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It is essential to monitor organic pollutants to control contamination levels in environmental water bodies. In this respect, the development of new materials based on functionalised polymeric films for the measurement of toxic compounds is of interest. In this study, we prepare new films based on polymer cellulose triacetate modified with multi-walled carbon nanotubes for the monitoring of selected compounds: a fungicide (chlorpyrifos) and two emerging contaminants, the musk tonalide and the bactericide triclosan, which are used in the formulation of personal care products. The films, upon contact with water samples and following the principles of thin film microextraction, allow the determination of organic pollutants at low concentration levels. The contact time of the film with a predetermined volume of water is fixed at 60 min, and the compounds are eluted with a small volume (1 mL) of organic solvent for GC-MS analysis. Parameters such as repeatability for different films and detection limits are found to be satisfactory. Applying the method to river water demonstrates its suitability and, in the cases of chlorpyrifos and tonalide, the absence of a significant matrix effect.

Thin films made of a polymer (cellulose triacetate, CTA) and a plasticizer have been studied as novel sorptive phases for chlorpyrifos, triclosan and tonalide. The preparation is reproducible and only requires the plasticizer to be added into an organic dispersion containing CTA. The evaporation of the solvent leaves an easy to manipulate continuous and homogeneous thin film, which has been investigated in terms of both composition and extraction efficiency for the different compounds. Six different plasticizers (namely dibutyl sebacate, bis(2-ethylhexyl) sebacate, bis(2-ethylhexyl) phthalate, bis(1-butylpentyl) adipate, 2-nitrophenyl octyl ether and 2-fluorophenyl 2- nitrophenyl ether) with different chemical structure and physical properties, such as lipophilicity, dielectric constant and viscosity, have been incorporated in the CTA matrix and the resulting polymeric membranes have been characterized by different techniques (scanning electron microscopy, thermal techniques, and contact angle). Preliminary tests were undertaken in 0.01 M NaCl solution enriched with 100 μg L-1 of each analyte to study the kinetics and efficiency of extraction. All analytes were effectively extracted after 6 h with all the polymeric phases, with different kinetics. Among the different elutants tested, ethyl acetate provided satisfactory recovery values. The membrane made of CTA and dibutyl sebacate has been selected and successfully applied for the microextraction of pollutants in simulated natural water, river water and a wastewater effluent with trace concentrations added (0.2–2 μg L-1) before GC–MS determination. The overall method is easy to perform and provides good reproducibility (RSD < 10%) and recoveries higher than 80% This work has been supported by the Ministerio de Ciencia, Innovación y Universidades (MCIU) through project PID2019-107033 GB-C22 / AEI / 10.13039/501100011033 Open Access funding provided thanks to the CRUE-CSIC agreement with Elsevier

In this study, the diffusive gradient in thin film (DGT) has been developed using three new materials derived from benzoylthiourea (PBTU, BTP1 and BTP2) for the determination of bioavailable mercury (Hg). The efficiency of these DGT devices was compared with the well-established 3-mercaptopropyl functionalized silica gel (3MFS) in laboratory and field conditions. It was found that PBTU lacked of consistency for handling and assembling in the DGT device, whereas the other two polymers provided mechanically stable binding gels and extracted satisfactorily Hg. However, BTP2 showed no correlation between Hg uptake and Hg present in the aqueous solution, and therefore, BTP1 gels was chosen as the binding layer used for DGT technique. The calculated diffusion coefficient of DGT-BTP1 was 4.0 10−6 cm 2 s−1 at 25 °C in 0.8 mm thick diffusion layer and 2.3% w/v of material in gel, whereas for DGT-3MFS, the D value was 9.1 × 10−6 cm 2 s−1. Moreover, it was found that neither the pH (range 4.5 – 9.5) nor the ionic strength (range 0.005–0.1 mol L−1) significantly affected the binding behavior of Hg (p > 0.05). Finally, the DGT-BTP1 devices were successfully used for in-situ measurements of Hg in Quito River (Colombia), impacted by artisanal gold mining, and were compared with DGT-3MFS. Results showed a good performance with values of the labile Hg concentration between 5 to 8% of the total Hg in water. This study demonstrates that benzoylthiourea based DGT is a useful tool for in situ monitoring of Hg in freshwaters., This work has been supported by the Ministry of Science, Technology and Innovation (MINCIENCIAS) in Colombia through project: Evaluation of the degree of contamination by mercury and other toxic substances and its impact on human health in the populations of the Atrato River basin, as a consequence of mining: financing contract RC No. 849-2018, MINCIENCIAS Code: 1112-894-66291. This work was also funded by the Ministerio de Ciencia, Innovación y Universidades (MCIU) through project PID2019-107033GB-C22/AEI/10.13039/501100011033, and the Spanish National Research Council (CSIC)[http://dx.doi.org/10.13039/501100003339] through project iCOOP 2018-COOPA20490. The authors would also like to acknowledge the CYTED (Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo) , for financing the MercuRed Network (420RT0007). The authors thank the members of the Toxicology and Environmental Management Laboratory of the University of Córdoba, and the members of the Technological University of Chocó ‘DLC’ (Colombia).

