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Öğe Magnetite nanoparticles grafted with murexide-terminated polyamidoamine dendrimers for removal of lead (II) from aqueous solution: synthesis, characterization, adsorption and antimicrobial activity studies(Journals & Books, 2021-03) Ekinci, Selma; İlter, Zülfiye; Ercan, Selami; Çınar, Ercan; Çakmak, ReşitIn this study, new, efficient, eco-friendly and magnetically separable nanoadsorbents, MNPs-G1-Mu and MNPs-G2-Mu, were successfully prepared by covalently grafting murexide-terminated polyamidoamine dendrimers on 3-aminopropyl functionalized silica-coated magnetite nanoparticles, and used for rapid removal of lead (II) from aqueous medium. After each adsorption process, the supernatant was successfully acquired from reaction mixture by the magnetic separation, and then analyzed by employing ICP-OES. Chemical and physical characterizations of new nanomaterials were confirmed by XRD, FT-IR, SEM, TEM, and VSM. Maximum adsorption capacities (qm) of both prepared new nanostructured adsorbents were compared with each other and also with some other adsorbents. The kinetic data were appraised by using pseudo-first-order and pseudo-second-order kinetic models. Adsorption isotherms were found to be suitable with both Langmuir and Freundlich isotherm linear equations. The maximum adsorption capacities for MNPs-G1-Mu and MNPs-G2-Mu were calculated as 208.33 mg g−1 and 232.56 mg g−1, respectively. Antimicrobial activities of nanoparticles were also examined against various microorganisms by using microdilution method. It was determined that MNPs-G1-Mu, MNPs-G2-Mu and lead (II) adsorbed MNPs-G2-Mu showed good antimicrobial activity against S. aureus ATTC 29213 and C. Parapsilosis ATTC 22019. MNPs-G1-Mu also showed antimicrobial activity against C. albicans ATTC 10231.Öğe The investigation of kinetic and thermodynamic properties of the adsorption of trypan blue dyestuff by chitosan and chitosan phthalate(International Journal of Scientific and Technological Research, 2019-01) Ekinci, Selma; Güzel, FuatIn this article, toxic Trypan Blue dyestuff was uptaken from water by adsorption method. Chitosan and synthesized chitosan phthalate were used as adsorbents. Adsorption processes were consisted of kinetic and thermodynamic studies. First kinetical experiments were made and the results were practiced to Lagergren, Weber- Morris and Ho- Mckay equations. Adsorption rate constants (kads) and pore diffusion rate constants (kp) were calculated. Then, thermodynamic experiments were performed at different temperatures. Some thermodynamic parameters (ΔH, ΔG and ΔS) and adsorption isotherms were determined. Because Langmuir adsorption isotherms were more suitable, Langmuir constants were calculated. These experiments were performed with both chitosan and chitosan phthalate and the results were evaluated.Öğe Adsorption of toxic indigo carmen dyestuff from aqueous solution by chitosan and chitosan phthalate(Applied Chemical Engineering, 2018-11) Ekinci, Selma; Güzel, FuatToxic indigo carmen dyestuff was removed from the aqueous solution by adsorption. Adsorption was examined kinetically and thermodynamically based on temperature. Derivative of chitosan which is called chitosan phthalate was synthesized and used in removal of indigo carmen from aqueous solution. Some kinetic and thermodynamic parameters were calculated. Adsorption isotherms were drawn. Lastly, the adsorption of indigo carmen from the aqueous solution by chitosan and chitosan phthalate were compared.Öğe Analysis of the effect of experimental adsorption uncertainty on CH 4 production and CO 2 sequestration in Dadas shale gas reservoir by numerical simulations(Elsevier, 2019) Merey, ŞükrüThe importance of unconventional gas reservoirs such as shale gas reservoirs has increased with the decline of conventional gas reservoirs and advancement in horizontal drilling and hydraulic fracturing in the world. Recently, there have been many exploration activities in Dadas shales, Turkey. Previously, the adsorption capacities of CH 4 and CO 2 on Dadas shale samples were measured by using volumetric adsorption experimental set-up. Although adsorption uncertainties of these experiments were calculated, their effects on CH 4 production or CO 2 sequestration in Dadas shales were not evaluated in field scale. In this study, the numerical simulations for CH 4 gas production via 500 m long horizontal well from Dadas shale gas reservoir with different adsorption cases due to experimental adsorption uncertainties were conducted by using TOUGH + RealGasBrine. It was observed that initial CH 4 adsorption capacity of Dadas shales varies from 2.1% to 20.9% because of experimental adsorption uncertainty and absorbed gas volume corrections. Numerical simulations showed initial adsorbed gas % and final adsorbed gas % vary significantly. Similarly, the injection of CO 2 into the depleted Dadas shale gas reservoir was analyzed by numerical simulations at different adsorption cases due to experimental adsorption uncertainty and adsorbed gas volume correction. Final adsorbed CO 2 % varies from 18.1% to 27.5%. Furthermore, there are important differences in the amount of CO 2 injected, final adsorbed CH 4 % and final adsorbed CO 2 % during CO 2 injection simulations. The main reasons of these differences are experimental adsorption uncertainty and adsorbed gas volume correction. This study showed that the volumetric adsorption experimental method is not reliable in low adsorption values as in Dadas shales. It only gives adsorption ranges. The implication of this study is that the effect of experimental adsorption uncertainty obtained with the volumetric adsorption method on CH 4 production or CO 2 sequestration in Dadas shale gas reservoir is significant in field scale.
