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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.

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

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.

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).

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).

The transport of Cd ions from chloride media high in salinity and acidity through a polymer inclusion membrane has been investigated. The membrane consisted of cellulose triacetate as the polymeric support, o -nitrophenyl octyl ether (NPOE) as the plasticizer and Aliquat 336 as the carrier. The influence of aqueous and membrane components on the metal flux has been evaluated. The transport system designed here is shown to be effective for the transport of Cd in both highly saline and highly acidic media, with similar flux values being reached for both in the range studied. The effect of carrier and plasticizer content in the membrane has been investigated; the maximum flux value was achieved with a carrier content of 3 mg cm −2 and 0.3 mL of NPOE. The results showed that the absence of plasticizer inhibited the transport of the metal at low carrier content, but when dealing with membranes containing a high amount of carrier, the transport of Cd was possible. This highlights the ability of this carrier to create intramembrane pathways in which the complex formed by metal species and a carrier can be transported. Finally, the separation system developed has been successfully applied to the removal of this toxic metallic pollutant from different aqueous samples, such as spiked seawater and a Ni–Cd battery leaching.

This paper describes a comparative study of activated composite (ACM) and hybrid membranes (HM), both incorporating the commercial anion exchanger Aliquat 336 as a carrier, for the transport of Pt(IV) ions in chloride media. The incorporation of the carrier molecules in the polymeric network of both types of membranes is one of the approaches to overcome supported liquid membrane (SLM) instability. ACM are membranes with a bilayer structure: a porous lower polymeric support prepared by phase inversion (polysulfone) and a dense upper layer made by interfacial polymerisation (polyamide). HM are plasticized membranes consisting of a polymeric matrix of cellulose triacetate with a plasticizer and modified by the incorporation of an inorganic material (silanes) prepared by a sol–gel route. The efficiency of both types of membrane for the transport of Pt(IV) ions has been investigated, and several parameters affecting metal transport have been evaluated, such as the composition of the stripping phase and the selectivity of the membranes in the presence of Pd(II) ions. Moreover, comparative studies for both ACM and HM systems have been made by contacting the same feed solution in a triple-compartment cell. Finally, the results of these membrane systems are compared with those previously reported using polymer inclusion membranes (PIM) and SLM for the transport of Pt(IV) under similar experimental conditions.

The adsorption of palladium(II), rhodium(III), and platinum(IV) from diluted hydrochloric acid solutions onto Fe(3)O(4) nanoparticles has been investigated. The parameters studied include the contact time and the concentrations of metals and other solutes such as H(+) and chloride. The equilibrium time was reached in less than 20 min for all metals. The maximum loading capacity of Fe(3)O(4) nanoparticles for Pd(II), Rh(III), and Pt(IV) was determined to be 0.103, 0.149, and 0.068 mmol g(-1), respectively. A sorption mechanism for Pd(II), Rh(III), and Pt(IV) has been proposed and their conditional adsorption equilibrium constants have been determined to be logK=1.72, 1.69, and 1.84, respectively. Different compositions of eluting solution were tested for the recovery of Pt(IV), Pd(II), and Rh(III) from Fe(3)O(4) nanoparticles. It was found that 0.5 mol L(-1) HNO(3) can elute all of the metal ions simultaneously, while 1 mol L(-1) NaHSO(3) was an effective eluting solution for Rh(III), and 0.5 mol L(-1) NaClO(4) for Pt(IV). In competitive adsorption, the nanoparticles showed stronger affinity for Rh(III) than for Pd(II) and Pt(IV).

A supported liquid membrane (SLM) system for the separation and concentration of palladium from aqueous feed chloride solutions containing SCN − has been developed and characterized by using triisobuthylphosphine sulfide (Cyanex 471) as a carrier. Special attention has been paid to the effect of the organic solvent on the stability of the membrane. Among the different solvents tested in this work, the aliphatic diluent decaline provided the best results in terms of the stability of the LM. Moreover, the influence of chemical parameters such as Cyanex 471 and SCN − concentration on palladium permeability has also been determined for the liquid membrane in flat-sheet configuration. Based on these results, the system was implemented in hollow fiber geometry and the influence of chemical parameters as well as the mode of operation of the HFSLM system has been studied. The selectivity of the proposed LM system was evaluated by using synthetic feed solutions containing Pd(II), Pt(IV) and Rh(III) in chloride media to which small amounts of thiocyanate were added. The results revealed palladium as the only metal transported. This HFSLM system has been successfully applied for the selective recovery and concentration of palladium from solutions obtained from the leaching of spent automotive catalysts.