The sequential application of a polymer inclusion membrane (PIM), composed of poly(vinylidenefluoride-co-hexafluoropropylene) and the anionic extractant Aliquat 336, and a microporous polytetrafluoroethylene (PTFE) gas-permeable membrane was utilized for the first time to develop a flow analysis (FA) system, for the automatic determination of trace levels of arsenate (As(V)) in drinking water as arsine. The system incorporated a flow-through extraction cell for separation and preconcentration of arsenate and a gas-diffusion cell for the separation of arsine prior to its spectrophotometric determination based on the discoloration of a potassium permanganate solution. Under optimal conditions the FA system is characterized by a limit of detection of 3.0 μg L −1 As(V) and repeatability of 1.8% (n = 5, 25 μg L −1 As(V)) and 2.8% (n = 5, 50 μg L −1 As(V)). The newly developed FA method was successfully applied to the determination of arsenate in drinking water samples in the μg L −1 concentration range The financial support of the Spanish government through research project CTM2016-78798-C2-2-P (AEI/FEDER/UE) is acknowledged. R. Vera acknowledges a grant from Spanish Ministerio de Economía y Competitividad ref. BES-2014-068314. The authors would like to thank the Australian Research Council for financial support of this research (Grant LP100100800)

Peri-urban agriculture provides environmental benefits to the nearby urban areas. However, domestic and industrial infrastructures can be sources of pollution that can affect agricultural production. In this work, the diffusive gradient in thin film (DGT) technique was used to assess the bioavailability of mercury (Hg) in organic-amended agricultural soils, and uptake by lettuce. Two different amendments were studied individually in three different sets using a wood-based biochar at two rates (3% and 6%, w/w), and compost at one rate (30% w/w). The effect of the amendments on Hg bioavailability, mobility and uptake was investigated by means of both DGT analyses and accumulation of Hg by lettuce. DGT manufactured in-house devices with polyacrylamide gel using both open and restricted diffusive layers (ODL and RDL, respectively) were used to determine organic and inorganic Hg labile species in soils, respectively. The Hg concentration in lettuce leaves and roots were analyzed and compared with DGT measurements to predict the uptake of Hg from the different organic-amended soils and the non-amended soils. Results show that the application of biochar reduces the bioavailability of Hg in soil and, in consequence, the Hg uptake by lettuce. Inorganic Hg species were predominant in all the different sets of the experiment (62–97%), although the addition of the different amendments reduced the free ionic species in soil. © 2019, The authors gratefully acknowledge the financial support of the Spanish Ministry of Economy, Industry, and Competitiveness (MEIC) through Project AGL2017-89518-R and CTM2016-78798-C2-2-P (AEI/FEDER/UE). The authors would further like to thank the officers and farmers of the Baix Llobregat Agrarian Park for their assistance, as well as Ms. Yolanda Rodríguez and Ms. Rui You for their technical assistance with the sampling and sample preparation.

The uptake of nutrients or toxicants by different organisms in aquatic systems is known to correlate with different fractions of the nutrient's or toxicant's total concentration. These fractions can be provided by different analytical techniques, from which the better correlation is expected to be found for those with a characteristic length comparable to that in the considered organism uptake. An effective concentration signature can be built up with the concentration values associated to the availability (i.e. fluxes in dynamic techniques) of the nutrient or toxicant measured by various analytical techniques with different characteristic lengths. Here, this new representation was obtained for the pool of Zn complexes in the Mediterranean stream Riera d'Osor (Girona, Catalonia, Spain) with a suite of four analytical techniques. Absence of Gradients and Nernstian Equilibrium Stripping (AGNES) and Polymer Inclusion Membrane (PIM) devices provided the free Zn concentration. Linear Anodic Stripping Voltammetry provided a labile fraction (defined here as cLASV, higher than the free concentration), related to the diffusion layer scale. Diffusion Gradients in Thin-films provided higher labile fractions (known as DGT concentrations, cDGT) connected to the different characteristic lengths of different configurations (e.g. one or two resin discs) longer, in any case, than that corresponding to LASV. The combination of the information retrieved by the techniques allowed to quantify lability degrees of the pool of Zn complexes and to build up the effective concentration signature for this water Support from the Spanish Minister of Science and Innovation is gratefully acknowledged (Project PID2019-107033GB funded by MCIN/AEI/10.13039/501100011033). JSD acknowledges the University of Lleida for a fellowship PhD contract, and KRS his FISDUR grant (from Generalitat de Catalunya).

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.

Due to the polar and ionic characteristics of glyphosate and its main metabolite, aminomethylphosphonic acid, a derivatization reaction is required before performing liquid chromatographic determination of these compounds. In this study, reaction conditions using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as the derivatization reagent are assessed. A two-level full-factorial design is applied here to optimize the derivatization time (ranging from 0.5 to 20 min) and temperature (from 24 to 55°C). It is found that neither of these two variables have a significant effect on the derivatization process and that the reaction is quantitatively achieved in a few seconds at room temperature (24°C). The results obtained indicate that derivatization reaction with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate is achieved in milder conditions, with a faster kinetic reaction, than those required with the most conventional derivatization reagents used today, and the derivatives are more stable. It has been found that the most important parameter affecting the chromatographic separation is the pH of the mobile phase, as it has a significant effect on the retention time of the hydrolyzed excess of reagent. When ammonium acetate is used in the mobile phase, buffered solutions at pH around 5.0 are required.

