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Photo-Fenton like degradation of catechol using persulfate activated by UV and ferrous ions: Influencing operational parameters and feasibility studies
, Article Journal of Molecular Liquids ; Volume 249 , 2018 , Pages 463-469 ; 01677322 (ISSN) ; Takdastan, A ; Borghei, S. M ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In the present study, photo-Fenton degradation of catechol from aqueous solution was carried out using UV light and iron ions (Fe2+) as activators of persulfate (PS). Catechol degradation from solution was studied under different experimental variables such as solution pH (2.0–10.0), iron dosages (0.1–0.5 g/L), persulfate loadings (1.0–5.0 mM), initial catechol concentrations (20–100 mg/L) and scavengers (TBA and IPA). The comparative study of catechol removal showed that among the applied approaches, the order of degradation of catechol is as follows: PS/Fe2 +/UV > PS/Fe2 + > UV/PS > PS > UV. Furthermore, higher catechol degradation was observed with increasing iron dosage and PS...
An inhomogeneous theory for the analysis of an all-optical gain-stabilized multichannel erbium-doped fiber amplifier in the presence of ion pairs
, Article Optical Fiber Technology ; Volume 14, Issue 1D , 2008 , Pages 54-62 ; 10685200 (ISSN) ; Keyvaninia, S ; Karvar, M ; Sharif University of Technology
Academic Press Inc
2008
Abstract
In this paper the gain dynamics of an all-optical gain-clamped multichannel erbium-doped fiber amplifier (EDFA) with an inhomogeneous active medium in the presence of ion pairs is modeled. A two-level model for single ions and a three-level model for ion pairs are used to drive the propagation and rate equations of inhomogeneous laser medium. The governing equations are an uncountable system of partial differential equations (PDEs). Using the moment method, the system of PDEs is converted to a finite system of ordinary differential equations (ODEs). The solution of the system of ODEs is used to analyze the gain dynamics of all-optical gain-stabilized multi-wavelength heavy doped EDFA....
Synthesis and study of a new class of red pigments based on perovskite YAlO3 structure
, Article Ceramics International ; Volume 33, Issue 8 , December , 2007 , Pages 1427-1433 ; 02728842 (ISSN) ; Faghihi Sani, M. A ; Mirhabibi, A ; Sharif University of Technology
2007
Abstract
A red pigment has been prepared by substituting chromium ions in aluminum ion sites in YAlO3 perovskite structure. In a first step, effect of various mineralizers on YAlO3 formation has been investigated, which resulted in decrease of formation temperature down to 1400 °C. In the next step, a red pigment corresponding to YAl1-yCryO3 (y = 0.05), has been prepared by heating a mixture containing Y2O3, Al2O3 and Cr2O3 at 1500 °C for 6 h. Later, effect of the doped chromium amount on the pigment redness (a*) has been studied. The highest redness has been obtained when y was 0.04(YAl1-yCryO3). Application of the prepared red pigment in low and high temperature glazes, demonstrated its high...
Electrical properties of nanocontacts on silicon nanoparticles embedded in thin SiO2 synthesized by ultralow energy ion implantation
, Article Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures ; Volume 23, Issue 6 , 2005 , Pages 2821-2824 ; 10711023 (ISSN) ; Shalchian, M ; Coffin, H ; Claverie, A ; Grisolia, J ; Dumas, C ; Atarodi, S. M ; Sharif University of Technology
2005
Abstract
In this paper, we present the room temperature current-voltage characteristics of large (100×100 μ m2) and a nanoscale (100×100 nm2) metal-oxide-semiconductor (MOS) capacitor containing few silicon nanocrystals. The layer of silicon crystals is synthesized within the oxide of this capacitor by ultralow energy ion implantation and annealing. Current fluctuations in the form of discrete current steps and sharp peaks are apparent in the static and dynamic I (V) characteristics of the capacitor. These features have been associated to quantized charging and discharging of the nanoparticles and the resulting Coulomb interaction to the tunneling current. © 2005 American Vacuum Society
Application of the GV-MSA model to the electrolyte solutions containing mixed salts and mixed solvents
, Article Fluid Phase Equilibria ; Volume 231, Issue 1 , 2005 , Pages 67-76 ; 03783812 (ISSN) ; Taghikhani, V ; Ghotbi, C ; Sharif University of Technology
2005
Abstract
In this work the Ghotbi-Vera mean spherical approximation (GV-MSA) model, coupled with two different expressions for the cation-hydrated diameters, was used in predicting the mean ionic activity coefficients (MIAC) of electrolytes for a number of the mixed-solvent and mixed-salt electrolyte solutions at 25 °C. In all cases the cation diameters in solutions changed with concentration of electrolyte while the anion diameters were considered to be constant and equal to the corresponding Pauling diameters. In application of the GV-MSA model to the electrolyte systems, two different expressions were used for concentration dependency of cation-hydrated diameters, i.e., the GV-MSA1 and GV-MSA2...
