicliquids, are compared as electrocatalysts for the oxygen reductionreaction (ORR). Materials were synthesized through the hydrothermalcarbonization of glucose and by using the same method in the presence of1-butyl-3-methylimidazolium methanesulfonate {[}bmim]{[}MeSO3] as anadditive. Another two carbon-based materials were prepared by usingionic-liquid-based methods: ionothermal carbonization of glucose using{[}bmim]{[}MeSO3] as a recyclable medium for the carbonization reactionand by direct carbonization of the ionic liquid in a one-step methodusing {[}bmim]{[}MeSO3] as the precursor for N- and S-doped porouscarbon (Carb-IL). Characterization results showed the possibility ofmorphology and porosity control by using {[}bmim]{[}MeSO3]. Allmaterials were subsequently tested for the ORR in alkaline media.Carb-IL showed enhanced and stable electrocatalytic ORR activity, evenin the presence of methanol, ethanol, and borohydride, opening thepossibility for its application in fuel cells.

In this manuscript eight new 1,3-dialkylimidazolium bromide ionic liquids, {[}CnCmim]{[}Br], were synthesized and characterized. Densities of ionic liquids and their diluted aqueous solutions have been measured over the whole composition range at selected temperatures from (293.15 to 323.15) K and at atmospheric pressure (p = 0.1 MPa). Influence of alkyl chain length and cation symmetry on densities and volumetric properties as well as nature of the interactions in aqueous {[}CnCmim]{[}Br] solutions have been discussed and compared with previously published aqueous {[}C(2)C(4)im]{[}Br] system. Densities of pure bromide based ionic liquids decrease with increasing alkyl chain length on imidazolium cation and depend on total number of methyl group in both side alkyl chains. Apparent molar volumes at infinite dilution of investigated ionic liquids in water increase linearly with increase of the total number of the C atoms in the side alkyl chain. (C) 2018 Elsevier Ltd.

Commercially available pesticides were examined as Mus musculus and Homo sapiens acetylcholinesterase (mAChE and hAChE) inhibitors by means of ligand-based (LB) and structure-based (SB) in silico approaches. Initially, the crystal structures of simazine, monocrotophos, dimethoate, and acetamiprid were reproduced using various force fields. Subsequently, LB alignment rules were assessed and applied to determine the inter synaptic conformations of atrazine, propazine, carbofuran, carbaryl, tebufenozide, imidacloprid, diuron, monuron, and linuron. Afterwards, molecular docking and dynamics SB studies were performed on either mAChE or hAChE, to predict the listed pesticides’ binding modes. Calculated energies of global minima (Eglob_min) and free energies of binding (∆Gbinding) were correlated with the pesticides’ acute toxicities (i.e., the LD50 values) against mice, as well to generate the model that could predict the LD50s against humans. Although for most of the pesticides the low Eglob_min correlates with the high acute toxicity, it is the ∆Gbinding that conditions the LD50 values for all the evaluated pesticides. Derived pLD50 = f(∆Gbinding) mAChE model may predict the pLD50 against hAChE, too. The hAChE inhibition by atrazine, propazine, and simazine (the most toxic pesticides) was elucidated by SB quantum mechanics (QM) DFT mechanistic and concentration-dependent kinetic studies, enriching the knowledge for design of less toxic pesticides.

