Tag Archives: solid-state nmr

Removal of the synthetic hormone methyltestosterone from aqueous solution using a β-cyclodextrin/silica composite

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Lucas Bragança Carvalho, Pricila Maria BatistaChagas, Tamara Rezende Marques, Angelina Razafitianamaharavo, Manuel Pelletier, Pau Nolis, Carlos Jaime, Sérgio Scherrer Thomasi, Lucianade Matos Alves Pinto.

Journal of Environmental Chemical Engineering – Available online 20 October 2019

ABSTRACT Contamination of water with steroid residues can cause a number of environmental damages, affecting exposed organisms including man. The development of technologies for treatment or removal of this type of micropollutant from water is of paramount importance. In this study, citric acid was used to functionalize β-cyclodextrin (bCD) on the silica surface generating an organic-inorganic hybrid composite for application in molecular sequestration. The functionalization percentage was high, with about 62.6% of the composite mass corresponding to the organic part of the material. 13C NMR and infrared spectroscopic analysis indicate that the functionalization mechanism occurs by an esterification reaction between the citric acid with the silanol groups from silica and the primary hydroxyls of the bCDs. Fast adsorption of the methyltestosterone steroid was observed at acid pH, with a high adsorption capacity of 11 mg g-1. The best kinetic and isotherm models fit indicated that the adsorption occurred by a physical mechanism at independent sites with the steroid molecule possibly captured by two bCDs. The removal process was spontaneous and exothermic, with the existence of weak interactions between the hormone and the composite, and its regeneration is quite fast efficient with the displacement of the complexation equilibrium. The results obtained in this study demonstrate the considerable potential of the composite for use in the treatment of wastewater containing the steroid studied, and its efficacy should be evaluated for other steroid molecules. 

Solid State NMR supports a new study on hydride composite for hydrogen storage

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Bergemann, N., C. Pistidda, C. Milanese, M. Aramini, S. Huotari, P. Nolis, A. Santoru, M. R. Chierotti, A.-L. Chaudhary, M. D. Baro, T. Klassen & M. Dornheim. 2018. A hydride composite featuring mutual destabilisation and reversible boron exchange: Ca(BH4)2–Mg2NiH4. Journal of Materials Chemistry A 6(37). 17929–17946. DOI: 10.1039/c8ta04748k

The system Ca(BH4)2–Mg2NiH4 is used as a model to prove the unique possibility to fully reverse the borohydride decomposition process even in cases where the decomposition reaction leads to undesired stable boron containing species (boron sinks). The formation of MgNi2.5B2 directly from Ca(BH4)2 or from CaB12H12 and amorphous boron allows an unexpectedly easy transfer of the boron atoms to reversibly form Ca(BH4)2 during rehydrogenation. In addition, to the best of our knowledge, the mutual destabilisation of the starting reactants is observed for the first time in Ca(BH4)2 based Reactive Hydride Composite (RHC) systems. A detailed account of dehydrogenation and rehydrogenation reaction mechanisms as the function of applied experimental conditions is given.

Solid-State-NMR a useful tool for the characterization of Hydrogen Storage Composite System

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Karimi, Fahim, María V.C. Riglos, Antonio Santoru, Armin Hoell, Vikram S. Raghuwanshi, Chiara Milanese, Nils Bergemann, Claudio Pistidda, Pau Nolis , Maria D. Baro, Gökhan Gizer, Thi-Thu Le, P. Klaus Pranzas, Martin Dornheim, Thomas Klassen, Andreas Schrey & Julián Puszkiel. 2018. In Situ Formation of TiB2 Nanoparticles for Enhanced Dehydrogenation / Hydrogenation Reaction Kinetics of LiBH4–MgH2 as a Reversible Solid-State Hydrogen Storage Composite System. The Journal of Physical Chemistry C 122(22). 11671–11681. DOI: 10.1021/acs.jpcc.8b02258

To enhance the dehydrogenation/rehydrogenation kinetic behavior of the LiBH4–MgH2 composite system, TiF4 is used as an additive. The effect of this additive on the hydride composite system has been studied by means of laboratory and advanced synchrotron techniques. Investigations on the synthesis and mechanism upon hydrogen interaction show that the addition of TiF4 to the LiBH4–MgH2 composite system during the milling procedure leads to the in situ formation of well-distributed nanosized TiB2 particles. These TiB2 nanoparticles act as nucleation agents for the formation of MgB2 upon dehydrogenation process of the hydride composite system. The effect of TiB2 nanoparticles is maintained upon cycling.  

Storage properties of the Li-N-H system

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hydrogen_energy“Role of aluminum chloride on the reversible hydrogen storage properties of the Li-N-H system”

Fernández, L.; Garroni, S.; Larochette, P.; Nolis, P.; Mulas, G.; Enzo, S.; Baró, M.D.; Gennari, F. International Journal of Hydrogen Energy, IN PRESS 2015 doi:10.1016/j.ijhydene.2015.08.030

 In order to understand the role of AlCl3 addition on the Li–N–H system, we have systematically investigated the hydrogen sorption kinetics and the reactions between LiNH2–LiH and AlCl3 additive with a multitechnique approach involving differential scanning calorimetry (DSC), hydrogen volumetric measurements, X-ray powder diffraction (XRPD), Fourier transform infrared analysis (FTIR) and solid-state nuclear magnetic resonance (NMR). Continue reading Storage properties of the Li-N-H system →

