Aliquat Research Articles

Fe3O4 Nanorods‐RGO‐ionic Liquid Nanocomposite Based Electrochemical Sensor for Aflatoxin B1 in Ground Paprika

AbstractA novel and sensitive method for the determination of aflatoxin B1 (AFA−B1) in ground paprika using a methyltrioctylammonium chloride ionic liquid (IL), iron oxide nanorods (Fe3O4 nanorods) and reduced graphene oxide (RGO) fabricated glassy carbon electrode (GCE) was developed. The synthesized nanoparticles, nanocomposites and modified electrode surfaces were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA/DSC) and x‐ray diffraction (XRD) analyses. Moreover, the electrochemical performance of the developed sensor was determined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The obtained results demonstrate that the sensitivity of AFA−B1 is significantly enhanced on RGO‐Fe3O4 nanorods‐IL‐GCE in comparison with bare GCE, RGO‐GCE and RGO‐Fe3O4 nanorods‐GCE. The redox peak currents of AFA−B1 exhibited good linear relationship with its concentration in the range from 0.02 to 0.33 ng mL−1 with detection limit of (LOD) 0.03 ng mL−1 and limit of quantification (LOQ) 0.36 ng mL−1 respectively (S/N=3). In addition, the fabricated electrode showed good stability and reproducibility. The proposed technique was effectively applied to identify the AFA−B1 in real ground paprika samples with acceptable results.

Use of Ionic Liquid Pretreated and Fermented Sugarcane Bagasse as an Adsorbent for Congo Red Removal

A large amount of industrial wastewater containing pollutants including toxic dyes needs to be processed prior to its discharge into the environment. Biological materials such as sugarcane bagasse (SB) have been reported for their role as adsorbents to remove the dyes from water. In this study, the residue SB after fermentation was utilized for the dye removal. A combined pretreatment of NaOH and methyltrioctylammonium chloride was given to SB for lignin removal, and the pretreated SB was utilized for cellulase production from Bacillus aestuarii UE25. The strain produced 118 IU mL−1 of endoglucanse and 70 IU mL−1 of β-glucosidase. Scanning electron microscopy and FTIR spectra showed lignin and cellulose removal in fermented SB. This residue was utilized for the adsorption of an azo dye, congo red (CR). The thermodynamic, isotherm and kinetics studies for the adsorption of CR revealed distinct adsorption features of SB. Untreated SB followed Langmuir isotherm, whereas pretreated SB and fermented SB obeyed the Freundlich isotherm model. The pseudo-second-order model fitted well for the studied adsorbents. The results of thermodynamic studies revealed spontaneous adsorption with negative standard free energy values. Untreated SB showed a 90.36% removal tendency at 303.15 K temperature, whereas the adsorbents comprised of pretreated and fermented SB removed about 98.35% and 97.70%, respectively. The study provided a strategy to utilize SB for cellulase production and its use as an adsorbent for toxic dyes removal.

Recycling of residual valuable metals in cyanide-leached gold wastewater using the N263-TBP system

In this study, the synergistic extraction system of trioctylmethyl ammonium chloride (N263)-tributyl phosphate (TBP)-n-octanol-sulfonated kerosene was used to enrich and recover valuable metals from cyanide gold extraction of wastewater. The effects of the proportion of N263 and TBP, contact time, initial pH of water phase, temperature, and phase ratio (O/A) on the extraction percentage of metal cyanide complex ions and the synergistic extraction reaction mechanism were mainly investigated. Results showed that the single-stage extraction percentages of Cu, Zn, and Fe ions in wastewater were 99.87%, 99.8%, and 96.2%, respectively, and the saturated extraction capacity was 4356.4 mg/L under the conditions of N263 (20 vol%)-TBP (20 vol%)-n-octanol (10 vol%)-sulfonated kerosene system at 25 °C, O/A of 1:1, pH of 10, and contact time of 5 min. Fourier transform infrared spectroscopy (FT-IR) and electrospray ionization mass spectrometry (ESI-MS) analyses showed that metals entered the organic phase in the form of metal cyanide complex ions during extraction. Metal cyanide complex ions preferentially combined with TBP to lose hydrophilicity and then reacted with N263 cations to enter the organic phase. The saturated organic phase was stripped by NaOH and NaSCN mixed solution, and the total concentration of metal ions in the stripping solution reached 11,996.6 mg/L.

