The interest in hydrogen technologies has grown in recent years, mainly because an economy based on hydrogen can help to solve important challenges related to the global economy of the future: energy security and climate change. Taking advantage of this momentum, more and more countries are implementing a growing number of policies related to hydrogen. Indeed, the European Hydrogen [leer más]
Biofuels will play a key role in the energy of the future, especially in the transport sector, reducing the current dependence on oil and the greenhouse gas emissions associated with this sector. Biomass, and in particular lignocellulosic biomass, is the essential raw material for the production of renewable biofuels. Therefore, it is necessary to develop innovative, efficient and sustainable technologies for biomass valorization in an integrated biorefinery. This article [leer más]
Thermochemical cycles for H2O and CO2 splitting using CeO2 have demonstrated high efficiency (> 5%) and fast kinetics. Alternative multistage cycles based on stoichiometric oxides, such as Mn-Na, can potentially provide much larger efficiencies under less stringent operation conditions. However, these cycles consist of three stages operating at very different temperatures (from 50 degrees C to 1500 degrees C) and, accordingly, the overall energy yield of the cycle critically depends on efficient heat recovery. Despite of this, recently the [leer más]
Effect of surface area and physical-chemical properties of graphite and graphene-based materials on their adsorption capacity towards metronidazole and trimethoprim antibiotics in aqueous solution
Authors: Carrales-Alvarado, DH; Rodriguez-Ramos, I; Leyva-Ramos, R; Mendoza-Mendoza, E; Villela-Martinez, DE Article. Chem. Eng. J.. vol: 402. page: 1385-8947. Date: DEC 15. 2020. Doi:10.1016/j.cej.2020.126155. Abstract: The adsorption of metronidazole (MNZ) and trimethoprim (TMP) antibiotics from water on nanomaterials synthesized from graphene oxide and graphite, was examined thoroughly. The effect of the physicochemical properties and surface area onto the adsorption capacity of the nanomaterials was studied in detail. The nanocarbon materials used were graphene oxide (GO), and GO reduced in inert medium (rGO) or ammonia (N-rGO), and four high surface area graphites (HSAG100, HSAG300, HSAG400, HSAG500). The nanomaterials characterization was [leer más]
SBA-15 with short channels for laccase immobilization
Authors: Khanmohammadi, F; Molina, MA; Blanco, RM; Azizi, SN; Marquez-Alvarez, C; Diaz, I Article. Microporous Mesoporous Mat.. vol: 309. page: 1387-1811. Date: DEC 15. 2020. Doi:10.1016/j.micromeso.2020.110527. Abstract: Ordered Mesoporous Materials offer wide application areas in chemistry and biotechnology. SBA-15 displays hexagonal arrangement of parallel unidirectional channels, where pore size and particle morphology are the controlling parameters when used as enzyme support to favour the diffusion of the protein molecules. The synthesis conditions can be controlled to yield the desired structural and morphological features of the material, as well as the functionalization of its surface to improve chemical affinity with [leer más]
Article; Early Access.
ChemCatChem. vol: . page: 1867-3880. Date: . 03 December 2020 Doi:10.1002/cctc.202001619.
The one-pot combination of halogenation biocatalysis and Suzuki-type cross coupling enables the direct arylative cyclization of allenic alcohols with boronic acids. This modular approach to unsaturated five-membered O-heterocycles proceeds in an aqueous emulsion with air as terminal oxidant. Here, the enzymatic oxidative activation of simple halide salts acts as traceless ring-closure-inducing event to trigger the subsequent C-C coupling. With the original protocol merging soluble proteins and a homogeneous SPhos-based palladium catalyst as a template, a novel [leer más]
Bi2O3/g-C3N4 nanocomposites as proficient photocatalysts for hydrogen generation from aqueous glycerol solutions beneath visible light
Authors: Alhaddad, M; Navarro, RM; Hussein, MA; Mohamed, RM Article. Ceram. Int.. vol: 46. page: 0272-8842. Date: NOV. 2020. Doi:10.1016/j.ceramint.2020.06.271. Abstract: A sequence of Bi2O3/g-C3N4 nanocomposites with diverse Bi2O3 content (0.5-5 molar %) has been synthesized by the sonication-mixture method using mesoporous beta-Bi2O3 and g-C3N4 and utilized as efficient photocatalysts for hydrogen generation from aqueous glycerol solutions beneath visible light irradiation. Mesoporous Bi2O3 particles were effectively integrated at the exterior of two-dimensional (2D) g-C3N4 nanolayers producing effective heterojunctions that facilitate the charge transference amongst g-C3N4 and Bi2O3 and minimize the recombination of photocharges. The number and efficiency of the [leer más]
