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    Cu(II) sorption performance of novel chitosan/ter-(vinyl pivalate-maleic anhydride-N-tert-butylacrylamide) microcapsules
    (SPRINGER, 2019) Okudan, Ahmet.; Ataoglu, Busra Ebru.; Sengoz, Onur.; Arslan, Gulsin.
    In this study, first, the ter-polymerization reaction between vinyl pivalate (VP), maleic anhydride (MA), and N-tert-butylacrylamide (NTBA) was done in inert atmosphere (N-2). FT-IR and (HNMR)-H-1 spectroscopy was applied to study the chemical composition of the obtained ter-polymers. MA content of the ter-polymers was determined by following the chemical titration method. Second, novel chitosan/ter-(vinyl-pivalate-maleic-anhydride-N-tert-butylacrylamide) microcapsules were synthesized. In microcapsule production, chitosan polymer served as a matrix for acrylamide ter-polymers with four different molar ratios. The microcapsules were characterized by FT-IR and SEM analyses. Cu(II) sorption efficiency of the microcapsules were tested at different pH levels, temperature, sorbent dosage, and metal ion concentration. Comparison with blank chitosan microbeads revealed that incorporation of acrylamide ter-polymers into the cross-linked chitosan matrix increased the metal sorption. Sorption capacities of the sorbents were recorded; blank chitosan microbeads: 67.03 mg g(-1), and chitosan/acrylamide ter-polymer microcapsules: in range of 75.39-98.64 mg g(-1). The findings demonstrated chitosan/acrylamide ter-polymer microcapsules can be utilized in sorption of Cu(II) ions in water treatment.
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    Cu(II) sorption performance of silane-modified poly(NaSS-co-MA-co-AAm) and poly(NaSS-co-MA-co-NIPAM) terpolymers
    (SPRINGER, 2019) Okudan, Ahmet.; Ozviran, Emre.; Arslan, Gulsin.; Sargin, Idris.
    This study reports the adsorption of Cu(II) ion by 3-(2-aminoethylamino) propyldimethoxymethylsilane-modified terpolymers. Water-soluble poly(sodium 4-styrenesulfonate-co-maleic anhydride-co-acrylamide) [poly(NaSS-co-MA-co-AAm)] and poly(sodium 4-styrenesulfonate-co-maleic anhydride-co-N-isopropylacrylamide) [poly(NaSS-co-MA-co-NIPAM)] terpolymers were synthesized and then modified with silane to make them water-insoluble. H-1-NMR and FT-IR spectroscopy was used to study the chemical composition of the terpolymers. Also, acid number and viscosity of the polymers were determined. Cu(II) ion adsorption parameters (adsorbent dosage, contact time, pH and metal ion concentration) were studied, and the equilibrium data were evaluated using adsorption isotherm models; Freundlich isotherm gave the best fit. Cu(II) adsorption performance of poly(NaSS-co-MA-co-AAm) and poly(NaSS-co-MA-co-NIPAM) terpolymers was found to be 53.42 and 43.10%, respectively. The terpolymers can be used for removal of Cu(II) from aqueous media.
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    Green preparation of Carbon Quantum dots using Gingko biloba to sensitize TiO2 for the photohydrogen production
    (ELSEVIER SCI LTD, 2020) Genc, Munevver Tuna.; Yanalak, Gizem.; Arslan, Gulsin.; Patir, Imren Hatay.
    Carbon Quantum dots (CQDs) were obtained from Gingko biloba by using microwave technique, which is easy, time-saving, cost-effective, non-toxic and environmental friendly way. TiO2 were sensitized by green-prepared CQDs to obtain CQDs/TiO2 composite. The characterizations of the CQDs and CQDs/TiO2 were performed by Transmission Electron Microscopy (TEM), high-resolution TEM (HR-TEM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopic (XPS), Photoluminescence (PL) and Fourier Transformed Infrared (FT-IR) spectroscopy. The photocatalytic hydrogen evolution activity of CQDs/TiO2 system was studied under visible light (lambda > 420 nm) irradiation in the aqueous solution by using triethanolamine (TEOA) as a sacrificial electron donor. When Pt was used as a co-catalyst, CQDs/TiO2/Pt exhibited improved hydrogen evolution rate (1502 mu mol h(-1)g(-1)) compared to CQDs/TiO2 composite (665 mu mol h(-1)g(-1)).
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    Green synthesized carbon quantum dots as TiO2 sensitizers for photocatalytic hydrogen evolution
    (PERGAMON-ELSEVIER SCIENCE LTD, 2019) Sargin, Idris.; Yanalak, Gizem.; Arslan, Gulsin.; Patir, Imren Hatay.
    Carbon quantum dots (CQDs) have attracted growing interest due to their superior luminescent properties, which make them excellent photosensitizers for TiO2. This study presents the green-synthesis of CQDs from edible mushroom Agaricus bisporus through microwave irradiation. In the study as-synthesized CQDs were used as a sensitizer for TiO2 in photocatalytic hydrogen evolution in aqueous triethanolamine (sacrificial reagent) under visible-light irradiation. Photocatalytic hydrogen production activity of CQD-sensitized TiO2 was found to be 472 mu mol g(-1) h(-1) (without loading any noble metal co-catalyst) and 1458 mu mol g(-1) h(-1) (with loading Pt co-catalyst). The study revealed that the CQDs from mushroom A. bisporus can be used as an efficient sensitizer for TiO2 in photocatalytic hydrogen production. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.