In situ generation of COx-free H2 by catalytic ammonia decomposition over Ru-Al-monoliths

Ru catalysts supported on alumina coated monoliths has been prepared employing three different precursor, which are ruthenium chloride, ruthenium nitrosyl nitrate and ruthenium acetyl acetonate, by an equilibrium adsorption method. The Ru particle sizes could be controlled varying the metal precursor salt. Among the prepared catalysts, Ru catalyst prepared from nytrosyl nitrate exhibited the highest activity which is concomitant to the largest mean Ru particle size of 3.5 nm. The values of the apparent activation energy calculated from the Arrhenius equation are according to the Temkin-Phyzev model, indicating that the recombinative desorption of N ad-atoms is the rate-determining step of the reaction. However, the ratio between the kinetic orders with respect to ammonia and hydrogen (-a/ß), is not in agreement to the valued predict by Temkin formalism. This fact could be related to the different operational conditions used during the reaction, and/or catalyst nature, but not to any change on the controlling step of the reaction

Biobased catalyst in biorefinery processes: Sulphonated hydrothermal carbon for glycerol esterification

Sulphonated hydrothermal carbon (SHTC), obtained from D-glucose by mild hydrothermal carbonisation and subsequent sulphonation with sulphuric acid, is able to catalyse the esterification of glycerol with dif- ferent carboxylic acids, namely, acetic, butyric and caprylic acids. Product selectivity can be tuned by sim- ply controlling the reaction conditions. On the one hand, SHTC provides one of the best selectivity towards 20 monoacetins described up to now without the need for an excess of glycerol. On the other hand, excellent selectivity towards triacylglycerides (TAG) can be obtained, beyond those described with other solid cata- lysts, including well-known sulphonic resins. Recovery of the catalyst showed partial deactivation of the solid. The formation of sulphonate esters on the surface, confirmed by solid state NMR, was the cause of this behaviour. Acid treatment of the used catalyst, with subsequent hydrolysis of the surface sulphonate 25 esters, allows SHTC to recover its activity. The higher selectivity towards mono- and triesters and its renewable origin makes SHTC an attractive catalyst in biorefinery processe

Unique properties and behavior of type-II cellulose nanocrystals as carbon nanotube biocompatible dispersants

1 figure.-- Abstract of the work presented at the NanoteC19 conference, International Conference on Carbon Nanosciene and Nanotechnology, 27th-30th august 2019, Zaragoza (Spain).Nanocellulose (NC) is a carbon-based nanostructure, consisting of nanometric domains of crystalline cellulose, and has attracted significant interest due to its unique properties and availability.[1] NC is hydrophilic, thus fully processable in water.[2] Methods for the production of NC include either bottom-up approaches or top-down, being the latter usually performed by chemical treatments to a natural biomass source. Such treatments destroy the amorphous parts of cellulose chains, leaving intact the crystalline domains.[1-2] The best known crystalline forms (allomorphs) of cellulose are types I and II, where the chains are arranged in parallel and antiparallel fashions, respectively.[3] The production of type II NC is still challenging, being the only works reported on the use of strong and concentrated alkalis.[4] In this work we present the production of cellulose nanocrystals, in any of these two allomorphs, by only using acidic hydrolysis. All experimental variables (acid concentration, temperature and time of reaction, centrifugation settings) have been optimized to produce either type I or II NC in a selective way, and alternative to the alkaline procedure. As a proof of principle we have applied either type-I or type-II NC as a dispersant for singlewalled carbon nanotubes (SWCNTs). The obtained results demonstrate the substantially different morphologies that both allomorphs display as dispersing agents (Fig. 1). When the SWCNT-NC aqueous colloids are tested in human colon epithelium cells (Caco-2) a surprising result emerges, as only type-II based dispersions display anticancer activity while the type-I based ones remain fully innocuous.[5

Unique properties and behavior of non-mercerized type-II cellulose nanocrystals as carbon nanotube biocompatible dispersants

