scholarly journals Chemical Recycling of WEEE Plastics—Production of High Purity Monocyclic Aromatic Chemicals

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 530
Author(s):  
Tobias Rieger ◽  
Jessen C. Oey ◽  
Volodymyr Palchyk ◽  
Alexander Hofmann ◽  
Matthias Franke ◽  
...  
Keyword(s):  
High Purity ◽  
Fractional Distillation ◽  
Gas Chromatography Mass Spectrometry ◽  
Thermochemical Conversion ◽  
Chemical Recycling ◽  
Pyrolysis Oil ◽  
X Ray ◽  
Benzene Toluene ◽  
Halogen Content ◽  
Methyl Styrene

More than 200 kg real waste electrical and electronic equipment (WEEE) shredder residues from a German dismantling plant were treated at 650 °C in a demonstration scale thermochemical conversion plant. The focus within this work was the generation, purification, and analysis of pyrolysis oil. Subsequent filtration and fractional distillation were combined to yield basic chemicals in high purity. By means of fractional distillation, pure monocyclic aromatic fractions containing benzene, toluene, ethylbenzene, and xylene (BTEX aromatics) as well as styrene and α-methyl styrene were isolated for chemical recycling. Mass balances were determined, and gas chromatography–mass spectrometry (GC-MS) as well as energy dispersive X-ray fluorescence (EDXRF) measurements provided data on the purity and halogen content of each fraction. This work shows that thermochemical conversion and the subsequent refining by fractional distillation is capable of recycling WEEE shredder residues, producing pure BTEX and other monocyclic aromatic fractions. A significant decrease of halogen content (up to 99%) was achieved with the applied methods.

High-purity Ge x-ray detectors: Sensitivity factors and usefulness

1990 ◽  
Vol 48 (2) ◽  
pp. 548-548
Author(s):  
E. B. Steel
Keyword(s):  
High Purity ◽  
High Energy ◽  
Quantitative Chemical Analysis ◽  
Detector Performance ◽  
X Ray ◽  
Detector Sensitivity ◽  
Specimen Holder ◽  
Many Instruments ◽  
Charge Resolution ◽  
Sensitivity Factors

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

scholarly journals Investigation into the color stripping of the pigment printed cotton fabric using the ozone assisted process: A study on the decolorization and characterization

2021 ◽  
Vol 16 ◽  
pp. 155892502199275
Author(s):  
Ajinkya Powar ◽  
Anne Perwuelz ◽  
Nemeshwaree Behary ◽  
Le vinh Hoang ◽  
Thierry Aussenac ◽  
...  
Keyword(s):  
Cotton Fabric ◽  
Photoelectron Spectroscopy ◽  
Treatment Time ◽  
Pilot Scale ◽  
Chemical Recycling ◽  
X Ray ◽  
Cellulosic Fibers ◽  
Dyeing Process ◽  
Cellulosic Textiles ◽  
Ozonation Process

Color stripping is one of the most convenient ways to rectify the various shade faults occurred during printing or dyeing process of textiles. But, the conventional chemical assisted process poses serious risk of the environmental pollution. Secondly, the chemical recycling of the cellulosic fibers may be disrupted due to the presence of the impurities like colorants, finishes, and the additives in the discarded textiles. So, there is a need to study ways to remove such impurities from the discarded cellulosic textiles in a sustainable manner. This work examines the decolorization of the pigment prints on cellulosic fabrics at pilot scale using an ozone-assisted process. The effect of varying pH, ozone concentration and the treatment time on the decolorization of the pigment prints was optimized using the response surface methodology technique. The effects of ozonation process parameters on the mechanical properties of cellulosic cotton fabric were measured. Decolorization of pigment printed samples was studied with respect to the surface effects by a scanning electron microscopy (SEM), and the chemical removal effects of ozonation treatment were studied using X-ray photoelectron spectroscopy. The possible mechanism regarding the action of ozone for the decolorization is discussed.

scholarly journals Bacterial cellulose films with ZnO nanoparticles and propolis extracts: Synergistic antimicrobial effect