Separation and enrichment of Rb(I) in dicyclohexano 18 crown 6(DCH18C6)/PVC polymer inclusion membrane assisted by electric field

The effective extraction of liquid rubidium resources such as salt lake brine and seawater and the recovery of rubidium(I) at the end of the extraction process of lithium resources have always been a challenge in the industry. Two series of polymer inclusion membranes(PDA-PIM and PDT-PIM) were prepared to study the separation and enrichment of Rb(I). PDA-PIM and PDT-PIM used polyvinyl chloride (PVC) and dicyclohexano 18 crown 6(DCH18C6) as carriers, and tricaprylmethylammonium chloride (Aliquat 336) and trioctylphosphine oxide (TOPO) as a plasticizer, respectively. The optimal mass ratio (W/W) of PDA-PIM and PDT-PIM were P25D3.5A25 and P25D3.5T1, respectively. The applied electric field is a core condition for the mass transfer and separation of Rb(I). With the increase of voltage, the permeability coefficient P of Rb(I) and the separation factor (S) relative to Na(I) and K(I) increases. At 180 V, the PRb of PDA-PIM and PDT-PIM were 12.08 and 2.39 µm/s, and the SRB/NA were 11.21 and 14.44. After four mass transfer cycles of PDT-PIM, PRb only decreased by 4.6%. In addition, after 81.5 h of mass transfer, the enrichment ratio of Rb(I) was 3.02 times. These results show the excellent stability and mass transfer performance of PDT-PIM. It's of great significance for low concentration Rb(I) extraction.

Interfering elements on determination of hexavalent chromium in paper materials with UV-vis spectrophotometry

Abstract Regulation of hexavalent chromium is based on Waste Framework Directive 1994/62/EC, European Commission and publication of the World Health Organization. Herein, detection of hexavalent chromium was performed by alkaline digestion and instrumental analysis which was demonstrated in USEPA methods. However, UV-vis detection method could be affected by some metal ions reacted with diphenylcarbizide. Actually, various interfering elements, such as Ni, Fe, Al, and Cu, were detected and selected by ED-XRF in paper materials. In order to improve accuracy of analysis results of hexavalent chromium in paper materials based on USEPA methods, the interfering elements was removed by liquid–liquid extraction with carbonate media using tricaprylmethylammonium chloride and chloroform after alkaline digestion. Consequently, the temperature for alkaline digestion was between 85 and 95 °C. Hydrochloric acid was proper complex tricaprylmethylammonium-Cr(VI) in the procedure of liquid extraction. After that hexavalent chromium was completely extracted using of 1 M sodium hydroxide solution. The technique for analyzing the hexavalent chromium used in liquid–liquid extraction significantly reduced the errors caused by the interfering elements, Fe and Cu. Thus, application of the extraction method was efficient in removing the interfering elements, which increased the recovery ratio of the hexavalent chromium from paper materials by 90 %.

Separation of cobalt, lithium and nickel from the “black mass” of waste Li-ion batteries by ionic liquids, DESs and organophosphorous-based acids extraction

