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Christoph Janiak - One of the best experts on this subject based on the ideXlab platform.

  • Recent advances in adsorption heat transformation focusing on the development of adSorbent Materials
    Current Opinion in Chemical Engineering, 2019
    Co-Authors: Emrah Hastürk, Sebastian-johannes Ernst, Christoph Janiak
    Abstract:

    Adsorption heat transformation (AHT) is an environmentally friendly energy-saving process applied for air conditioning purposes, that is, either for cooling (including also ice making and refrigeration), or heating. AHT is based on the cycling adsorption and desorption of a working fluid in a porous Material. When the working fluid is driven to evaporation by the active empty Sorbent Material, the required heat of evaporation translates into useful cooling in thermally driven adsorption chillers. Driving heat regenerates the empty Sorbent Material through desorption of the working fluid. The heat of adsorption in the Sorbent Material and the heat of condensation of the working fluid can be used in the adsorption heat-pumping mode. Thus, adsorption heat transformation contributes to energy-saving technologies. AdSorbent development plays a critical role for the improvement of AHT technologies. Besides silica gel and zeolites as adSorbent Materials, which are up to now used in the commercially available AHT devices; especially metal-organic frameworks (MOFs) are getting more attentions in recent years. Composite Materials from salts with silica gels, zeolites and MOFs as well as activated carbons have also been researched to contribute to AHT technologies. Reduction of installation/production cost and enhancement of the efficiency of AHT devices need to be achieved to increase the wider usage of AHT.

  • water adsorption characteristics of mil 101 for heat transformation applications of mofs
    European Journal of Inorganic Chemistry, 2011
    Co-Authors: Stefan K. Henninger, Johannes Ehrenmann, Christoph Janiak
    Abstract:

    The adsorption of water vapor in the highly porous metal-organic framework (MOF) of 3D-[Cr3F(H2O)2O(bdc)3·~25H2O] (MIL-101) (bdc = benzene-1,4-dicarboxylate, terephthalate) of up to 1 g of water per gram of Sorbent Material (between 140 °C and 40 °C under a water vapor pressure of 5.6 kPa) together with the stability over several cycles makes MIL-101 the most promising Material, so far, for heat transformation applications like thermally driven heat pumps or adsorption chillers.

  • Water Adsorption Characteristics of MIL‐101 for Heat‐Transformation Applications of MOFs
    European Journal of Inorganic Chemistry, 2010
    Co-Authors: Johannes Ehrenmann, Stefan K. Henninger, Christoph Janiak
    Abstract:

    The adsorption of water vapor in the highly porous metal-organic framework (MOF) of 3D-[Cr3F(H2O)2O(bdc)3·~25H2O] (MIL-101) (bdc = benzene-1,4-dicarboxylate, terephthalate) of up to 1 g of water per gram of Sorbent Material (between 140 °C and 40 °C under a water vapor pressure of 5.6 kPa) together with the stability over several cycles makes MIL-101 the most promising Material, so far, for heat transformation applications like thermally driven heat pumps or adsorption chillers.

Jon R. Kirchhoff - One of the best experts on this subject based on the ideXlab platform.

  • solid phase microextraction of heavy metals in natural water with a polypyrrole carbon nanotube 1 10 phenanthroline composite Sorbent Material
    Talanta, 2018
    Co-Authors: Ahmad Rohanifar, Amila M. Devasurendra, Jon R. Kirchhoff, Jared L. Anderson, Lidia B. Rodriguez, Niloofar Alipourasiabi
    Abstract:

    Abstract A simple and sensitive method for simultaneous microextraction and determination of heavy metals using a new direct immersion solid-phase microextraction (DI–SPME) Sorbent Material combined with inductively coupled plasma mass spectrometry (ICP–MS) was investigated. In this method, Sorbent coating composites were prepared by simultaneous electropolymerization of pyrrole on pencil lead in the presence of carbon nanotubes (CNTs) and different metal chelating ligands. Among the coatings evaluated, a polypyrrole coating with entrapped CNTs and the chelator 1, 10 phenanthroline allowed the determination of silver, cadmium, cobalt, iron, nickel, lead, and zinc. Parameters influencing microextraction efficiency including pH, extraction time, and desorption time were optimized. The linear dynamic ranges were 1–1000 μg L−1 for Ag, 1–750 μg L−1 for Cd, Pb, and Zn, and 1–500 μg L−1 for Co, Fe, and Ni with limits of detection of 0.012–0.163 μg L−1 and limits of quantification of 0.039–0.542 μg L−1. The relative standard deviations (RSDs, n = 5) ranged from 1.85% to 5.01%. The effect of inorganic interferences on the determination of the heavy metals also was examined and finally, the method was successfully applied for the determination of heavy metals in real water samples.