This study is aimed at developing new stabilized membranes for the transport of Pt(IV) based on in situ anchoring anion-exchange groups to the pores of the host poly(propylene) membranes by photo-polymerization of the monòmers along with a crosslinker

To provide further insight into the diferent membrane possibilities for As transport, in this work PIM membranes based on poly(vinyl chloride) (PCV) have been developed and tested for As extraction. Parameters affecting the membrane composition as well as the effect of diferent ions present in natural wàters have been studied

The goal of this study is the development of a separation system based on PIMs for the transport of three TCs (i.e. tetracycline (TC), oxytetracycline (OTC) and doxycycline (DC), and four SAs (i.e. sulfathiazole (STZ), sulfamethazine (SMN), sulfamethoxazole (SMX) and sulfapyridine (SPY) contained in diferent environmental samples The financial suport by Ministerio de Ciencia e Innovación through Project CTM2011-28765-C02-02 is gratefully acknowledged. Aida Garcia wants to acknowledge a BR2011/27 research fellowship from the University of Girona

The presence of pharmaceuticals and endocrine-disrupting chemicals (EDCs) in wastewater treatment plant effluents is an issue of great concern due to the negative effects that these compounds may have on human health and ecosystems. The present study aims to assess the capacity of two aquatic plants (Lemna sp. and Spirogyra sp.), commonly found in polishing ponds, for removing six pharmaceutical compounds (diclofenac, acetaminophen, ibuprofen, carbamazepine, clofibric acid, and propranolol), two EDCs (17α-ethinylestradiol and bisphenol A), and one stimulant (caffeine) under laboratory-scale conditions. Planted and unplanted reactors fed with secondary-treated wastewater or ultrapure water in both covered and uncovered conditions were studied. The highest removal efficiencies, which ranged from 31 to 100 %, were achieved in uncovered planted systems containing secondary-treated wastewater after 20 days of incubation. The results demonstrated that non-charged compounds with a log Kow between 2 and 4 were affected by the presence of vegetation, probably due to their plant uptake, whereas negatively charged compounds were not. This highlights that the presence of plants in polishing ponds plays an important role in the removal of pharmaceuticals and EDCs The financial support of the Ministerio de Ciencia e Inovacion through project CTM2011-28765-C02-02 is gratefully acknowledged. Aida Garcia-Rodriguez thanks the University of Girona for research Grant BR2011/27

Antibiotics belong to the so called group of emerging organic contaminants (EOCs) and their presence in natural waters is of considerable environmental concern. Due to the need of their determination in natural waters at trace levels, we have developed a polymer inclusion membrane (PIM) capable of transporting six frequently used antibiotics (four sulfonamides, SAs, and two tetracyclines, TCs). Cellulose triacetate (CTA) and polyvinyl chloride (PVC) based membranes have been tested in transport experiments, with the former membranes exhibiting better permeability for the antibiotics studied. The addition of a plasticizer further improved the permeability of the CTA-based membranes. A PIM containing 30 wt% ETA, 26 wt% Aliquat 336, and 44 wt% 2-nitrophenyloctyl ether, provided the highest percentage of transport over a 24 h period, varying from 75% (sulfathiazole, STZ) to 100% (tetracycline, TC and oxytetracycline, OTC), except for sulfapyridine, (SPY) (55%). The feed solution in these transport experiments was at pH 9 while the stripping solution contained 1.0 M NaCl. A PIM-based device was constructed for the preconcentration of the antibiotics studied in its stripping solution and it was successfully applied to the preconcentration of these antibiotics in environmental water samples The financial support of the Ministerio de Economia y Competitividad through project CTM2013-48967-C2-2-P is gratefully acknowledged. Aida Garcia-Rodriguez would like to thank the University of Girona for a research fellowship (BR2011/27)

