Browsing by Subject "Removal efficiencies"

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    Removal of a reactive dye and hexavalent chromium by a reusable bacteria attached electrospun nanofibrous web
    (Royal Society of Chemistry, 2015) Keskin, N. O. S.; Celebioglu A.; Sarioglu O.F.; Ozkan A.D.; Uyar, Tamer; Tekinay, T.
    A contaminant resistant Lysinibacillus sp. NOSK was isolated from a soil sample and its Reactive Black 5 (RB5) and Cr(vi) removal efficiencies were investigated as a function of changes in the initial pH values, temperature, static/shaking conditions, reactive dye and Cr(vi) concentrations. In this study, an electrospun polysulfone nanofibrous web (PSU-NFW) was found to be effective in attachment of bacterial cells. Bacteria attached PSU-NFWs (bacteria/PSU-NFW) have shown highly efficient removal of RB5, as 99.7 ± 0.9% and 35.8 ± 0.4% for the pristine PSU-NFW. Moreover, the highest Cr(vi) removal efficiencies measured were 98.2 ± 0.6% for bacteria attached PSU-NFW and 32.6 ± 0.6% for the pristine PSU-NFW. Simultaneous removal of RB5 and Cr(vi) were also investigated. Reusability test results indicate that, bacteria/PSU-NFW can be reused for at least 7 cycles with 28.1 ± 0.6% and 66.7 ± 0.8% removal efficiencies for RB5 and Cr(vi), respectively.
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    Selective and efficient removal of volatile organic compounds by channel-type gamma-cyclodextrin assembly through inclusion complexation
    (American Chemical Society, 2017) Celebioglu A.; Ipek, S.; Durgun, Engin; Uyar, Tamer
    Cyclodextrins (CD), produced from enzymatic degradation of starch, are a form of biorenewable cyclic oligosaccharide which has an outstanding capability to form inclusion complexes with a variety of molecules including pollutants due to their toroid-shaped molecular structure. In this study, by a simple reprecipitation method, we obtained "channel-type" packing from γ-CD where CD molecules are stacked on top of each other to form long cylindrical channels. The γ-CD "channel-type" crystals have shown very effective removal of organic volatile compounds (VOCs; aniline and toluene) from the surroundings, whereas cage-type γ-CD could not entrap VOCs from the same environment. Encapsulation capability of channel-type γ-CD is at a ∼2:1 and ∼1:1 molar ratio for aniline/CD and toluene/CD, respectively. Thus, channel-type γ-CD crystals have shown higher removal efficiency for aniline compared to toluene. Channel-type γ-CD is also able to remove aniline selectively from surroundings. Additionally, computational modeling studies suggested that single γ-CD cavity can host two molecules of aniline or toluene for the complexation, yet, aniline is more insistent to make a complex with the γ-CD cavity when compared to toluene. We show that channel-type γ-CD can remove VOCs molecules (aniline and toluene) as efficiently as activated carbon. Hence, being a starch-based biorenewable cyclic oligosaccharide in the form of white powder, the use of "channel-type" γ-CD crystals could be a competitive alternative to activated carbon as an adsorbent for the VOC removal/filtering.