Kimya Bölümü Koleksiyonu
Bu koleksiyon için kalıcı URI
Güncel Gönderiler
Öğe The Preparation of p acrylonitrile-co- acrylamide hydrogels for uranyl ion recovery from aqueous environments(Hacettepe Üniversitesi, 2014) Alpaslan, Duygu; Aktaş, Nahit; Yılmaz, Selehattin; Şahiner, Nurettin; Güven, OlgunThe synthesis of poly acrylonitrile-co-acrylamide p AN-co-AAm hydrogels with different amounts of acrylonitrile AN and acrylamide AAm monomers were carried out by concurrent use of redox and microemulsion polymerization techniques. The prepared hydrogels were amidoximated for sorption of uranyl ion from aqueous medium. Batch type UO2 2+ ion sorption by p AN-co-AAm 0.25:1 mole ratio was carried out and an sorption capacity of 220 mg UO2 2+ mg/g dried hydrogel was found. The highest amount of UO22+ ion sorption, 277 mg/g dry gel was accomplished at pH 4Öğe Tannic acid-based bio-MOFs with antibacterial and antioxidant properties acquiring non-hemolytic and non-cytotoxic characteristics(Elsevier, 2025) Şahiner, Nurettin; Güven, Olgun; Demirci, Şahin; Sağbaş Suner, Selin; Şahiner, Mehtap; Arı, Betül; Can, MehmetTannic acid (TA) based bio-metal phenolic networks (bio-MPNs) were prepared by using Cu(II), Zn(II), Bi(III), Ce(III), La(III), and Ti(IV) metal ions. TA-based bio-MPNs exhibited wedge-shaped pores between 16.4 and 25.8 nm pore size ranges. The higher gravimetric yield% was achieved for TA-Bi(III), and TA-Ti(IV) bio-MPNs with more than 90 %, and higher surface area was observed for TA-La(IIII) bio-MPNs as 56.2 m(2)/g with 17.3 nm average pore sizes. All TA-based MPNs are non-hemolytic with less than 5 % hemolysis ratio, whereas TA-based Bio-MPNs do not affect blood clotting with > 90 % blood clotting indexes except for TA-Cu(II) Bio-MPNs at 0.1 mg/mL concentration. Moreover, TA-Bi(III) and TA-Ce(III) Bio-MPNs were found to be safer materials showing no significant toxicity on L929 fibroblast cells at 100 mu g/mL concentration, along with TA-based Bio-MPNs prepared with Cu(II), Zn(II), La(III), and Ti(IV) metal ions that could be safely used in in vivo applications at 1 mu g/mL concentration. It has been proven by 2 different antioxidant tests that the prepared TA-based Bio-MPNs show antioxidant properties even if their TA-derived antioxidant properties decrease. Furthermore, all types of TA-based Bio-MPNs show great antimicrobial activity depending on the metal ion or microorganism types and the highest antibacterial/antifungal effect was determined for TA-Cu(II), and TA-Zn(II) Bio-MPNs with the lowest MBC/MFC values against Pseudomonas aeruginosa ATCC 10145, Bacillus subtilis ATCC 6633, and Candida albicans ATCC 10231.Öğe Application of a novel anthracene derivative polymer for sensitive voltammetric determination of chloramphenicol in pharmaceutical and food samples(Pergamon-Elsevier Science Ltd, 2025) Karakaya, Serkan; Kaya, İsmet; Kolcu, Feyza; Dilgin, YusufThe application of new polymers for the preparation of modified electrodes is an interesting research area, which is highly significant in the electrochemical antibiotic drug sensors for food safety and environmental sides. Herein, we successfully report the synthesis of a new anthracene-based monomer (N1, N4-bis(anthracene-9-ylmethylene)-2,5-dichlorobenzene-1,4-diamine (ADCA) and Poly(ADCA) modified carbon-based electrode has been used in sensitive and selective differential pulse voltammetric determination of chloramphenicol (CPNL) for the first time. In this platform, the proposed monomer was successfully electro-polymerized onto a cheap, lowcost, and disposable pencil graphite electrode (PGE). The cyclic and differential pulse voltammetric experiments proved that the polymer-modified electrode Poly(ADCA)/PGE) has great electrocatalytic efficiency on the reduction of CPNL. The proposed platform shows a comparable performance in terms of wide linear ranges (2.0-100 and 100-1000 mu M), a low detection limit (0.55 mu M) and high sensitivity (11405 mu A mM- 1 cm- 2) by differential pulse voltammetry (DPV). Additionally, the Poly(ADCA)/PGE exhibited high selectivity and antiinterference facilities for the CPNL. The fabricated sensor showed a promising potential for the determination of CPNL in food (honey, and milk), bottled water, and pharmaceutical (eye ointment) samples with acceptable accuracies and precisions.