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexandra Mocanu ◽  
Gabriela Isopencu ◽  
Cristina Busuioc ◽  
Oana-Maria Popa ◽  
Paul Dietrich ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Bacterial Cellulose ◽  
Food Packaging ◽  
Antimicrobial Effect ◽  
Gas Chromatography Mass Spectrometry ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Zno Nps ◽  
X Ray ◽  
Cellulose Films ◽  
Trolox Equivalent

AbstractThis study aimed to obtain possible materials for future antimicrobial food packaging applications based on biodegradable bacterial cellulose (BC). BC is a fermentation product obtained by Gluconacetobacter xylinum using food or agricultural wastes as substrate. In this work we investigated the synergistic effect of zinc oxide nanoparticles (ZnO NPs) and propolis extracts deposited on BC. ZnO NPs were generated in the presence of ultrasounds directly on the surface of BC films. The BC-ZnO composites were further impregnated with ethanolic propolis extracts (EEP) with different concentrations.The composition of raw propolis and EEP were previously determined by gas-chromatography mass-spectrometry (GC-MS), while the antioxidant activity was evaluated by TEAC (Trolox equivalent antioxidant capacity). The analysis methods performed on BC-ZnO composites such as scanning electron microscopy (SEM), thermo-gravimetrically analysis (TGA), and energy-dispersive X-ray spectroscopy (EDX) proved that ZnO NPs were formed and embedded in the whole structure of BC films. The BC-ZnO-propolis films were characterized by SEM and X-ray photon spectroscopy (XPS) in order to investigate the surface modifications. The antimicrobial synergistic effect of the BC-ZnO-propolis films were evaluated against Escherichia coli, Bacillus subtilis, and Candida albicans. The experimental results revealed that BC-ZnO had no influence on Gram-negative and eukaryotic cells.

scholarly journals Maximizing Anhydrosugar Production from Fast Pyrolysis of Eucalyptus Using Sulfuric Acid as an Ash Catalyst Inhibitor

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 609 ◽  
Author(s):  
Dongyan Zhang ◽  
Yuyang Fan ◽  
Anqing Zheng ◽  
Zengli Zhao ◽  
Fengyun Wang ◽  
...  
Keyword(s):  
Rank Order ◽  
Maximum Yield ◽  
Fast Pyrolysis ◽  
Value Added ◽  
Gas Chromatography Mass Spectrometry ◽  
Cellulose Content ◽  
Pyrolysis Gas ◽  
X Ray ◽  
Theoretical Yield ◽  
Pure Cellulose

Anhydrosugars, such as levoglucosan (LG), are high value-added chemicals which are mainly derived from fast pyrolysis of pure cellulose. However, fast pyrolysis of raw lignocellulosic biomass usually produces a very low amount of levoglucosan, since alkali and alkaline earth metals (AAEM) present in the ash can serve as the catalysts to inhibit the formation of levoglucosan through accelerating the pyranose ring-opening reactions. In this study, eucalyptus was impregnated with H2SO4 solutions with varying concentrations (0.25–1.25%). The characteristics of ash derived from raw and H2SO4-impregnated eucalyptus were characterized by X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD). The pyrolysis behaviors of raw and H2SO4-impregnated eucalyptus were performed on the thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). TG analysis demonstrated that the H2SO4-impregnated eucalyptus produced less char than raw eucalyptus. Py-GC/MS analysis showed that even small amounts of H2SO4 can obviously improve the production of anhydrosugars and phenols and suppressed the formation of carboxylic acids, aldehydes, and ketones from fast pyrolysis of eucalyptus. The rank order of levoglucosan yield from raw and impregnated eucalyptus was raw < 1.25% H2SO4 < 1% H2SO4 < 0.75% H2SO4 < 0.25% H2SO4 < 0.5% H2SO4. The maximum yield of levoglucosan (21.3%) was obtained by fast pyrolysis of eucalyptus impregnated with 0.5% H2SO4, which was close to its theoretical yield based on the cellulose content. The results could be ascribed to that H2SO4 can react with AAEM (e.g., Na, K, Ca, and Mg) and lignin to form lignosulfonate, thus acting as an inhibitor to suppress the catalytic effects of AAEM during fast pyrolysis of eucalyptus.

