Selectivity Control of C-O Bond Cleavage for Catalytic Biomass Valorization

Increasing fossil fuels consumption and global warming have driven the global revolution towards renewable energy sources. Lignocellulosic biomass is the main source of renewable carbon-based fuels. The abundant intermolecular linkages and high oxygen content between cellulose, hemicellulose, and lignin limit the use of traditional fuels. Therefore, it is a promising strategy to break the above linkages and remove oxygen by selective catalytic cracking of C–O bond to further transform the main components of biomass into small molecular products. This mini-review discusses the significance of selectivity control in C–O bond cleavage with well-tailored catalytic systems or strategies for furnishing biofuels and value-added chemicals of high efficiency from lignocellulosic biomass. The current challenges and future opportunities of converting lignocellulose biomass into high-value chemicals are also summarized and analyzed.

Synergetic Effect of Potassium Oxysalts on Combustion and Ignition of Al/CuO Composites

In this study, we studied the synergetic effect of potassium oxysalts on combustion and ignition of nano aluminum (Al) and nano copper oxide (CuO) composites. Potassium periodate (KIO4) and potassium perchlorate (KClO4) are good oxidizers with high oxygen content and strong oxidizability. Different contents of KIO4 and KClO4 were added to nano Al/CuO and the composites were assembled by sonication. When the peak pressure of nano Al/CuO was increased ~5–13 times, the pressurization rate was improved by ~1–3 orders of magnitude, the ignition delay time was shortened by ~0.08 ms–0.52 ms and the reaction completeness was adjustable when 30–70% KIO4 and KClO4 were added into the composites. The reaction of Al/KIO4 and Al/KClO4 at a lower temperature was helpful to ignite the ternary composite. Meanwhile, CuO significantly reduced the peak temperature of oxygen released from the decomposition of KIO4 and KClO4. The synergetic effect of binary oxidizers made the combustion performance of the ternary composites better than that of the binary composites. The present work indicates that KIO4 and KClO4 are promising additives for nano Al/CuO to tune and promote the combustion performance. The ternary composites have potential application in energy devices and combustion apparatus.

On the Arrangement of Pentagonal Columns in Tetragonal Tungsten Bronze-Type Nb18W16O93

The evaluation of HAADF-STEM images of a sample with the composition Nb18W16O93 provided new insights into its real structure. The basic structure comprises an intact octahedral framework of the tetragonal tungsten bronze (TTB) type. The partial occupation of the pentagonal tunnels (PT) by metal–oxygen strings determines the oxygen-to-metal ratio (O/ΣM with M = Nb,W). For a large area, the O/ΣM was determined to be 2.755, which is bigger than the value of Nb18W16O93, which is O/ΣM = 2.735. To a large extent, the three-fold TTB superstructure of Nb8W9O47 with a high oxygen content is present (O/ΣM = 2.765). In addition, a new four-fold TTB superstructure was found in small domains. Nb12W11O63 with an O/ΣM = 2.739 obviously accommodates part of the sample’s metal excess compared to the stable phase Nb8W9O47.

Magnetics Hysteresis Properties and Microstructure of High-Energy (Nd,Dy)–Fe–B Magnets with Low Oxygen Content

Magnetic properties and microstructure of high-energy (Nd,Dy)–Fe–B magnets with Dy of no more than 1 wt % prepared via a low-oxygen routine are studied. Oxygen content in magnets does not exceed 0.20 wt %. 0.5 wt %–Dy addition reliably stabilizes the coercivity MHc higher than 13 kOe; in this case, the maximum energy density product (BH)max of magnets is 48.5–49.5 MG Oe. High magnetic hysteresis properties are gained via optimization of chemical and phase compositions of magnets, as well as their microstructure. The grain size of the main Nd2Fe14B phase is approximately 3.5 μm; and according to X-ray analysis, the weight fraction of additional Nd-rich phases (NdOx and Nd2O3) does not exceed 2.5%. Scanning electron microscopy study has demonstrated that in triple junctions of Nd2Fe14B grains there are two types of inclusions (В and С) of the NdOx phase, which significantly differ by their chemical composition. С-phase inclusions with low oxygen content (х ≈ 0.03) are enriched in Fe (40–50 wt %); whereas, В-phase with high oxygen content (х ≈ 0.70) contains 3–5 times less Fe. The angular dependences of coercivity of (Nd,Dy)–Fe–B magnets are presented.

Degradative Studies in the Picrotoxinin Series

<p>PICROTOXIN is a bitter principle of the berries of the species Mensiperum coculus and Anamirata coculus, creepers which are indigenous to the East Indies. It was first isolated in 1812, and subsequent elementary analysis showed that it contained only carbon, hydrogen, and oxygen. Because of its potent poisonous nature and its physiological action, together with its high oxygen content, picrotoxin has often been referred to as an “oxygen alkaloid”. It is a central nervous system stimulant and a powerful convulsant drug. It is used in medicine as an antidote to barbiturate poisoning, being still preferred for this purpose over many other drugs. It has also been used in cases of alcoholic intoxication, and as a fish poison.</p>

On the Arrangement of Pentagonal Columns in Tetragonal Tungsten Bronze-Type Nb18W16O93

The evaluation of HAADF-STEM images of a sample with the composition Nb18W16O93 provided new insights in its real structure. The basic structure comprises an intact octahedral framework of the tetragonal tungsten bronze (TTB) type. The partial occupation of the pentagonal tunnels (PT) by metal-oxygen strings determines the oxygen to metal ratio (O/SM with M = Nb,W). For a large area, the O/SM was determined to be 2.755 which is smaller than the value of Nb18W16O93 which is O/SM = 2. 735. To a large extent, the threefold TTB superstructure structure of Nb8W9O47 with a high oxygen content is present (O/SM = 2.765). In addition, a new fourfold TTB superstructure was found in small domains: Nb12W11O63 with an O/SM = 2.739 obviously accommodates a part of the sample’s metal excess compared to the stable phase Nb8W9O47.