Öğe Schiff bases and oligomers derived from trifluoromethylaniline-based monomers: Thermal, optical, electrochemical properties and applications as fluorescent probes for Sn2+(Elsevier, 2025) Karacan Yeldir, Elif; Kaya, İsmet; Tutluel, OğuzhanWithin the scope of the study, three different Schiff bases were synthesized from 3,5-bis(trifluoromethyl)aniline, a halogen-containing aniline derivative, with three different aldehydes, 3-hydroxy-4-methoxy-benzaldehyde, salicylaldehyde and 2-hydroxy-1-naphthaldehyde. These three synthesized Schiff bases were evaluated as monomers and oxidatively polymerized in the presence of sodium hypochlorite, a strong oxidant. The structural properties of these three monomers and three polymers were elucidated with the help of UV-Vis, FT-IR, 1 H NMR, 13C NMR spectra. Their molecular weights were determined by gel permeation chromatography (GPC) and it was determined that the macromolecules obtained as a result of the oxidation reaction were in the oligomer order. In order to investigate their electrochemical properties, cyclic voltammetry (CV) was used to find their oxidationreduction potentials. The HOMO-LUMO potentials and electrochemical band gap values of the synthesized Schiff bases and oligomers were calculated. Thermal stabilities of the monomers and oligomers were determined by thermogravimetric-differantial thermal analysis (TG-DTA). It was determined that the thermal stabilities of the obtained oligomers were higher than those of the Schiff bases. The glass transition temperature (Tg) and surface morphologies of oligomers were determined from DSC and SEM measurements, respectively. Their optical properties were examined by UV-Vis and fluorescence spectra. It was found that 1-(((3,5-bis(trifluoromethyl) phenyl)imino)methyl) naphthalene-2-ol (TFMHN), one of the Schiff bases, has a turn-on fluorescence sensor property with increasing fluorescence emission intensity in the presence of Sn2+ among a series of metal ions and can be used as a selective and sensitive fluorescence probe for Sn2+ with a limit of dedection (LOD) value of 7.14 x 10- 8 M.Öğe Synthesis and characterization of fluorescent and thermally stable poly (azomethine-ether)s: Optical and morphological properties(Elsevier Sci Ltd, 2025) Tezel, Ruhiye Nilay; Kaya, İsmetIn this work, we described the synthesis and characterization of dialdehyde monomers and poly(azomethineether)s based on them. In the first stage, aromatic bridged dialdehyde monomers were synthesized using 2,4Bis(chloromethyl)-1,3,5-trimethylbenzenedihalide with three different aldehydes (4-hydroxybenzaldehyde, 3methoxy-4-hydroxybenzaldehyde, and 3-ethoxy-4-hydroxybenzaldehyde). Subsequently, corresponding poly (azomethine-ether) derivatives were synthesized through the polycondensation reaction of synthesized dialdehyde monomers with o-toluidine and o-dianisidine diamine compounds. The structures of the obtained dialdehyde and poly(azomethine-ether)s were confirmed by FT-IR, UV-Vis and NMR measurements. The physicochemical properties of the as-prepared poly(azomethine-ether)s have been confirmed through X-ray diffraction (X-RD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX) spectroscopic techniques. In FT-IR, -CH--N- peak around at 1625 cm-1 attributed to the successful conversion of dialdehydes and diamines into poly(azomethine-ether). The semicrystalline nature of the poly (azomethine-ether)s was shown through the X-RD diffractometer. The optical band gaps were found to be in the range of 2.80-2.92 eV, as measured by UV/Vis analysis. These poly(azomethine-ether)s exhibit direct band gap values in the blue/violet region of visible light, which creates opportunities for future studies related to daylight optoelectronic devices. Additionally, thermal behavior was analyzed using TGA and DSC, revealing that the materials are highly stable and rigid.