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Drug loading onto ion-exchange microspheres: Modeling study and experimental verification
, Article Biomaterials ; Volume 27, Issue 19 , 2006 , Pages 3652-3662 ; 01429612 (ISSN) ; Wu, X. Y ; Sharif University of Technology
2006
Abstract
A new mathematical model was developed and an exact analytical solution without approximations of previous work was derived for the description of the kinetics and equilibrium characteristics of drug loading from a finite external solution onto ion-exchange microspheres. The influence of important parameters pertinent to material properties and loading conditions on the kinetics, efficiency, and equilibrium of drug loading was analyzed using the developed model and equations. The numerical results showed that the rate of drug loading increased with increasing initial drug concentration in the solution or with the relative volume of the external solution and the microsphere. The maximum...
Investigation of the Optimum Conditions for the Regeneration of Anion and Cation Exchange Resins of the TR System of Bushehr Nuclear Power Plant
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Seyed Kalal, Hossein (Supervisor) ; Habibian, Alireza (Co-Supervisor)
Abstract
The main purpose of this research is to select a suitable solution for regeneration of ion exchange resins of TR system of Bushehr nuclear power plant and also to compare and evaluate the possibility of using industrial cationic resin (Amberlite IR120) instead of nuclear grade cationic resin (Amberlite IRN97).First, different solutions for regeneration of cationic resins were investigated. For this purpose, three strong acids including hydrochloric acid (HCl), sulfuric acid (H2SO4) and nitric acid (HNO3) were selected and each of these acids was tested in two different concentrations and two different linear velocities; Also, to evaluate the appropriate solution for anionic resin...
Atomistic insight into the behavior of ions at an oil-bearing hydrated calcite surface: implication to ion-engineered waterflooding
, Article Energy and Fuels ; Volume 35, Issue 16 , 2021 , Pages 13039-13054 ; 08870624 (ISSN) ; Koleini, M. M ; Greenwell, H. C ; Ayatollahi, S ; Ghazanfari, M. H ; Sharif University of Technology
American Chemical Society
2021
Abstract
This research provides an atomistic picture of the role of ions in modulating the microstructural features of an oil-contaminated calcite surface. This is of crucial importance for the rational design of ion-engineered waterflooding, a promising technique for enhancing oil recovery from carbonate reservoirs. Inspired by a conventional lab-scale procedure, an integrated series of molecular dynamics (MD) simulations were carried out to resolve the relative contribution of the major ionic constituent of natural brines (i.e., Na+, Cl-, Mg2+, Ca2+, and SO42-) when soaking an oil-bearing calcite surface in different electrolyte solutions of same salinity, namely, CaCl2, MgCl2, Na2SO4, MgSO4, and...
A novel low-temperature growth of uniform CuInS2 thin films and their application in selenization/sulfurization-free CuInS2 solar cells
, Article Materials Today Communications ; Volume 26 , 2021 ; 23524928 (ISSN) ; Parvazian, E ; Alamgir Tehrani, N ; Taghavinia, N ; Samadpour, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In terms of manufacturability, there is a high tendency to deposit light-absorbing CuInS2 films by solution processing methods like ink-based depositions. In particular, for nanoparticle inks, the synthesis of highly dispersed and stable inks, with uniformity in the deposition process, is a serious challenge. Here, we demonstrate a novel two-step low-temperature CuInS2 film deposition method in which the In2S3 is deposited first. It then partially is converted into CuInS2 through the infiltration of Cu+ ions in the In2S3 layer in a dip-coating process. The resulting films are highly uniform, with diffraction peaks indicating the formation of pure CuInS2 phase. The proper stoichiometry of...
