A Focus on the Transformation Processes for the Valorization of Glycerol Derived from the Production Cycle of Biofuels

Glycerol is a valuable by-product in the biodiesel industries. However, the increase in biodiesel production resulted in an excess production of glycerol, with a limited market compared to its availability. Precisely because glycerol became a waste to be disposed of, the costs of biodiesel production have reduced. From an environmental point of view, identifying reactions that can convert glycerol into new products that can be reused in different applications has become a real necessity. According to the unique structural characteristics of glycerol, transformation processes can lead to different chemical functionalities through redox reactions, dehydration, esterification, and etherification, with the formation of products that can be applied both at the finest chemical level and to bulk chemistry.

Cobalt single atoms anchored on nitrogen-doped porous carbon as an efficient catalyst for oxidation of silanes

The oxidation reactions of organic compounds are important transformations for the fine and bulk chemistry industry. However, they usually involve the employment of noble metal catalysts and suffer from toxic...

AVA Biochem, Pioneer in Industrial Biobased Furan Chemistry

Swiss-based AVA Biochem AG is the global leader in the industrial production and sale of the bio-based platform chemical 5-hydroxymethylfurfural (5-HMF), a renewable and non-toxic alternative to a range of petroleum-based materials. 5-HMF has a broad range of applications in the chemical, pharmaceutical and food industries. Since 2014 AVA Biochem has been producing high-purity 5-HMF for research purposes and specialty chemicals markets, as well as technical-grade 5-HMF for bulk chemistry applications. AVA Biochem's own R&D department also develops the downstream chemistry of 5-HMF and thus opens the door to biobased furan chemistry on an industrial scale.

Evidence for complex iron oxides in the deep mantle from FeNi(Cu) inclusions in superdeep diamond

The recent discovery in high-pressure experiments of compounds stable to 24–26 GPa with Fe4O5, Fe5O6, Fe7O9, and Fe9O11stoichiometry has raised questions about their existence within the Earth’s mantle. Incorporating both ferric and ferrous iron in their structures, these oxides if present within the Earth could also provide insight into diamond-forming processes at depth in the planet. Here we report the discovery of metallic particles, dominantly of FeNi (Fe0.71Ni0.24Cu0.05), in close spatial relation with nearly pure magnetite grains from a so-called superdeep diamond from the Earth’s mantle. The microstructural relation of magnetite within a ferropericlase (Mg0.60Fe0.40)O matrix suggests exsolution of the former. Taking into account the bulk chemistry reconstructed from the FeNi(Cu) alloy, we propose that it formed by decomposition of a complex metalMoxide (M4O5) with a stoichiometry of (Fe3+2.15Fe2+1.59Ni2+0.17Cu+0.04)Σ=3.95O5. We further suggest a possible link between this phase and variably oxidized ferropericlase that is commonly trapped in superdeep diamond. The observation of FeNi(Cu) metal in relation to magnetite exsolved from ferropericlase is interpreted as arising from a multistage process that starts from diamond encapsulation of ferropericlase followed by decompression and cooling under oxidized conditions, leading to the formation of complex oxides such as Fe4O5that subsequently decompose at shallowerP-Tconditions.

Iceland-Faroe Ridge overflow dynamics, 55-6 ka BP

<p>The understanding of the past changes in this critical area of oceanic circulation will be beneficial to predict future climate conditions and their related socio-economic impacts. Sediment cores recovered from the western flank of the Iceland-Faroe Ridge (IFR; P457-905 and -909) provide unique archives to reconstruct changes in the Iceland-Scotland overflow water (ISOW), an important component of the Atlantic Meridional Overturning Circulation (AMOC) over the last 55-6 ka BP. We provide high-resolution records of lithogenic grain-size and XRF bulk chemistry on millennial timescales. The age models of both cores have been constrained by radiocarbon datings of planktonic foraminifera and distinct tephra layers, which include the well-known Faroe-Marine-Ash-Zones (FMAZ) II and III. Both grain-size and XRF bulk chemistry (Zr/Rb and Ti/K) reveal prominent Dansgaard-Oeschger sedimentary cycles, which reflect considerable changes in near-bottom current strength and sediment transport/deposition. The transition between cold Greenland Stadials (GSs) and warm Greenland Interstadials (GIs) occur in typical, recurring sedimentation patterns. The GIs are characterized by relatively strong bottom currents and the transport/deposition of basaltic (Ti-rich) silts from local volcanic sources resembling the modern ocean circulation pattern. In contrast, fine grained felsic (K-rich) sediments were deposited during GSs, when the ISOW was weak. In particular, the Heinrich (like) Stadials HS1 and HS2 stand out as intervals of very fine felsic sediment deposition and hence, slackened bottom currents. The bottom currents appear to progressively strengthen throughout the GIs, and sharply decline towards the GSs. This pattern contrasts with records from north of the IFR, which might be explained by a diminishing contribution of the flow cascading over the IFR. Together, these new records show strong changes in bottom current dynamics related to the Iceland-Scotland overflow, which has a strong influence on the past and modern climate of the North Atlantic Region. However, climate change is an interdisciplinary field of research. HOSST-TOSST transatlantic interdisciplinary research program provides the unique opportunity for constructive communication and collaboration among scientists with different skills filling knowledge gaps and bridging the earth sciences with social and economic disciplines. Such interdisciplinary programs at early stages in an academic career is necessary to move and encourage the new generation of the scientific community toward a tradition of broad‐scale interactions.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p>