Öğe Nanocellulose hydrogels from agricultural wastes: methods, properties, and application prospects(Royal Soc Chemistry, 2025) Altynov, Yerkebulan; Bexeitova, Kalampyr; Nazhipkyzy, Meruyert; Azat, Seitkhan; Konarov, Aishuak; Rakhman, Damira; Şahiner, NurettinEscalating environmental concerns and the depletion of non-renewable resources have intensified interest in sustainable and eco-friendly materials. Cellulose-based hydrogels, renowned for their biocompatibility, biodegradability, and excellent mechanical properties, have emerged as promising candidates for diverse applications, including biomedicine, agriculture, and water purification. This review focuses on methods for extracting nanocellulose from agricultural wastes and their use in creating cellulose hydrogels. Special emphasis is placed on the mechanical, chemical, thermal, and environmental properties of nanocellulose, as well as its applications in packaging materials, medical devices, biocomposites, and filtration systems. The literature review examines cellulose extraction methods, hydrogel properties, and their industrial applications. The key advantages and disadvantages of these methods are identified, and directions for future research are proposed. This work provides a comprehensive overview of the current state of research on cellulose-based hydrogels and contributes to the development of more efficient and sustainable production methods for these materials.Öğe Nanoparticles for Biomedical Use Derived from Natural Biomolecules: Tannic Acid and Arginine(MDPI, 2025) Şahiner, Mehtap; Sağbas Suner, Selin; Şahiner, NurettinBackground/Objectives: Tannic acid (TA) is a well-known natural phenolic acid composed of ten gallic acids linked to each other with ester bonding possessing excellent antioxidant properties in addition to antimicrobial and anticancer characteristics. Arginine (ARG) is a positively charged amino acid at physiological pH because of nitrogen-rich side chain. Method: Here, poly(tannic acid-co-arginine) (p(TA-co-ARG)) particles at three mole ratios, TA:ARG = 1:1, 1:2, and 1:3, were prepared via a Mannich condensation reaction between TA and ARG by utilizing formaldehyde as a linking agent. Results: The p(TA-co-ARG) particles in 300-1000 nm size range with smooth surfaces visualized via SEM analysis were attained. Abundant numbers of functional groups, -OH, -NH2, and -COOH stemming from TA and ARG constituent confirmed by FT-IR analysis. The isoelectric point (IEP) of the particles increased from pH 4.98 to pH 7.30 by increasing the ARG ratios in p(TA-co-ARG) particles. The antioxidant capacity of p(TA-co-ARG) particles via gallic acid (GA) and rosmarinic acid (RA) equivalents tests revealed that particles possess concentration-dependent antioxidant potency and increased by TA content. The alpha-glucosidase inhibition of p(TA-co-ARG) particles (2 mg/mL) 1:1 and 1:2 mole ratios revealed significant enzyme inhibition ability, e.g., 91.3 +/- 3.1% and 77.6 +/- 12.0%. Interestingly, p(TA-co-ARG) (1:3 ratio) possessed significant antibacterial effectiveness against Escherichia coli (ATCC 8739) and Staphylococcus aureus (ATCC 6538) bacteria. Furthermore, all p(TA-co-ARG) particles at 1000 mg/mL concentration showed >80% toxicity on L929 fibroblast cells and increased as ARG content of p(TA-co-ARG) particles is increased. Conclusions: p(TA-co-ARG) showed significant potential as natural biomaterials for biomedical use.