An analytical method for the simultaneous determination of eight pharmaceutical compounds in biosolids from urban wastewater treatment plants (WWTPs) was developed and validated. The compounds evaluated were non-steroidal anti-inflammatory drugs (naproxen, diclofenac, and ibuprofen), lipid regulators (clofibric acid), and antibiotics (sulfathiazole, sulfapyridine, sulfamethazine, and sulfamethoxazole). Ultrasound assisted extraction with a water–methanol solvent mixture (1:1, v:v) was performed and the compounds were then determined by liquid chromatography coupled with tandem mass spectrometry. The design of the method was based on the application of the standard addition calibration methodology to reduce matrix interferences. Validation procedures were conducted with rabbit excrements as blank samples. Recoveries of the target analytes ranged from 76 to 131% in spiked samples at 50, 200 or 1000 ng g−1 dry weight (dw). The relative standard deviations were in the range of 5–15% and the method detection limits ranged from 2 to 12 ng g−1dw. The method was applied to monitor pharmaceutical concentrations in biosolids from different WWTPs over an eight-month period (May to December 2011). Diclofenac, sulfapyridine and ibuprofen were detected in most of the samples whereas sulfamethazine and ibuprofen were the pharmaceuticals found in the highest concentrations (>200 ng g−1 dw on average) The financial support of the Ministerio de Ciencia e Inovación through projects CTM2008-0647-C02-02/TECNO, CTM2011-28765-C02-02 and CGL2010-22168-C03-03 is gratefully acknowledged

The effect of aquatic vegetation (Spyrogira sp. and Zannichellia palustris), light exposure and water quality (secondary-treated wastewater vs. ultrapure water) on the removal efficiency of six antibiotics (sulfonamides and tetracyclines) is studied in laboratory-scale reactors. After 20d of treatment, 3-59% of sulfonamides were eliminated in the reactors exposed to light. Removal was about 10% in unplanted reactors in darkness. The elimination of tetracycline (TC) and oxytetracycline (OTC) ranged between 83% and 97% in both planted and unplanted reactors. However, in dark unplanted reactors, OTC was largely removed (88%) while only 15% of TC was eliminated. These results suggest that TC was mainly removed by photodegradation whereas biodegradation or hydrolysis process seems to be significant processes for OTC. Sulfonamides were mainly eliminated by biodegradation or indirect photodegradation processes. Pseudo-first order kinetics removal rates ranged from 0.003 and 0.007d-1 for Sulfamethazine and TC in the covered control reactors to 0.13 and 0.21d-1 for TC and OTC in the uncovered control reactors, with half-lives from 3 to 350d. A TC photodegradation product was tentatively identified in uncovered reactors. This study highlights the important role played by light exposure in the elimination of antibiotics in polishing ponds This study has been financed by the Spanish Ministry of Science and Innovation, project CTM2011-28765-C02-02. AG acknowledges a BR2011/27 research grant from the University of Girona

This study involves the preparation and optimization of polymer inclusion membranes (PIMs) based on the polymer cellulose triacetate and the extractant (carrier) Aliquat 336 (a mixture of quaternary ammonium chlorides) for the transport of inorganic As species (arsenite and arsenate) from their aqueous solutions. The influence of the composition of the membranes on its extraction and transport properties was investigated. Better membrane performance was obtained when the membranes did not contain plasticizer and the concentration of the extractant was high. Under these conditions arsenate (As(V)) could be quantitatively separated from As(III) within 5 h even in the presence of common anions (i.e. chloride, phosphate, nitrate, sulfate and carbonate) often encountered in natural waters and industrial and domestic wastewaters.Electrical impedance spectroscopy measurements allowed the determination of the dielectric constant and conductivity values of the PIMs of interest. These results suggested that the extracted As(V) species was HAsO4 2- which was further transported across the membrane by a hopping mechanism, counter currently to the transport of the chloride anions present at a high concentration in the stripping solution.The overall performance of the proposed PIM in terms of stability, selectivity and permeability compared favorably to those of an Aliquat 336 based supported liquid membrane and a commercial multi-valent anion exchange membrane This work was supported by the Spanish Ministerio de Ciencia e Inovación, through Project (CTM2008-06847-C02 02/TECNO). R. Güell gratefully acknowledges a grant awarded by the University of Girona (Ref. BR06/10)