Confining light metal hydrides in micro- or mesoporous scaffolds

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JournalMaterialResearch“Unusual Oxidation Behavior of Light Metal Hydride by Tetrahydrofurane Solvent Molecules Confined in Ordered
Mesoporous Carbon” Klose, M.; Lindemann, I.; Minella, C.; Pinkert, K.; Zier, M.; Giebeler, L.; Nolis, P.; Baro, M.; Oswald, S.; Gutfleisch, O.; Ehrenberg, H.; Eckert, J. Journal Of Materials Research, 2014, 29, 55-63 DOI:10.1557/jmr.2013.199

Confining light metal hydrides in micro- or mesoporous scaffolds is considered to be a promising way to overcome the existing challenges for these materials, e.g. their application in hydrogen storage. Different techniques exist which allow us to homogeneously fill pores of a host matrix with the respective hydride, thus yielding well defined composite materials. Continue reading Confining light metal hydrides in micro- or mesoporous scaffolds →

Structural evolution upon decomposition of the LiAlH4+LiBH4 system

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jalloysStructural evolution upon decomposition of the LiAlH4+LiBH4 system. S. Soru, A. Taras, C. Pistiddb, C. Milanese, C. Bonatto Minella, E. Masolo, P. Nolis, M. D. Baró, A. Marinic, M. Tolkiehn,M. Dornheim, S. Enzo, G. Mulas, S. Garroni. Journal of Alloys and Compounds 2014, in press. DOI: 10.1016/j.jallcom.2013.12.027

In the present work we focus the attention on the phase structural transformations occurring upon the desorption process of the LiBH4 + LiAlH4 system. Continue reading Structural evolution upon decomposition of the LiAlH4+LiBH4 system →

NaAlH4 confined in Ordered Mesoporous Carbon

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hydrogen_energyNaAlH4 confined in Ordered Mesoporous Carbon

Bonatto, C.; Lindemann, I.; Nolis, P.; KieBling, A.; Baró, M. D.; Klose, M.; Giebler, L.; Rellinghaus, B.; Eckert, J.; Schultz, L.; Gutfleisch, O.

In this paper we performed a comprehensive investigation of the structural and sorption properties of a 40 wt. % NaAlH4 confined in a ordered mesoporous carbon (OMC, i.e. CMK-3) by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), 23Na{1H} and 27Al{1H} solid-state magic angle spinning-nuclear magnetic resonance (MAS-NMR).

This study evidences a remarkable improvement of the sorption kinetics of NaAlH4 due to its existence in nanometer size within the OMC. The pressure composition isotherm (PCI) analysis (for the re-absorption step) of the nanoconfined NaAlH4 would suggest an alteration of its equilibrium thermodynamic properties.

13hydrogen_energy_fig4

Additives on the Ca(BH) system

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jpccck_v116i051.indd“Chemical State, Distribution and Role of Ti- and Nb-Based Additives on the Ca(BH4)2 System” by Christian Bonatto Minella, Eva Pellicer, Emma Rossinyol, Fahim Karini, Claudio Pistidda,Sebastiano Garroni, Chiara Milanese, Pau Nolis, Maria Dolors Baró, Oliver Gutfleisch, Klaus Pranzas, Andreas Schreyer, Thomas Klassen, Rüdiger Bormann and Martin Dornheim. The Journal of Physical Chemistry C. 117:4394-4403 (2013). DOI: 10.1021/jp3116275

Light metal tetrahydroborates are regarded as promising materials for solid state hydrogen storage. Due to both a high gravimetric hydrogen capacity of 11.5 wt. % and an ideal de-hydrogenation enthalpy of 32 kJ mol-1 H2, Ca(BH4)2 is considered to be one of the most interesting compounds in this class of materials. In this work, a comprehensive investigation of the effect of different selected additives (TiF4, NbF5, Ti-isopropoxide and CaF2) on the reversible hydrogenation reaction of calcium borohydride is presented combining different investigation techniques.  Continue reading Additives on the Ca(BH) system →

Ca(BH4)2 + MgH2: Desorption Reaction

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jpccck_v117i005.indd“Ca(BH4)2 + MgH2: Desorption Reaction and Role of Mg on its Reversibility” by Christian Bonatto Minella, Claudio Pistidda, Sebastiano Garroni, Pau Nolis, Maria Dolors Baró, Oliver Gutfleisch, Thomas Klassen, Rüdiger Bormann, and Martin Dornheim. The Journal of Physical Chemistry C. 117:3846-3852 (2013). DOI: 10.1021/jp312271s

The Ca(BH4)2-MgH2 composite system represents a promising candidate for mobile hydrogen storage due to a 10.5 wt. % theoretical hydrogen storage capacity and an estimated equilibrium temperature lower than 160 °C. For this system, the reversibility was achieved without further addition of additives. Continue reading Ca(BH4)2 + MgH2: Desorption Reaction →

Organic composition in soil studied by solid state NMR

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“Changes in soil bacterial community: diversity, composition and function triggered by drought-induced gap succession preceded changes in soil C stocks and quality ” Curiel-Yuste J., Barba J., Fernandez-Gonzalez A.J., Fernandez-Lopez M., Mattana S., Martinez-Vilalta J., Pau Nolis, Lloret F. Ecology and Evolution. Accepted 2012.

We investigated soil bacterial taxonomic composition, soil respiration and soil organic matter quantity and quality in a mixed Mediterranean forest where the Scots pine (Pinus sylvestris) population is affected by climatic drought-induced die-off, and replaced by Holm-oak (Quercus ilex) populations as the dominant tree species. Continue reading Organic composition in soil studied by solid state NMR →