Öğe Natural Molecule-Derived Nanogels from Hematoxylin and l-lysine for Biomedical Use with Antimicrobial Properties(MDPI, 2025) Şahiner, Mehtap; Tian, Zhi; Allen-Gipson, Diane; Sunol, Aydın K.; Şahiner, NurettinHematoxylin (HT) is a natural staining dye used in histopathology, often combined with Eosin for H&E staining. A poly(hematoxylin-co-l-lysine) (p(HT-co-l)) nanonetwork was synthesized through a one-step Mannich condensation reaction using formaldehyde as a linking agent. The resulting p(HT-co-l) nanogels had an average size of about 200 nm and exhibited a smooth surface and desirable functional groups such as -OH, -NH2, and -COOH, as recognized by FT-IR analysis. The isoelectric point (IEP) of the p(HT-co-l) nanogel was determined as pH 7.9, close to physiological environments, despite HT being acidic IEP at pH 1.7 and l-lysine being basic IPE at pH 8.7. The time-dependent swelling studies of p(HT-co-l) nanogels were carried out using dynamic light scattering (DLS) in different salt solutions, e.g., MgCl2, KNO3, KCl, PBS, and DI water environments revealed that nanogels have high swelling ability depending on the medium, e.g., >10-fold in a saline solution compared to distilled water within 1.5 h. Hydrolytic degradation studies in PBS demonstrated a linear release profile up to 125 h at 37.5 degrees C. The p(HT-co-l) nanogels also demonstrated significant antimicrobial and antifungal activities against E. coli (ATCC 8739), S. aureus (ATCC 6538), and C. albicans (ATCC 10231). Furthermore, biocompatibility tests indicated that p(HT-co-l) nanogels are more biocompatible than HT alone, as tested with human Nuli-1 bronchial epithelial cells.Öğe Hydrogen Production from Chemical Hydrides via Porous Carbon Particle Composite Catalyst Embedding of Metal Nanoparticles(MDPI, 2025) Demirci, Şahin; Polat, Osman; Şahiner, NurettinPorous carbon particles (PCPs) prepared from sucrose via the hydrothermal method and its modified forms with polyethyleneimine (PEI) as PCP-PEI were used as templates as in situ metal nanoparticles as M@PCP and M@PCP-PEI (M:Co, Ni, or Cu), respectively. The prepared M@PCP and M@PCP-PEI composites were used as catalysts in the hydrolysis of NaBH4 and NH3BH3 to produce hydrogen (H2). The amount of Co nanoparticles within the Co@PCP-PEI structure was steadily increased via multiple loading/reducing cycles, e.g., from 29.8 +/- 1.1 mg/g at the first loading/reducing cycles to 44.3 +/- 4.9 mg/g after the third loading/reducing cycles. The Co@PCP-PEI catalyzed the hydrolysis of NaBH4 within 120 min with 251 +/- 1 mL H2 production and a 100% conversion ratio with a 3.8 +/- 0.3 mol H2/(mmol catmin) turn-over frequency (TOF) and a lower activation energy (Ea), 29.3 kJ/mol. In addition, the Co@PCP-PEI-catalyzed hydrolysis of NH3BH3 was completed in 28 min with 181 +/- 1 mL H2 production at 100% conversion with a 4.8 +/- 0.3 mol H2/(mmol catmin) TOF value and an Ea value of 32.5 kJ/mol. Moreover, Co@PCP-PEI composite catalysts were afforded 100% activity up to 7 and 5 consecutive uses in NaBH4 and NH3B3 hydrolysis reactions, respectively, with all displaying 100% conversions for both hydrolysis reactions in the 10 successive uses of the catalyst.Öğe AChE Inhibition Capability of Nanogels Derived from Natural Molecules: Tannic Acid and Lysine for Alzheimer's Disease(MDPI, 2025) Şahiner, Mehtap; Sağbaş Suner, Selin; Şahiner, NurettinBackground/Objectives: Tannic acid (TA), a known natural polyphenolic acid with many bioactivities including antioxidants, antibacterial, and antiviral, can be combined with a natural essential amino acid L-lysine (LYS) in nanogel formulations to produce p(TA-co-LYS) (p(TA-co-LYS)) nanogels. Methods: A 1:1 mole ratio of TA:LYS was used to prepare corresponding spherical nanogels employing formaldehyde as a linker via the Mannich reaction. Results: The attained p(TA-co-LYS) particles were in 283 +/- 57 nm size ranges (via SEM analysis) and possessed smooth surfaces. The zeta potential measurements of p(TA-co-LYS) nanogels suspension at different solution pHs revealed the isoelectric point (IEP) of pH 4.9, suggesting that the particles are negatively charged at the physiological pH range (e.g., at 7.4). In addition to the antioxidant efficacy of nanogels confirmed by three different tests, p(TA-co-LYS) particles showed significant Fe(II) ion chelating capacity at 350 mu g/mL concentrations compared to bare TA, which is 