New methods of metal extraction from the “black mass” (BM) from spent lithium-ion batteries have been presented with ionic liquids (ILs), Deep Eutectic Solvents (DESs) and organophosphorous-based acids. The low-temperature method of extraction of cobalt, nickel, lithium and other metals without pre-leaching of BM with acids have been proposed in comparison with many methods already described in the literature. Extraction has been studied in detail with ILs: methyltrioctylammonium chloride ([N8,8,8,1][Cl], Aliquat 336), trihexyltetradecylphosphonium chloride ([P6,6,6,14][Cl], Cyphos IL 101), trihexyltetradecylphosphonium thiocyanate ([P6,6,6,14][SCN]), benzethonium tricyanomethanide ([Benzet][TCM]), as well as with DESs mixtures and well known organophosphorous-based acids: bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) and di-(2-ethylhexyl) phosphoric acid (D2EHPA). It was shown that fast and efficient extraction, with 90–100 wt% recovery of Co(II), may be obtained using DESs. Well known for the extraction of metal ions from the aqueous phase ILs, binary mixtures of ILs (synergistic effect) and Aqueous Biphasic System (ABS) method with NaCl, {[P4,4,4,14][Cl] + NaCl + Co(II)} have shown very low efficiency in the recovery of metals from BM. The extraction of cobalt (30–58 wt%) and the high extraction efficiency of lithium (41–92 wt%) and nickel (37–52 wt%) was obtained using Cyanex 272 in a mixture with diethyl phosphite. Process factors such as solvent content, extraction additivities, stripping and precipitation methods, temperature, holding time, pH and liquid/solid as well as organic/water ratios were studied. For all extractions, the selectivity and distribution ratios were described. A schematic flow chart for the selective recovery of cobalt(II), lithium(I) and nickel(II) from BM has been proposed. The presented extraction processes can compete with the costly hydrometallurgical methods for recovering metals from secondary waste.

Extraction and determination of strobilurin fungicides residues in apple samples using ultrasound-assisted dispersive liquid-liquid microextraction based on a novel hydrophobic deep eutectic solvent followed by H.P.L.C-U.V

ABSTRACT In this study, several novel and natural hydrophobic deep eutectic solvents (D.E.Ss) were prepared using methyl trioctylammonium chloride (M.T.O.A.C) as H.B.A and different types of straight chain alcohols as H.B.Ds. One of the D.E.Ss composed of M.T.O.A.C and n-butanol was advantageously used to develop an ultrasound-assisted dispersive liquid-liquid microextraction (U.A−D.L.L.M.E) method combined with high-performance liquid chromatography-ultraviolet detection (H.P.L.C−U.V) for the determination of some strobilurin fungicides in apple samples. Several important parameters influencing extraction efficiency were investigated and optimised, including the type and volume of extractant in ultrasound stage, sonication time, the type and volume of D.E.S, sample solution pH and effect of salt addition. Under optimal experimental conditions, the method showed good linearity with correlation coefficients (R 2) of 0.9985 − 0.9991 in the linear range of 4−1500 μg kg−1, low limits of detection of 1.5−2 μg kg−1 and acceptable extraction recoveries in the range of 76−92%. Enrichment factor was in the range of 95–115. The proposed method was successfully applied for the extraction and preconcentration of trace fungicides in apple samples, and the results demonstrated the potential of the synthesised D.E.S for the extraction and determination of contaminants in aqueous samples.

Ultrasonic assisted magnetic solid phase extraction based on the use of magnetic waste-tyre derived activated carbon modified with methyltrioctylammonium chloride adsorbent for the preconcentration and analysis of non-steroidal anti-inflammatory drugs in wastewater

In this study, a magnetic waste-tyre derived activated carbon modified with methyltrioctylammonium chloride, was successfully synthesized, characterised, and applied for the extraction and preconcentration of four non-steroidal anti-inflammatory drugs in wastewater. The scanning electron microscopy and N 2 -adsorption/desorption analysis results confirmed that the synthesized nanocomposite was porous with a large specific surface area of 570 m 2 g −1 . The significant factors affecting the Ultrasonic assisted magnetic solid phase extraction method were investigated using univariate approach and response surface methodology. The optimum conditions for the extraction and preconcentration of the target analytes were 0%, 15 min, 6.5 and 30 mg, for ionic strength, extraction time, pH and adsorbent mass respectively. The quantification of the target analytes was performed using high performance liquid chromatography equipped with diode array detector. Under optimum conditions, low limits of detection and quantification ranging between 0.054–0.38 μg L −1 and 0.18–1.27 μg L −1 , respectively, were obtained. A wide linearity (ranging from limit of detection – 500 μg L −1 with R 2 ≥ 0.99) and precision lower than 7%, were achieved. The applicability of proposed method was evaluated for the determination of naproxen, ketoprofen and diclofenac in wastewater.