In this study, four hydrophilic ionic liquids (ILs) containing 1-alkyl-3-methylimidazolim cation and either salicylate or chloride anions were synthetized and studied as new task-specific ionic liquids (TSILs) suitable for aqueous biphasic system (ABS) formation and selective one-step extraction of copper(II). TSILs are designed so that the anion is responsible for forming the complex with metal(II) and preventing hydrolysis of metal cations at very strong alkaline pH, whereas the cation is responsible for selective extraction of metal(II)-salicylate complexes. It was found that 1-butyl-3-methylimidazolium salicylate could be used for selective extraction of Cu(II) in the presence of Zn(II), Cd(II), and Pb(II) at very alkaline solution without metal hydroxide formation. It was assumed that formation of metal(II)-salicylate complexes prevents the hydrolysis of the metal ions in alkaline solutions. The determined stability constants for Cu(II)-salicylate complexes, where salicylate was derived from different ionic liquids, indicated that there was no significant influence of the cation of the ionic liquid on the stability of the complexes. The ABS based on 1-butyl-3-methylimidazolium salicylate has been applied as the sample preparation step prior to voltammetric determination of Cu(II). The effect of volume of aqueous sample and IL and extraction time were investigated and optimum extraction conditions were determined. The obtained detection limits were 8 ng dm(-3). The optimized method was applied for the determination of Cu(II) in tap water, wastewater, and urine. The study indicated that application of the ABS based on 1-butyl-3-methylimidazolium salicylate ionic liquid could be successfully applied as the sample preparation method for the determination of Cu(II) from various environmental samples.

In this work, a new carbon paste electrode, prepared from nitrogen-doped hydrothermal carbon (CHTCN) was applied for the electrochemical detection and determination of carbendazim fungicide. CHTCN samples with the nominal nitrogen content 0.05-0.5 wt. % in glucose precursor were prepared by simple, low-cost synthesis with the accompanying carbonization to 1273 K. The presence of nitrogen in CHTCN samples was confirmed by elemental analysis. Characterization of CHTCN as material for carbon paste electrode was achieved by cyclic voltammetry measurement of the Fe(CN)(6)(3-/4-) redox couple. The results showed that best electrochemical response was obtained from the sample with a nominal nitrogen concentration of 0.1 wt. % and with tricresyl phosphate as a binder. During the development of a differential pulse stripping voltammetric method for carbendazim determination applying new electrode, the following experimental parameters were studied: the sort and amount of binding liquid, the effect of pH, accumulation potential and accumulation time. Under optimal conditions, the electrode offered linearity in the wide concentration range from 25 to 490 ng cm(-3) and an estimated detection limit of 1.21 ng cm(-3). Moreover, the electrode showed good stability, high selectivity and satisfactory anti-interference ability. Finally, the developed method was successfully applied for the determination of carbendazim traces in spiked tap and river water samples.

A new method for the electroanalytical determination of carbendazim is reported using a novel ionic liquid-based carbon paste electrode. 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethyl-sulfonyl)imide were used as additives in the paste for electrode fabrication. The electrodes were characterized by cyclic voltammetry of the http://www.w3.org/1999/xlink couple and scanning electron microscopy. The carbon paste electrode containing 19% 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide was selected for the electrochemical determination of carbendazim by differential pulse adsorptive stripping voltammetry. The influence of electrolyte pH, accumulation potential and time, and the presence of selected pesticides on electrochemical behavior of carbendazim were characterized. The optimal conditions for differential pulse adsorptive stripping voltammetry of carbendazim were determined to be a pH 5.0 Britton-Robinson buffer, an accumulation potential of -0.05V, an accumulation time of 120s, a start potential of -0.10V vs. the reference; an end potential of +1.30V, and a scan rate of 0.050Vs(-1). The linear dynamic range of the method was from 0.010 to 0.247mgL(-1) with a correlation coefficient of 0.9995. The recovery was 104.1% in fortified tap water, demonstrating its suitability for the analysis of water.

A two-phase membrane extraction in a hollow fibre contactor with feed-stream recycle was applied to remove selected pesticides (tebufenozide, linuron, imidacloprid, acetamiprid and dimethoate) from their mixed aqueous solutions. The contactor consisted of 50 polypropylene hollow fibres impregnated with 5% tri-n-octylphosphine oxide in di-n-hexyl ether. For low-polar pesticides with log P2 (tebufenozide and linuron), the maximum removal efficiency increased linearly from 85% to 96% with increasing the feed flow rate. The maximum removal efficiencies of more polar pesticides were significantly higher under feed recirculation (86%) than in a continuous single-pass operation (30%). It was found from the Wilsons plot that the mass transfer resistance of the liquid membrane can be neglected for low-polar pesticides. The pesticide removals from commercial formulations were similar to those from pure pesticide solutions, indicating that built-in adjuvants did not affect the extraction process.