In this paper, we explore the synthesis, characterization, and photophysical properties of a novel indigo derivative, N-octyl-7,7 ‘-diazaindigo, being the first time that diazaindigos have been studied as photophysically-active chemical entities. Reduction of the neutral “keto-form” to the so-called “leuco-form” changes the global spectroscopic and photophysical behaviors. Both species have been investigated by different photophysical studies, such as analysis of absorption and emission spectra, fluorescence quantum yields (phi(F)) and lifetimes. Finally, to appraise in depth the deactivation of the [leer más]
Polymer electrolyte fuel cells with alkaline anion exchange membranes (AAEMs) have gained increasing attention because of the faster reaction kinetics associated with the alkaline environment compared to acidic media. While the development of anion exchange polymer membranes is increasing, the catalytic layer structure and composition of electrodes is of paramount importance to maximize fuel cell performance. In this work, we examine the preparation procedures for electrodes by catalyst-coated substrate to be used with a well-known commercial AAEM, [leer más]
The effects of residual NaNO3 on the modification of Cu/ZnO-Al2O3 catalysts have been extensively documented, but the modification mechanism is so far unclear. This work studies in detail the influence of the residual sodium nitrate present in the hydroxycarbonate precursors on their decomposition during calcination and how it affects to the formation and configuration of the final active sites of the Cu/ZnO-Al2O3 catalysts. Different samples with varying sodium content after washing (from 0.01 to 7.3 wt%) were prepared and [leer más]
Cascade reactions have been described as efficient and universal tools, and are of substantial interest in synthetic organic chemistry. This review article provides an overview of the novel and recent achievements in enzyme cascade processes catalyzed by multi-enzymatic or chemoenzymatic systems. The examples here selected collect the advances related to the application of the sequential use of enzymes in natural or genetically modified combination; second, the important combination of enzymes and metal complex systems, and finally we described the application of [leer más]
The removal of the commonly used herbicides is essential for environmental remediation. In this study, mesoporous TiO2 photocatalysts modified with PtO were synthetized by the template-assisted scheme to develop highly effective materials for the elimination of Imazapyr herbicide under visible-light preservation. The effect of the PtO loading was investigated, and the xPtO-TiO2 materials were deeply considered by N-2 physisorption, XRD, HRTEM, FTIR, DRS UV-Vis, Raman, XPS, PL and photocurrent measurements. Total Imazapyr photodegradation was archived on mesoporous TiO2 photocatalysts loaded with 0.6 and [leer más]
Strong effect of light scattering by distribution of TiO2 particle aggregates on photocatalytic efficiency in aqueous suspensions
Authors: Tolosana-Moranchel, A; Pecharroman, C; Faraldos, M; Bahamonde, A Article. Chem. Eng. J.. vol: 403. page: 1385-8947. Date: JAN 1. 2021. Doi:10.1016/j.cej.2020.126186. Abstract: This work examines the important role of light power absorbed by TiO2 on the photocatalytic degradation of dichloroacetic acid (DCA) in a semi-continuous slurry photoreactor with UV-Vis radiation. This system is an excellent model for understanding the light matter interaction, because DCA is transparent and the acid pH of the solution prevents the formation of large TiO2 aggregates. Under these conditions, the light power absorbed by four different commercial Titania photocatalysts, along the whole volume of [leer más]
Ordered mesoporous materials have attracted considerable attention due to their potential applications in catalysis, adsorption, and separation technologies, as well as biomedical applications. In the present manuscript, we aim at a rational design to obtain the desired surface functionality (Ti and/or hydrophobic groups) while obtaining short channels (short diffusion paths) and large pore size (>10 nm). Santa Barbara Amorphous material SBA-15 and periodic mesoporous organosilica PMO materials are synthesized using Pluronic PE 10400 (P104) surfactant under mild acidic conditions to obtain hexagonal platelet-like particles with very short [leer más]
Ficin: A protease extract with relevance in biotechnology and biocatalysis
Authors: Morellon-Sterling, R; El-Siar, H; Tavano, OL; Berenguer-Murcia, A; Fernandez-Lafuente, R Review. Int. J. Biol. Macromol.. vol: 162. page: 0141-8130. Date: nov-01. 2020. Doi:10.1016/j.ijbiomac.2020.06.144. Abstract: Due to the problems raised by the use of animal or microbial recombinant proteases, the use of proteases from vegetable origin is becoming increasingly popular.. Among them, sulfidryl proteases have a special interest. Ficin is an outstanding example of this kind of proteases. This paper aims to be to make a comprehensive review of the recent uses of this enzyme, including for example protein hydrolysis, the production of bioactive peptides and antibodies fragments (researchers [leer más]
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