Development and validation of the HPLC-DAD method for the quantification of 16 synthetic dyes in various foods and the use of liquid anion exchange extraction for qualitative expression determination

Synthetic dyes can cause many health problems, and their use as food additives is rigorously regulated worldwide. Two methods for the determination of synthetic dyes in food are described in this article. The visual qualitative expression method was based on the extraction of synthetic dyes using a liquid anion exchanger (0.01 M solution of trioctylmethylammonium chloride in chloroform). Using this reagent, an optimal transition of 15 anionic synthetic dyes from the aqueous to the organic phase was achieved (R > 99.8%). It was applicable for testing food that must not contain synthetic dyes (wines, juices, etc.) in a very short time (5–10 min). In the case of colouring of the organic phase, identification and quantification was carried out using the HPLC-DAD method described. The rapid and simple method allows for simultaneous determination of 16 synthetic dyes from all food types. The LOD and LOQ ranged from 0.026 to 0.086 μg mL−1 and from 0.077 to 0.262 μg mL−1 respectively, and recovery was 83.7–107.5%.Hypothesis: anionic synthetic dyes have hydrophobic properties, as a result they are retained on the non-polar stationary phase of the chromatographic column and are easily extracted from aqueous solutions by liquid anion exchangers.

Adsorption of Silicate Anions from Geothermal Brine Using Chitosan-Polyethylene Glycol Composite to Prevent Silica Scaling on the Dieng Geo Dipa Geothermal Energy System

Silica scaling is a common problem in geothermal power generation facilities which inhibits electricity generation. In order to provide a solution to this problem, the removal of silicate ions using CPEG-TOMAC (Chitosan-polyethylene glycol–trioctyl methyl ammonium chloride) membrane adsorbent was investigated for geothermal brine from Geo Dipa Energy, Dieng. The process is dependent on contact time, pH, and the concentration of silicate. An adsorption batch study that used adsorbents for the geothermal brine of the Dieng Geo Dipa reactor 28A showed that CPEG TOMAC at pH 6 resulted in an adsorption capacity of 72.6 mg g–1. Furthermore, the adsorption of silicate ions onto the membrane followed pseudo-second-order kinetics and the Freundlich isotherm model.

Simultaneous determination of lobetyolin and atractylenolide III in Codonopsis Radix by dispersive liquid-liquid microextraction based on hydrophobic deep eutectic solvent

In order to achieve the determination and quantification of trace lobetyolin and atractylenolide III in Codonopsis Radix, a procedure of dispersive liquid-liquid microextraction utilizing a hydrophobic deep eutectic solvent as the extractant combined with high performance liquid chromatography was developed. The primary variables affecting the extraction process, including the type, ratio and volume of extractant, pH and salt concentration in sample phase, type and volume of dispersant, extraction time, centrifugal speed and time were optimized. In this experiment, the deep eutectic solvent prepared by methyltrioctylammonium chloride and n-butanol was the best extractant. The both target analytes showed good linearity (r2 > 0.990) in their respective linear ranges (0.01–2.5 µg/mL and 0.009–2.0 µg/mL). And the limits of detection and quantification were 6 × 10−4 and 2 × 10−3 µg/mL for lobetyolin, 3 × 10−3 and 9 × 10−3 µg/mL for atractylenolide III. The enrichment factors were 37 for lobetyolin and 154 for atractylenolide III respectively. The relative standard deviations of precision were 1.2–6.4% and the spiked recovery values were in the range of 87.6–114.7% with the relative standard deviations of 1.5–4.7%. It is successful to objectively and clearly distinguish the three origins of Codonopsis Radix by comparing the contents of the both analytes with proposed method.

Highly sensitive determination of methionine by solvent-based de-emulsification dispersive liquid-liquid microextraction using bio-stabilized silver nanoparticles.