In this paper we report a simultaneous one-step extraction of five pesticides (acetamiprid, imidaclopride, simazine, linuron and tebufenozide) of different polarity using aqueous biphasic system based on 1-butyl-3(methyl or ethyl) substituted imidazolium or pyrrolidinium ionic liquids with bromide or dicyanamide anion and potassium carbonate as a salting-out agent. Experimentally data obtained for the ternary system (ionic liquid + K2CO3 + H2O) were fitted and correlated by Merchuk equation with satisfactory high correlation factor. The effect of the cation alkyl chain length and the variation of anions of the ionic liquid on the aqueous biphasic system formation and the efficiency of pesticide extraction were investigated. Complete extraction of all studied pesticides was obtained applying aqueous biphasic system based on 1-butyl-3-ethyl imidazolium dicyanamide. It was shown that simultaneous extraction of the different polarity pesticides is achieved in a single-step procedure applying properly tailored ionic liquids in the aqueous biphasic system formulation. In order to explain excellent extraction of the polar pesticides in the studied aqueous biphasic systems, molecular dynamics was applied and the binding energies and non-covalent interactions were calculated. It was found that 1-butyl-3-ethyl imidazolium dicyanamide achieves the strongest interactions with the polar pesticides (acetamiprid and imidaclopride) leading to the highest partition coefficients. It was shown that combination of experimental and computational approach can be successfully applied for the selection and design of suitable ionic liquids for efficient extraction of various polarity pesticides using simple aqueous biphasic ionic liquid based systems. (C) 2017 Elsevier B.V. All rights reserved.

A sensitive method for the determination of six varying polarity pesticides (imidacloprid, acetamiprid, carbendazim, simazine, linuron, and tebufenozide) based on a solid-phase extraction disk with multiwalled nanotubes is proposed. A dispersion of multiwalled nanotubes in a surfactant aqueous solution (Triton X-100) was used for the preparation of the solid-phase extraction disk. The effect of surfactant on the functional groups of multiwalled nanotubes was examined by applying temperature-programmed desorption. It was found that this treatment increased the amount of oxygen groups of treated multiwalled nanotubes comparing with untreated ones. The factors that may influence the adsorption and recovery such as the kind and volume of eluent, volume, flow rate and pH of sample were investigated and optimized. Under the optimized conditions, the maximal enrichment factors for low polar pesticides are ranging from 4000 to 4985 and for more polar are 2250 and 2750. The linear range of calibration curves was 10-500 ng/L with correlation coefficient higher than 0.9960, and the detection limit was 6.2-23.7 ng/L. Finally optimized method was applied for determination trace level of five out of six pesticides in tap and river water samples with good recovery.

In this work, novel phase diagrams for aqueous solutions of 1-alkyl-3-methylimidazolium- and 1-butyl-3-ethylimidazolium-based ILs combined with phosphate-based salts, namely, K3PO4 or K2HPO4, are reported and discussed. To correlate the binodal data, the Merchuk equation is applied. The tie lines and tie-line lengths are also presented. The anion influence on the ability to form aqueous biphasic system (ABS) is investigated for the IL with the same1-butyl-3-methylimidazolium cation, [bmim](+), and various anions, for example, salicylate, [SAL](-); trifluoromethanesulfonate, [TFS](-); dicyanamide, [DCA](-); and chloride, [Cl](-). The order of studied anions to form ABS is [TFS](-) GT [SAL](-) GT [DCA](-) GT [Cl](-). The effect of alkyl chain length on imidazolium ion on liquidliquid equilibrium is discussed in terms of increasing ionic liquid hydrophobicity and poorer affinity for water. It is shown that 1-hexyl-3-methylimidazolium chloride ionic liquid has a better ability to form ABS comparing to ionic liquid with butyl chain and the same anion. Newly synthesized ionic-liquid-containing ethyl group 1-butyl-3-ethylimidazolium bromide was also investigated, showing the influence of both ethyl group and bromide anion on the ability of ABS formation.