Spinel H4Ti5O12 nanotubes for Li recovery from aqueous solutions: Thermodynamics and kinetics study
, Article Journal of Environmental Chemical Engineering ; Volume 9, Issue 1 , 2021 ; 22133437 (ISSN) ; Ghasemi, S ; Askari, M ; Khosravi, A ; Hasan Zadeh, A ; Alamolhoda, A. A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In this study, H4Ti5O12 nanotubes have been prepared as Li+ adsorbent by acid treatment of Li4Ti5O12 nanotubes. Li4Ti5O12 nanotubes were synthesized via a hydrothermal method in which TiO2(B) nanNotubes were used as a precursor. The prepared Li-ion sieve showed a significant high ion-exchange capacity (160.6 mgg−1) for lithium ions due to its large specific surface area of 115.4 m2 g-1 compared to the other related studies. The kinetics and isotherm investigation revealed that the pseudo-second-order equation well described the adsorption kinetics, and the Langmuir model well fitted the isotherm data. Furthermore, the low value of adsorption energy obtained from the Dubinin-Radushkevitch...
A simple 2-step purification process of α-amylase from bacillus subtilis: optimization by response surface methodology
, Article International Journal of Biological Macromolecules ; Volume 192 , 2021 , Pages 64-71 ; 01418130 (ISSN) ; Naderi-Manesh, H ; Roostaazad, R ; Yeganeh, S ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Purification of extracellular α-amylase from Bacillus subtilis was carried out via fractional precipitation by acetone and ion exchange chromatography. These steps provide fast precipitation as well as purification of α-amylase to improve enzyme purity, activity and stability. Compared with two-phase methods in which the yield was less than 1, this method resulted in a yield of more than 3. Moreover, 95% of acetone was recovered that enhanced the economy of the downstream process. Using the data provided by 2D electrophoresis, purification was done by a single step ion exchange chromatography. The enzyme exhibited a molecular mass (SDS-PAGE) of 50KD and the pI of 5. Maximum “yield” and...
Optimization of a combined heat and power PEFC by exergy analysis
, Article Journal of Power Sources ; Volume 143, Issue 1-2 , 2005 , Pages 179-184 ; 03787753 (ISSN) ; Ehyaei, M. A ; Abbasi, A ; Sharif University of Technology
2005
Abstract
In this paper, design and exergy method optimization of a 5 kW power output polymer electrolyte fuel cell (PEFC) fuel cell with cogeneration application has been investigated. It is assumed that cooling water is passed through the fuel cell cooling channel, warmed up and supplied for space heating applications. The performance of the proposed system has been optimized by the second law based on exergy analysis. Results show that for maximum system efficiency and minimum entropy generation, fuel cell temperature and voltage should be as high as possible in the range of application. Also, the fuel cell pressure and stoichiometric air:fuel ratio should be as low as possible in the range of...
Modified CMC. 3. Carboxymethylcellulose-g-poly(acrylamidrazone) as a new metal adsorbent
, Article Journal of Polymer Materials ; Volume 21, Issue 3 , 2004 , Pages 315-320 ; 09738622 (ISSN) ; Pourjavadi, A ; Salehi Rad, M ; Sharif University of Technology
2004
Abstract
A new poly(acrylamidrazone) chelating resin was prepared from carboxymethylcellulose (CMC) via a two-step process. First, acrylonitrile was graft polymerized onto the substrate. The CMC-polyacrylonitrile graft copolymer was then treated with hydrazine to yield a triply modified cellulose containing amidrazone functional groups. The resin was characterized using infrared spectroscopy. The sorption capacity of the resin towards bivalent metal ions was evaluated versus variation of pH and hydrochloric acid concentration. The adsorption capacities at pH 6 were found to be in order Cu2+> Zn2+>Cd2+>Co2+>Ni2+. The metal ion sorption capacities were varied in the range of 2.0-20.0 mmol metal per...
Modified CMC. 2. Novel carboxymethylcellulose-based poly(amidoxime) chelating resin with high metal sorption capacity
, Article Reactive and Functional Polymers ; Volume 61, Issue 1 , 2004 , Pages 23-31 ; 13815148 (ISSN) ; Pourjavadi, A ; Salehi Rad, M ; Sharif University of Technology
2004
Abstract
Carboxymethylcellulose sodium salt (CMC) was doubly modified to prepare a novel poly(acrylamidoxime) chelating resin. Acrylonitrile was firstly graft polymerized onto CMC using cerium ammonium nitrate as an initiator. The polyacrylonitrile (PAN) grafted CMC was then amidoximized via treatment with hydroxylamine to prepare the ion exchange resin. The sorption capacity of the resin towards bivalent metal ions was evaluated while varying the pH, the loading of the PAN and the initial metal ion concentration. The adsorption kinetics were investigated for the cupric ion. The chelating resin exhibited very high metal sorption capacity in comparison with either synthetic or polysaccharide-based...