Determining bioavailable trace concentrations of mercury (Hg) in water is still a challenging analytical task. In this study, we report a methodology for determining labile Hg in natural waters using newly developed sorbents. Silicon dioxide at a nanoparticle range (Si-np) and cellulose powder at a microparticle range (Cel-p), both modified with the ionic liquid trioctylmethylammonium thiosalicylate (TOMATS), have been tested as sorbents (sorb-TOMATS) for Hg(II) uptake from solution. These novel sorb-TOMATS materials were characterized, and parameters affecting the uptake were examined. A similar Hg(II) uptake efficiency (97%) and binding capacity (9 mg Hg/g) was obtained for both sorb-TOMATS, while only a 25% of Hg(II) was taken up using non-impregnated materials. Moreover, these sorb-TOMATS were effectively embedded in agarose gel and were tested as a novel binding phase for the Diffusive Gradients in Thin Films (DGT) technique. Research revealed Si(np)-TOMATS sorbent as a suitable binding phase in the DGT technique for Hg(II) measurements, since it also allowed the efficient elution of the bound Hg(II). This new binding phase showed strong linear correlation between the accumulated Hg(II) mass and deployment time, which is in agreement with the DGT principle. In summary, this novel sorbent has a great potential to improve Hg monitoring in natural waters when integrated it in the DGT design. © 2019 Elsevier Ltd, This work was supported by the Ministerio de Economía, Industria y Competitividad under project CTM 2016-78798-C2-2-P (AEI/FEDER/UE); G. Elias would like to express her gratitude for scholarship IFUdG 2016-2018. We would also like to acknowledge the participation of M. López in the laboratory work.

The presence of heavy metals in water resources directly affects consumer health. The quality of surface water resources in Central America is usually low due to the presence of metals and other pollutants. The lack of analytical instrumentation to perform routine monitoring of water has encouraged the development of easy tools to facilitate the determination of heavy metals in waters in remote sites. In this study, we evaluated the use of different sorbents, such as Adsorbsia As600 (titanium dioxide), Iontosorb Oxin, 8-hydroxyquinoline bearing functional groups, and Duolite GT-73, with thiol functionality, for Cd, Ni, Cu, Zn, and Al extraction. It was found that both Adsorbsia As600 and Iontosorb Oxin allowed the adsorption of all metals, and the recovery was achieved using either HCl or ethylenediaminetetraacetic sodium salt (EDTA) solutions. Hence, Adsorbsia As600 was employed for in situ sampling in the metal contamination evaluation of water samples (from 15 wells and nine storage tanks) from the municipality of Torola, Mozarán, El Salvador. The developed procedure allowed all the metals in the samples to be detected, and Ni and Al were found to be above Salvadoran guidelines for drinking water quality The financial support of research project CTM2016-78798-C2-2-P (AEI/FEDER/UE) is also acknowledged

A simple and effective method for the detection of three pesticides (chlorpyrifos, diazinon and cyprodinil) is developed using a polymer inclusion membrane (PIM) prior to gas chromatography and mass spectrometry detection (GC-MS). Analytes are extracted from natural water samples using a 3 cm2 PIM made of the polymer, cellulose triacetate (CTA), and the plasticizer, nitrophenyl octyl ether (NPOE). Addition of the plasticizer to the CTA matrix is found to be necessary for the extraction of pesticides. After extraction, analytes are recovered from the membrane with 1 mL of acetonitrile and injected into the GC-MS system. The main factors affecting the extraction efficiency are evaluated, including membrane composition, stirring mode, extraction and elution time. Ultrasonic assisted elution of the extracted pesticides is accomplished after 15 min of contact. The PIM-assisted extraction method makes it possible for pesticides to be determined in the range of 50–1000 ng L−1 with good linearity (coefficient of determination ≥0.995) and suitable recoveries (85–119%) and precision (

A novel and simple method is presented for the preconcentration and determination of mercury (Hg) from natural waters through its extraction into a polymer inclusion membrane (PIM) containing the task-specific ionic liquid trioctylmethylammonium thiosalicylate (TOMATS) followed by Energy Dispersive X-ray fluorescence (EDXRF) analysis. The determination was made directly on the membrane without any treatment or elution step, and due to the characteristics of the PIM no matrix or thickness corrections were required in EDXRF analysis. Under the best extracting and EDXRF operating conditions, a Hg limit of detection of 0.2 μg Hg L

TiO2 in situ growth on three commercial membranes (polysulfone – PS, polyvinylidene fluoride – PVDF and polytetrafluoroethylene – PTFE) and its hydrothermal post-crystallization to transform TiO2 into a photocatalytically-active phase, were investigated under mild synthesis conditions to preserve the textural properties of the supports. The membranes were successfully prepared and characterized by scanning electron microscopy, thermogravimetry analysis, N2 physisorption, X-ray diffraction, and water contact angle measurements, among other techniques. Membrane supports with a more opened porosity and high hydrophilicity allowed to enhance the content and distribution of the anatase TiO2 nanoparticles on the membrane surface. The efficiency and the permeate flux of the developed membranes were investigated to simultaneously remove diclofenac (DCF) and 17α-ethinylestradiol (EE2) from water by adsorption and UV–LED (light-emitting diode) photocatalysis under continuous recirculating mode. All TiO2 membranes achieved removal efficiencies above 90% for both contaminants, EE2 being always preferentially adsorbed over DCF due to electrostatic repulsions between the DCF molecules and the surface of these membranes. The permeate flux of TiO2 membranes was enhanced after UV-LED exposure as a consequence of the degradation of the contaminants adsorbed on the membrane surface during the dark phase. Moreover, the stability of TiO2 nanoparticles on these membranes was studied by static tests under sonication and several consecutive reaction cycles. The TiO2 membrane prepared with PVDF was the most stable, also presenting a high photocatalytic activity.