21%, whereas the LYS molecule had a chelating capacity of 100% at the same concentrations. Moreover, it was found that p(TA-co-LYS) nanogels inhibited the Acetylcholinesterase enzyme (AChE) at a concentration-dependent profile, e.g., at 333 mu g/mL concentration of p(TA-co-LYS), 57.2% of the enzyme AChE activity was inhibited. Furthermore, the minimum inhibition concentrations of p(TA-co-LYS) nanogels of Gram-negative Escherichia coli (ATCC 8739) and Gram-positive Staphylococcus aureus (ATCC 6538) were determined as 12.5 mg/mL. Conclusions: As cytotoxicity studies of p(TA-co-LYS) nanogels on L929 fibroblast cells also ascertained that these particles can be safely used in many biomedical applications, including antioxidant materials, drug delivery devices, and enzyme inhibitors.Öğe Toxicity Evaluation of Sulfobetainized Branched Polyethyleneimine via Antibacterial and Biocompatibility Assays(MDPI, 2025) Şahiner, Mehtap; Sağbaş Suner, Selin; Demirci, Şahin; Ayyala, Ramesh S.; Şahiner, NurettinBranched polyethyleneimine (PEI), possessing different types of amines-e.g., primary, secondary, and tertiary-in the polymer chains are well known for their antibacterial properties and DNA condensing ability, affording substantial advantages in many biomedical uses, including gene therapy. However, because of PEI's toxicity, depending on the molecular weight, its widespread biomedical use is hindered. Therefore, in this study, PEIs with different molecular weights-i.e., 600, 1200, and 1800 g/mol-were modified with 1,3-propane sultone, undergoing a sulfobetainization reaction in a single step to attain a zwitterionic structure: sulfobetainized PEI (b-PEI). The sulfobetainization reaction was carried out twice to increase the zwitterionic repeating unit on PEI chains. The increasing number of SO3- groups on the PEI chains was confirmed by the increased peak intensities around 1160 and 1035 cm-1 on the FT-IR spectrum, which are assigned to symmetric and asymmetric S=O peaks. The elemental analysis results for first- and second- betainization PEIs, abbreviated as b1-PEI and b2-PEI, respectively, were revealedthe increased wt% of S confirming the successful multiple-sulfobetainization of the PEI chains. Thermal stability analyses of PEIs and their corresponding multiple-sulfobetainized forms showed that multiple-sulfobetainization reactions increased the thermal stability of bare PEI chains. PEIs with lower molecular weights exhibited more antimicrobial properties. As PEI is sulfobetainated, its antimicrobial properties can be further adjusted via sulfobetainization (once or twice), or by adjusting the corresponding solution pH, or by protonating them with different acids with different counter anions. The cell toxicity of PEI on L929 fibroblast cells was slightly increased by increasing the molecular weight of the PEI, but all forms of sulfobetainized PEIs were found to be safe (no toxicity), even at 1000 mu g/mL concentrations.Öğe Mechanically stable superhydrophilic antifog surface by microwave assisted sol-gel method(Elsevier B.V., 2021) Okkay, Hikmet; Satı, Sadık; Cengiz, UğurIn this study, optically transparent and mechanically stable of superhydrophilic composite thin films were fabricated via a low-cost one-step one pot microwave-assisted sol-gel technique. The microwave reaction time was optimized according to surface characterization of homo TMOS surfaces. The reaction time was arranged as 17.5 min having low cost compared to the conventional sol-gel technic. The wettability performance and antifogging behavior of PVA-TMOS composite films were investigated according to variation of the PVA content. The static contact angle values of the composite surfaces were found to vary between 30o and 5o. Superhydrophilic surface having tilt angle is 9o showed a good antifogging performance. Mechanical durability of the composite surface was also characterized by scratching and adhesive tape test. In addition, the time depending water contact angle was also measured for 100 days. It is found that TMPV96 composite film having 0.096 (wt,%) content of PVA showed higher mechanical performance with transparent superhydrophilic surface.