Tunable interlayer hydrophobicity in a nanostructured high charge organo-mica

A tunable hydrophobicity, from a fully hydrophobic medium to an amphiphilic quasi-solution, has been obtained in the interlayer space of a synthetic high charged mica by ion exchange reaction with amine cations. The structural and intercalation properties of the hybrids after the exchange with the n-alkylammonium cations: [RNH3]+, [RNH(CH3)2]+ and [RN(CH3]3+ with C16 alkyl chain length have been determined by termogravimetric/differential scanning calorimetry analysis (TGA-DSC) and mass spectrometry (MS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Transmission electron microscopy (TEM) has been used as a complementary technique to provide new insights into the morphology of the exchanged products. Coverage and cation distribution have been correlated with layer charge and steric effects. Thus, a full organo-clay is obtained when the primary amine cations are adsorbed between the layers. However, a homogenous single phase of mixed organic/inorganic cations is formed in the same interlayer with the tertiary amine cations. Mixed ion clays combining both exchangeable inorganic and adsorbent organic ions in their interlayer space can be potential materials to be used as adsorbents for water decontamination, independently of the hydrophilic/hydrophobic nature of the pollutants. For the quaternary amine cations steric effects preclude the coexistence of both organic and inorganic species in the same interlayer of the clay so phase segregation together with a heterogeneous phase of organic and inorganic galleries in the same particle can be observed.Funding from the Ministerio de Economía y Competitividad, under project MAT2015-63929-R is also acknowledged. Fernando Aguado received funding from the Ministerio de Economía y Competitividad, project MAT2015-69508-P

Adsorptive capture of ionic and non-ionic pollutants using a versatile hybrid amphiphilic-nanomica

A versatile, functional nanomaterial for the removal of ionic and non-ionic pollutants is presented in this work. For that purpose, the high charge mica Na-4-Mica was exchanged with the cationic surfactant (C16H33NH(CH3)2)+. The intercalation of the tertiary amine in the swellable nano-clay provides the optimal hydrophilic/hydrophobic nature in the bidimensional galleries of the nanomaterial responsible for the dual functionality. The organo-mica, made by functionalization with C16H33NH3+, was also synthesized for comparison purposes. Both samples were characterized by X-ray diffraction techniques and transmission electron microscopy. Then, the samples were exposed to a saturated atmosphere of cyclohexylamine for two days, and the adsorption capacity was evaluated by thermogravimetric measurements. Eu3+ cations served as a proof of concept for the adsorption of ionic pollutants in an aqueous solution. Optical measurements were used to identify the adsorption mechanism of Eu3+ cations, since Eu3+ emissions, including the relative intensity of different f–f transitions and the luminescence lifetime, can be used as an ideal spectroscopic probe to characterize the local environment. Finally, the stability of the amphiphilic hybrid nanomaterial after the adsorption was also tested.We would like to thank IDIVAL for financial support, project number INNVAL19/1

Eu3+ luminescence in high charge mica: an in situ probe for the encapsulation of radioactive waste in geological repositories

Isolation of high-level radioactive waste (HLW) in deep geological repositories (DGR) through a multibarrier concept is the most accepted approach to ensure long-term safety. Clay minerals are one of the most promising materials to be used as engineered barriers. In particular, high charge micas, as components of the engineered barrier, show superselectivity for some radioactive isotopes and a large adsorption capacity, which is almost twice that of the other low charge aluminosilicates. In addition, high charge micas are optimum candidates for decontamination of nuclear waste through two different mechanisms; namely an ion exchange reaction and a nonreversible mechanism involving the formation of new stable crystalline phases under hydrothermal conditions. In this work, we report a new in situ optical sensor based on the incorporation of Eu3+ in these high charge micas for tracking the long-term physical-chemical behavior of HLW contaminants in DRG under mild hydrothermal conditions. The incorporation of Eu3+ into the interlayer space of the mica originates a well resolved green and red luminescence, from both the 5D1 and 5D0 excited states, respectively. The formation of new crystalline phases under hydrothermal conditions involves important changes in the Eu3+ emission spectra and lifetime. The most interesting features of Eu3+ luminescence to be used as an optical sensor are (1) the presence or absence of the Eu3+ green emission from the 5D1 excited state, (2) the energy shift of the 5D0 → 7F0 transition, (3) the crystal-field splitting of the 7F1 Eu3+ level, and (4) the observed luminescence lifetimes, which are directly related to the interaction mechanisms between the lanthanide ions and the silicate network.Funding from projects MAT2015-63929-R, MAT2015-69508-P, PI16/00496, and NVAL16/17-IDIVAL is gratefully acknowledged