In this work three 1-alkyl-3-ethylimidazolium bromide ionic liquids (alkyl = ethyl, hexyl and octyl) were synthesized applying both, conventional and microwave assisted synthetic paths. The phase diagrams for aqueous solutions of 1-alkyl-3-ethylimidazolium bromide ionic liquids as novel extractants combined with phosphate-based salts are reported and discussed in terms of aqueous biphasic system (ABS) formation. Merchuk equation was applied in order to correlate the,experimental binodal data. The liquid-liquid equilibrium data (tie-line compositions and tie-line length) were also experimentally determined by a gravimetric method. The influence of the alkyl chain length on ABS formation ability was investigated. It was found that ability to form ABS increases with the increase of the alkyl chain length on the imidazolium cation. Also, it was found that ionic liquids with ethyl group in the N-3 position better form ABS compared to those with methyl substituent. This was discussed in terms of increasing ionic liquid hydrophobicity and poor affinity for water. In order to better understand the impact of the alkyl side chain of the imidazolium ion and the efficiency of ABS formation, computer simulations were performed using investigated ionic liquids with the ethyl group in the position N-3 of the cation and different alkyl substituents in the position N-1. Also, extraction of selected organic dyes was performed to demonstrate application of studied ionic liquids as novel extractants. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Boron doped hydrothermal carbon microspheres were synthesized by introducing boric acid into glucose precursor solution to obtain boron concentration from 0.1 to 1 wt. %. Following hydrothermal treatment, samples were thermally treated to 1000 degrees C. For obtained samples structural and surface characterization were performed. Characterization of obtained samples as material for carbon paste electrode was achieved by measurement of the Fe (CN)(6)(3-/4-) redox couple and linuron determination. Catalytic effect of boric acid on hydrothermal reaction induced enlargement of particle size for boron doped samples. Significant reduction of specific surface area for samples with highest boron concentration was observed. Boron was substitutionally incorporated in the structure of doped samples and incorporation up to 0.6 wt. % in precursor solution generates structure ordering, which induces a reduction of surface active sites for oxygen adsorption in a greater extent. It was found that modified structural and surface characteristics are responsible for good electron transfer property of carbon paste electrode based on doped samples with nominal boron concentration range from 0.2 to 0.6 wt. %. However, it has been shown that sample with nominal boron concentration of 0.2 wt. % proved to be most promising candidate as a material for carbon paste electrode.

Separation of yttrium(III) from strontium(II) with 15% (v/v) di(2-ethylhexyl)phosphoric acid (DEHPA) in dodecane was carried out in a hollow fiber supported liquid membrane (SLM) extraction system operated under closed-loop recirculation of the donor and acceptor phase. The donor phase was a mixture of 5.7 mmol dm(-3) of Sr(II) and 0.23 mmol dm(-3) of Y(III) in 0.1 mol dm(-3) HCl, the acceptor solution was 3 mol dm(-3) HCl, and the donor to acceptor phase volume ratio was 6.2. At the donor flow rate of 4.7 cm(3) min(-1) and the acceptor flow rate of 0.8 cm(3) min(-1), the yield of Y(III) in the acceptor phase (in the form suitable for radiopharmaceutical preparation) reached 60% after 360 min with a molar ratio of Y(III) to Sr(II) in the acceptor of 250:1, as compared to 1:25 in the donor phase. The yield of Y(III) was 72% at the acceptor flow rate to 1.9 cm3 min(-1), but a breakthrough of Sr(II) through liquid membrane increased from 0.02 to 0.2%. (C) 2015 The Institution a Chemical Engineers. Published by Elsevier B.V. All rights reserved.

