Reversed Mg-Based Smectites: A New Approach for CO Adsorption.

Addressing climate change requires transitioning to cleaner energy sources and adopting advanced CO capture techniques. Clay minerals are effective in CO adsorption due to their regenerative properties. Recent advancements in nanotechnology further improve their efficiency and potential for use in carbon capture and storage.

Microwave-assisted acid treatment for the mineral transformation of chrysotile as an alternative for asbestos waste management.

In this work, the effect of microwave-assisted acid treatments on the morphological and crystallochemical characteristics of chrysotile fibers is investigated. A low concentration of nitric acid (0.2 N) is used to remove Mg-species located in the octahedral sheet of its structure, thereby causing a crystallo-chemical change forming a skeleton of non-crystalline amorphous silica.

Molecular Aspects in Porous Silicas Related to Adsorption and Catalytic Processes.

The aim of this special issue is to show the advances in the different applications that inorganic materials based on silica have had in recent years [...

Preparation of a heterogeneous biocatalyst through Thermomyces lanuginosus lipase immobilization on pore-expanded SBA-15.

Heterogeneous biocatalysts were prepared by adsorbing T. lanuginosus lipase (TLL) onto uncalcined (SBAUC-TLL) and calcined (SBAC-TLL) SBA-15, using ammonium fluoride as a pore expander to facilitate TLL immobilization. At an enzyme load of 1 mg/g, high immobilization yields (>90 %) and recovered activities (>80 % for SBAUC-TLL and 70 % for SBAC-TLL) were achieved.

Promoter Effect of Pt on Zr Catalysts to Increase the Conversion of Furfural to γ-Valerolactone Using Batch and Continuous Flow Reactors: Influence of the Way of the Incorporation of the Pt Sites.

The valorization of biomass and its transformation into fuels are highly interesting due to the abundance of biomass and its almost neutral carbon emissions. In this article, we show the production of γ-valerolactone (GVL), a valuable product, from furfural (FF), a compound that can be easily obtained from biomass. This FF to GVL transformation involves a catalytic cascade reaction with two hydrogenation steps.

Zeolites synthesis from phyllosilicates and their performance for CO adsorption.

Five phyllosilicates (kaolinite, montmorillonite, saponite, sepiolite and palygorskite) have been selected as starting materials for the synthesis of zeolites. Among them, kaolinite and montmorillonite display the lowest Si/Al molar ratio leading to aluminosilicates with high crystallinity. Thus, the hydrothermal treatment under basic conditions forms 4A zeolite when kaolinite is used as starting material while 13X zeolite is obtained when montmorillonite is used as starting material.

Resembling Graphene/Polymer Aerogel Morphology for Advancing the CO/N Selectivity of the Postcombustion CO Capture Process.

The separation of CO from N remains a highly challenging task in postcombustion CO capture processes, primarily due to the relatively low CO content (3-15%) compared to that of N (70%). This challenge is particularly prominent for carbon-based adsorbents that exhibit relatively low selectivity. In this study, we present a successfully implemented strategy to enhance the selectivity of composite aerogels made of reduced graphene oxide (rGO) and functionalized polymer particles.

Nb-Based Catalysts for the Valorization of Furfural into Valuable Product through in One-Pot Reaction.

Nb-based catalysts supported on porous silica with different textural properties have been synthesized, characterized, and tested in the one-pot reaction of furfural to obtain valuable chemicals. The catalytic results reveal that the presence of fluoride in the synthesis, which limits the growing of the porous silica, limits diffusional problems of the porous silica, obtaining higher conversion values at shorter reaction times. On the other hand, the incorporation of NbO species in the porous silica provides Lewis acid sites and a small proportion of Brönsted acid sites, in such a way that the main products are alkyl furfuryl ethers, which can be used as fuel additives.

One-Pot Synthesis and Surfactant Removal from MCM-41 Using Microwave Irradiation.

This research pioneers the application of microwave irradiation as an innovative strategy for one-pot synthesis and surfactant elimination (cetyltrimethylammonium bromide-CTAB) from MCM-41, introducing a rapid and efficient methodology. MCM-41 silica is widely utilized in various applications due to its unique textural and structural properties. Nonetheless, the presence of residual surfactants after synthesis poses a challenge to its effective application.

Microwave-Assisted Synthesis of Zeolite A from Metakaolinite for CO Adsorption.

The global demand for energy and industrial growth has generated an exponential use of fossil fuels in recent years. It is well known that carbon dioxide (CO) is mainly produced, but not only from fuels, which has a negative impact on the environment, such as the increasing emission of greenhouse gases. Thus, thinking about reducing this problem, this study analyzes microwave irradiation as an alternative to conventional heating to optimize zeolite A synthesis conditions for CO capture.

Recent Advances in Mesoporous Materials and Their Biomedical Applications.

Since the beginning of civilization, porous materials have been used for medical purposes [...

Tailoring of Textural Properties of 3D Reduced Graphene Oxide Composite Monoliths by Using Highly Crosslinked Polymer Particles toward Improved CO Sorption.

The main constraint on developing a full potential for CO adsorption of 3D composite monoliths made of reduced graphene oxide (rGO) and polymer materials is the lack of control of their textural properties, along with the diffusional limitation to the CO adsorption due to the pronounced polymers' microporosity. In this work, the textural properties of the composites were altered by employing highly crosslinked polymer particles, synthesized by emulsion polymerization in aqueous media. For that aim, waterborne methyl methacrylate (MMA) particles were prepared, in which the crosslinking was induced by using different quantities of divinyl benzene (DVB).

