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Öğe Acid-modulated zirconium based metal organic frameworks for removal of organic micropollutants(Elsevier Sci Ltd, 2020) Bayazit, Sahika Sena; Sahin, SelinUiO-66 is one of the most applied metal organic frameworks on environmental remediation. In this study, UiO-66 was prepared and modified it by acid treatment. Acid treatment causes defected sites in the crystals. These defected sites provide increasing the adsorption capacities of crystals. The surface properties of prepared UiO-66 crystals were examined by X-ray diffraction spectroscopy (XRD), Fourier transform Infrared spectroscopy (FTIR), BET surface area analysis, particle size distribution analysis, and Scanning electron microscopy (SEM), respectively. 2,4-dichlorophenoxy acetic acid (2,4-D), ciprofloxacin (CPX) and naproxen (NPX) were adsorbed on UiO-66 crystals. Some adsorption variables were examined. These variables are amount of adsorbent, pH of adsorbate solution, initial adsorbate concentration, and contact time. The equilibrium times were determined as 120 min for 2,4-D, 45 min for CPX and 120 min for NPX. Pseudo second order (PSO), fractional power and Elovich kinetic models were calculated. Additionally, Langmuir, Freundlich, Sips and Radke-Prausnitz isotherms were also calculated. PSO kinetic model has been suited the adsorption of all three micropollutants. Langmuir isotherm has been fitted to 2,4-D, CPX and NPX adsorption. The calculated maximum adsorption uptake values of 2,4-D, CPX and NPX are 370.37, 111.71 and 43.86 mg/g, respectively.Öğe Comparison of different polymeric resins for naproxen removal from wastewater(Elsevier Science Bv, 2017) Kurtulbas, Ebru; Bilgin, Mehmet; Sahin, Selin; Bayazit, Sahika SenaThe polymeric resins are eco-friendly, cheap and have good surface properties. These resins were used for Naproxen (NPX) adsorption from aqueous solutions. Three different resins were chosen. These are Amberlite XAD-2, XAD-4 and XAD-16. The effects of adsorption variables were tested. The variables were selected as adsorbent quantity, NPX concentration, pH of solution, temperature and contact time. Langmuir and Freundlich isotherm models were applied to the experimental data. And it was observed that Langmuir isotherm model fitted the experimental data properly. The pseudo second order kinetic model and Weber-Morris intraparticle diffusion model were used for kinetic analysis of NPX adsorption. The pseudo second order model was the best fitted kinetic model for NPX adsorption. The rate-controlling step was determined as the intraparticle diffusion step. The NPX adsorption on Amberlite resins was exothermic process. According to isotherm parameters, separation factor (R-L) values, kinetic and thermodynamic data, XAD-4 was found to be the most suitable adsorbent for NPX adsorption. Amberlite XAD-4 reached the maximum removal percentage (99.88%) at 0.5 g of adsorbent. NPX adsorption capacity of XAD-4 was 6.52 mg/g at 308 K, according to Langmuir isotherm model. (C) 2017 Elsevier B.V. All rights reserved.Öğe Investigation of extractive interaction between ionic liquids and carbamazepine(Elsevier Science Bv, 2018) Sahin, Selin; Elhussein, Elaf Abdelillah Ali; Bilgin, Mehmet; Kurtulbas, Ebru; Bayazit, Sahika SenaInvestigation of carbamazepine (CBP) extraction by four solvent systems containing ionic liquids (1-Butyl-3-methylimidazolium tetrafluoroborate-IL-1 and 1-Butyl-3-methyl-imidazolium hexafluoro phosphate-IL-2) as extractant in four diluents (diethyl adipate-DEA, diethyl malonate-DEM, diethyl succinate-DES and dibutyl phthalate-DBP) was performed at ambient temperature. The results were evaluated in terms of extraction yield (%) and distribution coefficient. IL-2 + DEA extractant system had the highest yield of CBP recovery with 88.45%. Regarding IL-1, the best performance was achieved by DEM with 82.03% of CBP recovery. Neutral media with the lowest addition of ionic liquid (20%, v/v) was found to be the optimum conditions to obtain the maximum recovery. (C) 2018 Elsevier B.V. All rights reserved.