52 research outputs found
Ion Exchange
No full textThis book provides broad coverage of ion exchange and its applications. Different chapters focus on the importance of ion exchange applications such as strengtening dental porcelains, gradient changes in glass refraction, and resins as effective sorbents. Each chapter includes a brief historical overview of ion exchange and its applications. The authors also give a brief overview of these applications as well as review current experimental data on the subject
Ion Exchange
No full textThis book provides broad coverage of ion exchange and its applications. Different chapters focus on the importance of ion exchange applications such as strengtening dental porcelains, gradient changes in glass refraction, and resins as effective sorbents. Each chapter includes a brief historical overview of ion exchange and its applications. The authors also give a brief overview of these applications as well as review current experimental data on the subject
The effect of various cations and pH on the adsorption of U(VI) on Amberlite IR-118H resin
No full textThe effects of various metal cations and pH on the adsorption of uranium(VI) on strongly acidic cation exchanger Amberlite IR-118H (AIR-118H) were studied. The metal cations suppress U(VI) adsorption differently depending on their ionic radii. Adsorption of U(VI) on AIR-118H peaks at pH 3.4, which was attributed to the occurrence of different forms of U(VI) at different pH values. The adsorption data were then processed using the Frumkin-Fowler-Guggenheim equation, and the standard free energy of adsorption was calculated. (C) 2003 Elsevier Science Ltd. All rights reserved
Adsorption of uranium from aqueous solution on heat and acid treated sepiolites
No full textIn this work adsorption of uranium on natural, heat and acid treated sepiolite was studied. For acid treatment HCl and H(2)SO(4) were used separately. Heat and acid treatment caused some, changes in sepiolite such as surface area, micropore volume (cm(3)/g) and average pore diameter (A). Different amounts of Mg ions were extracted from the lattice depending on the type of acid. After acid treatment with MCl, the amount of Mg left in the sepiolite changed a little. During H(2)SO(4) treatment the sepiolite structure was progressively transformed into amorphous silica. These heat and acid treatments changed adsorption capacity and mechanism of uranium on sepiolite. Data obtained from the adsorption experiments were applied to Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. Using these isotherms different adsorption capacities were found for natural and treated sepiolite samples. The capacity values were 3.58 x 10(-3), 3.14 x 10(-3), 2.78 x 10(-3) and 1.55 x 10(-3) mol/g for HCl treated, heat treated, natural and H(2)SO(4) treated sepiolite samples, respectively. In order to evaluate the adsorption mechanism adsorption energies were calculated by the D-R isotherm. According to the adsorption energy values uranium fixed to the natural and heat treated sepiolite surface with ion exchange (12.75 and 12.12 kJ/mol, respectively). Simple physical attractions were the driving force for adsorption on HCl and H(2)SO(4) treated ones (6.62 and 6.87 kJ/mol, respectively). (C) 2010 Elsevier Ltd. All rights reserved
THE ADSORPTION BEHAVIOR OF NATURAL SAND IN CONTACT WITH URANIUM CONTAMINATED SEAWATER
No full textThis study was undertaken to investigate the interaction between uranium contaminated seawater and the sand in contact with this seawater. Adsorption data have been evaluated from column experiments of seawater from Marmara, Black Sea and Mediterranean contaminated with 10(-7) M uranium. The uranium uptake on the fractionated and non-fractionated sand of these sea have been measured as a function of time. The adsorption proceeds via a rather fast stage followed by a slower one. Results could be correlated with particle size and porosity of the sand. Adsorption isotherms are also derived from amount of adsorbed uranium vs. time plots and the results have been analyzed by the Langmuir, Freundlich and Dubinin-Radushckevich (D-R) isotherm equations over the entire range of uranium concentrations. By fitting the data to D-R isotherm, we have calculated the adsorption energy and decided to type of the adsorption
Design, characterization and evaluation of the drug-loaded chitosan/cerium oxide nanoparticles with pH-controlled drug release
No full textIn recent years, polymer/metal oxide nanoparticles as a high-performance nanomaterials have gained great attention in different industrial areas such as biotechnology, cosmetic, automotive, textile, and concrete. In this study, novel chitosan/cerium oxide nanoparticles (Chi/CeO2 NPs) were synthesized to improve the bioavailability of the drug based on the assembly of inorganic nanoparticles at the polymer-NPs interfaces. The surface morphological property, chemical structure and drug release profile of synthesized NPs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrophotometer (FTIR) X-ray diffractometer (XRD), and UV-visible technique. The particle size of spherical Chi/CeO2 NPs was found to be < 40 nm with a prepotent surface. Different kinetic model parameters such as zero-order, first-order, Higuchi, Bhaskar, and Ritger-Peppas models were calculated to investigate the drug release mechanism. The amount of Methotrexate (MTX) release from the surface of CeO2 NPs and the interface of Chi/CeO2 NPs were found to be 12.4% and 66.26%, respectively. According to experimental results, we observed that interfaces between Chi/CeO2 NPs and MTX in a structure could have a profound effect on the percentage of MTX drug release. We showed that the synthesized inorganic NPs could be proposed potentially as an effective inorganic nanocarrier with controlled MTX release
Design, characterization and evaluation of the drug-loaded chitosan/cerium oxide nanoparticles with pH-controlled drug release
No full textIn recent years, polymer/metal oxide nanoparticles as a high-performance nanomaterials have gained great attention in different industrial areas such as biotechnology, cosmetic, automotive, textile, and concrete. In this study, novel chitosan/cerium oxide nanoparticles (Chi/CeO2 NPs) were synthesized to improve the bioavailability of the drug based on the assembly of inorganic nanoparticles at the polymer-NPs interfaces. The surface morphological property, chemical structure and drug release profile of synthesized NPs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrophotometer (FTIR) X-ray diffractometer (XRD), and UV-visible technique. The particle size of spherical Chi/CeO2 NPs was found to be < 40 nm with a prepotent surface. Different kinetic model parameters such as zero-order, first-order, Higuchi, Bhaskar, and Ritger-Peppas models were calculated to investigate the drug release mechanism. The amount of Methotrexate (MTX) release from the surface of CeO2 NPs and the interface of Chi/CeO2 NPs were found to be 12.4% and 66.26%, respectively. According to experimental results, we observed that interfaces between Chi/CeO2 NPs and MTX in a structure could have a profound effect on the percentage of MTX drug release. We showed that the synthesized inorganic NPs could be proposed potentially as an effective inorganic nanocarrier with controlled MTX release.Scientific Research Projects Coordination Unit of Istanbul University [32437]This work was supported by Scientific Research Projects Coordination Unit of Istanbul University- Cerrahpasa. Project number: 3243
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