Öğe Synthesis and multicolor, photophysical, thermal, and conductivity properties of poly(imine)s(Elsevier B.V., 2021) Kaya, İsmet; Solak, Elif; Kamacı, MusaBackground: Thiazole-based conjugated have been attracted much attention due to their desirable photophysical properties. Based on this, we aimed to prepare thiazole-based poly(imine)s with tunable multicolor emission behavior in the present paper. Methods: Thiazole-based Schiff bases and poly(imine)s were prepared via condensation, and oxidation reactions, respectively. The tunable multicolor behavior of the poly(imine)s was also clarified using fluorescent measurements. Findings: The conductivity, thermal, photophysical, multicolor, morphological and electrochemical properties of the thiazole-based compounds were also clarified. Multicolor behavior of the poly(imine)s was demonstrated that they were emitted blue, green, and yellow emission colors when excited at 350, 420, and 480 nm, respectively. Thermal properties showed that the (poly(imine)s were exhibited good thermal stability. It was found that the thiazole-based poly(imine)s were exhibited a semiconductor behavior after iodine doped. The results indicated that the prepared poly(imine)s were exhibited tunable multicolor property with good thermal stability, and electrical conductivity.Öğe Modification of halloysite clay nanotubes with various alkyl halides, and their characterization, blood compatibility, biocompatibility, and genotoxicity(Elsevier Ltd, 2021) Can, Mehmet; Demirci, Şahin; Yıldırım, Yıldız; Çakır Çoban, Canan; Türk, Mustafa; Şahiner, NurettinHalloysite nanotubes (HNTs) clay were modified with alkyl halides, bromoethane (BrE), bromodecane (BrD), and bromooctadecane (BrOD), respectively. The FT-IR spectra of modified HNTs demonstrated an increase in the intensity of aliphatic –CH2 peaks at 2920 and 2850 cm−1 proportional to the number of C atoms in the modifying agent confirming the success of chemical modification with corresponding alkyl halides. Surface charge of NaOH treated HNTs, −65.7 ± 5.1 mV was increased to −37.1 ± 2.4, −40.6 ± 5.3, and −44.7 ± 1.9 mV, respectively upon chemical modification with BrE, BrD, and BrOD. The Surface area of the HNT clays, 43.2 ± 1.3 m2/g was also increased to 59.8 ± 2.7, 56.9 ± 2.1, and 47.9 ± 1.7 m2/g for BrE, BrD, and BrOD modified HNT clays, respectively. Base-activated HNT clays at 1 mg/mL concentration found to be nonhemolytic with 3.5 ± 1.2% hemolysis ratio, whereas HNT-BrOD clays were slightly exceeded hemolytic safety level with 6.6 ± 0.2% hemolysis induction. Base-activated HNT and HNT-BrOD clays were found to show antithrombogenic character with more than 100% blood clotting indexes,107.6 ± 1.8, and 106.5 ± 1.9%, respectively. Cytotoxicity studies of HNTs on L929 fibroblast cells revealed that HNTs in 12.5–200 μg/mL concentration range were shown dose-dependent cell viability, and above 50% cell viability was maintained at 200 μg/mL in all forms of HNT based clays administered.Öğe Amperometric nonenzymatic glucose biosensor based on graphite rod electrode modified by Ni-nanoparticle/polypyrrole composite(Elsevier Inc., 2021) Emir, Gamze; Dilgin, Yusuf; Ramanaviciene, Almira; Ramanavicius, ArunasThis study reports non-ezymatic electrocatalytic amperometric glucose biosensor based on a graphite rod electrode (GRE) modified with biomimetic-composite consisting of Ni nanoparticles (Ni-NPs) and polypyrrole (Ppy) prepared by 1 cycle electro polymerization of pyrrole monomer (Ni-NPs/Ppy(1)/GRE). During the modification of GRE, the electropolymerization of pyrrole and the electrodeposition of Ni-NPs onto GRE surface were consequentially performed by potential cycling. Surface morphology of Ni-NPs/Ppy(1)/GRE electrode was evaluated by atomic force microscopy and scanning electron microscopy based imaging, and electrochemical characterization