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Öğe Adsorption of thorium (IV) ions by metal ion doped ZnO nanomaterial prepared with combustion synthesis: Empirical modelling and process optimization by response surface methodology (RSM)(Pergamon-Elsevier Science Ltd, 2021) Kaynar, U. H.; Kaynar, S. Cam; Karali, E. Ekdal; Ayvacikli, M.; Can, N.Environmental problems have reached enormous dimensions, driving efforts to remove and recycle waste from energy and industrial production. In particular, removing the radionuclide contamination that occurs as the nuclear industry grows is difficult and costly, but it is vital. Technologic and economical methods and advanced facilities are needed for the separation and purification of radioactive elements arising from the nuclear industry and uranium and thorium mining. With the adsorption method, which is the most basic separation and recovery method, the use of high-capacity nanomaterials has recently gained great importance in reducing the activity of the waste, reducing its volume by transforming it into solid form, and recovering and removing liquid radioactive wastes that might harm the ecological environment. This study aimed to determine the adsorption properties of metal ion-doped nano ZnO (nano-ZnO:Al) material synthesized by the microwave-assisted gel combustion method for the adsorption of thorium (IV) from aqueous media. First, characterization processes such as XRD, SEM, BET and zeta potential were performed to observe changes in the host ZnO adsorbent structure caused by the doping process. Later, this was optimized via the response surface method (RSM), which is widely used in the characterization of the adsorption properties of thorium (IV) from aqueous solutions. Such characterization is commonly used in industrial research. We tested how pH (3-8), temperature (20-60 degrees C), Th (IV) concentration (25-125 mg/L) and adsorbent amount (0.01-0.1 g) affect adsorption efficiency. The best possible combinations of these parameters were determined by RSM. It was calculated by RSM that the design fits the second order (quadratic) model using the central composite design (CCD) for the design of experimental conditions. R-2 and R-2 adjusted values from the parameters showing the model fit were 0.9923 and 0.9856, respectively. According to the model, the experimental adsorption capacity was 192.3 mg/g for the doped-ZnO nanomaterial under the theoretically specified optimum conditions. Also, the suitability of Th (IV) adsorption to isotherms was examined and thermodynamic parameters were calculated.Öğe Enhancement of luminescence and thermal stability in Eu3+-doped K3Y(BO2)6 with Li+ and Na+ co-doping (vol 35, 104695, 2024)(Elsevier, 2024) Kaynar, U. H.; Aydin, H.; Altowyan, Abeer S.; Hakami, J.; Coban, M. B.; Ayvacikli, M.; Karali, E. Ekdal; Canimoglu, A.; Can, N.[Abstract Not Available]Öğe Synthesis and beta particle excited thermoluminescence of BaSiF6 phosphor(Pergamon-Elsevier Science Ltd, 2022) Souadi, G.; Akca-Ozalp, S.; Karali, E. Ekdal; Kaynar, U. H.; Ayvacikli, M.; Topaksu, M.; Can, N.BaSiF6 phosphor was synthesized by a gel combustion method. The crystalline size was found to be 54.17 +/- 4.36 nm using Williamson-Hall (W-H) approximation. The TL data collected by means of a combination of a commercial BG39 and HC575/25 filters was studied to evaluate basic kinetic parameters. Three TL glow peaks of BaSiF6 phosphors are centered at around 84, 190 and 322 degrees C. T-m-T-stop, various heating rate (VHR) and computerized glow-curve deconvolution (CGCD) method were utilized to analyse collected data. Our findings indicate that luminescence process in scrutinized material may obey second order kinetics. The TL dose response of the TL glow peaks exhibits a linear characteristic up to 100 Gy. Deconvolution of the glow curve reveals that the number of the component TL glow peaks in the complex glow curve is composed of well-isolated six overlapping glow peaks. The FOM value is 2.32.Öğe Thermal quenching and evaluation of trapping parameters of thermoluminescence glow-peaks of beta irradiated NaBaBO3: Tb3+ for TLD applications(Elsevier, 2022) Oglakci, M.; Topaksu, M.; Alajlani, Y.; Can, N.; Karali, E. EkdalHere, we report the thermoluminescence (TL) characteristics and trapping parameters under beta ray excitations of pelletized Tb incorporated NaBaBO3 synthesized through the gel combustion method. The chemical composition of this new phosphor was confirmed using X-ray diffraction (XRD). The best doping concentration of Tb was 2 mass%, which results in the highest luminous efficiency. The glow curves of the pellet-formed samples exposed to beta irradiation at various doses showed glow peaks at about 188 degrees C, and 288 degrees C with a heating rate of 2 degrees Cs-1. The trapping parameters (E, b, s) related with the prominent the TL glow peaks were determined using T-m-T-stop, initial rise (IR), computerized glow curve deconvolution (CGCD), and variable heating rate (VHR) methods. In the range of 0.1-40 Gy, the total integral values of TL output enlarge linearly with increased dose. The GCD approach was also used to calculate the number of the glow peaks necessary to ensure an appropriate match to the TL response of the phosphor sample and seven TL glow peaks were estimated for all doses (FOM 1.75%), similar to the analysis of T-m-T-stop. The thermal quenching parameters of Tb activated NaBaBO3 for the 1st and 2nd peaks are measured to be W = 0.39 +/- 0.04 eV, C = 3.11 x 10(2), and W = 0.31 +/- 0.03 eV, C = 3.11 x 10(2), respectively. The current results indicate that the NaBaBO3:Tb3+ phosphor is a suitable option in radiation dosimetry for environmental monitoring.Öğe Thermoluminescence characterization of Ag-doped Li2B4O7 single crystal materials(Wiley, 2017) Kurali, D.; Karali, E. Ekdal; Kelemen, A.; Holovey, V.; Can, N.; Karali, T.In this study, the thermoluminescence (TL) characteristics of Ag-doped and undoped lithium tetraborate (Li2B4O7, LTB) materials, grown using the Czochralski method, were reported. The TL properties of LTB:Ag, such as glow curve structure, dose response, fading and reproducibility, were investigated. The glow curve of the Li2B4O7:Ag single crystal consists of four peaks located at approximately 75, 130, 190 and 275 degrees C; in undoped LTB, the single crystal shows a broad glow curve with peaks at 65, 90, 125, 160 and 190 degrees C using a heating rate of 5 degrees C/s in the 50-350 degrees C temperature region. The high temperature peak of Ag-doped sample at 275 degrees C has a nonlinear dose response within the range from 33mGy to 9Gy. There is a linear response in the range of 33-800mGy; after which, a sublinear region appears up to 9Gy for Ag-doped LTB single crystal. For undoped single crystal, the dose response is supralinear for low doses and linear for the region between 1 and 9Gy. The thermal fading ratio of the undoped material is almost 60% for the high temperature peak after 7days. Ag-doped LTB single crystal exhibits different behaviour over a period of 7days.