  • Solid-phase microextraction of heavy metals in natural water with a polypyrrole/carbon nanotube/1, 10-phenanthroline composite Sorbent Material
    Talanta, 2018
    Co-Authors: Ahmad Rohanifar, Amila M. Devasurendra, Jared L. Anderson, Lidia B. Rodriguez, Niloofar Alipourasiabi, Jon R. Kirchhoff
    Abstract:

    Abstract A simple and sensitive method for simultaneous microextraction and determination of heavy metals using a new direct immersion solid-phase microextraction (DI–SPME) Sorbent Material combined with inductively coupled plasma mass spectrometry (ICP–MS) was investigated. In this method, Sorbent coating composites were prepared by simultaneous electropolymerization of pyrrole on pencil lead in the presence of carbon nanotubes (CNTs) and different metal chelating ligands. Among the coatings evaluated, a polypyrrole coating with entrapped CNTs and the chelator 1, 10 phenanthroline allowed the determination of silver, cadmium, cobalt, iron, nickel, lead, and zinc. Parameters influencing microextraction efficiency including pH, extraction time, and desorption time were optimized. The linear dynamic ranges were 1–1000 μg L−1 for Ag, 1–750 μg L−1 for Cd, Pb, and Zn, and 1–500 μg L−1 for Co, Fe, and Ni with limits of detection of 0.012–0.163 μg L−1 and limits of quantification of 0.039–0.542 μg L−1. The relative standard deviations (RSDs, n = 5) ranged from 1.85% to 5.01%. The effect of inorganic interferences on the determination of the heavy metals also was examined and finally, the method was successfully applied for the determination of heavy metals in real water samples.

  • Solid-phase extraction, quantification, and selective determination of microcystins in water with a gold-polypyrrole nanocomposite Sorbent Material.
    Journal of chromatography. A, 2018
    Co-Authors: Amila M. Devasurendra, Dilrukshika S.w. Palagama, Ahmad Rohanifar, Dragan Isailovic, Jon R. Kirchhoff, Jared L. Anderson
    Abstract:

    Abstract A novel Sorbent Material, gold-polypyrrole (Au-PPy) nanocomposite-coated silica, is described for the efficient solid-phase extraction (SPE) of six common microcystins (MCs) well below the recommended United States EPA and World Health Organization (WHO) guidelines. With the optimized SPE protocol, samples spiked with MCs were determined at ng/L concentrations by liquid chromatography-mass spectrometry (LC–MS) in different aqueous sample matrices, including HPLC-grade, tap, and lake water. The average recoveries for all MCs tested in the three water matrices ranged from 94.1–103.2% with relative standard deviations (RSDs) of 1.6–5.4%, which indicated excellent extraction efficiency and reproducibility. Limits of detection (LODs) and limits of quantification (LOQs) for all MCs in both tap and lake water samples were determined to be ≤1.5 ng/L and 5.0 ng/L, respectively. The Au-PPy nanocomposite-coated Sorbent Material was reusable for at least three independent MC extractions with a single SPE cartridge in the concentration range of 10–500 ng/L. Importantly, off-column selective separation at the sample preparation and preconcentration stage between more hydrophilic and more hydrophobic MCs was achieved by sequential elution through changes in the solvent composition and SPE bed size. Therefore, the Au-PPy nanocomposite-coated silica Sorbent is a promising new Material for the quantification of MC variants in water samples.

Jean-françois Brilhac - One of the best experts on this subject based on the ideXlab platform.

  • modeling sox trapping on a copper doped cuo sba 15 Sorbent Material
    Journal of Hazardous Materials, 2020
    Co-Authors: Marc Berger, Alain Brillard, Sophie Dorge, David Habermacher, Habiba Nouali, Pierre Kerdoncuff, Matthieu Vierling, Michel Moliere, Joël Patarin, Jean-françois Brilhac
    Abstract:

    Abstract A mixture of SO2 and air was continuously injected in a fixed bed reactor containing a CuO/SBA-15 Sorbent Material and submitted to an isothermal temperature between 325 and 400 °C. The SO2 emissions were measured at the exit of the reactor. Different isothermal temperatures, different injected SO2 concentrations and different Sorbent masses, all representative of industrial conditions, were tested. The purpose of the paper was to propose efficient global models which simulate the breakthrough curves whatever the experimental conditions. A simplified model was first considered assuming that the oxidation and trapping processes can occur on each copper site. The values of the four kinetic parameters which are involved were determined solving this model using Scilab software and an optimization routine. Because this model failed to reproduce in a satisfying way the breakthrough curves for different Sorbent masses, a second model was introduced which involves surface and bulk trapping sites and six kinetic parameters. The breakthrough curves simulated with this second model following the same resolution techniques were in better agreement with the experimental ones, whatever the experimental conditions. For comparison, a simulation of the breakthrough curves returned by a model with bulk diffusion was presented.

  • Modeling SOx trapping on a copper-doped CuO/SBA-15 Sorbent Material.
    Journal of hazardous materials, 2019
    Co-Authors: Marc Berger, Alain Brillard, Sophie Dorge, David Habermacher, Habiba Nouali, Pierre Kerdoncuff, Matthieu Vierling, Michel Moliere, Joël Patarin, Jean-françois Brilhac
    Abstract:

    Abstract A mixture of SO2 and air was continuously injected in a fixed bed reactor containing a CuO/SBA-15 Sorbent Material and submitted to an isothermal temperature between 325 and 400 °C. The SO2 emissions were measured at the exit of the reactor. Different isothermal temperatures, different injected SO2 concentrations and different Sorbent masses, all representative of industrial conditions, were tested. The purpose of the paper was to propose efficient global models which simulate the breakthrough curves whatever the experimental conditions. A simplified model was first considered assuming that the oxidation and trapping processes can occur on each copper site. The values of the four kinetic parameters which are involved were determined solving this model using Scilab software and an optimization routine. Because this model failed to reproduce in a satisfying way the breakthrough curves for different Sorbent masses, a second model was introduced which involves surface and bulk trapping sites and six kinetic parameters. The breakthrough curves simulated with this second model following the same resolution techniques were in better agreement with the experimental ones, whatever the experimental conditions. For comparison, a simulation of the breakthrough curves returned by a model with bulk diffusion was presented.

Miguel Valcárcel - One of the best experts on this subject based on the ideXlab platform.

  • β cyclodextrin decorated nanocellulose a smart approach towards the selective fluorimetric determination of danofloxacin in milk samples
    Analyst, 2015
    Co-Authors: Celia Ruizpalomero, Laura M Soriano, Miguel Valcárcel
    Abstract:

    An innovative and versatile strategy of Solid Phase Microextraction (SPME) is shown by using a new type of β-cyclodextrin-modified nanocellulose (CD-NC) as a Sorbent Material. β-cyclodextrin (used as an inclusion-type selector) was covalently bonded to amine-modified nanocellulose by an amidation reaction. Such novel nanocavities were successfully applied to the selective recognition of danofloxacin (DAN), an antibiotic used to treat animal diseases, via supramolecular host–guest interactions. The SPME methodology, using a platform based on β-cyclodextrin-“decorated” nanocellulose as a Sorbent Material, showed a wide linear fluorimetric response against DAN from 8 to 800 μg L−1 and a detection limit of 2.5 μg L−1. The specific recognition of DAN has been proven to be highly selective and efficient against this metabolite and other fluoroquinolones. The reusability and the high efficiency in the extraction and preconcentration of DAN in milk samples allow recoveries of 94%.

  • Coiled carbon nanotubes combined with ionic liquid: a new soft Material for SPE
    Analytical and Bioanalytical Chemistry, 2012
    Co-Authors: M. L. Polo-luque, Bartolomé M. Simonet, Miguel Valcárcel
    Abstract:

    For the first time a soft Material formed from coiled carbon nanotubes and 1-hexyl-3-methylimidazolium hexafluorophosphate has been used as Sorbent Material. The soft Material has high stability as well as a high capacity to adsorb analytes. In this work we propose using a natural cotton fiber impregnated with the soft Material to miniaturize the system. The system was tested for the analysis of polycyclic aromatic hydrocarbons in spiked river water samples. The absolute recovery ranged between 97.5 and 105.5 %, demonstrating the usefulness of the soft Material. The limit of detection ranged from 2.5 to 6.1 μg/L and the precision expressed as the relative standard deviation for the analysis of five consecutive analyses ranged between 2.5 and 5.8 %.