Supported liquid membranes (SLMs) have demonstrated all along the years every high selectivity in facilitated transport of metal ions, however, they have some well known limitations, such as the gradual loss of the organic phase to the aqueous solutions. This paper describes two different types of novel membranes developed for the general purpose of separating and concentrating metal ions of interest in order to improve SLM physical and chemical characteristics. Both hybrid (organic—inorganic) membranes and activated composite membranes have been tested for the selective transport of Zn/Cd and Pt/Pd mixtures. For this purpose, different carriers have been used: 2-ethylhexyldithiophosphoric acid and 2-ethylhexylphosphoric acid for the separation of Zn and Cd whereas Aliquat 336 for Pt/Pd mixtures. The choice of these metal couples is related to environmental detoxification and catalyst recovery, respectively.

This work was aimed to achieve improved instrumental sensitivity and detection limits for the determination of several elements (Cr (VI), Cd, Pd and Pt) in liquid samples by using conventional energy dispersive x-ray fluorescence (EDXRF) and wavelength dispersive x-ray fluorescence (WDXRF) instrumentation. In all cases, the preconcentration of metals from liquid solutions was performed by using membranes activated with the commercial anionic exchanger Aliquat 336 (a quaternary ammonium salt), which also permits the isolation of Cr (VI) species for further x-ray fluorescence analysis. Likewise, for the improvement of the instrumental sensitivity, a special sample holder device was used in the case of Cd determination by EDXRF (tungsten x-ray source) instrumentation. ForWDXRF analysis, the spectral evaluation was carried out by the integration of the peak area (using WinQXAS software) instead of the common net peak line intensity traditionally used in conventional WDXRF systems.With the proposed methodologies, a linear response between themetal present in the aqueous solutions and the metal extracted in the membranes was obtained, highlighting the feasibility of using these membranes as standards for x-ray fluorescence spectrometry (XRF) analysis for future determination of these elements when contained in liquid samples. Concerning the calculated detection limits, in all cases, theywere in the μg l−1 range, indicating the possibilities of the proposed methodology for trace determination content of Cd, Cr(VI), Pd and Pt in liquid solutions using conventional EDXRF andWDXRF instrumentation., This study was financed by the Spanish National Research Programme (projects CGL2007-66861-C04 and Consolider Tragua, ref. CSD2006-00044).

In medicinal chemistry, Pd is perhaps the most-widely utilized precious metal, as catalyst in reactions which represent key transformations toward the synthesis of new active pharmaceutical ingredients (APIs). The disadvantage of this metal-catalyzed chemistry is that expensive and toxic metal residues are invariably left bound to the desired product. Thus, stringent regulatory guidelines exist for the amount of residual Pd that a drug candidate is allowed to contain. In this work, a rapid and simple method for the determination of Pd in API samples by high-energy polarized-beam energy dispersive X-ray fluorescence spectrometry has been developed and validated according to the specification limits of current legislation (10 mg kg−1 Pd) and the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH guidelines). Sample and calibration standards preparation includes a first step of homogenization and then, in a second step, the pressing of the powdered material into pellets without any chemical treatment. The use of several synthetic calibration standards made of cellulose to simulate the API matrix appears to be an effective means to obtain reliable calibration curves with a good spread of data points over the working range. With the use of the best measuring conditions, the limit of detection (0.11 mg kg−1 Pd) as well as the limit of quantitation (0.37 mg kg−1 Pd) achieved meet rigorous requirements. The repeatability of the XRF measurement appeared to be less than 2%, while the precision of the whole method was around 7%. Trueness was evaluated by analyzing spiked API samples at the level of the specification limit and calculating the recovery factor, which was better than 95%. To study the applicability of the developed methodology for the intended purpose, three batches of the studied API were analyzed for their Pd content, and the attained results were comparable to those obtained by the daily routine method (acid digestion plus atomic spectroscopy) used in most pharmaceutical laboratories., This work was supported by the Spanish National Research Programme (Project CGL2007-66861-C4).