Degradative Studies in the Picrotoxinin Series

<p>PICROTOXIN is a bitter principle of the berries of the species Mensiperum coculus and Anamirata coculus, creepers which are indigenous to the East Indies. It was first isolated in 1812, and subsequent elementary analysis showed that it contained only carbon, hydrogen, and oxygen. Because of its potent poisonous nature and its physiological action, together with its high oxygen content, picrotoxin has often been referred to as an “oxygen alkaloid”. It is a central nervous system stimulant and a powerful convulsant drug. It is used in medicine as an antidote to barbiturate poisoning, being still preferred for this purpose over many other drugs. It has also been used in cases of alcoholic intoxication, and as a fish poison.</p>

Damage caused by black inks to the chemical properties of archaeological papyrus – analytical study

Purpose The purpose of this study is to determine the nature of archaeological papyrus damage and monitoring the mechanics of damage caused by black inks to the chemical properties of ancient papyrus. Design/methodology/approach This study the papyrus surface with a digital microscopy “USB,” examination and analyzing by “Scanning Electron Microscope,” characterization of black ink used in writing the ancient papyrus using “Scanning Electron Microscopy” with (EDX). Detection of changes in the chemical bonds of ancient papyrus samples by “Fourier transform infrared” FTIR. Findings The result confirmed that SEM examination showed the organization of the parenchyma cells that make up papyrus tissue. Characteristic waveform appears, it indicates the ancient Egyptian manufacturer’s use of the (Strips Method) in the process of manufacturing the archaeological papyrus. Also, the appearance of (Over Lapping) stacking of papyrus slides. EDX analysis showed that the black ink used to write the papyrus was (Carbon Ink). High oxygen content in the papyrus sample analysis indicates deterioration of the cellulose fibers. FTIR spectrum showed that Arabic gum is the bonding material for carbon ink particles, it also showed that archaeological papyrus suffers from hydrolysis due to exposure of papyrus fibers to high moisture content or direct water, resulting in smudge, bleeding and fading of carbon ink on the archaeological papyrus support. Originality/value The study is archaeological papyrus with black ink scripts from the excavation of the Qasr I brim.

Application of Pyrolysis and Hydrothermal Liquefaction Process to Convert Bio-Fuel from Biomass

Rapid increase in demand of fuels creates the challenge for scientific community. The fossil fuel resources are declining day by day. So, biomass derived fuel starts to feel an exquisite alternative option, by reason of it develop from residual cooking oil, animal fats, or vegetable oils, etc. In present work biomass is converted into bio-fuel by the process of pyrolysis and hydrothermal liquefaction. But if it is compared with fossil fuel some undesirable properties have been found such like high oxygen content high water content, high corrosiveness and high viscosity etc. Directly biofuels cannot be used in IC engine due to their unwanted content in the fuel. Therefore upgrading of bio-fuel is needed to improve its properties for liquid fuels by the pre-treatment process of biomass. The purpose of biomass pre-treatment is the degradation of cellulose phibrils, lowering their crystallization and polymerization levels, hemicelluloses separation and degradation of cellulose. However application to this bio-fuel have been needed to enhance its properties for CI engine fuel using blending for direct use in engine application.

Particularities of High Oxygen Content Biofuels Pyrolysis Process

Generating capacities supplied by solid biomass (renewable waste) gather at the moment less than 4.5% of the total renewable power installed worldwide. Given the two folded implications of such technology development and spreading (i.e. energy production and waste management), researches regarding efficient conversion processes and improved power facilities are of great interest currently. In this context, the paper addresses the particularities of high oxygen content biofuels pyrolysis, proposing innovative solutions to overcome the issues found in experimental investigations. Based on thorough experimental research conducted on agricultural wooden biomass and poultry manure, a number of problems arise. Among them, it is highlighted the heating in the absence of oxidants, an undesirable internal process caused by the high oxygen content, which contravenes the general principles regarding pyrolysis. Furthermore, the high oxygen content is associated with great moisture percentages. The present paper reveals the challenges determined by some negative aspects emerging during the pyrolysis of high oxygen content biofuels. Several solutions are proposed to improve the efficiency of the conversion process through adequate control. For instance, it is pointed out that the temperature level at which the pyrolysis process develops plays a crucial role in the general energy balance. On this matter, investigating poultry manure pyrolysis at low temperatures, a significant decrease of the final coke product is noticed. Poultry manure pyrolysis results as a suitable and simple solution to be employed for waste treatment purposes, as its combustible effects (combustible gases and semicoke / coke) are good candidates for energy production.