Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    A Viability Study of Thermal Pre-Treatment for Recycling of Pharmaceutical Blisters
    (Mdpi, 2024) Gokelma, Mertol; Diaz, Fabian; Capkin, Irem Yaren; Friedrich, Bernd
    Pharmaceutical packaging is one of the most used packaging types which contains aluminum and plastics. Due to increasing amounts of waste and rising environmental concerns, recycling approaches are being investigated. Since blisters usually contain a balanced amount of plastics and metals, most of the approaches focus on recycling only one material. Therefore, more sustainable recycling approaches which recover both plastic and aluminum fractions are needed. This study investigates the thermal behavior and degradation mechanisms of plastic-rich and aluminum-rich pharmaceutical blisters using various analytical techniques. Structural characterization revealed that plastic-rich blisters have a thicker profile with plastic and aluminum layers, while aluminum-rich blisters consist of plastic layers between aluminum sheets. Thermal degradation analysis showed two main stages for both types: plastic-rich blisters (polyvinyl chloride) exhibited significant weight loss and long-chain hydrocarbon formation between 210 and 285 degrees C, and aluminum-rich blisters (polyamide/nylon) degraded from 240 to 270 degrees C. Differential Scanning Calorimetry and Fourier Transform Infrared Spectroscopy analyses confirmed the endothermic behavior of such a transformation. The gas emissions analysis indicated an increased formation of gasses from the thermal treatment of plastic-rich blisters, with the presence of oxygen leading to the formation of carbon dioxide, water, and carbon monoxide. Thermal treatment with 5% O2 in the carrier gas benefited plastic-rich blister treatment, reducing organic waste by up to 80% and minimizing burning risk, leveraging pyrolytic carbon for protection. This method is unsuitable for aluminum-rich blisters, requiring reduced oxygen or temperature to prevent pyrolytic carbon combustion and aluminum oxidation.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Continuous Flow Pyrolysis of Virgin and Waste Polyolefins: a Comparative Study, Process Optimization and Product Characterization
    (Springer, 2024) Ekici, Ecrin; Yildiz, Guray; Yildiz, Magdalena Joka; Kalinowska, Monika; Seker, Erol; Wang, Jiawei
    Under optimal process conditions, pyrolysis of polyolefins can yield ca. 90 wt % of liquid product, i.e., combination of light oil fraction and heavier wax. In this work, the experimental findings reported in a selected group of publications concerning the non-catalytic pyrolysis of polyolefins were collected, reviewed, and compared with the ones obtained in a continuously operated bench-scale pyrolysis reactor. Optimized process parameters were used for the pyrolysis of waste and virgin counterparts of high-density polyethylene, low-density polyethylene, polypropylene and a defined mixture of those (i.e., 25:25:50 wt %, respectively). To mitigate temperature drops and enhance heat transfer, an increased feed intake is employed to create a hot melt plastic pool. With 1.5 g<middle dot>min-1 feed intake, 1.1 L<middle dot>min-1 nitrogen flow rate, and a moderate pyrolysis temperature of 450 degrees C, the formation of light hydrocarbons was favored, while wax formation was limited for polypropylene-rich mixtures. Pyrolysis of virgin plastics yielded more liquid (maximum 73.3 wt %) than that of waste plastics (maximum 66 wt %). Blending polyethylenes with polypropylene favored the production of liquids and increased the formation of gasoline-range hydrocarbons. Gas products were mainly composed of C3 hydrocarbons, and no hydrogen production was detected due to moderate pyrolysis temperature.