, M.Sc. Thesis Sharif University of Technology ; Pourjavadi, Ali (Supervisor) ; Zohurian Mehr, Mohammad Jalal (Supervisor)
Abstract
Polyampholyte hydrogels are hydrophilic networks that contain both positively- and negatively-charged functional groups on their structure. Polysulfobetaines are the most important type of polyampholytes, which have been extensively studied. However, these hydrogels exhibited poor gel strength causing limitation of their applications. Consequently, much attention has been focused on the preparation of nanocomposite hydrogels with high gel strength and lower cost using organomodified clays. In this project, Novel polyampholytic superabsorbing nanocomposites based on the zwitterionic sulfobetaine monomer [3-(methacrylamido)propyl)]dimethyl(3-sulfopropyl) ammonium hydroxide (MPDSAH) were...
An Investigation About Using Engineering Polymers, Polycarbonate and Polysulfone, as Membrane in Fuel Cells
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad (Supervisor) ; Musavi, Abbas (Supervisor)
Abstract
In this work, sulfonated polycarbonate (SPC ) membranes with different acid contents have been prepared by conducting sulfonation reaction at room temperature using Chlorosulfonic acid (CSA) as sulfonating agent at different concentration of acid in reacting solution. The SPC membranes were obtained by casting from 10% solution of SPC in chloroform at room temperature. The prepared membranes were characterized using Ion exchange capacity (IEC), and degree of sulfonation (DS), Fourier Transform Infrared (FTIR), NMR spectra, Thermal Gravimetric Analysis (TGA) and Water uptake. The obtained results showed that with increaseing in Chlorosulfonic acid content in sulfonation reaction IEC and DS of...
Uranium Recovery From Liquid Waste of UCF Plant With Ion Exchange Resin Method in Continuous Mode
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Sepehrian, Hamid (Supervisor) ; Ghasemi, Mohammad Reza (Co-Advisor)
Abstract
During various stages of processing uranium in Uranium conversion facility (UCF) in Isfahan, significant amounts of liquid waste is produced which leads to evaporation ponds. Since the concentration of uranium in evaporation ponds is relatively high, it seems to addition to environmental issues with recycled uranium from existing pools is also economically. Various physical and chemical methods for removal of uranium waste is used such as solvent extraction, ion exchange, chemical precipitation, membrane processes, etc. Each method has advantages and disadvantages. The ion exchange method, The due to lower cost, less acid pollution with organic copmpounds, convenience and high selectivity...
Experimental Investigation of Henna powder as an Additive to Drilling Fluid
, M.Sc. Thesis Sharif University of Technology ; Masihi, Mohsen (Supervisor) ; Shadizadeh, Reza (Supervisor)
Abstract
A critical property in designing drilling fluids is the concerns for environmental damages and cost efficiency of mud additives used to complete a well safely and economically. Designing drilling fluids for harsh environments such as high temperature, high salinity formation water, lime and cement contamination demands proper selection of deflocculant (thinner) materials to achieve a successful drilling operation. This study presents a novel thinner material that satisfies the goal of an environmentally and economically acceptable mud in drilling lime contamination areas where drilling carbonate formations with high concentration of calcium ions tends to flocculate clay particles in...
Hydrothermal synthesis and characterization of titanium dioxide nanotubes as novel lithium adsorbents
, Article Materials Research Bulletin ; Vol. 61, issue , January , 2014 , p. 70-75 ; Hajipour, H ; Askari, M ; Nusheh, M ; Sharif University of Technology
Abstract
The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. To achieve this goal, it is vital to use an effective adsorbent with maximum lithium adsorption potential together with a stable structure during extraction and insertion of the ions. In this study, titanium dioxide and then lithium titanate spinel with nanotube morphology was synthesized via a simple two-step hydrothermal process. The produced Li4Ti5O12 spinel ternary oxide nanotube with about 70 nm diameter was then treated with dilute acidic solution in order to prepare an adsorbent suitable for lithium adsorption from local brine. Morphological and...
Theoretical investigation on the structure and properties of alumazine⋯m complexes (M = Li+, Na+, K+, Be2+, Mg2+, and Ca2+)
, Article Journal of Theoretical and Computational Chemistry ; Volume 12, Issue 5 , August , 2013 ; 02196336 (ISSN) ; Sharif University of Technology
2013
Abstract
The nature of alumazine⋯M (M = Li+, Na+, K+, Be2+, Mg2+, AND Ca2+) interactions was studied by ab initio calculations. The interaction energies were calculated at MP2/6-311++G(d,p)//B3LYP/6-311++G(d,p) level. The calculations suggest that the size and charge of cation are two important factors that affect the interaction energy, charge transfer values and the variation in aromaticity of alumazine ring upon complexation. The theory of atoms in molecules (AIM) and natural bond orbital (NBO) analyses of complexes indicate that the variation of densities and the extent of charge shifts upon complexation correlate well with the obtained interaction energies. Finally, nucleus independent chemical...