In this study, a solvent-based de-emulsification dispersive liquid-liquid microextraction method coupled with surface plasmon resonance of silver nanoparticles was developed for determination of trace levels of methionine. The stable and dispersed silver nanoparticles were synthesized by applying ascorbic acid as reducer and Stenotrophomonas sp. bacterial suspension as bio-stabilizer and then preconcentrated in organic phase according to a facile dispersive liquid-liquid microextraction procedure based on 1-octanol as extraction solvent, methyltrioctylammonium chloride (aliquat 336) as disperser and acetone as de-emulsifier. The presence of methionine influenced the intensity of plasmon resonance absorbance of silver nanoparticles, which was employed as a colorimetric probe for the determination of this amino acid. Under the optimal conditions, the linear analytical range of 5.6 to 234.5nmol/L and a detection limit of 3.4nmol/L were achieved for methionine. The relative standard deviation for seven replicate measurements of 33.5 and 107.2nmol/L of methionine was 4.3 and 2.1%, respectively. The suggested method was successfully applied for the determination of methionine in biological samples.

Deep eutectic solvent extraction of cortisol and cortisone from human saliva followed by LC-UV analysis

A novel extraction method was developed for the determination of cortisol and cortisone. In this study, we prepared a hydrophobic deep eutectic solvent (DES) by mixing trioctylmethylammonium chloride and pentafluorophenol as a hydrogen bond acceptor and a hydrogen bond donor, respectively, for use as the extraction solvent. The extraction of cortisol and cortisone was performed by adding a small volume of the DES to the aqueous sample. After centrifugation, the resulting sedimented DES phase was injected into a reversed-phase liquid chroamtography column, and the analytes were detected with an ultraviolet detector at 254 nm. Under the optimized extraction conditions, the enrichment factors of cortisol and cortisone were 9.3 and 8.5, respectively. Furthermore, the linear dynamic ranges were established over a concentration range of 10–200 pmol mL−1 (r2 > 0.9992), and the limits of detection of cortisol and cortisone were found to be 2.1 and 1.8 pmol mL−1, respectively. The applicability of this method was evaluated by analyzing the cortisol and cortisone contents of human saliva samples.

Novel recyclable acidic hydrophobic deep eutectic solvents for highly efficient extraction of calcium dobesilate in water and urine samples

Deep eutectic solvents (DESs) have been considered to be one of the most promising green alternatives of conventional volatile solvents for liquid-liquid separation. However, acidic hydrophobic DESs have been less studied although they are of great importance for the extraction of compounds which are unstable in alkaline conditions. In this study, a novel family of acidic hydrophobic deep eutectic solvents was designed and prepared from methyl trioctyl ammonium chloride and a series of haloacetic acids. For the first time, the obtained DESs were used for extraction and determination of calcium dobesilate, which is an extensively used medicine for treating vascular diseases, but it can be easily oxidized under alkaline and neutral conditions. The factors influencing extraction process including pH, temperature, extract time, inorganic salts and organic coexistence were systematically investigated. It is found that these DESs exhibited outstanding extraction performance towards calcium dobesilate. The extraction equilibrium time was only 3 min in a wide range of pH (1.2–9.2) at room temperature and the extraction capacity was up to 504 mg/g. The detection limit of calcium dobesilate extracting from water samples was 0.05 μg/L and the limit of quantification was 0.5 μg/L. A variety of inorganic salts with the concentration up to 1.0 mol/L and common coexisting organic compounds, such as glucose and starch, with the concentration more than 1000 times higher than the target analyte had no obvious impact on the extraction efficiency. The relative recovery for real samples ranged from 93.2% to 108.6%. Furthermore, the DESs could be recycled and regenerated through back extraction. After fifteen cycles, the extraction efficiency was still up to 99%. Finally, the extraction and back extraction mechanism was discussed in detail.

Thermodynamic Modeling of Salting Effects in Solvent Extraction of Cobalt(II) from Chloride Media by the Basic Extractant Methyltrioctylammonium Chloride.