Polymer inclusion membranes (PIMs) have been prepared using cellulose triacetate (CTA) as polymer and derivatives of the commercial ionic liquid (IL) Aliquat 336, trioctyl methylammonium chloride (AlqCl), as extractants. The different ILs were prepared by exchanging chloride anion from AlqCl for other more lipophilic anions, obtaining IL derivatives AlqNO 3 and AlqSCN. PIMs containing these extractants at two different concentrations (30% and 60%) were prepared and characterized using X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), contact angle and impedance spectroscopy to obtain information on the material properties of both the surface and bulk membranes. The IL counter-anion affects the membrane's electrical parameters (dielectric constant and conductivity) as well as its hydrophobic character, which also depends on the IL concentration in the PIM formulation. Passive transport across the different PIMs using HCl and NaCl aqueous solutions was also considered, and the results obtained seem to be directly related to the hydrophilic/hydrophobic character of the studied membranes The financial support of the Spanish government through research project CTM2013-48967-C2-2-P is acknowledged. R. Vera acknowledges a grant from the Spanish Ministerio de Economía y Competitividad (ref. BES-2014-068314)

A novel and environmentally-friendly procedure for the preparation of polymer inclusion membranes (PIMs) containing an ionic liquid is presented for the first time. Traditionally, PIMs are prepared by a solvent casting method with the use of harmful organic solvents. Here we report a new solvent-free procedure based on a thermal-compression technique which involve the melting of the components of the PIM and the application of a high pressure to the melted specimen to form a flat-sheet film. In our study, we have tested different polymers, such as two cellulose derivatives as well as two thermoplastic polymers, polyurethane (TPU) and poli ε-caprolactone (PCL). The ionic liquid (IL) trioctylmethylammonium chloride (Aliquat 336) has been used to produce PIMs with a fixed composition of 70% polymer–30% IL (w/w). Both TPU and PCL polymers provide successful membranes, which have been thoroughly characterized. PIMs based on the polymer PCL showed a high stability. To test whether the properties of the IL were affected by the preparation conditions, the extraction ability of Aliquat 336 was investigated for both PCL and TPU membranes in terms of Cr(VI) extraction. Satisfactory values (90% extraction) were obtained for both membranes tested, showing this novel procedure as a green alternative for the preparation of PIMs with ILs This research was funded by the Spanish government through research projects CTM2013-48967-C2-2-P and CTM2016-78798-C2-2-P (AEI/FEDER/UE)

Este artículo contiene 6 páginas, 3 figuras, 1 tabla., The presence of Zn in surface waters from abandoned mining zones is a critical issue since excess Zn concentrations may affect aquatic life and whole ecosystems. We present, for the first time, a simple tool based on a polymer inclusion membrane (PIM) intended to monitor Zn in river water by mimicking metal accumulation in the biofilm. The PIM-based probe contains a polymeric membrane prepared using cellulose triacetate (CTA, 50% w/w) as the base polymer, nitrophenyloctyl ether (NPOE) as the plasticizer (20% w/w), and the ionic liquid (IL) Cyphos 104 as the extractant (30% w/w). The accumulation of Zn in the acceptor phase (0.01 M HNO3) was evaluated for different free metal concentrations at 4 h accumulation time resulting in a good correlation between the free metal concentration and the accumulated one. We also found that the metal accumulated agrees with the free metal fraction upon addition of EDTA in the donor solution. The results for Zn accumulation with the PIM-based probe were found to be comparable to those obtained for a biofilm that was grown in a stream from an abandoned mine area and subsequently translocated to the laboratory and put in contact with Zn polluted stream water, so confirming the effectiveness of this new probe in mimicking Zn accumulation in the biofilm., The financial support of the research project CTM2016-78798-C2-2- P (AEI/FEDER/UE) is acknowledged.

The presence of mercury (Hg) in the environment is a major concern because mercury is toxic for living organisms. Estimating the Hg toxicity of environmental samples is difficult because contaminants occur in pools of various bioavailabilities, and thus, measuring the total concentration of a contaminant rarely reflects the real toxicity and risk. There is therefore a need to design advanced methods to measure the bioavailable fraction of the contaminants. Here, we used the diffusive gradient in thin films (DGT) method to determine the bioavailability of Hg in agricultural soils containing 0.02 and 0.64 mg kg−1 of Hg. Specifically, we used homemade manufactured open and restricted diffusive layers to distinguish between inorganic and organic bioavailable Hg species in soil. The findings demonstrate for the first time the successful use of restricted gel for the determination of inorganic Hg species in soil. Moreover, a model program has been used to calculate the effective concentration for predicting Hg concentration uptake by plants. For this purpose, lettuces were planted in soils to assess Hg soil-to-plant transfer. Concentrations of Hg obtained by DGT measurements in soils matched the Hg concentration found in lettuce roots, thus confirming the effectiveness of this technique in predicting Hg uptake by plants. © 2019, Springer Nature Switzerland AG., The authors gratefully acknowledge the financial support of the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) through projects AGL2017-89518-R and CTM2016-78798-C2-2-P (AEI/FEDER/UE). Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