of electrodes was performed by electrochemical impedance spectroscopy and cyclic voltammetry. Cyclic voltammograms recorded in the presence of glucose show that Ni-NPs/Ppy(1)/GRE at + 500 mV vs Ag/AgCl exhibits efficient electrocatalytic oxidation activity towards glucose, while the oxidation of glucose was not observed at a bare GRE. Amperometric sensing of glucose was performed by Ni-NPs/Ppy(1)/GRE at constant + 450 mV vs Ag/AgCl electrode potential in 0.10 mol L−1 NaOH. Ni-NPs/Ppy(1)/GRE-based sensor, which was characterized by a wide linear glucose determination range between 1.0 and 1000 µmol L−1 with a limit of detection of 0.4 µmol L−1 and a sensitivity of 2873 µA mmol−1 L cm−2. The applicability of here reported Ni-NPs/Ppy(1)/GRE-based sensor has been demonstrated by the determination of glucose concentrations in real samples.Öğe Synthesis, spectral properties, crystal structure and theoretical calculations of a new geminal diamine: 2,2,2-Trichloro-N,N′-bis(2-nitrophenyl)-ethane-1,1-diamine(Elsevier B.V., 2021) Aydın, Fatma; Arslan, N. BurcuA new 2,2,2-trichloro-N,N׳-bis(2-nitrophenyl)-ethane-1,1-diamine was synthesized by the reaction of 2-nitroaniline in DCM with the chloral formed by distillation of chloral hydrate over concentrated H2SO4. The structure of the title compound was identified by means of FT-IR, 1H NMR, and 13C NMR spectroscopic techniques. The crystal structure of the title compound has also been examined by using X-ray crystallographic techniques and found to be crystallized in the monoclinic crystal system and space group P21/n with the unit cell parameters: a = 7.7075(12) Å, b = 7.7396(10) Å, c = 28.247(4) Å, β = 93.602(5)°, V = 1681.7(4) Å3, Dx = 1.602 Mg m − 3, and Z = 4 respectively. The calculated electronic structure properties of the title molecule such as HOMO-LUMO analysis, molecular electrostatic potential (MEP) map, and the Mulliken charge distributions were investigated by using the density functional theory (DFT) method. Theoretically calculated values exhibit the chemically hard, high kinetic stable and less reactive molecule.Öğe Synthesis and characterization of magnetic ZnCl2-activated carbon produced from coconut shell for the adsorption of methylene blue(Elsevier B.V., 2021) Karaer Yağmur, Hatice; Kaya, İsmetIn this research, a magnetic-activated carbon composite was synthesized to investigate its adsorption to methylene blue dye. Active carbon (ACz) was produced by ZnCl2 activation of coconut shell (char: ZnCl2, 2:1). Magnetic activated carbon (MACz) was prepared via an easy method by chemical co-precipitation of Fe3+/Fe2+. The pore diameter, pore-volume, and surface area of MACz were determined from N2 adsorption isotherms. The ACz and MACz were characterized by several techniques such as BET, SEM/EDX, FT-IR, XRF, VSM, TGA, and pHpzc analysis. The average particle size, particle size distribution, and zeta potential of MACz were determined by Zetasizer. The zero point charge of the MACz was determined as approximately 4.9 pH. Moreover, the adsorption by MACz was investigated as kinetically and thermodynamically for removal of methylene blue (MB) from aqueous solution. The kinetics and thermodynamic parameters were also calculated. According to the results, the adsorption process was determined as endothermic. The Langmuir and Freundlich isotherms models were used and it was found that adsorption of MB onto MACz best fitted to Freundlich model according to RMSE, SSE, and R2 values. The maximum adsorption capacity of the composite was calculated as 156.25 mg/g. Thermodynamic parameters (ΔHo, ΔGo, and ΔSo) were also calculated, which revealed that the adsorption process is spontaneous.