The effects of porosity distribution variation in GDL on PEM fuel cell performance
, Article Second International Conference on Fuel Cell Science, Engineering and Technology, Rochester, NY, 14 June 2004 through 16 June 2004 ; 2004 , Pages 587-594 ; 0791841650 (ISBN); 9780791841655 (ISBN) ; Farhanieh, B ; Saievar Iranizad, E ; Sharif University of Technology
American Society of Mechanical Engineers
2004
Abstract
Gas diffusion layers are one of the important parts of the PEM fuel cell as they serve to transport the reactant gases to the catalyst layer. Porosity of this layer has a large effect on the PEM fuel cell performance. The spatial variation in porosity arises due to two effects: 1. Compression of the electrode on the solid landing areas and 2. Water produced at the cathode side of gas diffusion layers. Both of these factors change the porosity of gas diffusion layers and affects fuel cell performance. To implement this performance analysis, a mathematical model which considers oxygen and hydrogen mass fraction in gas diffusion layer and the electrical current density in the catalyst layer,...
Lithium Adsorption on TiO2 Ion-sieve from Magnesium Treated Brine Sources
, M.Sc. Thesis Sharif University of Technology ; Asgari, Masoud (Supervisor)
Abstract
Brines are one of the main resources for lithium extraction and Iran has got many high magnesium and low lithium brine resources. In order to extract lithium, it is required to carefully identify these resources and their associated compounds and then an appropriate method can be adopted to extract lithium. Among the Previous researches, Bahadori, Jandaghi and Moazeni developed methods for removal of undesirable brines elements, Deposition of lithium from refined brine and lithium adsorption anatase ion-sieves membrane respectively; in this study it has been tried to investigate the optimization of the adsorption process, onto the TiO2-B ion sieve with nanotube morphology. TiO2-B nanotubes...
Optical slab waveguides based on ion exchange method: Fabrication, test, characterization and mathematical profiling
, Article Iranian Journal of Science and Technology, Transaction B: Technology ; Volume 24, Issue 1 , 2000 , Pages 122-123 ; 03601307 (ISSN) ; Sheikhi, M. H ; Sharif University of Technology
2000
Abstract
In this paper the fabrication, testing and results of inverse profiling of optical slab waveguides in glass are reported. This is the first successful report of fabricating ion exchange optical waveguides in Iran. © Shiraz University
Synthesis and Evaluation of Modified Zeolites for Separation of Acidic Gases
, M.Sc. Thesis Sharif University of Technology ; Khorasheh, Farhad (Supervisor) ; Soltanali, Saeed (Supervisor) ; Ghasabzadeh, Hamid (Co-Supervisor)
Abstract
The adsorption equilibria of carbon dioxide, methane, and nitrogen on pelletized cation-exchanged faujasite zeolite (with alkali, alkaline earth, and transition metal ions) have been investigated by a volumetric apparatus. The standard instrumental analytical techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray spectroscopy (EDX), and atomic absorption spectroscopy (AAS) were utilized to characterize binder-free modified zeolites. The EDX spectra and AAS results revealed that the ion-exchange was successfully achieved with expected tendencies. The results indicate that the type of cation present in the zeolite...
Study on Immobilization of the Spent Ion Exchange Resins of Tehran Research Reactor in Borosilicate Glass
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Yadollahi, Ali (Supervisor) ; Sepehrian, Hamid (Co-Supervisor)
Abstract
Considering the operation of the current nuclear reactors and the country's policy to achieve 10,000 megawatts of nuclear power in the horizon of 1420, as well as the construction of research reactors, we will face a huge amount of radioactive waste in the coming years. Meanwhile, spent ion exchange resins constitute a large amount of low and intermediate level (LILW) solid radioactive waste produced from the nuclear industry. Therefore, appropriate precautionary measures should be taken for the immobilization and disposal of these radioactive wastes in order to ensure the sustainable development of the nuclear industry and the protection of the environment and human health. In this study,...
