Novel bimetallic 1%M-Fe/Al2O3-Cr2O3 (2:1) (M = Ru, Au, Pt, Pd) catalysts for Fischer-Tropsch synthesis

The main objective of this work was to study the physicochemical and catalytic properties of bimetallic supported catalysts [1%M-Fe/Al2O3-Cr2O3 (2:1) (M = Ru, Au, Pt, Pd)] in Fischer-Tropsch synthesis. Furthermore, the study investigated the effect of noble metal addition to iron-supported catalysts on their physicochemical properties and reactivity. The physicochemical properties of the catalysts were studied using a range of characterization techniques such as X-ray diffraction (XRD), temperature-programmed reduction (TPR-H2), temperature-programmed desorption of ammonia (TPD-NH3) and BET (Brunauer – Emmett - Teller method). The activity tests were performed by Fischer-Tropsch synthesis in a high-pressure fixed-bed reactor using a gas mixture of H2 and CO with a molar ratio of 1:1. The correlation between the physicochemical properties of the investigated catalysts and their catalytic performance in CO hydrogenation was also investigated. The reactivity results showed that the most active system exhibited a high specific surface area, the highest total acidity and was the most reducible catalyst compared to the other catalysts tested. In addition, the Au–Fe system showed high selectivity towards liquid product formation during CO hydrogenation

Nanoparticles Surface Chemistry Influence on Protein Corona Composition and Inflammatory Responses

Nanoparticles are widely used for biomedical applications such as vaccine, drug delivery, diagnostics, and therapeutics. This study aims to reveal the influence of nanoparticle surface functionalization on protein corona formation from blood serum and plasma and the subsequent effects on the innate immune cellular responses. To achieve this goal, the surface chemistry of silica nanoparticles of 20 nm diameter was tailored via plasma polymerization with amine, carboxylic acid, oxazolines, and alkane functionalities. The results of this study show significant surface chemistry-induced differences in protein corona composition, which reflect in the subsequent inflammatory consequences. Nanoparticles rich with carboxylic acid surface functionalities increased the production of pro-inflammatory cytokines in response to higher level of complement proteins and decreased the number of lipoproteins found in their protein coronas. On another hand, amine rich coatings led to increased expressions of anti-inflammatory markers such as arginase. The findings demonstrate the potential to direct physiological responses to nanomaterials via tailoring their surface chemical composition

Adsorption of Wine Constituents on Functionalized Surfaces

The adsorption of macromolecules on solid surfaces is of great importance in the field of nanotechnology, biomaterials, biotechnological, and food processes. In the field of oenology adsorption of wine macromolecules such as polyphenols, polysaccharides, and proteins is much less desirable on membrane materials because of fouling and reduced filtering performance. On the other hand, adsorption of these molecules on processing aids is very beneficial for achieving wine clarity and stability. In this article, the effect of surface chemical functionalities on the adsorption of white, rosé, and red wine constituents was evaluated. Allylamine, acrylic acid, and ethanol were selected as precursors for plasma polymerization in order to generate coatings rich in amine, carboxyl, and hydroxyl chemical groups, respectively. The surface chemical functionalities were characterized by X-ray photoelectron spectroscopy (XPS) and the ability of different surface chemical functionalities to adsorb wine constituents were characterized by quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM). The results demonstrated that the amine and carboxyl modified surfaces encourage adsorption of constituents from white wine. The hydroxyl modified surfaces have the ability to preferentially adsorb rosé wine constituents, whereas red wine adsorbed to the highest extent on acrylic acid surface

Fluorescence sensing technology for the rapid detection of haze-forming proteins in white wine

The methods currently available for determining haze proteins in wine are time-consuming, expensive, and often not sufficiently accurate. The latter may lead to bentonite over-fining of a wine, which might strip wine phenolics and aroma compounds, or wine under-fining, which increases the risk of protein instability. In this work, an efficient and rapid fluorescence-based technology to detect haze-forming proteins in white wines was developed. A fluorescent compound was synthesised to selectively bind haze-forming proteins. Studies involving HPLC demonstrated a linear dependence over a range of relevant haze protein concentrations and a low detection limit of 2 mg/L. Forty-eight control and bentonite fined wines were analysed to validate the analytical performance of the fluorescent dye in the detection of haze-forming proteins. The method can be deployed rapidly, without sample preparation, presenting an opportunity to use in routine testing and overcome limitations of the “heat test” currently used in the wine industry

The effect of impurities and cleavage characteristics on talc hydrophobicity and polymer adsorption