Öğe Dye sensitized solar cell-based optoelectronic device using novel [Ru(L1)(L2)(NCS)2] complex(Elsevier B.V., 2021) Dayan, Osman; Gençer İmer, Arife; Tercan, Melek; Dere, Ayşegül; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; Yakuphanoğlu, FahrettinA dye sensitized solar cell-based photodiode was prepared using novel [Ru(L1)(L2)(NCS)2] complex for solar energy and optoelectronic applications. The new heteroleptic ruthenium(II) complex [Ru(L1)(L2)(NCS)2], was synthesized from the reaction of (pyridyl)benzimidazole ligands. The possible usage of [Ru(L1)(L2)(NCS)2] complex in dye synthesized solar cell-based photodiode was investigated using electrical and capacitance characteristics. The device was irradiated under various solar light intensities. The change in photocurrent of the device confirms the photoconducting behavior of prepared device. The device exhibited both the photocapacitance and photoresponse behavior with solar illumination. The obtained optoelectrical results suggest that the studied photodiode with [Ru(L1)(L2)(NCS)2] complex could be used in optoelectronic device for optical switching and controlling applications.Öğe Synthesis and characterization of biodegradable and antioxidant phosphazene-tannic acid nanospheres and their utilization as drug carrier material(Elsevier Ltd, 2021) Önder, Alper; Özay, HavaIn this study, hexachlorocyclotriphosphazene (HCCP) and tannic acid (TA) were used at different stoichiometric ratios to synthesize cyclomatrix-type polymeric materials with different surface features and dimensions. Using different reactive ratios, the structure and surface functional groups of the synthesized polymeric particles were explained using Fourier-Transform Infrared Spectroscopic (FTIR), Scanning Electron Microscope (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray Photoelectron Spectroscopy (XPS) and Thermogravimetric (TG) analysis techniques. With morphologically fully spherical structure and mean 234.82 ± 49.37 nm dimensions, Phz-TA (4:1) nanospheres were researched for in vitro biodegradability, antioxidant features, and usability as a drug release system. In vitro biodegradability of Phz-TA (4:1) nanospheres was investigated at pH = 7.0 and pH = 1.2. Determined to degrade in 8–10 h at these pH values, nanospheres were used for releasing of Rhodamine 6G as a model drug. Due to the rich phenolic structure of the contained tannic acid units, nanospheres were determined to simultaneously have antioxidant features. Thus, this study determined that Phz-TA nanospheres with in vitro biodegradability and antioxidant features are promising polymeric materials for use as a potential drug-carrier in the future.Öğe Boron Rejection from Aqueous Solution and Wastewater by Direct Contact Membrane Distillation(2020) Tan, Burcu; Selengil, Uğur; Bektaş, Tijen EnnilBoron is widely used in various areas of modern technology. Due to the environmental problems arising during the production and use, the studies on the removal and recovery of boron from wastewater have been increased recently. Membrane distillation (MD) system is smaller in size with respect to other common distillation systems and needs lower operating temperatures. In addition, the equipment costs are reduced and the safety of the process increases since it operates at lower pressures. Moreover, the membrane distillation process can remove pollutants from water without using chemicals. In this study, boron rejection from aqueous solutions and wastewater was investigated by using direct contact membrane distillation (DCMD) system where both surfaces of a porous hydrophobic membrane were in contact with liquid streams. The effects of various parameters (pH, feed concentration, feed temperature, etc.) on boron rejection were investigated and the highest boron rejection was found to be 50 % when pH=10 at 50 degrees C and with feeding by a pump of 54 rpm. According to the test results of wastewater from Kirka Borax treatment plants, the mean distillate fluxes were found as 13, 16 and 14 L/m(2)h at the feed temperatures of 30, 40 and 50 degrees C, respectively. The boron removal percentages were found to be 47, 64 and 48 % at 30, 40 and 50 degrees C, respectively. It was observed in the XRD spectra that the crystals in wastewater mainly consist of Na2B(OH)(4)Cl and Mg2B2O5 structures.
