Chemistry / Kimya
Permanent URI for this collectionhttps://hdl.handle.net/11147/4072
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Article Development of Chemometrics Method Based on Infrared Spectroscopy for the Determination of Cement Composition and Process Optimization [article](ACG Publications, 2022) Özdemir, Durmuş; Gümüş, Mehmet Gökhan; Tepeli, DilekIn combination with a multivariate calibration method, FTIR-ATR spectroscopy was presented as a rapid method for the determination of some major oxides (CaO, SiO2, Al2O3, Fe2O3) and minor oxides (MgO, SO4, Na2O, and K2O) in diverse materials (raw material, raw meal, additives, clinker, and types of cement) in cement manufacturing. The FTIR spectroscopy based multivariate models were generated by taking X-ray fluorescence (XRF) as a reference method. Among a number of spectral preprocessing methods, extended multiplicative scatter correction (EMSC) yielded the best PLS models. The standard error of prediction (SEP) for the optimal FTIR based PLS models ranged from 0.10 to 2.07 (w/w%), and the regression coefficient (R2) ranged from 0.95 to 0.99 for PLS predicted vs XRF reference plots. Statistical evaluation of the both methods was carried out by paired t-test at the 95% confidence level and the results showed that the FTIR-ATR combined with PLS model results are consistent with the XRF reference measurements for all the oxides studied. Compared to the XRF method, which can take anywhere from a few minutes to an hour for each measurement, the proposed method is faster, cheaper, and safer. The presented technology also allows rapid monitoring of a cement factory production line.Article Citation - WoS: 8Citation - Scopus: 7The Use of Mussel Shell as a Bio-Additive for Poly(lactic Acid) Based Green Composites(Lviv Polytechnic National University, 2021) Lap, Metehan Oğulcan; Kanbur, Yasin; Tayfun, ÜmitMussel shell is one of the most hazardous aquaculture wastes and its powder was used as an additive for bio-degradable poly (lactic acid) in this current study. Bio-composites were fabricated via conventional melt mixing technique followed by an injection moulding process. The effects of mussel shell powder inclusion on mechanical, melt-flow, water uptake and morphological performance of poly (lactic acid)-based green composites were reported.Article Citation - WoS: 1Citation - Scopus: 1Amalgamation Performances of Gold-Coated Quartz Wool, Alumina, Silica, Sand and Carbon Fiber for the Determination of Inorganic Mercury in Waters by Cold Vapor Atomic Absorption Spectrometry(Pleiades Publishing, 2017) Erdem Şimşek, Arzu; Erdem Yayayürük, Aslı; Shahwan, Talal; Eroğlu, Ahmet EminDifferent gold-coated sorbents for amalgamation were applied for the determination of inorganic mercury in waters using a home-made cold vapor generation unit coupled to atomic absorption spectrometry. Among the gold-coated materials investigated (quartz wool, alumina, silica, sand and carbon fiber) quartz wool was found to give the most efficient results in terms of sorption and release. Analytical performance of the system without and with amalgamation was investigated and it was found that when amalgamation was applied, the linearity and slope of the calibration plots were independent on the sample volume for 1.0, 5.0 and 10.0 mL. Method validation was realized through the analysis of a sample of spring water spiked with 1.0 μg/L inorganic mercury and the spike recoveries were found to be 95 ± 1, 91 ± 3, and 99 ± 5% for 1.0, 5.0, and 10.0 mL, respectively. The results demonstrated that the methodology can be applied to these types of samples directly or after amalgamation, depending on the mercury concentration.Article Citation - WoS: 5Citation - Scopus: 5Use of