Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article An Experimental Study on Microplastic Settling Velocities in Different Water Environments: Which Factors Shape the Settling Process(Pergamon-Elsevier Science Ltd, 2025) Alpergun, Cumana; Alyuruk, Nefise; Baycan, Neval; Gunduz, OrhanUnderstanding the behavior of microplastics in aquatic environments is crucial, given their widespread presence and potential ecological impact. This study investigated the effects of biofilm formation and weathering processes on the settling rates of microplastics across different water matrices. To this end, nine different polymer types were examined in four distinct conditions-pristine, biofilm-coated, aged, and biofilm-coated after weathering-across three defined size categories. A total of 648 experimental results representing different conditions were analyzed. The results revealed that the settling velocities of microplastics ranging from 0.5 to 4.5 mm varied between 0.012 and 0.154 m/s. Polybutylene terephthalate and polyethylene terephthalate particles exhibited the fastest settling rates (0.154 and 0.145 m/s), whereas acrylonitrile butadiene styrene showed the slowest (0.012 m/s). Although microplastic density and size were found to be significant factors of settling velocity, water matrix, biofilm formation, and weathering processes did not show a statistically significant difference under the conditions of this study. This was related to insufficient time for biofilm growth, limited structural changes due to weathering, and the controlled laboratory environment. Biofilm formation was observed to be more pronounced on rough and matte surfaces, while it was less prominent on shiny and slippery surfaces. Additionally, it was determined that weathering alters surface morphology and potential adsorption capacity, which plays a critical role in the environmental interactions of microplastics. Furthermore, the experimentally determined settling velocities were compared with theoretical estimations obtained using two different models from the literature. A comparison between the experimental settling data and theoretical models demonstrated a strong alignment with the models proposed by Waldschla<spacing diaeresis>ger and Sch & uuml;ttrumpf (2019) and Akdogan and Guven (2024), particularly for microplastics with irregular shapes. These results suggest that such theoretical approaches can reliably predict the settling behavior of specific polymer types. Overall, the findings underscore the practical applicability of these models for estimating the transport and fate of microplastics in natural aquatic systems, offering a valuable foundation for future environmental assessments.Article Citation - WoS: 5Citation - Scopus: 5Effects of Diborolane Containing Oxo/Amine Compounds on Clinically Important Bacteria and Candida Species(Elsevier B.V., 2024) Şahin,Y.; Çoban,E.P.; Özgener,H.; Bıyık,H.H.; Sevincek,R.; Aygün,M.; Gürbüz,B.A good yield of 1,2-diborolanderivatives 2-8 was obtained from the reaction of 1,2-dichloro-1,2-diborolane 1 and R2NLi/ArNHLi/PhOLi/H2O. The structures of these new derivatives were characterized by nuclear magnetic resonance spectroscopy. The molecular structures of 4 and 7a were also determined using single-crystal X-ray diffraction. The antimicrobial activities of synthesized compounds were tested against clinically important Gram-positive, Gram-negative bacteria, and Candida species. The most effective substances were found to be compounds 2, 3, 4, 6 and 8 among the tested compounds. Therefore, the activity of these substances were investigated against Staphylococcus aureus ATCC 43300 and Enterococcus faecalis ATCC 51575, which form biofilms and have antibiotic resistance. Compound 2, 6 and 8 appears to be a promising candidate for potential antibacterial agents against these bacterial strains, especially given its potent activity against biofilm-forming and antibiotic resistant strains. The results indicate that these new materials will be evaluated as potential drugs against infectious diseases in the future. © 2024 Elsevier B.V.