The design and optimization of solvent extraction processes for metal separations are challenging tasks due to the large number of adjustable parameters. A quantitative predictive solvent extraction model could help to determine the optimal parameters for solvent extraction flow sheets, but such predictive models are not available yet. The main difficulties for such models are the large deviations from ideal thermodynamic behavior in both the aqueous and organic phases due to high solute concentrations. We constructed a molecular thermodynamic model for the extraction of CoCl2 from different chloride salts by 0.2 mol L–1 trioctylmethylammonium chloride in toluene using the OLI mixed-solvent electrolyte (OLI-MSE) framework. This was accomplished by analyzing the water and hydrochloric acid content of the organic phase, measuring the water activity of the system, and using metal complex speciation and solvent extraction data. The full extractant concentration range cannot be modeled by the OLI-MSE framework as this framework lacks a description for reversed micelle formation. Nevertheless, salting effects and the behavior of hydrochloric acid can be accurately described with the presented extraction model, without determining specific Co(II)–salt cation interaction parameters. The resulting model shows that the salting effects originate from indirect salt cation–solvent interactions that influence the availability of water in the aqueous and organic phases.

Inhibition of asphaltene precipitation using hydrophobic deep eutectic solvents and ionic liquid

Precipitation and subsequent deposition of asphaltene in oil reservoirs may cause severe flow assurance problems due to clogging/blocking of pore spaces and wettability alteration of reservoir rocks towards oil-wetness. The present study focuses, for the first time, on the potential application of three hydrophobic deep eutectic solvents (HDESs) prepared by mixing methyltrioctylammonium chloride (N81Cl) as their hydrogen bond acceptor (HBA) with alcoholic hydrogen bond donors (HBDs), namely 1-propanol, 1,3-propanediol, and glycerol. The performance of HDESs was compared with a phosphonium-based hydrophobic ionic liquid (IL), Trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate (TTPBP), as well as dodecylbenzene sulfonic acid (DBSA), a conventional asphaltene precipitation inhibitor. Initially, the kinetic and onset of asphaltene precipitation were evaluated using an ultraviolet-visible (UV-Vis) spectrophotometer to determine the chemicals' inhibition propensity. Next, Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric (TGA), and elemental analyses were used for the recovered asphaltenes from HDESs and TTPBP solutions to examine their structures. Spectrophotometry results revealed that glycerol-based HDES (HDES 3) and TTPBP could effectively inhibit the asphaltene precipitation, where their performances were comparable to that of DBSA. Besides, aromaticity index, thermal degradation, and H:C and oxygen contents provided evidence that HDES 3 and TTPBP could disrupt the asphaltenes structure, thus stabilizing them in the oleic environment.

Environmentally benign hydrophobic deep eutectic solvents for palladium(II) extraction from hydrochloric acid solution

Hydrophobic deep eutectic solvents (DESs) are considered to be clean and green alternatives to traditional organic solvents for metal ion extraction. Herein, a series of novel hydrophobic DESs were synthesized via the combination of methyltrioctylammonium chloride ([N8881]Cl) as hydrogen bond acceptors (HBAs) and saturated fatty acids or saturated fatty alcohols as hydrogen bond donors (HBDs). Then, the DESs were used for palladium(II) recovery from acid solution. The factors that affect palladium(II) extraction (including the DES species, contact time, DES dose, solution pH, and temperature) were extensively investigated. The DESs exhibit excellent performance for extracting palladium(II) from hydrochloric acid media, and more than 99% of palladium(II) was extracted under optimal conditions. UV–vis, 1H NMR, and FTIR spectral characterizations confirm that the extraction mechanism of palladium(II) involves an anion exchange reaction whereby PdCl42− anions in the aqueous phase replace Cl− anions in DES to form ion-pairs with [N8881+] via electrostatic interactions. Meanwhile, N8881Cl:1-hexanol (1:1) and N8881Cl:hexanoic acid (1:2) exhibit excellent selectivity for palladium(II) over other impurity metal ions. Also, palladium(II) in the loaded DES phase was efficiently recovered as elemental palladium via the hydrazine hydrate reduction method; thus, the DES could be reused for at least 5 cycles.