Modification of the Textural Properties of Chitosan to Obtain Biochars for CO-Capture Processes.

Three chitosans with different morphologies have been used (commercial chitosan powder, chitosan in film form and chitosan in globular form synthesized by the freeze-dried method) for the synthesis of biochars. The pyrolytic treatment has revealed that the biochar synthesized from the chitosan formed by the freeze-dried method reaches the highest CO-adsorption capacity (4.11 mmol/g at 0 °C and a pressure of 1 bar) due to this adsorbent is highly microporous.

Porous SiO Nanospheres Modified with ZrO and Their Use in One-Pot Catalytic Processes to Obtain Value-Added Chemicals from Furfural.

Porous SiO nanospheres were modified with different loadings of ZrO to obtain catalysts with a Si/Zr molar ratio from 2.5 to 30. These materials were characterized by X-ray diffraction, transmission and scanning electron microscopies, N adsorption-desorption at -196 °C, X-ray photoelectron spectroscopy and pyridine and 2-6-dimethylpyridine thermoprogrammed desorption.

Protein Adsorption onto Modified Porous Silica by Single and Binary Human Serum Protein Solutions.

Typical porous silica (SBA-15) has been modified with pore expander agent (1,3,5-trimethylbenzene) and fluoride-species to diminish the length of the channels to obtain materials with different textural properties, varying the Si/Zr molar ratio between 20 and 5. These porous materials were characterized by X-ray Diffraction (XRD), N adsorption/desorption isotherms at -196 °C and X-ray Photoelectron Spectroscopy (XPS), obtaining adsorbent with a surface area between 420-337 m g and an average pore diameter with a maximum between 20-25 nm. These materials were studied in the adsorption of human blood serum proteins (human serum albumin-HSA and immunoglobulin G-IgG).

Effect of Polyvinyl Alcohol Ligands on Supported Gold Nano-Catalysts: Morphological and Kinetics Studies.

The effect of polyvinyl alcohol (PVA) stabilizers and gold nanoparticles supported on active carbon (AuNPs/AC) was investigated in this article. Polymers with different molecular weights and hydrolysis degrees have been synthesized and used, like the stabilizing agent of Au nano-catalysts obtained by the sol-immobilization method. The reduction of 4-nitrophenol with NaBH has been used as a model reaction to investigate the catalytic activity of synthesized Au/AC catalysts.

CO Valorization and Its Subsequent Valorization.

After the industrial revolution, the increase in the world population and the consumption of fossil fuels has led to an increase in anthropogenic CO emissions [...

Assessing CO Adsorption on Amino-Functionalized Mesocellular Foams Synthesized at Different Aging Temperatures.

A wide variety of solid sorbents has recently been synthesized for application in CO adsorption. Among them, mesoporous silicas deserve attention because of their ability to accommodate large concentrations of different chemicals as a consequence of their surface chemistry and tunable pore structure. Functionalized materials exhibit promising features for CO adsorption at high temperatures and low CO concentrations.

Chitosan: A Natural Biopolymer with a Wide and Varied Range of Applications.

Although chitin is of the most available biopolymers on Earth its uses and applications are limited due to its low solubility. The deacetylation of chitin leads to chitosan. This biopolymer, composed of randomly distributed β-(1-4)-linked D-units, has better physicochemical properties due to the facts that it is possible to dissolve this biopolymer under acidic conditions, it can adopt several conformations or structures and it can be functionalized with a wide range of functional groups to modulate its superficial composition to a specific application.

Enhanced NiO Dispersion on a High Surface Area Pillared Heterostructure Covered by Niobium Leads to Optimal Behaviour in the Oxidative Dehydrogenation of Ethane.

A Nb-containing siliceous porous clay heterostructure (PCH) with Nb contents from 0 to 30 wt %) was prepared from a bentonite and used as support in the preparation of supported NiO catalysts with NiO loading from 15 to 80 wt %. Supports and NiO-containing catalysts were characterised by several physicochemical techniques and tested in the oxidative dehydrogenation (ODH) of ethane. The characterisation studies on Nb-containing supports showed the presence of well-anchored Nb species without the formation of Nb O crystals.

Photocatalyzed preferential oxidation of CO under simulated sunlight using Au-transition metal oxide-sepiolite catalysts.

In the present study a series of Au-transition metal oxides supported on a clay mineral such as sepiolite were tested in the preferential oxidation of CO in an excess of H under simulated solar light irradiation and in the absence of light, at 30 °C and atmospheric pressure. Transition metal oxides (ZnO, FeO, NiO, MnO, and CoO) were dispersed over the sepiolite surface where, subsequently, Au nanoparticles with an average particle size between 2 and 3 nm were successfully deposited-precipitated. The obtained photocatalysts were characterized by XRD, XRF, DRUV-Vis, N adsorption-desorption and HRTEM in order to evaluate the optical, structural and chemical properties of the prepared samples.

Lignin Depolymerization to BTXs.

Lignin, one of the main components of lignocellulosic biomass, is the largest renewable source of aromatics on the planet and presents an extraordinary opportunity for being used in the production of bio-based products. It can be transformed for the substitution of aromatic chemical-derived petrol as BTXs. The wide range of applications that it can be obtained from BTXs building blocks makes the selective depolymerization of lignin a great scientific challenge.

Mesoporous Materials: From Synthesis to Applications.

Mesoporous silica are inorganic materials, which are formed by the condensation of sodium silicate or silicon alkoxides around an ordered surfactant used as template [...