A new and easy method for anchoring manganese salen on MCM-41

This work reports a new method to covalently attach manganese salophen complex onto MCM-41, using a diisocyanate as a binder. The prepared catalyst was tested on the liquid phase limonene oxidation reaction. Diluted t-Butyl hydroperoxide was used as oxygen supplier. Limonene oxide, carveol and carvone are formed, but the main product obtained was a polymer. The preservation of the MCM-41 channel system was checked by X-ray diffraction and nitrogen adsorption analysis. The use of the same catalyst sample in four consecutive experiments, without loss of activity, is a confirmation of the success of the anchoring process.     

Ice cream supplemented with grape juice residue as a source of antioxidants

Grape juice residue was incorporated into ice cream at 2.5%, 5.0% and 10.0% to obtain a product with functional characteristics. The chemical composition, colour, total phenolic compounds, antioxidant capacity and sensory acceptance of the ice creams were analysed at day 0 and after 40 days of storage. Ice creams containing grape juice residue had a higher concentration of phenolic compounds and antioxidant activity compared to the control samples. Consumers’ acceptance was similar for all products. At the end of storage, the polyphenol content and antioxidant activity had decreased. Grape juice residue has potential as a natural source of antioxidants to develop new products.     

Simultaneous removal of 3d transition metals from multi-component solutions by activated carbons from co-mingled wastes

The main purpose of the present work was to study the simultaneous removal of 3d transition metals from multi-component solutions by novel porous material obtained from carbon-containing liquid and solid waste. The activated carbon was prepared from co-mingled natural organic waste: 25% sunflower husks, 50% petroleum waste and 25% low-grade bituminous coal. The porous carbon material was obtained via stages of pre-oxidation with binary eutectic Na/K carbonates (in order to avoid melting and coke formation), followed by “step by step” carbonization at 100–400 °C in an inert atmosphere and activation with steam at 850 °C.

The adsorption of the 3d transition metals: copper (II), cobalt (III), nickel (II), iron (III), and chromium (III), on novel activated carbons has been investigated using multi-component model solutions. Experiments have been carried out on the thermodynamics of the simultaneous adsorption of the 3d transition metals in a static mode. The total metal removal combines the process of metal hydroxide precipitation in the solution with the metal cation adsorption on negatively charged carbon surface in a single operation unit. The carbon/metals interaction at the surface of spent adsorbents is discussed.     

Sampling sufficiency for estimating zooplankton diversity in neotropical floodplain lakes

This study focuses on determining how many samples are needed to effectively assess the species richness of a community. Zooplankton samples at 40 sampling sites distributed among four lakes in the floodplain of the middle Araguaia River (Central‐West region of Brazil) were evaluated to determine the effect of the accumulation of collecting points by lake on species richness estimates. The results indicated the zooplankton community has high spatial heterogeneity. Thus, using a single sampling unit per lake would not be sufficient to accurately estimate their diversity (i.e. the zooplankton composition in these cases would be represented mainly by abundant species). Sampling designs that include a minimum of seven sampling sites in each lake are needed to record 70% of the total species richness. It is recommended, therefore, that researchers use a larger number of sampling sites per lake or, alternatively, that the water obtained and filtered through plankton nets is extracted from a wide area and in different lake compartments, rather than from a single site.     

Natural Pigments: Stabilization Methods of Anthocyanins for Food Applications

The production of natural food pigments continues to grow worldwide. The global market is expected to grow at a compound annual growth rate of 6.22%, by revenue, over the period 2015 to 2019. Pigments such as anthocyanins, carotenoids, betalains, and chlorophylls have been used to color foods. However, there are challenges related to color losses during food processing, storage, and commercialization due to a low stability of natural pigments compared to synthetic colorants. This review summarizes the most recent studies and patents aimed at enhancing anthocyanin stability in food systems. The stabilizing methods include additions of copigment compounds, such as polymers, phenolic compounds, and metals. In addition, the exclusion of O₂ during processing and storage, hard‐panned candy coating methods for blue, green, and brown colors, and various encapsulation techniques were considered. Combining strategies and evaluating new materials capable of stabilizing anthocyanins will enhance their potential for use as value‐added natural food pigments.     

Nanohybrid structure analysis and biomolecule release behavior of polysaccharide-CDHA drug carriers

Nanoscaled polymer composites were prepared from polysaccharide chitosan (CS) and Ca-deficient hydroxyapatite (CDHA). CS-CDHA nanocomposites were synthesized by in situ precipitation at pH 9, and the CS-CDHA carriers were then fabricated by ionic cross-linking methods using tripolyphosphate and chemical cross-linking methods by glutaraldehyde and genipin. Certain biomolecules such as vitamin B₁₂, cytochrome c, and bovine serum albumin were loaded into the CS-CDHA carriers, and their release behaviors were investigated. Furthermore, these CS-CDHA carriers were examined by transmission electron microscopy, electron spectroscopy for chemical analysis, and X-ray diffraction. The release behavior of the biomolecules was controlled by the CS/CDHA ratios and cross-linked agents. By increasing the concentration of CS and the concentration of the cross-linking agents, cross-linking within carriers increases, and the release rate of the biomolecules is decreased. Moreover, the release rate of the biomolecules from the CS-CDHA carriers at pH 4 was higher than that at pH 10, displaying a pH-sensitive behavior. Therefore, these CS-CDHA hydrogel beads may be useful for intelligent drug release and accelerate bone reconstruction.     

Meshless method for solving radiative transfer problems in complex two-dimensional and three-dimensional geometries

A meshless method is presented to solve the radiative transfer equation in complex 2D and 3D geometries. In order to avoid numerical oscillations, the even parity formulation of the discrete ordinates method is used. A moving least squares approximation meshless method is used to solve the second order partial differential equations. Prediction results of radiative heat transfer problems obtained by the proposed method are compared with reference in order to assess the correctness of the present method.     

Limonene oxidation over V2O5/TiO2 catalysts

Vanadia-titania catalysts prepared by different sol–gel procedures were studied as heterogeneous catalysts for the liquid phase oxidation of limonene. The catalysts were characterized by XRD, XPS, ICP and nitrogen adsorption. According to the XRD results the catalyst samples can be divided in two different groups: anatase samples and anatase + rutile samples. XRD signals of vanadia are not found in the diffractograms.

The main reaction products are polymers. Limonene oxide, limonene glycol, carveol and carvone are obtained in small amounts. A number of autoxidation products, alcohols, aldehydes and ketones, are also obtained.

The effects of titania composition on the reaction orientation are discussed.