Highly selective solvent extraction of Zn(II) and Cr(III) with trioctylmethylammonium chloride ionic liquid

AbstractThis study investigates the recovery of Zn(II) and Cr(III) from aqueous solutions based on solvent extraction with trioctylmethylammonium chloride [TOMA+][Cl‐], commercialy named Aliquat 336. Single metal solutions and binary mixtures of both metals were considered. The effect of relevant operating conditions such as pH, contact time, initial concentration, O/A phase volumetric ratio, and temperature were evaluated. Additionally, loading capacity and stripping studies were performed. Results showed that [TOMA+][Cl−] is an effective extracting agent for Zn(II), reaching maximum removal capacity at pH 1.8 and demonstrating fast extraction kinetics. Extraction efficiencies above 99% were achieved at 0.5, 0.75, and 1.00 O/A volumetric phase ratios for 0.1 g/L initial Zn(II) concentration. At 1 g/L and 10 g/L concentration, for the same O/A ratios, approximately 88% of the initial Zn(II) was extracted. In contrast, it was found that negligible amounts of Cr(III) were transferred to the [TOMA+][Cl−] phase at the 1‐5 pH range. Selectivity studies showed that Zn(II) removal is boosted in the presence of Cr(III), although no Cr(III) is extracted. [TOMA+][Cl−] exhibited a high Zn(II) storage capacity, since after 25 loading cycles with 1 g/L, the loading capacity reached approximately 13.5 g/L, and after five loading cycles with 5 g/L, the capacity reached 19.4 g/L. Stripping tests revealed that NaOH is an efficient agent for the removal of Zn(II) from the ionic liquids, reaching 98.5% removal after two cycles, whereas HNO3 is not a suitable agent, reaching less than 40% removal after three cycles. [TOMA+][Cl−] revealed high potential for separating Zn(II) from Cr(III).

Separation of no-carrier-added 71,72As from 46 MeV alpha particle irradiated gallium oxide target

Abstract No-carrier-added (NCA) 71,72As radionuclides were produced by irradiating gallium oxide target by 46 MeV α-particles. NCA 71,72As was separated from the target matrix by liquid-liquid extraction (LLX) using trioctyl amine (TOA) and tricaprylmethylammonium chloride (aliquat-336) diluted in cyclohexane. The bulk gallium was quantitatively extracted into the organic phase leaving 71,72As in the aqueous phase. Complete separation was observed at 3 M HCl + 0.1 M TOA and 2 M HCl + 0.01 M aliquat-336.

Preparation and Characterization of Nanoparticle-Doped Polymer Inclusion Membranes. Application to the Removal of Arsenate and Phosphate from Waters.

Nanoparticle-doped polymer inclusion membranes (NP-PIMs) have been prepared and characterized as new materials for the removal of arsenate and phosphate from waters. PIMs are made of a polymer, cellulose triacetate (CTA), and an extractant, which interacts with the compound of interest. We have used the ionic liquid (IL) trioctylmethylammonium chloride (Aliquat 336) as the extractant and have investigated how the addition of nanoparticles can modify membrane properties. To this end, inorganic nanoparticles, such as ferrite (Fe3O4), SiO2 and TiO2, and multiwalled carbon nanotubes (MWCNTs), were blended with the polymer/extractant mixture. Scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), and contact angle measurements have been used to characterize the material. Moreover, PIM stability was checked by measuring the mass loss during the experiments. Since Aliquat 336 acts as an anion exchanger, the NP-PIMs have been explored in two different applications: (i) as sorbent materials for the extraction of arsenate and phosphate anions; (ii) as an organic phase for the separation of arsenate and phosphate in a three-phase system. The presence of oleate-coated ferrite NP in the PIM formulation represents an improvement in the efficiency of NP-PIMs used as sorbents; nevertheless, a decrease in the transport efficiency for arsenate but not for phosphate was obtained. The ease with which the NP-PIMs are prepared suggests good potential for future applications in the treatment of polluted water. Future work will address three main aspects: firstly, the implementation of the Fe3O4-PIMs for the removal of As(V) in real water containing complex matrices; secondly, the study of phosphate recovery with other cell designs that allow large volumes of contaminated water to be treated; and thirdly, the investigation of the role of MWCNTs in PIM stability.