In this study, we have evaluated two different ionic liquids (IL) as extractants based on the same cation (trioctylmethylammonium) but bearing the anion thiosalicylate (TOMATS) or salicylate (TOMAS). Both IL have been incorporated as carriers in polymer inclusion membranes (PIMs), and mercury (Hg) has been preconcentrated using a special device. Results show that among the tested IL, TOMATS has given better results. A PIM made of 50% cellulose triacetate, 30% TOMATS and 20% nitrophenyl octyl ether as a plasticizer enabled the effective transport of Hg to a 10−3M cysteine solution used as a stripping phase. This novel and simple PIM-device system allows the transport of Hg at low concentration levels in different types of natural waters such as rivers, groundwater and seawater without any previous treatment. Since no matrix effect was observed on Hg transport efficiency with different waters, this newly developed PIM-system could be used as a global detection system for this metal. The effect of biofilm growth on the surface of PIMs has been investigated for the first time, and no significant differences on Hg transport have been found when using a fresh PIM and a PIM deployed for 7 days in a pond. © 2019 Elsevier B.V., The financial support of the Ministerio de Economía y Competitividad through projects CTM2013-48967-C2-2-P and CTM2016-78798-C2-2-P (AEI/FEDER/UE) is gratefully acknowledged. Gemma Elias would also like to thank the scholarship IFUdG2016-2018 from University of Girona. C. Martínez and E. Ubasart are also acknowledged for their participation in the laboratory works.

A polymer inclusion membrane (PIM) containing the ionic liquid methyltrioctylammonium chloride (Aliquat 336) as the carrier has been used satisfactorily for the preconcentration of arsenate present in groundwater samples, allowing its determination by a simple colorimetric method. The optimization of different chemical and physical parameters affecting the membrane performance allowed its applicability to be broadened. The transport of As(V) was not affected by the polymer used to make the PIM (cellulose triacetate (CTA) or poly(vinyl chloride) (PVC)) nor the thickness of the membrane. Moreover, the use of a 2 M NaCl solution as a stripping phase was found to allow the effective transport of arsenate despite the presence of other major anions in groundwater. Using the PIM for the analysis of different groundwaters spiked at 100 &mu, g L&minus, 1 resulted in recoveries from 79% to 124% after only 5 h of contact time. Finally, the validated PIM-based method was successfully applied to the analysis of waters containing naturally occurring arsenate.

A supported liquid membrane is developed for the separation of Cd from either high in salinity or acidity aqueous media. The membrane consisted of a durapore (polyvinylidene difluoride) polymeric support impregnated with a 0.5 M Aliquat 336 solution in decaline. The effect of carrier concentration, organic solvent and feed and receiving solutions on the metal permeability is studied. This system allows the effective transport of trace levels of Cd through the formation of CdCl42−, which is the predominant species responsible for the extraction process, in both NaCl and HCl solutions. The supported liquid membrane system in a hollow fibre configuration allows the enrichment and separation of trace levels of Cd from spiked seawater samples, facilitating the analytical determination of this toxic metal The financial support of the Ministerio de Economía y Competitividad through project CTM2016-78798-C2-2-P (AEI/FEDER/UE) is gratefully acknowledged

Metal speciation studies can be performed with a new technique based on a functionalized membrane. The estimation of not only the total amount of metal, but also the metal available to living organisms is very important. In this context, we have investigated the use of a polymer inclusion membrane (PIM) in a new tool for the determination of free metal ion concentration. In order to check the usefulness of PIM devices in metal speciation studies and metal availability to potato plants (Solanum tuberosum), Zn has been chosen as a case study. The PIM designed for Zn transport uses polyvinyl chloride (PVC) as polymer and di-(2-ethylhexyl) phosphoric acid (D2EHPA) as carrier, with 0.01M nitric acid in the receiving solution. The stability of the PIM has been demonstrated and good linearity of PIM-device fluxes (JPIM) with free metal concentration was observed for total metal concentrations ranging from 3 µM up to 70 µM. The presence of different ligands, such as ethylenediaminetetraacetic acid (EDTA), humic acid (HA) and citrate, greatly influences the measured JPIM because the formation of metal complexes in the donor phase decreases the free Zn concentration in the sample. Good correlation has been found when comparing PIM fluxes and metal accumulation in potato plants roots in the presence of EDTA. But, the root uptake did not change when adding citrate and HA to the hydroponic medium, so the uptake does not always follows the Free Ion Activity Model (FIAM). These ligands might induce physiological changes in the roots and enhance metal uptake. The financial support of the Spanish government through research projects CTM2013-48967 and CTM2016-78798 (AEI/FEDER/UE) is acknowledged. R. Vera acknowledges a grant from Spanish Ministerio de Economía y Competitividad ref. BES-2014-068314.

