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Chemical modification of the surface of halloysite nanotubes (HNT) by alkalization (with sodium hydroxide (NaOH)) and grafting with silanes (bis(trimethylsilyl)amine (HMDS)) was carried out. The efficiency of the alkalization and grafting process was evaluated by X–ray diffraction (XRD), Fourier–transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and the nitrogen adsorption method were used. XRD and FTIR analysis confirmed the formation of bonds of trimethylsilyl groups to the HNT surface which changed the nature of the surface from hydrophilic to hydrophobic. In addition, it was noted that grafting with silanes decreases by 7.2% the specific surface area of the halloysite compared to the alkalized material. High–density polyethylene (HDPE) composites with halloysite (HNT), alkalized halloysite (alk–HNT), and HMDS–modified halloysite (m–HNT) were processed in the molten state in a Brabender mixer chamber. On SEM/EDS micrographs of HDPE composites with silanized HNT, a change in surface characteristics from smooth to ductile was observed. Higher melting point values based on differential scanning calorimetry (DSC) analysis of HDPE composites with 5%wt silanized halloysite in comparison with HNT and alk–HNT of, respectively, 2.2% and 1.4% were found, which indicates a slight beneficial influence of the filler on the quality of ordering of the crystalline phase of the matrix. [ABSTRACT FROM AUTHOR]

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This study investigates the effects of the addition of tungsten on the structure, phase composition, textural properties and activities of β-SiC-based catalysts in the aqueous phase hydrogenation of furfural. Carbothermal reduction of SiO2 in the presence of WO3 at 1550 °C in argon resulted in the formation of WxC-β-SiC nanocomposite powders with significant variations in particle morphology and content of WxC-tipped β-SiC nano-whiskers, as revealed by TEM and SEM-EDS. The specific surface area (SSA) of the nanocomposite strongly depended on the amount of tungsten and had a notable impact on its catalytic properties for the production of furfuryl alcohol (FA) and tetrahydrofurfuryl alcohol (THFA). Nanocomposite WxC-β-SiC catalysts with 10 wt % W in the starting mixture had the highest SSA and the smallest WxC crystallites. Some 10 wt % W nanocomposite catalysts demonstrated up to 90% yield of THFA, in particular in the reduction of furfural derived from biomass, although the reproducible performance of such catalysts has yet to be achieved. [ABSTRACT FROM AUTHOR]

A functional magnesium hydroxide/lignin hybrid system was prepared by grinding and mixing the pure precursors using a planetary ball mill. In addition, the thermal stability was assessed based on the total mass loss of the hybrid system within the temperature range of 30-1000 °C, which amounted to 38%. Moreover, the average particle size was at 4.9 μm as determined by the laser diffraction method. The effect of addition of the prepared and characterized Mg(OH)2/lignin hybrid filler at concentrations ranging from 2.5 wt % to 10 wt % on the processing as well as mechanical and thermal properties of composites on the matrix of the unplasticized PVC compound was also evaluated. The addition of a filler to the poly(vinyl chloride) matrix causes a significant improvement of its thermal stability, which is approximately three times higher compared to a polymer without a filler. Furthermore, the prepared composites are additionally characterized by advantageous mechanical properties, especially higher Young's modulus. A 10% increase in the oxygen index of PVC composites upon addition of 10 wt % hybrid fillers has also been observed, which contributes to an extended range of their application under conditions that require notable fire resistance. [ABSTRACT FROM AUTHOR]

This study investigates a simultaneous processing of sugar beet pulp (SBP) for furfural, hydrogen and methane production using various pretreatment methods. In the experiments, sugar beet pulp was first subjected to thermal and thermochemical pretreatment at 140 °C. Then hydrolysates from these operations were investigated for their potential for methane and hydrogen production in batch tests. The experiments showed that thermal pretreatment of SBP resulted in the highest biogas and methane yields of 945 dm3/kg volatile solids (VS) and 374 dm3 CH4/kg VS, respectively, and a moderate hydrogen production of 113 dm3 H2/kg VS, which corresponded to a calculated energy production of 142 kWh/t; however, only low amount of furfural was obtained (1.63 g/L). Conversely, the highest furfural yield of 12 g/L was achieved via thermochemical pretreatment of SBP; however, biogas production from hydrolysate was much lower (215 dm3/kg VS) and contained only 67 dm3/kg VS of hydrogen. Meanwhile, in the experiment with lower amounts of sulfuric acid (2%) used for pretreatment, a moderate furfural production of 4 g/L was achieved with as high as 220 dm3/kg VS of hydrogen and the corresponding energy yield of 75 kWh/t. [ABSTRACT FROM AUTHOR]