A supported liquid membrane extraction of different pesticides (acetamiprid, dimethoate, imidacloprid, linuron, and tebufenozide) from an aqueous solution containing 20 mg dm(-3) of each pesticide by 5% TOPO (tri-n-octylphosphine oxide) in DHE (di-n-hexyl ether) has been investigated in a hollow fiber contactor having an aqueous feed/organic interfacial area of 15.4 cm(2). In a single-pass operation, the maximum removal efficiency of 95% was achieved for the most nonpolar (log P = 4.38) pesticide tebufenozide at the feed flow rate of 0.5 cm(3) min(-1). The diffusion through the boundary layer of the feed stream was a rate-controlling step in the extraction of nonpolar pesticides (linuron and tebufenozide) with a mass-transfer coefficient in the feed stream being proportional to the feed flow rate raised to the power of 0.51-0.57. The maximum overall mass-transfer coefficient based on the feed phase of K-F = 0.18 cm min(-1) was obtained for tebufenozide at the feed flow rate of 1.8 cm(3) min(-1). The organic phase entrapped in the membrane pores offered a major resistance to the mass transfer of polar pesticides (log P LT 1) and accounted for 85% of the overall mass-transfer resistance for imidacloprid at 1.8 cm(3) min(-1). The pesticides removed from the feed solution were almost completely accumulated in the organic phase but were recovered from the membrane pores to a large extent (50-90%) by rinsing the membrane with methanol after extraction.

The removal of Pb(II), Cd(II), Cu(II), and Zn(II) from aqueous solutions using (un)modified Serbian interstratified montmorillonite/kaolinite clay as an adsorbent was investigated. The clay was modified by mechanochemical activation for different time periods. X-ray diffraction patterns and particle size distributions were used to characterize the samples. Batch adsorption studies were conducted to optimize various conditions. The adsorption equilibrium was established within 60 min, and the maximum adsorption occurred in the pH range of 4.5-6.5. The milled clays exhibited greater equilibrium adsorption capacities (q(e)) for all of the metals than the raw clay. A difference in q(e) values for clays milled for 2 and 19 h could be observed only for initial concentrations (C-i) of GT = 100 mg dm(-3). This was related to the amorphization (i.e., exfoliation) of 19-h-milled clay particles. The adsorption equilibrium data of heavy metals on both raw and modified clays fit the Langmuir equation, although there were changes in the microstructure of the clay. The mechanochemical treatment of the clay reduced the amount of adsorbent necessary to achieve a highly efficient removal of heavy metals by a factor of 5. Thus, the mechanochemically treated interstratified clay can be considered as an efficient adsorbent for the simultaneous removal of divalent heavy metals.

In this study, a carbon paste electrode based on tricresyl phosphate (TCP-CPE) as a binder has been applied to the voltammetric characterization and determination of Carbendazim fungicide (methyl-1H-benzimidazol-2-yl-carbamate, MBC). The pH effect (in Britton-Robinson buffers, pH 2.0-8.0), as well as the presence of 2-hydroxypropyl-beta-cyclodextrin (HPCD) on the electrochemical behavior of MBC were investigated. In the potential range of interest, the oxidation signal was observed with the overall shape strongly dependent upon pH and exhibiting the most favorable signal-to-noise ratio in mild acidic solutions (pH 4.0). This has indicated that also protons are involved in the electrode transformation of MBC. Furthermore, it was confirmed that addition of 3.6.10(-5) mol L-1 HPCD significantly enhanced the sensitivity towards the target analyte. The experimental conditions optimised for the determination of MBC in the differential pulse adsorptive stripping voltammetric mode (DPAdSV) were as follows: initial potential, -0.10 V vs. Ag/AgCl; final potential, +1.30 V; accumulation potential, -0.35 V; accumulation time, 120 s, and the scan rate, 100 mV s(-1). The method developed offers linearity in the concentration range of 5.0 .10(-7) - 1.0.10(-5) mol L-1 MBC, with r = 0.995 and the limit of detection of about 3.0.10(-7) mol L-1. In a model sample of spiked river water, the recovery rate achieved was 101.9 % (at the concentrations from 1.0.10(-6) to 3.0.10(-6) mol L-1 MBC), suggesting one that the procedure can be applied in analysis of real samples.