The use of pesticides to manage pest problems for crop protection is common practice around the world, and their accumulation in soils and contamination of water bodies is a global environmental problem. In Australia, an organomercury (Hg)-based fungicide is the most popular for control of pineapple disease of sugarcane. However, the presence of Hg is of great concern because of potential adverse effects in the environment. The purpose of this work was to evaluate the residual levels of Hg in soils of sugarcane cultivation from a catchment in North Queensland (Australia). Mercury was surveyed in soils close to the Tully River at 3 different depths (100, 200 and 300mm). Additionally, total Hg (THg) and the labile fraction of Hg in water (measured by the diffusive gradient in thin film technique) were determined in the Tully River. A pristine site, the Tully Gorge National Park upstream of sugarcane fields, was selected for background Hg concentration estimation. In soils, Hg levels ranged from 18 to 264μgkg-1, with one of the soil samples being almost 10 times higher than at other sites at the surface level (199μgkg-1). Total and labile concentrations of Hg in water increased from the Hg-elevated soil sampling sites (0.085μgL-1 and 0.061μgL-1) to downstream sites (0.082μgL-1 and 0.066μgL-1), which is likely due to agricultural runoff. Indeed, except for the upstream control site, the THg concentration in water is over the limit permitted by the Australian freshwater quality guideline for protection of 99% species (0.06μgL-1). These findings point to the need to perform further research to reveal the mechanisms for release of Hg from soil and whether this might be causing important adverse effects to the Great Barrier Reef located in front of this river catchment.

In the present work, a novel and simple detection system for As inorganic species contained in groundwater is presented. To reach the required detection limit, the proposed methodology is based on two steps: first is the transport and preconcentration of the inorganic arsenic species using a polymer inclusion membrane (PIM) system and second is the formation of a coloured complex, the absorbance of which is measured. Different parameters related to the membrane composition and the transport kinetics have been studied, and it was found that membranes made of polyvinyl chloride (PVC) as a polymer, and Aliquat 336 as a carrier, ensured efficient arsenic transport when the carrier content was at least 31 % (w/w). The implementation of the designed PIM in a special device that contained only 5 mL of the stripping solution (0.1 M NaCl) allowed As preconcentration from a 100-mL water sample, thus facilitating its detection with the colorimetric method. The new method developed here was validated, and its analytical figures of merit were determined, i.e. limit of detection of 4.5 μg L(-1) at 820 nm and a relative standard deviation within the range 8-10 %. Finally, the method was successfully applied to the analysis of different water samples from Catalonia region with naturally occurring As.

The effect of the base-polymer and carrier concentration on the physical–chemical characteristics of polymer inclusion membranes (PIMs) is investigated. Two typical polymers used to manufacture PIMs have been tested, i.e. poly(vinyl chloride) (PVC) and cellulose triacetate (CTA), and different amounts of the ionic liquid (IL) Aliquat 336, used as extractant, were the PIMs constituents. The resulting PIMs have been characterized using different techniques to provide information on both the surface and bulk material properties. XPS results do not practically show differences in the surfaces of CTA and PVC based membranes with similar Aliquat 336 content, and the total surface coverage for Aliquat 336 concentration higher than 40% (w/w) was obtained, which was also corroborated with the results of contact angle measurements. However, membrane elastic response seems to be strongly dependent on both base-polymer and Aliquat 336 concentration, which affect Young modulus and elongation at break. The IL concentration also increases dielectric constant and the conductivity of the PIMs from both polymers according to impedance spectroscopy results, providing a rather conductive character to both kind of samples for Aliquat 336 content higher than 40% (w/w) (average conductivity around 10 −3 (Ω m) −1 ). CTA and PVC-based PIMs with Aliquat 336 content around 45% have been used in order to compare the influence of the polymer on the transport of As(V).

Biologically based wastewater treatment systems are considered a sustainable, cost-effective alternative to conventional wastewater treatment systems. These systems have been used and studied for the treatment of urban sewage from small communities, and recently, it has been reported that they can also effectively remove emerging organic contaminants (EOCs). EOCs are a new group of unregulated contaminants which include pharmaceutical and personal care products, some pesticides, veterinary products, and industrial compounds among others that are thought to have long-term adverse effects on human health and ecosystems. This review is focused on reporting the ability of biologically based wastewater treatment systems to remove EOCs and the main elimination mechanisms and degradation processes (i.e., biodegradation, photodegradation, phytoremediation, and sorption) taking place in constructed wetlands, ponds, and Daphnia and fungal reactors.

A highly sensitive flow analysis system has been developed for the trace determination of reactive phosphate in natural waters, which uses a polymer inclusion membrane (PIM) with Aliquat 336 as the carrier for on-line analyte separation and preconcentration. The system operates under flow injection (FI) and continuous flow (CF) conditions. Under optimal FI conditions the system is characterised by a linear concentration range between 0.5 and 1000 μg L(-1)P, a sampling rate of 10h(-1), a limit of detection of 0.5 μgL(-1)P and RSDs of 3.2% (n = 10, 100 μg L(-1)) and 7.7% (n = 10, 10 μg L(-1)). Under CF conditions with 10 min stop-flow time and sample solution flow rate of 1.32 mL min(-1) the flow system offers a limit of detection of 0.04 μg L(-1)P, a sampling rate of 5h(-1) and an RSD of 3.4% (n=5, 2.0 μg L(-1)). Interference studies revealed that anions commonly found in natural waters did not interfere when in excess of at least one order of magnitude. The flow system, operating under CF conditions, was successfully applied to the analysis of natural water samples containing concentrations of phosphate in the low μg L(-1)P range, using the multipoint standard addition method.