2 Esquemas,7 Figuras.-- Información suplementaria disponible en la página web del editor.- This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Biomacromolecules 2019,20,8,3147-3160, copyright © American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/acs.biomac.9b00722Nanocellulose is increasingly being investigated as a paradigm of a sustainable nanomaterial because of its extraordinary physical and chemical properties, together with its renewable nature and worldwide abundance. The rich structural diversity of cellulose materials is represented by different crystalline allomorphs, from which types I and II stand out. While type I is naturally and ubiquitously present, type II is man-made and requires harsh and caustic synthesis conditions such as the so-called mercerization process. Here, we provide an optimal scenario to obtain either type-I or II nanocrystalline cellulose (NCC) by a mercerization-free method consisting only of the acid hydrolysis commonly used to produce nanocellulose from microcellulose. The possibility of having nonmercerized type-II NCC acquires a great relevance since this nanostructure shows particularly appealing properties. Moreover, an entangled and wrapped system arises when used as a dispersing agent for single-walled carbon nanotubes (SWCNTs), significantly different from that of type I. The biological testing of each NCC type and their respective SWCNT–NCC dispersions in human intestinal (Caco-2) cells reveals a general innocuous behavior in both cancer and normal stages of differentiation; however, the type-II-based SWCNT–NCC dispersions display cytotoxicity for cancer cells while enhancing mitochondrial metabolism of normal cells.J.M.G.-D. and E.C. acknowledge Spanish MINEICO for their Juan de la Cierva Incorporación research contract (ref IJCI-2016-27789) and PhD fellowship (FPI, ref BES-2017-080020, and associated EU Social Funds), respectively. This work has received funding from the Spanish Ministry of Economy, Industry and Competitiveness (MINEICO) and the Spanish Research Agency (AEI) through GRAPEROS project (ref ENE2016-79282-C5-1-R1 and associated EU Regional Development Funds). Additional funding from Gobierno de Aragón (Grupo Reconocido DGA T03_17R, A02_17R and associated EU Regional Development Funds) is acknowledged.Peer reviewe

Waterborne graphene-and nanocellulose-based inks for functional conductive films and 3D structures

11 figures, 1 table.-- Supplementary information available.In the vast field of conductive inks, graphene-based nanomaterials, including chemical derivatives such as graphene oxide as well as carbon nanotubes, offer important advantages as per their excellent physical properties. However, inks filled with carbon nanostructures are usually based on toxic and contaminating organic solvents or surfactants, posing serious health and environmental risks. Water is the most desirable medium for any envisioned application, thus, in this context, nanocellulose, an emerging nanomaterial, enables the dispersion of carbon nanomaterials in aqueous media within a sustainable and environmentally friendly scenario. In this work, we present the development of water-based inks made of a ternary system (graphene oxide, carbon nanotubes and nanocellulose) employing an autoclave method. Upon controlling the experimental variables, low-viscosity inks, high-viscosity pastes or self-standing hydrogels can be obtained in a tailored way. The resulting inks and pastes are further processed by spray- or rod-coating technologies into conductive films, and the hydrogels can be turned into aerogels by freeze-drying. The film properties, with respect to electrical surface resistance, surface morphology and robustness, present favorable opportunities as metal-free conductive layers in liquid-phase processed electronic device structures.This research was funded by Spanish MINEICO/MICINN, under project references ENE2016-79282-C5-1-R (AEI/UE/FEDER) and PID2019-104272RB-C51/AEI/10.13039/501100011033, and the Gobierno de Aragón (Grupo Reconocido DGA-T03_20R). J.M.G.-D. greatly acknowledges Spanish MINEICO for his ‘Juan de la Cierva Incorporation’ contract and associated research funds (ref. IJCI-2016-27789). The APC predoctoral contracts of E.C. and M.Á.Á.-S. were funded by the Spanish MINEICO (BES2017-080020, including EU Social Funds) and the Gobierno de Aragón, respectively. The work performed at the University of Zaragoza was funded by the MICINN (PID2019-104307GB-I00/AEI/10.13039/501100011033) and Gobierno de Aragón (E47_20R).Peer reviewe

Recomendaciones de «hacer» y «no hacer» en el tratamiento de los pacientes críticos ante la pandemia por coronavirus causante de COVID-19 de los Grupos de Trabajo de la Sociedad Española de Medicina Intensiva, Crítica y Unidades Coronarias (SEMICYUC)

[spa] El 11 de marzo de 2020 el director general de la Organización Mundial de la Salud (OMS) declaró la enfermedad causada por el SARS-CoV-2 (COVID-19) como una pandemia. La propagación y evolución de la pandemia está poniendo a prueba los sistemas sanitarios de decenas de países, y ha dado lugar a una miríada de artículos de opinión, planes de contingencia, series de casos e incipientes ensayos. Abarcar toda esta literatura es complejo. De forma breve y sintética, en la línea de las anteriores recomendaciones de los Grupos de Trabajo, la Sociedad Española de Medicina Intensiva, Crítica y Unidades Coronarias (SEMICYUC) ha elaborado esta serie de recomendaciones básicas para la asistencia a pacientes en el contexto de la pandemia. Palabras clave: COVID-19, Coronavirus, Paciente crítico, Recomendaciones, Unidad de cuidados intensivo