  • evaluation of carbon nanocones disks as Sorbent Material for solid phase extraction
    Journal of Chromatography A, 2009
    Co-Authors: Juan Manuel Jimenezsoto, Soledad Cárdenas, Miguel Valcárcel
    Abstract:

    The potential of carbon nanocones/disks as Sorbent Material in solid-phase extraction (SPE) procedures has been evaluated. For this aim, a model analytical problem, the determination of chlorophenols in water samples, was selected. An accurately weighed amount of 20mg of purified carbon nanocones/disks was packed in 3 mL commercial SPE cartridges. Once conditioned, up to 8 mL of water samples can be preconcentrated without analyte losses. The chlorophenols were eluted by using 200 microL of hexane. Aliquots of 2 microL of the organic extract were injected in the gas chromatograph-mass spectrometer for separation and quantification. The purification of the commercial nanocones/disks to reduce the presence of amorphous carbon has been successfully achieved by heating the carbon nanocones/disks at 450 degrees C for 20 min. Detection limits of chlorophenols were in the range 0.3-8 ng mL(-1) by using 2 mL of sample. Moreover, excellent average recovery values (98.8-100.9%) have been obtained after the analysis of water samples from different nature. Finally, the performance of the carbon nanocones/disks as Sorbent Material has been compared with that of multiwalled carbon nanotubes, providing the former better results under the experimental conditions assayed.

  • Evaluation of carbon nanocones/disks as Sorbent Material for solid-phase extraction.
    Journal of chromatography. A, 2009
    Co-Authors: Juan Manuel Jiménez-soto, Soledad Cárdenas, Miguel Valcárcel
    Abstract:

    The potential of carbon nanocones/disks as Sorbent Material in solid-phase extraction (SPE) procedures has been evaluated. For this aim, a model analytical problem, the determination of chlorophenols in water samples, was selected. An accurately weighed amount of 20mg of purified carbon nanocones/disks was packed in 3 mL commercial SPE cartridges. Once conditioned, up to 8 mL of water samples can be preconcentrated without analyte losses. The chlorophenols were eluted by using 200 microL of hexane. Aliquots of 2 microL of the organic extract were injected in the gas chromatograph-mass spectrometer for separation and quantification. The purification of the commercial nanocones/disks to reduce the presence of amorphous carbon has been successfully achieved by heating the carbon nanocones/disks at 450 degrees C for 20 min. Detection limits of chlorophenols were in the range 0.3-8 ng mL(-1) by using 2 mL of sample. Moreover, excellent average recovery values (98.8-100.9%) have been obtained after the analysis of water samples from different nature. Finally, the performance of the carbon nanocones/disks as Sorbent Material has been compared with that of multiwalled carbon nanotubes, providing the former better results under the experimental conditions assayed.

  • Fullerenes as Sorbent Materials for Metal Preconcentration
    Analytical Chemistry, 1994
    Co-Authors: Mercedes Gallego, Yaneira Petit. De Pena, Miguel Valcárcel
    Abstract:

    The analytical potential of C[sub 60] fullerenes as Sorbent Materials for preconcentration of metal traces by formation of neutral chelates was studied for the first time in this work. The model system used for this purpose was the determination of lead traces in waters by using ammonium pyrrolidinedithiocarbamate as ligand. The chelate is formed in a continuous-flow system, sorbed on a C[sub 60] fullerene minicolumn, and subsequently eluted for transfer to an atomic absorption spectrometer. Two other simultaneous batches of experiments were performed in parallel by using C[sub 18] bonded silica and activated carbon as Sorbents in order to study the features of the new Sorbent Material and its advantages. The primary assets of C[sub 60] fullerenes in this respect are a high sensitivity arising from efficient adsorption and also high selectivity derived from the special features of this new type of Sorbent Material. 27 refs., 3 figs., 2 tabs.

Jared L. Anderson - One of the best experts on this subject based on the ideXlab platform.