Mercury-based screen-printed electrodes (SPE) combined with square-wave anodic stripping voltammetry (SWASV) techniques for the analysis of copper, cadmium, lead, and zinc in different water samples have been applied. The detection system has been implemented in a flow cell and different experimental conditions have been tested in view of its application for in-situ monitoring. In particular, an acetate buffer together with a low chloride concentration (0.025 M NaCl) provided best performance and reproducible results. Additionally, the flow system was validated for the first time in terms of limits of detection, linearity, repeatability and recovery. Limits of detection of 2.8 μg L-1, 4.1 μg L-1, and 7.5 μg L-1 for cadmium, lead and copper respectively and repeatabilities lower than 10% (as RSD) were found. Good recoveries have been obtained for the three cations and in particular for copper, even in the presence of zinc. Finally, the method has shown its efficiency for the rapid screening of lead, cadmium and copper contained in both natural waters and wastewater samples. © 2013 Copyright Taylor and Francis Group, LLC., Financial support from CTQ2008-06847-C02-02/TECNO, MAT2008-03079/NAN and WARMER project (FP6-034472) are acknowledged.

This study investigated the formation of eight N-nitrosamines (N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosodi-n-propylamine (NDPA), N-nitrosomorpholine (NMOR), 1-nitrosopyrrolidine (NPYR), 1-nitrosopiperidine (NPIP), and N-nitrosodibutylamine (NDBA)) after the chlorination (with NaOCl) of wastewater effluents from two wastewater treatment plants (WWTPs) located in North East Spain. Two different WWTPs, one with nitrification-denitrification process (CB1) and the other without (CB2) have been chosen. The concentrations of individual N-nitrosamines in non-chlorinated tertiary treated wastewater effluents ranged from

We have evaluated a new titanium dioxide (Adsorbsia As600) for the adsorption of both inorganic As (V) and As (III) species. In order to characterize the sorbent, batch experiments were undertaken to determine the capacities of As (III) and As (V) at pH 7.3, which were found to be 0.21 and 0.14 mmol g−1, respectively. Elution of adsorbed species was only possible using basic solutions, and arsenic desorbed under batch conditions was 50 % when 60 mg of loaded titanium dioxide was treated with 0.5 M NaOH solution. Moreover, its use as a sorbent for solid-phase extraction and preconcentration of arsenic species from well waters has been investigated, without any previous pretreatment of the sample. Solid-phase extraction was implemented by packing several minicolumns with Adsorbsia As600. The method has been validated showing good accuracy and precision. Acceptable recoveries were obtained when spiked waters at 100–200 μg L−1 were measured. The presence of major anions commonly found in waters did not affect arsenic adsoption, and only silicate at 100 mg L−1 level severely competed with arsenic species to bind to the material. Finally, the measured concentrations in water samples containing arsenic from the Pyrinees (Catalonia, Spain) showed good agreement with the ICP-MS results The financial support of the Spanish government through research project CTM2013-48967-C2-2-P is acknowledged. R. Vera acknowledges a grant from Spanish Ministerio de Economía y Competitividad ref. B ES-2014-068314

We aimed to achieve improved instrumental sensitivity and detection limits for the analysis of several elements (Cu, Ni, Zn, Pb and Cd) in aqueous samples with energy dispersive X-ray fluorescence spectrometry (EDXRF). The metals were pre-concentrated from aqueous solutions using commercially available organic-based solid-phase extraction (SPE) disks functionalized with iminodiacetate groups. These thin-layer organic materials provide an ideal support for XRF analysis. The elements were collected on the SPE extraction disks using a simple filtration procedure (starting with 1 L of aqueous sample) that allows direct XRF measurements to be performed in the field (in situ). We evaluated the analytical possibilities and drawbacks of using this pre-concentration procedure in combination with the following XRF configurations: a handheld unit, a benchtop EDXRF system and a high-energy polarized-beam EDXRF instrument (HE-P-EDXRF). Using the HE-P-EDXRF system, the detection limits for all metals were more than one order of magnitude lower than those attained using handheld and benchtop EDXRF instrumentation. For the detection of metal concentrations higher than ~ 20 μg/L, however, handheld or benchtop systems remain a very good option due to their extreme simplicity of operation and low-cost, compact design. We demonstrate the application of these methodologies, using the three equipment systems, to the analysis of trace concentrations of metals in different types of aqueous samples, including tap water and waste water. © 2011 Elsevier B.V., This work was supported by the Spanish “Consolider Ingenio 2010” Program (Project ref. CSD2006-00044) and the Spanish National Research Programs (Project ref. CGL2007-66861-C4 and CGL2010-22168-C03-01).

This work deals with the evaluation of different thiacalix[4]arene derivatives included in polymeric PVC membranes for the optical sensing of metallic cations. Two ligands have been studied: thiacalix[4]arene (ligand 4) and its p-tert-butyl-derivative (ligand 2). Membranes including ligand 4 were tested for different metals and better results were obtained for Cd2+, Ag+, and Pb2+. In the case of films incorporating the neutral ionophore, ligand 2, a pH sensitive dye (ETH 2439), and an anionic additive were also added. A selective response to Ag+ was achieved in acetate buffer at pH 5.