Extraction of Lu(III) from an aqueous LuCl3 solution at pH 3.5 into an organic phase containing 5% (v/v) di(2-ethylhexyl)phosphoric acid (DEHPA) in di-n-hexyl ether (DHE) immobilized within a polypropylene hollow fiber membrane and a simultaneous back extraction of Lu(III) into 2 mol dm(-3) HCl solution has been investigated using two miniaturized supported liquid membrane (SLM) systems: (i) a single hollow fiber membrane, with stagnant acceptor phase in the lumen, immersed into a donor phase reservoir; and (ii) a U-shaped module containing a single hollow fiber membrane with a closed loop recirculation of aqueous phases through the module. In the stagnant SLM system, the maximum extraction efficiency was 8.8% due to limited acceptor volume and absence of flow within the lumen. In recirculating SLM system, after 80 mm of operation at the donor phase flow rate of 5.3 cm(3) min(-1), the acceptor phase flow rate of 0.4 cm(3) min(-1) and the donor-to-acceptor phase volume ratio of 6.7, the equilibrium removal efficiency of Lu(III) reached 88% and less than 5% of Lu(III) extracted from the feed solution was kept in the organic phase. For shell side flow of the donor phase at Reynolds numbers of Re = 3-34, the overall mass-transfer coefficient was proportional to the donor flow rate raised to the power of 0.63 and increased from 2.3 x 10(-5) m s(-1) to 8.8 x 10(-5) m s(-1). The rate-limiting step was the mass transfer of Lu(III) within the boundary layer of the donor phase adjacent to the outer wall of the hollow fiber.

This paper summarises the results of voltammetric studies on the herbicide 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (Linuron), using a carbon paste electrode containing tricresyl phosphate (TCP-CPE) as liquid binder. The principal experimental conditions, such as the pH effect, investigated in Britton-Robinson buffer solutions (pH 2.0-7.0), the peak characteristics for the analyte of interest, or instrumental parameters for the differential pulse voltammetric mode were optimized for the method. As found out, the best electroanalytical performance of the TCP-CPE was achieved at pH 2.0, whereby the oxidation peak of Linuron appeared at ca. + 1.3 V vs. SCE. The analytical procedure developed offers good linearity in the concentration range of 1.25-44.20 mu g mL(-1) (1.77 x 10(-4)-5.05 x 10(-6) mol L-1), showing-for the first time-the applicability of the TCP-CPE for anodic oxidations in direct voltammetry (without accumulation). The method was then verified by determining Linuron in a spiked river water sample and a commercial formulation and the results obtained agreed well with those obtained by the reference HPLC/UV determination.

An optimised extraction and cleanup method for the analysis of pesticide in natural water samples is presented. Sixteen pesticides of different polarity and from the different chemical classes (organophosphates, triazines, benzimidazoles, carbamates, carbamides, neonicotinoides, methylureas, phenylureas and benzohydrazides), most frequently used in Serbia, were selected for the analysis. Liquid-phase microextraction in a single hollow fibre (HF-LPME) has been applied for sample preparation. The concentrations of pesticides were determined using HPLC-MS/MS method with electrospray ionisation. The extraction behaviour and selection of the experimental conditions was predicted based on log D and pK (a) values of targeted pesticides, which were calculated applying the computer software ACD/Labs PhysChem Suite v12. The influence of the donor pH and concentration of pesticides, organic phase composition as well as the extraction time on the extraction efficiency was investigated. Optimum extraction conditions were evaluated with respect to the investigated parameters of the extraction. The extraction method was validated for 10 out of 16 studied pesticides. Linear range of the pesticides was 0.1-5 A mu g L(-1) with the correlation coefficient from 0.991 to 0.9998, and the relative standard deviation for three standard measurements was between 0.2 and 11.8%. The limits of detections ranged from 0.026 to 0.237 A mu g L(-1) and the limits of quantifications from 0.094 to 0.793 A mu g L(-1). The optimised two-phase HF-LPME method was successfully applied for determination of moderately polar as well low-polar pesticides in the environmental water samples.