  • solid phase microextraction of heavy metals in natural water with a polypyrrole carbon nanotube 1 10 phenanthroline composite Sorbent Material
    Talanta, 2018
    Co-Authors: Ahmad Rohanifar, Amila M. Devasurendra, Jon R. Kirchhoff, Jared L. Anderson, Lidia B. Rodriguez, Niloofar Alipourasiabi
    Abstract:

    Abstract A simple and sensitive method for simultaneous microextraction and determination of heavy metals using a new direct immersion solid-phase microextraction (DI–SPME) Sorbent Material combined with inductively coupled plasma mass spectrometry (ICP–MS) was investigated. In this method, Sorbent coating composites were prepared by simultaneous electropolymerization of pyrrole on pencil lead in the presence of carbon nanotubes (CNTs) and different metal chelating ligands. Among the coatings evaluated, a polypyrrole coating with entrapped CNTs and the chelator 1, 10 phenanthroline allowed the determination of silver, cadmium, cobalt, iron, nickel, lead, and zinc. Parameters influencing microextraction efficiency including pH, extraction time, and desorption time were optimized. The linear dynamic ranges were 1–1000 μg L−1 for Ag, 1–750 μg L−1 for Cd, Pb, and Zn, and 1–500 μg L−1 for Co, Fe, and Ni with limits of detection of 0.012–0.163 μg L−1 and limits of quantification of 0.039–0.542 μg L−1. The relative standard deviations (RSDs, n = 5) ranged from 1.85% to 5.01%. The effect of inorganic interferences on the determination of the heavy metals also was examined and finally, the method was successfully applied for the determination of heavy metals in real water samples.

  • Solid-phase microextraction of heavy metals in natural water with a polypyrrole/carbon nanotube/1, 10-phenanthroline composite Sorbent Material
    Talanta, 2018
    Co-Authors: Ahmad Rohanifar, Amila M. Devasurendra, Jared L. Anderson, Lidia B. Rodriguez, Niloofar Alipourasiabi, Jon R. Kirchhoff
    Abstract:

    Abstract A simple and sensitive method for simultaneous microextraction and determination of heavy metals using a new direct immersion solid-phase microextraction (DI–SPME) Sorbent Material combined with inductively coupled plasma mass spectrometry (ICP–MS) was investigated. In this method, Sorbent coating composites were prepared by simultaneous electropolymerization of pyrrole on pencil lead in the presence of carbon nanotubes (CNTs) and different metal chelating ligands. Among the coatings evaluated, a polypyrrole coating with entrapped CNTs and the chelator 1, 10 phenanthroline allowed the determination of silver, cadmium, cobalt, iron, nickel, lead, and zinc. Parameters influencing microextraction efficiency including pH, extraction time, and desorption time were optimized. The linear dynamic ranges were 1–1000 μg L−1 for Ag, 1–750 μg L−1 for Cd, Pb, and Zn, and 1–500 μg L−1 for Co, Fe, and Ni with limits of detection of 0.012–0.163 μg L−1 and limits of quantification of 0.039–0.542 μg L−1. The relative standard deviations (RSDs, n = 5) ranged from 1.85% to 5.01%. The effect of inorganic interferences on the determination of the heavy metals also was examined and finally, the method was successfully applied for the determination of heavy metals in real water samples.

  • Solid-phase extraction, quantification, and selective determination of microcystins in water with a gold-polypyrrole nanocomposite Sorbent Material.
    Journal of chromatography. A, 2018
    Co-Authors: Amila M. Devasurendra, Dilrukshika S.w. Palagama, Ahmad Rohanifar, Dragan Isailovic, Jon R. Kirchhoff, Jared L. Anderson
    Abstract:

    Abstract A novel Sorbent Material, gold-polypyrrole (Au-PPy) nanocomposite-coated silica, is described for the efficient solid-phase extraction (SPE) of six common microcystins (MCs) well below the recommended United States EPA and World Health Organization (WHO) guidelines. With the optimized SPE protocol, samples spiked with MCs were determined at ng/L concentrations by liquid chromatography-mass spectrometry (LC–MS) in different aqueous sample matrices, including HPLC-grade, tap, and lake water. The average recoveries for all MCs tested in the three water matrices ranged from 94.1–103.2% with relative standard deviations (RSDs) of 1.6–5.4%, which indicated excellent extraction efficiency and reproducibility. Limits of detection (LODs) and limits of quantification (LOQs) for all MCs in both tap and lake water samples were determined to be ≤1.5 ng/L and 5.0 ng/L, respectively. The Au-PPy nanocomposite-coated Sorbent Material was reusable for at least three independent MC extractions with a single SPE cartridge in the concentration range of 10–500 ng/L. Importantly, off-column selective separation at the sample preparation and preconcentration stage between more hydrophilic and more hydrophobic MCs was achieved by sequential elution through changes in the solvent composition and SPE bed size. Therefore, the Au-PPy nanocomposite-coated silica Sorbent is a promising new Material for the quantification of MC variants in water samples.