This article gives an overview of the state-of-the-art of multi-element and single-element preconcentration procedures prior to X-ray fluorescence (XRF) analysis of liquid samples. Many of these preconcentration methods were developed long ago and the purpose of this review is to present some new efficient variations of these methods and new techniques extending the possibilities of XRF for liquid solutions analysis. In addition, trends and future perspectives in this domain are also commented on and discussed in the last section of the review.

This study investigates the transport of arsenic species through a supported liquid membrane (SLM) using Aliquat 336. Preliminary liquid–liquid extraction experiments were performed and several conditions affecting the extraction, such as the organic solvent and pH of the aqueous phase, were evaluated. The best results were obtained when using a mixture of dodecane modified with 4% dodecanol at pH 13. The experimental distribution data were numerically analysed by Letagrop-DISTR software to obtain a thermodynamic model corresponding to the extraction for both As(V) and As(III) species. Taking into account the good results obtained in liquid–liquid experiments, a supported liquid membrane (SLM) system was developed based on the best separation conditions. As(V) was stripped using 0.1 M HCl. The SLM enabled the separation of As(V) and As(III) species based on their different kinetic behaviour. The system also permitted the transport of As(V) at ppb levels and the removal of As(V) from real matrices, such as spiked tap water and river water.

The use of commercially available solid phase extraction (SPE) anion‐exchange cartridges for the separation and preconcentration of Pd(II), Pt(IV) and Rh(III) in chloride aqueous samples is described and characterised. Platinum Group Metals (PGMs) form anionic species in aqueous chloride solutions permitting their adsorption via an ion‐exchange mechanism by commercially available sorbents containing quaternary ammonium substituents or protonated aminopropyl groups. The difficulties associated with the extraction processes, interference of chloride ions in the case of Pd and Pt, and the low extraction efficiency in the case of Rh, are overcome modifying the metal speciation in the source solution by adding thiocyanate and tin chloride. These refined processes give quantitative metal adsorptions. The use of acidic thiourea solutions allows the quantitative recovery of Pd, Pt, and Rh in the case of the Isolute‐SAX cartridge. High preconcentration factors were obtained with Isolute‐NH2 and sodium ch...

This work was aimed at improving the instrumental sensitivity and detection limits for Cd determination in liquid samples by using conventional Wavelength Dispersive X-ray Fluorescence (WDXRF) instrumentation equipped with Rh-anode X-ray sources. The fact that the background is drastically reduced when using activated membranes as a preconcentration tool to collect Cd from liquid samples permits an improvement of the sensitivity compared with the direct analysis of liquid samples. Instrumental WDXRF parameters, as well as the study of Cd-K and Cd-L series spectral lines, were evaluated to select the best conditions for Cd quantitation. The Cd-L α spectral line was found to be the best choice in terms of sensitivity and repeatability. The calculated detection limit when this spectral line was used to carry out the measurements was 0.17 mg L − 1 Cd, which is suitable for Cd determination in most liquid samples involved in environmental studies.

Sensitive and stable monitoring of heavy metals in seawater using screen-printed electrodes (SPE) is presented. The analytical performance of SPE coupled with square wave anodic stripping voltammetry (SWASV) for the simultaneous determination of Pb and Cd in seawater samples, in the low microgL(-1) range, is evaluated. The stripping response for the heavy metals following 2min deposition was linear over the concentration range examined (10-2000microgL(-1)) with detection limits of 1.8 and 2.9microgL(-1) for Pb and Cd, respectively. The accuracy of the method was validated by analyzing metal contents in different spiked seawater samples and comparing these results to those obtained with the well-established anodic stripping voltammetry using the hanging mercury drop electrode. Moreover, a certified reference material was also used and the results obtained were satisfactory.

A hollow fiber supported liquid membrane (HFSLM) system for the removal and preconcentration of Cr(VI) has been developed and characterized using Aliquat 336 as carrier. The influence of the chemical composition on the efficiency of the membrane system has been investigated, such as the organic solvent and the stripping composition. Among the stripping reagents tested, a solution of 0.5 M HNO 3 was found to be the most effective to strip Cr(VI) from the loaded organic phase. Moreover, physical parameters such as the stability of the membrane and the operation mode of the module were also evaluated. The results demonstrated the effectiveness of the HFSLM system during 8 non-stop days’ operation. This membrane-based separation system has effectively been used to remove Cr(VI) from different aqueous samples, such as industrial waters and spiked natural waters at μg L −1 levels. Moreover, the system has allowed both the separation and enrichment of the metal and, thus, facilitating the detection of chromate contained in aqueous samples and reducing the volume of polluted water to be treated.

The synthesis of a new coordinating polymer containing nitrogen atoms by the copolymerization of a 15-membered triolefinic azamacrocycle, 9, named (E,E,E)-1-[(4-methylphenyl)sulfonyl]-6-[(2-trimethylsilylethyl)sulfonyl]-11-[(4-vinylphenyl)sulfonyl)]-1,6,11-triazacyclopentadeca-3,8,13-triene, with styrene is achieved. The novel polymeric material is characterized by means of elemental analysis, IR, 13C-CP MAS, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. We also report the study of palladium and platinum sorption from acidic solutions. A capacity of 0.36 mmol g−1 of polymer for Pd(II) and 0.28 mmol g−1 of polymer for Pt(IV) is determined by the batch-mode. The functionalised polymer presents a high selectivity towards precious metals over base metals such us Cu(II) and Ni(II).