Exploring the local environment of the engineered nanoclay Mica-4 under hydrothermal conditions using Eu3+ as a luminescent probe

High charge mica Na4Al4Si4Mg6O20F4, Mica-4, is a promising candidate as a filling material to immobilize high-level radioactive waste in deep geological repositories due to its extraordinary adsorption capacity. In contrast to traditional clay materials, the structural composition of this mica, with a high content of aluminum in the tetrahedral sheet, enhances its chemical reactivity, favoring the formation of new crystalline phases under mild hydrothermal conditions, and thus providing a definitive isolation of the radionuclides in the engineered barrier. Moreover, this synthetic clay has some features that allow its use as an optical sensor by doping with luminescent rare earth cations such as Eu3+. In this paper we discuss the local structure of the nanoclay Mica-4 using Eu3+ as a local probe to track the physical and chemical modifications under hydrothermal conditions. For that purpose, a set of hydrothermal experiments has been carried out heating Mica-4 and an aqueous Eu(NO3)3 solution in a stainless steel reactor at different temperatures and times. Optical properties of the as-treated samples were characterized by spectroscopic measurements. The fine peak structure of emission and the relative intensity of different Eu3+ transitions as well as the luminescence lifetime have been correlated with the structure and composition of this nanoclay, and the interaction mechanisms between the lanthanide ions and the clay mineral at different temperatures and times. Special attention has been paid to understanding the role of the aluminum content, which may act as either an aggregating or dispersing agent, in the optical features and reactivity of the system.We would like to thank Instituto de Investigación Marqués de Valdecilla (IDIVAL) (Projects NVAL16/17 and INNVAL19/18) and Ministerio de Ciencia, Innovación y Universidades (Project PGC2018–101464-B-100) for financial support

CO2 capture at low temperature by nanoporous silica modified with amine groups

MCM-41 and SBA-15 were chosen as nanoporous materials based on silica for its modification with aminegroups. This modification was done by two methods: grafting method and wet impregnation method. The firstmethod grafted-amine groups by chemical reaction between surface silanol groups in the nanoporousmaterials and 3-aminopropyltrimetoxilane (APTMS).In the wet impregnation method, low molecular weightpolyethylenimine (PEI) is incorporated trough this method. These modified materials capture CO2 at lowtemperature. CO2 capture on the sorption sites by amine loading is believed to occur via chemisorptionmechanism by formation of ammonium carbamate. The evaluation and analysis of CO2 adsorption was carriedout by two methods: static mode and dynamic mode. The static mode is a pure CO2 adsorption-desorptionisotherms at 298K. The isotherms of the functionalized materials show a behavior by chemisorption, captureat low pressure, being the desorption branch almost horizontal, while nanoporous silica isotherms is due aphysical adsorption, low CO2 capture at low pressure and dependence with pressure, a complete reversibilityof the desorption process. The dynamic mode is a thermogravimetry study at different N2/CO2 concentrations.Isothermal CO2 captures at 298K were carried out to evaluate the suitability of the samples for cyclicoperation. The mass increase during the capture step was interpreted as CO2 adsorption capacity of thesamples. The results obtained by both methods were compared, and, its differences were analyzed

Inhibition of growth and metastasis of breast cancer in mice by milk fermented with Lactobacillus casei CRL 431

Breast cancer is the second cause of death in women, Who are especially related to uncontrolled metastasis. It was previously demonstrated that the administration of milk fermented by Lactobacillus casei CRL 431 [fermented milk (FM)] delayed the tumor growth in a murine breast cancer model. In this work we evaluated if the administration of FM to mice, starting when the tumor was measurable, can affect not only the tumor growth, but also the extravasation of tumor cells and the lung metastasis. The evaluation of immune cells?infiltrating tumors and lungs was also performed. Tumor volume was calculated. Whole blood, lungs, and liver were processed to count the number of colonies formed by tumor cells. Blood serum was obtained for monocyte chemoattractant protein-1, interleukin (IL)-10, and IL-6 determination, lung tissues for histologic observations, and tumor tissues for angiogenesis determination. Mice that received FM were compared with animals given milk or to the controls without any especial supplementation. The results showed that FM administration to mice decreased or suppressed tumor growth, with less tumor vascularity,extravasation of tumor cells, and lung metastasis. These benefits were associated to modulation of the immune response by decreasing the infiltration of macrophages in both the tumor and the lungs. FM administration maintained an increased antitumor response associated to CD8+ lymphocytes, and also increased CD4+ lymphocytes that can be involved in the modulation of the immune response. The future evaluation of cytokine profiles will allow knowing more about subpopulation of macrophages and lymphocytes associated to the beneficial effect of this probiotic in the breast cancer model.Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); ArgentinaFil: Aragón, Félix Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); ArgentinaFil: Carino, Silvia. Universidad Nacional de Tucumán. Facultad de Odontología; ArgentinaFil: Perdigón, Gabriela del Valle. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Cátedra de Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentin

Luminescent sensor for monitoring radioactive waste and its use

[ES] El objeto de la presente invención es un sensor luminiscente para el seguimiento de los mecanismos de adsorción y retención de residuos radiactivos de alta actividad en la barrera de ingeniería de depósitos geológicos profundos. El sensor está formado por la combinación de la mica de carga 4, como componente mayoritario, y cationes Eu3+ para el seguimiento de los mecanismos de interacción de los residuos radiactivos y la barrera de ingeniería. Los cationes Eu3+ se encontrarían en forma de sal, cloruro o nitrato, incorporados en el contenedor o barrera física. La luminiscencia se produce bajo excitación del Eu3+ adsorbido en la arcilla.[EN] The object of the present invention is a luminescent sensor for monitoring the adsorption and retention mechanisms of high-activity radioactive waste in the engineering barrier of deep geological deposits. The sensor is made up of the combination of charge mica 4, as the majority component, and Eu3+ cations for monitoring the interaction mechanisms of radioactive waste and the engineering barrier. The Eu3+ cations would be found in the form of salt, chloride or nitrate, incorporated in the container or physical barrier. Luminescence occurs under excitation of the Eu3+ adsorbed on the clay.NoUniversidad de Cantabria, Consejo Superior de Investigaciones Científicas (CSIC)B2 Patente con examen previ

Sensor luminiscente para la monitorización de residuos radiactivos y uso del mismo

Sensor luminiscente para la monitorización de residuos radiactivos y uso del mismo. El objeto de la presente invención es un sensor luminiscente para el seguimiento de los mecanismos de adsorción y retención de residuos radiactivos de alta actividad en la barrera de ingeniería de depósitos geológicos profundos. El sensor está formado por la combinación de la mica de carga 4, como componente mayoritario, y cationes Eu3+ para el seguimiento de los mecanismos de interacción de los residuos radiactivos y la barrera de ingeniería. Los cationes Eu3+ se encontrarían en forma de sal, cloruro o nitrato, incorporados en el contenedor o barrera física. La luminiscencia se produce bajo excitación del Eu3+ adsorbido en la arcilla. [ES]The present invention relates to a luminescent sensor for monitoring mechanisms for adsorbing and retaining high-level radioactive waste in the engineered barrier of deep geological repositories. The sensor is formed by the combination of mica having a charge of 4, as a main component, and Eu3+ cations for monitoring the interaction mechanisms of the radioactive waste and the engineered barrier. The Eu3+ cations are in salt form, chloride or nitrate, and are incorporated into the container or physical barrier. Luminescence is produced under the excitation of the Eu3+ adsorbed into the clay. [EN]Peer reviewedUniversidad de Cantabria, Consejo Superior de Investigaciones Científicas (CSIC)A1 Solicitud de patente con informe sobre el estado de la técnic

Sensor luminiscente para la monitorización de residuos radiactivos y uso del mismo

El objeto de la presente Invención es un sensor luminiscente para el seguimiento de ios mecanismos de adsorción y retención de residuos radiactivos de alta actividad en la barrera de ingeniería de depósitos geológicos profundos. El sensor está formado por la combinación de la mica de carga 4, como componente mayoritario, y cationes Eu3+ para el seguimiento de los mecanismos de interacción de los residuos radiactivos y la barrera de ingeniería. Los cationes Eu3+ se encontrarían en forma de sal, cloruro o nitrato, incorporados en el contenedor o barrera física. La luminiscencia se produce bajo excitación del Eu3+ adsorbido en la arcilla. [ES]The present invention relates to a luminescent sensor for monitoring mechanisms for adsorbing and retaining high-level radioactive waste in the engineered barrier of deep geological repositories. The sensor is formed by the combination of mica having a charge of 4, as a main component, and Eu3+ cations for monitoring the interaction mechanisms of the radioactive waste and the engineered barrier. The Eu3+ cations are in salt form, chloride or nitrate, and are incorporated into the container or physical barrier. Luminescence is produced under the excitation of the Eu3+ adsorbed into the clay. [EN]Peer reviewedUniversidad de Cantabria, Consejo Superior de Investigaciones Científicas (CSIC)A1 Solicitud de patente con informe sobre el estado de la técnic