Öğe Investigation of Formic Acid Separation from Aqueous Solution by Reactive Extraction: Effects of Extractant and Diluent(Amer Chemical Soc, 2010) Sahin, Selin; Bayazit, Sahika Sena; Bilgin, Mehmet; Inci, IsmailThis study aims to investigate the extraction of formic acid by a high molecular-weight aliphatic amine, tridodecylamine (TDA), and a phosphorus-bonded, oxygen-containing extractant, tributyl phosphate (TBP), dissolved in five different diluents (ethyl valerate. diethyl adipate, diethyl sebacate, I-octanol, and heptane) each The experiments were carried out at 298 15 K Comparisons of the results were made using the distribution coefficient, loading factor, separation factor, and the percentage of extraction yield. The results demonstrated that combination of TDA and diethyl adipate had the greatest synergistic effects with a distribution value of 6 The maximum value of the extraction efficiency was found to be 87 % with a 1 09 mol . L(-1) concentration of TDA in diethyl Alpine.Öğe Preparation of CeO2 nanofibers derived from Ce-BTC metal-organic frameworks and its application on pesticide adsorption(Elsevier Science Bv, 2018) Elhussein, Elaf Abdelillah Ali; Sahin, Selin; Bayazit, Sahika SenaIn this study, CeO2 nanofibers derived from Ce(1,3,5-BTC)(H2O)(6) (Ce-BTC) metal organic frameworks were prepared, and then the affinity of CeO2 towards 2,4-dichlorophenoxyacetic acid (2,4-D) was investigated. After the Ce-BTC nanoparticles were synthesized by hydrothermal method, the Ce-BTC was calcinated, and CeO2 nanofibers were obtained. The Ce-BTC and CeO2 were characterized by SEM, XRD, MR and AFM methods, respectively. The adsorption studies of 2,4-D from water with CeO2 were carried out as batch type. The Langmuir, Freundlich and Sips isotherms were applied to the experimental data. And pseudo second order, intra-particle diffusion and Bangham kinetic models were used for determination of the kinetic mechanism of the adsorption. The maximum adsorption capacity for 2,4-D was found to be 86.16, 95.78 and 84.29 mg/g for each temperature (298, 308 and 318 K), respectively. (C) 2018 Elsevier B.V. All rights reserved.Öğe Preparation of chromium fumarate metal-organic frameworks for removal of pharmaceutical compounds from water(Korean Institute Chemical Engineers, 2022) Kurtulbas, Ebru; Sahin, Selin; Bilgin, Mehmet; Bayazit, Sahika SenaPharmaceutical pollution in water is the major cause of antibiotic resistance, so remediation of water from pharmaceuticals is a very important issue. Different methods are used for this purpose, with adsorption as one of the most preferred. Different adsorbents have been used for water treatment processes. Metal-organic frameworks that have highly porous structures have gained attention in the last decades. In this study, novel chromium fumarate (Cr-Fum) was prepared, and the efficiency of Cr-Fum was tested by ciprofloxacin (CPX) adsorption. Cr-Fum was prepared under reflux and characterized by scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA), and differential scanning calorimetry (DSC). The general approach of the process was monolayer adsorption at low temperature and heterogeneous adsorption at high temperature. 2.5 mg of adsorbent was adsorbed 4.97 mg/g and 11.47% of CPX. 10 mg of Cr-Fum was adsorbed 0.82 mg/g and 7.27% of CPX. Partition coefficients were calculated and 0.07 mg/g/mu M was found at 298 K. The reaction followed pseudo-first- and pseudo-second-order kinetic models. Thermodynamic analysis showed that the reaction is spontaneous and exothermic. Additional ions caused decreasing CPX adsorption, but this study showed that Cr-Fum has NaCl adsorption capacity. In future studies, NaCl adsorption should be investigated. Desorption studies were applied to Cr-Fum after the adsorption processes. 