scholarly journals Oxidative Desulfurization of Tire Pyrolysis Oil over Molybdenum Heteropolyacid Loaded Mesoporous Catalysts

Reactions ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 457-472
Author(s):  
Jasmine Kaur ◽  
Sundaramurthy Vedachalam ◽  
Philip Boahene ◽  
Ajay K. Dalai
Keyword(s):  
Sulfur Content ◽  
Photoelectron Spectroscopy ◽  
Supported Catalysts ◽  
Surface Acidity ◽  
Oxidative Desulfurization ◽  
Acid Catalyst ◽  
Acid Sites ◽  
Process Conditions ◽  
Pyrolysis Oil ◽  
X Ray

Pyrolysis oil derived from waste tires consists of sulfur content in the range of 7000 to 9000 ppm. For use in diesel engines, its sulfur content must be lowered to 10 to 15 ppm. Though conventional hydrodesulfurization is suitable for the removal of sulfur from tire pyrolysis oil, its high cost provides an avenue for alternative desulfurization technologies to be explored. In this study, oxidative desulfurization (ODS), a low-cost technology, was explored for the desulfurization of tire pyrolysis oil. Two categories of titanium-incorporated mesoporous supports with 20 wt% loaded heteropoly molybdic acid catalyst (HPMo/Ti-Al2O3 and HPMo/Ti-TUD-1) were developed and tested for ODS of tire pyrolysis oil at mild process conditions. Catalysts were characterized by X-ray diffraction, BET-N2 physisorption, and X-ray photoelectron spectroscopy (XPS). The incorporation of Ti into Al2O3 and TUD-1 frameworks was confirmed by XPS. The surface acidity of catalysts was studied by the temperature-programmed desorption of NH3 and pyridine FTIR analyses. HPMo/Ti-Al2O3 and HPMo/Ti-TUD-1 catalysts contained both Lewis and Brønsted acid sites. The presence of titanium in catalysts was found to promote the ODS activity of phosphomolybdic acid. The Ti-TUD-1-supported catalysts performed better than the Ti-Al2O3-supported catalysts for the ODS of tire pyrolysis oil. Hydrogen peroxide and cumene peroxide were found to be better oxidants than tert-butyl hydroperoxide for oxidizing sulfur compounds of tire pyrolysis oil. Process parameter optimization by the design of experiments was conducted with an optimal catalyst along with the catalyst regeneration study. An ANOVA statistical analysis demonstrated that the oxidant/sulfur and catalyst/oil ratios were more significant than the reaction temperature for the ODS of tire pyrolysis oil. It followed the pseudo-first-order kinetics over HPMo/Ti-TUD-1.

Chemical Recycling of Epoxide-Anhydride Hardened Networks Using Near-Critical Water

2013 ◽  
Vol 658 ◽  
pp. 153-157 ◽  
Author(s):  
Yu Yan Liu ◽  
Song Quan Wu ◽  
Li Li ◽  
Yu Ting Liu ◽  
Guo Hua Shan
Keyword(s):  
Epoxy Resin ◽  
Degradation Rate ◽  
Diglycidyl Ether ◽  
Gas Chromatography Mass Spectrometry ◽  
Chemical Recycling ◽  
Reaction Products ◽  
Degradation Behaviour ◽  
Bisphenol A Diglycidyl Ether ◽  
Stainless Steel Reactor ◽  
Degradation Reaction

The degradation behaviour of an anhydride-cured bisphenol A diglycidyl ether (DGEBA) epoxy resin in near-critical water was studied in this paper. The experiments were performed in a stainless steel reactor (100ml) without stirring. Epoxy resin could be decomposed successfully at 270°C for 30 min. The degradation rate of epoxy resin increased with an increase in reaction temperature and reaction pressure. The degradation reaction products were characterized by gas chromatography-mass spectrometry (GC-MS). The degradation reaction was associated with the scission of ester and ether bonds which further destabilizes the epoxy network.

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