Amberlite Xad-7hp for the Separation of Mn(ii) and Mn(vii) in Waters(Pleiades Publishing, 2017) Erdem Yayayürük, Aslı; Eroğlu, Ahmet EminA simple method is proposed for the determination and speciation of Mn(II) and Mn(VII) in waters utilizing a macroporous resin, Amberlite XAD-7HP. The batch method was employed and flame atomic absorption spectrometry was used in all determinations. Amberlite XAD-7HP resin was shown to retain Mn(VII) between pH 4 and 12. If the solution contains only one of the species, either Mn(II) or Mn(VII), the resin behaves selectively depending on the pH of the solution. The elution from the sorbent was realized using K2C2O4 in HNO3. The efficiency of the method was checked via spike recovery experiments. The proposed method was successfully applied to industrial wastewater samples and quantitative recoveries (≥96.0%) confirmed the accuracy of the method.Article Citation - WoS: 21Citation - Scopus: 23Adsorption of Methylene Blue From Aqueous Solution on High Lime Fly Ash: Kinetic, Equilibrium, and Thermodynamic Studies(Taylor and Francis Ltd., 2012) Keleşoğlu, Serkan; Kes, Mürşide; Sütçü, Leman; Polat, HürriyetKinetic, equilibrium, and thermodynamic studies were performed for the batch adsorption of methylene blue (MB) on the high lime fly ash as a low cost adsorbent material. The studied operating variables were adsorbent amount, contact time, dye concentration, and temperature. The kinetic data were analyzed using the pseudo-first order and pseudo-second order kinetic models and the adsorption kinetic was followed well by the pseudo-second order kinetic model. The equilibrium data were fitted with the Freundlich, Langmuir, and Dubinin Radushkevich (D-R) isotherms and the equilibrium data were found to be well represented by the Freundlich and D-R isotherms. Based on these two isotherms MB is taken by chemical ion exchange and active sites on the high lime fly ash have different affinities to MB molecules. Various thermodynamic parameters such as enthalpy of adsorption (ΔH°), free energy change (ΔG°), and entropy change (ΔS°) were investigated. The positive value of ΔH° and negative value of ΔG° indicate that the adsorption is endothermic and spontaneous. The positive value of ΔS° shows the increased randomness at the solid-liquid interface during the adsorption. A single-stage batch adsorber was also designed based on the Freundlich isotherm for the removal of MB by the high lime fly ash. © 2012 Copyright Taylor and Francis Group, LLC.Article Citation - WoS: 23Citation - Scopus: 26Development of Practical Hplc Methods for the Separation and Determination of Eggplant Steroidal Glycoalkaloids and Their Aglycones(Taylor and Francis Ltd., 2008) Eanes, Ritchie C.; Tek, Neslihan; Kırsoy, Öyküm; Frary, Anne; Doğanlar, Sami; Almeida, Adelia E.A practical set of HPLC methods was developed for the separation and determination of the eggplant steroidal glycoalkaloids, solanine, chaconine, solasonine, solamargine, and their aglycones, solasodine and solanidine. A gradient method was initially developed, but proved to be neither robust nor practical. Three separate isocratic methods using acetonitrile and ammonium dihydrogen phosphate were developed and shown to be more repeatable, less subject to fluctuations in mobile phase composition, and less time consuming. The effect of adjusting buffer pH, column temperature, and buffer type (triethylammonium phosphate vs. ammonium dihydrogen phosphate) were evaluated. It was also discovered that, by addition of 10% methanol to the acetonitrile portion of the mobile phase, more control over the separations was possible. The use of methanol as a mobile phase entrainer greatly improved separations in some cases and its effectiveness was