We have investigated three natural talc samples from different geographical locations (Rhode Island (USA), Delaware (USA), and Flinders Range (Australia)) to determine the effect of impurities and cleavage characteristics on hydrophobicity and polymer adsorption. Bulk (electron microprobe) and surface (X-ray photoelectron spectroscopy) composition measurements have indicated that the Rhode Island and Delaware talcs have the lowest level of Al atoms substituted within the talc structure (0.008%), and detectable at the cleaved basal plane surface (1.5 and 1.7%), and that the Flinders Range talc has the highest level of Al atoms (8.5% bulk; 8.2% surface). Contact angle measurements have highlighted the role of Al atom substitution and step-edge density (as revealed by AFM imaging) on themeasured hydrophobicity of the cleaved surfaces, with the Flinders Range talc and the Rhode Island talc having significantly lower contact angles than the Delaware talc (65° and 83°, respectively, versus 90° for the Delaware). In addition, we have characterised the adsorption of two polysaccharide polymers on the three talc samples (CMC and Dextrin TY) using in situ tapping mode AFM. CMC adsorbs with the same morphology on all three talc samples, whereas Dextrin TY presents three different morphologies on the talc surfaces. The potential implications of the observed variation in adsorption behaviour on mineral flotation are discussed.

Regeneration of Magnetic Nanoparticles Used in the Removal of Pathogenesis-Related Proteins from White Wines

Protein haze remains a serious problem for the wine industry and requires costly bentonite treatment, leading to significant wine volume loss. Recently developed magnetic separation technology that allows a fast and efficient separation of haze proteins from wine shows promise for the development of an alternative method for white wine fining. The key purpose of this study was to understand the potential of the nanoparticles to be reused in multiple fining and regeneration cycles. Bare and acrylic-acid-based plasma polymer coated magnetic nanoparticles were cleaned with water, 10% SDS/water and acetone/water solution after each adsorption cycle to investigate their restored efficiency in removing pathogenesis-related proteins from three unfined white wines. The concentrations of metals, acids and phenolics were monitored to determine changes in the concentration of these essential wine constituents. The regeneration study verified that the acrylic acid plasma-coated magnetic nanoparticles, which underwent ten successive adsorption-desorption processes, still retained close to the original removal capacity for haze proteins from wines when 10% SDS solution and water were used for surface regeneration. In addition, the concentrations of organic acids and wine phenolic content remained almost unchanged, which are important indicators for the retention of the original wine composition

Plasma-assisted catalysis for CH4 and CO2 conversion

This paper presents a critical review of recent advances in the processes of converting CO2 and CH4 gases into fine chemicals using plasma-assisted catalysis. The general principles of plasma-catalytic processes are summarized, presenting schematics and operation principles of typical plasma reactors for applications in catalysis. The applications of plasma in various catalytic CO2 and/or CH4 conversion processes are discussed and the advantages of using plasma in catalysis compared to traditional thermal processes are highlighted. Among all the plasma reactors presented in the review, the use of the DBD reactor for CO2 and CH4 conversion is described in detail due to its simplicity, possible configuration changes, easy catalyst replacement and its mild operating conditions during the process compared to other types of plasma reactors. The paper presents also the postulated reaction paths and a comparison of the efficiency and the selectivities obtained during the dry reforming of methane process using various type of reactors. Current challenges and outlook for plasma-assisted catalytic processes are also presented

Plasma-assisted catalysis for CH4 and CO2 conversion

This paper presents a critical review of recent advances in the processes of converting CO2 and CH4 gases into fine chemicals using plasma-assisted catalysis. The general principles of plasma-catalytic processes are summarized, presenting schematics and operation principles of typical plasma reactors for applications in catalysis. The applications of plasma in various catalytic CO2 and/or CH4 conversion processes are discussed and the advantages of using plasma in catalysis compared to traditional thermal processes are highlighted. Among all the plasma reactors presented in the review, the use of the DBD reactor for CO2 and CH4 conversion is described in detail due to its simplicity, possible configuration changes, easy catalyst replacement and its mild operating conditions during the process compared to other types of plasma reactors. The paper presents also the postulated reaction paths and a comparison of the efficiency and the selectivities obtained during the dry reforming of methane process using various type of reactors. Current challenges and outlook for plasma-assisted catalytic processes are also presented.</p

Small surface nanotopography encourages fibroblast and osteoblast cell adhesion

In this paper, we report the initial response of 3T3 fibroblast and MG63 osteoblast cells to engineered nanotopography gradients of three nanoparticle diameters (16 nm, 38 nm and 68 nm). These nanoengineered surfaces were designed to provide a range of nanoparticle densities and comparable surface area across the gradients of different nanoparticle sizes. Importantly, we provided a uniform surface chemistry in order to be able to examine the effect of pure surface nanotopography. We found that nanotopography features of 16 nm encourage the adhesion of both cell types and that there is a critical nanoparticle density between 50 and 140 particles per μm2 where cells adhered in the greatest numbers. When nanotopography features increased to 38 nm the 3T3 cells adhered and spread well, however, the MG63 cells adhered and spread poorly. Both cell types adhered in lower numbers when the nanotopography feature size increased to 68 nm. This work demonstrates that there is a specific nanotopography scale that encourages cell adhesion and spreading, however, the preferential lateral spacing and height of the nanotopography is different for different cell types.