MgO-containing porous carbon spheres derived from magnesium lignosulfonate as sustainable basic catalysts

The presence of alkalis in lignosulfonate allows an easy preparation of sustainable MgO-containing carbon catalysts with surface basicity by carbonization of magnesium lignosulfonate and/or further partial gasification of the produced char with CO2. Carbon spheres with different chemical and physical properties were obtained from lignosulfonate treated at temperatures ranging from 500 to 900 ºC. Carbonization at 900 °C generates hollow porous carbon spheres (pore volume of 0.20 cm3/g and apparent surface area of 465 m2/g) with magnesium content of 12%. A kinetic study of CO2 gasification of the carbon spheres obtained at 900 °C at temperatures in the range of 700 – 800 °C revealed that the gasification rate can be accurately described by the random pore model up to conversion values of 0.5. Based on this study, in order to develop additional porosity on the carbon spheres obtained at 900 °C, a partial gasification with CO2 at 750 °C for 30 min was carried out, reaching surface areas higher than 700 m2/g and 15.3% of Mg loading, with an overall preparation yield of 30%. All the obtained carbon materials were tested as catalyst for 2-propanol decomposition, showing a high selectivity to acetone, evidencing the basic character of these carbon catalysts. The highest activity and selectivity were shown by the CO2-activated carbon spheres (conversion and acetone selectivity higher than 90% at 420 °C), indicating that magnesium lignosulfonate is an attractive raw material for the preparation of sustainable carbon catalysts for biorefinery applicationsThe authors wish to thank MICINN (RTI2018-097555-B-100) and Junta de Andalucía (UMA18-FEDERJA-110 and P18-RT-4592) for financial support. M.G.R. acknowledges the assistance of MICINN through an FPU Grant (FPU 18/01402). // Funding for open access charge: Universidad de Málaga / CBU

Residual Oil Aerosol Measurements on Refridgerators and Liquefiers

The purity of the process gas is essential for the reliability of refrigerators and liquefiers. Filtration and adsorption of impurities like water, nitrogen, and oil result in a major effort, cost, and maintenance in the helium process. Expensive impurity monitors for moisture, nitrogen, and hydrocarbon contents are required to identify filter failures and leakage immediately during the operation. While water and nitrogen contaminants can be detected reliably, the measurement of oil aerosols at the ppb level is challenging. We present a novel diagnostic oil aerosol measurement system able to measure particles in the sub amp; 956;m range. This unit enabled us to evaluate and improve the oil separation system on a LINDE TCF 50 helium liquefie

Decomposition of Cr(OH)₃ to form active Cr₂C₃

This study was concerned with the sinterability of Cr₂C₃ powders produced by the calcination of a Cr(OH)₃ gel. The decomposition of the gel was investigated by thermogravimetric analysis, X-ray analysis and microscopic examination. Comparison was made between the size of crystallites as determined by X-ray line broadening and the size of aggregated particles as determined by independent means. These lineal measurements were compared to surface area measurements on the calcined powders. The degree of sinterability was judged from the density measurements on Cr₂C₃ pellets fired under air, oxygen and nitrogen atmospheres. Energies of activation of 25 and 20 kilocalories per mole were found for the decomposition process and the crystallite growth process, respectively. The decomposition process can be described as a unimolecular mechanism obeying first-order reaction kinetics. The calcined powders were found to be composed of small hexagonal platelets arranged in loosely packed aggregates. The optimum calcination temperature was determined to be approximately 500⁰C. A maximum sintered density of 4.35 grams per cubic centimeter illustrated the effectiveness of a nitrogen sintering atmosphere --Abstract, page ii-iii

Three published books of sermons delivered in Malta between 1694 and 1754

The identification of texts of sermons delivered in Malta during the seventeenth and eighteenth centuries would make possible a study of the oratorical styles, themes treated, and languages used in their delivery. This, in turn, would enable a better understanding of the impact that such an important albeit ignored means of verbal communication had on its contemporary audience. In the present short study three unrecorded published books containing sermons are described and briefly discussed.peer-reviewe

Characterization of Molybdenum-reduction by an Acrylamide-degrading Antarctic Bacterium

The Ninth Symposium on Polar Science/Ordinary sessions: [OB] Polar biology, Wed. 5 Dec. / Entrance Hall (1st floor), National Institute of Polar Researc