also dependent upon column temperature. Assessments of the method recovery, limit of detection, and limit of quantitation were made using extracts from S. melongena and S. linnaeanum.Article Citation - WoS: 2Citation - Scopus: 2Solid-Phase Microextraction (spme) Followed by On-Fiber Derivatization of Solasodine and Solanidine Aglycones of Steroidal Glycoalkaloids(Taylor and Francis Ltd., 2008) Eanes, Ritchie C.; Tek, NeslihanSolid-phase microextraction (SPME), followed by on-fiber derivatization was investigated for the analysis of the steroidal glycoalkaloid aglycones, solasodine and solanidine. The aglycones were first extracted by direct immersion of the SPME fiber in the sample medium and then derivatized on the fiber in a separate step using 1-(trimethylsilyl)imidazole (TMSI). The derivatized compounds were then desorbed from the SPME fiber and detected by GC-MS. Polydimethylsiloxane/Divinylbenzene (PDMS-DVB), Carboxen/ Polydimethylsiloxane (CAR-PDMS), and Carbowax/Divinylbenzene (CW-DVB) fibers were employed with the CW-DVB fibers being the most successful, as expected. Closed-end capillary tubes were used to hold the extraction media. Both aglycones were successfully extracted, derivatized, and detected by GC-MS. Solasodine always required derivatization, but solanidine did not. The same method was successfully applied to cholesterol so that it could be used as an internal standard. Also, using the closed-end capillary tubes, a two-phase extraction system was also investigated, whereby the fiber was only exposed to the phase in which it was presumed to be less damaged. However, in all cases, fiber degradation was significant, preventing the use of extended extraction times and limiting reuse of the fibers. However, the results represent a first look into the feasibility of the method. With the development of more suitable SPME phases, this method could potentially provide a complementary route for routine determinations of glycoalkaloids for both research and food quality control.Article Citation - WoS: 4Citation - Scopus: 5Crystal Structure of Distrontium Manganese (iii) Tetraoxophosphate Heptaoxodiphosphate, Sr2mn[po4] [p2o 7](Walter de Gruyter GmbH, 2007) Doğan, Leyla; Eanes, MehtapMnO11P3Sr2, monoclinic, P121/c1 (no. 14), a = 6.641(1) Å, b = 6.834(1) Å, c = 19.554(4) Å, β = 99.22(3)°, V = 876.0 Å3, Z = 4, Rgt(F) = 0.051, wRref(F2) = 0.090, T = 298 K.Article Citation - WoS: 6Citation - Scopus: 6Crystal Structure of Lead(ii) Trioxovanadate(v) Chloride, Pb[vo 3]cl(Walter de Gruyter GmbH, 2007) Şahin, Aytaç; Eanes, MehtapClO3PbV, orthorhombic, Pnma (no. 62), a = 10.022(2) Å, b = 5.288(1) Å, c = 7.171(1) Å, V= 380.0 Å3, Z = 4, Rgt(F) = 0.035, wRref(F2) = 0.105, T= 153 K.Article Citation - WoS: 5Citation - Scopus: 6Oxo-Bridged (haloarylimido)[tris(3,5-Dimethylpyrazolyl)borato] Molybdenum(v) Complexes: Crystal Structures of Geometric Isomers of [motp*(o)cl](µ-O)[motp*(cl)(?nc6h 4br)](De Gruyter, 2005) Sözüer, Hikmet Işıl; Dülger İrdem, Seçkiner; Jeffery, John J.; Hamidov, Hayrullah; Şentürk, Ozan SanlıThe reaction between [MoTp*(O)Cl2], [Tp* = hydrotris(3,5-dimetylpyrazol-1-yl)borate] and 4-bromoaniline in refluxing toluene gave geometric isomers of [MoTp*(O)Cl](μ-O)[MoTp*(Cl) (≡NC6H4Br)] (1a, cis; 1b, trans), but a similar reaction between [MoTp*(O)Cl2] and 4-chloroaniline yielded only one product, [MoTp*(O)Cl](μ-O)[MoTp*(Cl)(≡NC 6H4Cl)] (2) as a red crystalline solid. The new compounds were characterized by microanalytical data, mass, IR and 1H NMR spectroscopy. The X-ray structure analysis of 1a and 1b revealed that the complexes are geometric isomers, the two chloro ligands being cis in 1a and trans in 1b. Both compounds have Mo-O-Mo linkages and nearly linear arylimido moieties.