0.1 M NaOH and phosphate buffer (pH=7.4) solution were used as desorption eluents. The desorption period was chosen as 6 h. NaOH solution desorbed 67.38% of CPX at first cycle and buffer solution desorbed 26.87% of CPX at second cycle.Öğe Recovery of ?-Carotene on Graphene Nanoplatelets UiO-66 Nanocomposites(Amer Chemical Soc, 2020) Sahin, Selin; Bayazit, Sahika SenaRecovery of beta-carotene from n-hexane solution onto Zr-based metal organic frameworks (UiO-66)/graphene nano platelets (GPNPs) has been investigated. The nanocomposite has been characterized by X-ray diffraction, scanning electron microscopy, specific surface area (Brunauer-Emmett-Teller) analysis, particle size distribution analysis, and Fourier transform infrared spectroscopy methods. The highest adsorption yield was found to be approximately 60% under optimum conditions (0.01 g of UiO-66/GPNP for the adsorption of approximate to 8 mg L-1 beta-carotene solution at 150 rpm mixing speed of the shaking bath). The relevant adsorption system was an endothermic, nonspontaneous, and chemisorption process depending on the kinetics (pseudo first order, pseudo second order, fractional power, and Elovich models), equilibrium (Langmuir, Freundlich, Redlich-Peterson, and Radke-Prausnitz isotherm equations), and thermodynamic parameters.Öğe Recovery of polyphenols from water using Zr-based metal-organic frameworks and their nanocomposites with graphene nanoplatelets(Elsevier Science Inc, 2019) Sahin, Selin; Elhussein, Elaf Abdelillah Ali; Salam, Mohamed Abdel; Bayazit, Sahika SenaIn this study, Zr-based metal organic frameworks (UiO-66) and graphene nanoplatelets UiO-66 nanocomposites (GNP/UiO-66) were prepared using acid promoted method, and used for adsorption of two different polyphenols; oleuropein and hydroxytyrosol. Different characterization techniques used for exploring the morphological and structure properties of the UiO-66 and GNP/UiO-66 nano composites. The adsorption of oleuropein and hydroxytyrosol was studied by UiO-66 and different GNP/UiO-66 nanocomposites and results showed that most of the oleuropein and hydroxytyrosol were removed from the solution in 60 min and 180 min, respectively. The kinetic modelling of adsorption was studied. The adsorption isotherms were constructed at different pH values. (C) 2019 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.Öğe Removal of carbamazepine using UiO-66 and UiO-66/graphene nanoplatelet composite(Elsevier Sci Ltd, 2020) ElHussein, Elaf Abdelillah Ali; Sahin, Selin; Bayazit, Sahika SenaCarbamazepine (CBZ) is an endocrine disrupting and psychoactive chemical. The application area of this chemical is wide and the presence of CBZ concentration in water is very high. The half life of CBZ is 25 - 65 h. So, purification of water from CBZ is a very important issue. In this study, adsorption method was used for this purpose. UiO-66 (Universitetet i Oslo) is one of the most popular metal organic frameworks. The adsorption ability of UiO-66 is very high. UiO-66 and graphene nanoplatelet (GNP)/UiO-66 composites were prepared by hydrothermal method. Then, XRD, FTIR, SEM, surface area and particle size distribution methods were applied for characterization of nanoparticles. The prepared adsorbents were used for CBZ adsorption. Some adsorption parameters were tested. These parameters are amount of adsorbent, volume of adsorbate, pH of solution, contact time of solid and liquid phase and initial CBZ concentration. Pseudo first order kinetic model and pseudo second order kinetic model were applied to contact time data. Non-linear Langmuir isotherm and non-linear Freundlich isotherm were applied to initial CBZ concentration experimental data. Also, these isotherm studies were repeated for different temperatures, 20 degrees C, 25 degrees C, 30 degrees C, 40 degrees C and 50 degrees C. According to Langmuir isotherm, maximum CBZ adsorption capacity of UiO-66 nanoparticles were calculated as 16.69 mg/g, and maximum CBZ adsorption capacity of UiO-66/GNP nanoparticles were found as 51.17 mg/g.