Fly ashes bulk chemistry: a new approach for XRF measurements

<p>In this contribution we present the first results for proposing an analytical protocol to analyze fly ashes (FA) with XRF.</p><p>Fly ashes resulting from the incineration of municipal solid waste (MSW) should be considered as a hazardous material, mainly due to its potential high heavy metal content. Therefore, they have to be chemically fully characterized to facilitate primarily their safety storage and subsequently the recovery as second raw material resource. It’s worth noticing that fly ashes bulk chemistry (including volatile contents) depends on many types of variables [i.e.: geography; air pollution control devices (APCDs) and sampling sites], all related to the nature of the waste. On the basis of available data from different European waste-incineration plants, the bulk major elements contents are: Al <0.1-4.6 wt%; Ca 23.7-38.9 wt%; Fe 0.20-2.17wt%; K 0.1-2.4 wt%; Mg 0.5-1.7 wt%; Mn 0.02-0.12 wt%;  Na <0.15-2.5 wt%; P <0.02-0.92wt%; Si 0.2-8.7 wt% Cl, 7.5-28.3wt%, with volatile contents (tested by Loss of Ignition) in the range of 15-40 wt% (De Boom e Degrez, 2012; Bodénan and Deniard, 2003). </p><p>If we consider fly ashes as “rock type” material, x-ray fluorescence (XRF) is used effectively for determining the major rock-forming elements.  However, the lack of standard calibration for this material suggested us to adopt a different strategy of calibration, using the method of Standard Addition (SA) to determine SiO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub> having similar mass absorption coefficients (https://physics.nist.gov/PhysRefData/XrayMassCoef/tab3.html).  </p><p>The SA method was originally designed to determine trace elements contents by addition of comparative amounts of analytes. In order to keep the characteristics of bulk chemistry invariant, in this modified calibration procedure we prepared eleven pressed powders by adding several known aliquots of SiO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub> (“excipients”) to the same amount of unknown FA in the constant proportion of 10% and 90%, respectively.</p><p>Plotting together the intensity values of the two analytes with the various percentages by weight of “excipients”, it was possible to generate calibration lines and acquired the percentage by weight of the two analytes in the unknown material. The Si and Al contents obtained by the calibration lines are 1.93 wt% and 1.64 wt%, respectively.</p><p>These values are different from those (2.86 wt% and 1.40 wt% for Si and Al, respectively), obtained by measurements of pure FA with routine XRF standard calibrations for silicatic rocks (Franzini et al. 1975). More measurements are needed to evaluate the accuracy of the method, however, the results presented here are promising, and hint that XRF may be used efficiently to measure FA major element chemistry, by applying the modified standard addition calibration.</p><p>References:</p><p>Bodénan, F. and Deniard P. (2003). Chemosphere, 51; 335-347</p><p>De Boom A. and Degrez  M. (2012). Waste Management, 32; 1163-1170</p><p>Franzini M., Leoni L. and Saitta M. (1975). Rend. S.I.M.P., 31: 365-378.</p>

Reconciling multiphase reactivity of oleic acid with ozone using a kinetic flux model

<p>The ozonolysis of oleic acid on aerosol particles has been extensively studied in the past and is often used as a benchmark reaction for the study of organic particle oxidation. However, to date, no single kinetic model has reconciled the vastly differing reactive uptake coefficients reported in the literature that were obtained at different oxidant concentrations, particle sizes and with various commonly used laboratory setups (single-particle trap, aerosol flow tube, and environmental chamber). We combine the kinetic multi-layer model of aerosol surface and bulk chemistry (KM-SUB, Shiraiwa et al. 2012) with the Monte Carlo Genetic Algorithm (MCGA, Berkemeier et al. 2017) to simultaneously describe nine experimental data sets with a single set of kinetic parameters. The KM-SUB model treats chemistry and mass transport of reactants and products in the gas and particle phases explicitly, based on molecular-level chemical and physical properties. The MCGA algorithm is a global optimization routine that aids in unbiased determination of these model parameters and can be used to assess parameter uncertainty. This methodology enables us to derive information from laboratory experiments using a “big data approach” by accounting for a large amount of data at the same time.</p><p>We show that a simple reaction mechanism including the surface and bulk ozonolysis of oleic acid only allows for the reconciliation of some of the data sets. An accurate description of the entire reaction system can only be accomplished if secondary chemistry is considered and present an extended reaction mechanism including reactive oxygen intermediates. The presence of reactive oxygen species on surfaces of particulate matter might play an important role in understanding aerosol surface phenomena, organic aerosol evolution, and their health effects.</p><p> </p><p>References</p><p>Berkemeier, T. et al.: Technical note: Monte Carlo genetic algorithm (MCGA) for model analysis of multiphase chemical kinetics to determine transport and reaction rate coefficients using multiple experimental data sets, Atmos. Chem. Phys., 17, 8021-8029, 2017.</p><p>Shiraiwa, M., Pfrang, C., and Pöschl, U.: Kinetic multi-layer model of aerosol surface and bulk chemistry (KM-SUB): the influence of interfacial transport and bulk diffusion on the oxidation of oleic acid by ozone, Atmos. Chem. Phys., 10, 3673-3691, 2010.</p>

Tutorial review on structure – dendrite growth relations in metal battery anode supports

This tutorial review explains surface and bulk chemistry – electrochemical performance relations of lithium, sodium and potassium metal anodes.