Investigation on various types of ion-exchange membranes in vanadium redox flow batteries: Experiment and modeling
, Article Journal of Energy Storage ; Volume 54 , 2022 ; 2352152X (ISSN) ; Rahimi, M ; Molaei Dehkordi, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Choosing the appropriate ion exchange membrane in vanadium redox flow batteries plays an important role in achieving optimal system performance. In this article, the implementation of commercial cation exchange membranes (Nafion 115, Nafion 117, and Nafion 212), anion exchange membranes (FAP 450 and QA-PFE), and the combination of them are investigated. In this regard, the effects of membrane type, thickness, electrical conductivity, and the transfer of vanadium species at different current densities are examined carefully. In addition, the influences of the flow rate and the concentration of electrolytes are investigated using a comprehensive developed model. The model predictions are...
Oppositely charged MXene fibers as a highly efficient osmotic power generator from sea and river water
, Article Journal of Materials Chemistry A ; Volume 10, Issue 46 , 2022 , Pages 24915-24926 ; 20507488 (ISSN) ; Esfandiar, A ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
Ion-exchange membrane-based reverse electrodialysis (RED) shows great potential for harvesting osmotic energy from seawater and converting it to electricity. However, their low energy conversion efficiency and huge ionic resistance hinder their application on large scales. The implementation of nanofluidic channels in RED devices can significantly improve the performance of osmotic power generators due to their selective and fast ion transport. However, technical challenges in scalable processing at the nanoscale and ion-selective membranes restrict their development in economically viable generators. Here, we report fibrous-based channels as positively and negatively charged MXene fibers...
Ruthenium/Ruthenium oxide hybrid nanoparticles anchored on hollow spherical Copper-Cobalt Nitride/Nitrogen doped carbon nanostructures to promote alkaline water splitting: Boosting catalytic performance via synergy between morphology engineering, electron transfer tuning and electronic behavior modulation
, Article Journal of Colloid and Interface Science ; Volume 626 , 2022 , Pages 1070-1084 ; 00219797 (ISSN) ; Shahrokhian, S ; Sharif University of Technology
Academic Press Inc
2022
Abstract
Exploring bi-functional electrocatalysts with excellent activity, good durability, and cost-effectiveness for electrochemical hydrogen and oxygen evolution reactions (HER and OER) in the same electrolyte is a critical step towards a sustainable hydrogen economy. Three main features such as high density of active sites, improved charge transfer, and optimized electronic configuration have positive effects on the electrocatalyst activity. In this context, understanding structure–composition–property relationships and catalyst activity is very important and highly desirable. Herein, for the first time, we present the design and fabrication of novel MOF-derived ultra-small Ru/RuO2 nanoparticles...
Electrodialysis of Llithium from Spent Lithium-Ion Battries
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
In this study, Lithium recovery process from lithium-ion battery was investigated by electrodialysis method. First, the cathode of the battery was leached in NMP to separate cathode from aluminum foil. Then, the cathode was leached in sulfuric acid with concentration 3.25 M and 10 volume percent hydrogen peroxide that pulp density was 55 g/L at 60°C for 100 minutes. in the next step, an electrodialysis cell was designed and created to recover lithium. And the influence of time, voltage, flow rate of feed solution, concentration of electrode solution and concentration of feed solution on process was investigated. Purpose of this project were investigated lithium ion recovery rate, lithium...
CO2 storage in carbonate rocks: An experimental and geochemical modeling study
, Article Journal of Geochemical Exploration ; Volume 234 , 2022 ; 03756742 (ISSN) ; Zhao, Y ; An, Z ; Shabani, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Carbon dioxide storage in geological formations is one of the mature strategies developed for controlling global warming. This paper represents a comprehensive experimental and geochemical modeling study to analyze CO2-brine-rock interactions in a carbonate rock containing calcite and dolomite minerals. PHREEQC geochemical package has been applied for modeling the geochemical reactions in the studied porous media. Firstly, dynamic experiments are performed to calibrate the geochemical model. Then, static experiments are conducted to study the geochemical reactions in the CO2-brine-rock interaction system. This study contributes to analyzing the precipitation-dissolution and ion exchange...