Influence of metal complexation on acidity of cytosine nucleosides: Part I, Li +, Na + and K + cation
, Article Scientia Iranica ; Volume 19, Issue 3 , June , 2012 , Pages 535-545 ; 10263098 (ISSN) ; Fattahi, A ; Pourjavadi, A ; Sharif University of Technology
2012
Abstract
Gas-phase acidities of nucleosides, combined with the knowledge of deprotonation sites, could improve our understanding of chemical reactions to biological systems. In this paper, we mainly focus our attention on the influence of cation coordination on acidities of multiple sites in cytosine nucleosides. The acidities of multiple sites in M +-L (where L represents cytosine nucleosides and M + is an alkali metal ion, including Li +, Na + and K +) complexes have been investigated theoretically, employing B3LY P6-311++G(d,p) basis sets. The geometrical characters, gas-phase acidities, sugar puckering and electronic properties of non-deprotonated and/or deprotonated complexes have been...
Adsorption behavior of toxic metal Ions on nano-structured CuO granules
, Article Separation Science and Technology (Philadelphia) ; Volume 47, Issue 7 , 2012 , Pages 1063-1069 ; 01496395 (ISSN) ; Sadjadi, S ; Hosseinpour, M ; Sharif University of Technology
2012
Abstract
In this study, copper oxide nano particles were synthesized by batchwise supercritical hydrothermal method. After preparation of CuO nano particles, they were immobilized into the porous matrix of sodium alginate. The drying process formed a very porous structure that is useful for enhancing of adsorption activity. Produced CuO particles were characterized by X-ray diffractometery (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and BET for measuring the surface area. The prepared materials were then used as adsorbent in the removal of toxic metal ions in aqueous solution. To optimize the adsorption system, the effect of various parameters such as adsorbent...
Theoretical study of borazine: cation-π (Be 2+, Mg 2+, and Ca 2+) interaction
, Article Structural Chemistry ; 2012 , Pages 1-7 ; 10400400 (ISSN) ; Sharif University of Technology
2012
Abstract
The geometries of the complexes of Be 2+, Mg 2+, and Ca 2+ metal cations with borazine ring were studied. The complexes were optimized at the B3LYP level and the 6-311++G(d,p) basis set. Then, the interaction energies corrected by basis set super position error were calculated in the same level. The results show that interaction energy is strongly dependent on the charge-to-size ratio of the cation. Therefore, Be 2+ cation has the most interaction energy value with respect to Mg 2+ and Ca 2+ metal cations. Natural bond orbital analysis was performed to calculate the charge transfer and natural population analysis of the complexes. Quantum theory of atoms in molecules was also applied to...
DFT study on conformational behavior of hydrogen ion abstractions of cytosine nucleosides: AIM and NBO analysis
, Article Journal of Theoretical and Computational Chemistry ; Volume 10, Issue 6 , 2011 , Pages 803-817 ; 02196336 (ISSN) ; Fattahi, A ; Javan, M. J ; Hashemi, M. M ; Sharif University of Technology
Abstract
In this paper, we explore theoretically energetic and structural properties of the possible cations formed via hydride ion abstraction at various sites of sugar part of cytosine nucleosides by employing B3LYP exchange-correlation functional with 6-311++G (d,p) orbital basis sets. In general, the hydride ion abstracted sugar cations of cytosine nucleosides have the following stability sequence: caH2′ > caH1′ > caH3′ > caH4′ > caH5′ for cytidine and caH1′ > caH4′ > caH3′ > caH5′ > caH2′ for deoxycytidine. Furthermore, the effect of solvent environment on the stability order of cations integral equation formalism of the polarized model (IEF-PCM) was employed to model aqueous solution. The...
Hydrothermal synthesis and characterization of titanium dioxide nanotubes as novel lithium adsorbents
, Article Materials Research Bulletin ; Volume 61 , 2015 , Pages 70-75 ; 00255408 (ISSN) ; Hajipour, H ; Askari, M ; Nusheh, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. To achieve this goal, it is vital to use an effective adsorbent with maximum lithium adsorption potential together with a stable structure during extraction and insertion of the ions. In this study, titanium dioxide and then lithium titanate spinel with nanotube morphology was synthesized via a simple two-step hydrothermal process. The produced Li4Ti5O12 spinel ternary oxide nanotube with about 70 nm diameter was then treated with dilute acidic solution in order to prepare an adsorbent suitable for lithium adsorption from local brine. Morphological and...
Explicit analytic solution for the nonlinear ion sound waves equation
, Article Applied Mathematical Sciences ; Volume 4, Issue 21-24 , 2010 , Pages 1183-1195 ; 1312885X (ISSN) ; Sharifi, A ; Jafari, A. J ; Oskoui, R. N ; Sharif University of Technology
2010
Abstract
In this article, we use an efficient analytical method called homotopy analysis method (HAM) to derive an approximate solution of nonlinear ion sound waves equation. Actually, we solved Korteweg-de Vries equation arises in a one-dimensional macroscopic plasma model describing the weakly nonlinear evolution of ion sound speed by the HAM. Unlike the perturbation method, the HAM does not require the addition of a small physically parameter to the differential equation. It is applica-ble to strongly and weakly nonlinear problems. Moreover, the HAM involves an auxiliary parameter, which renders the convergence param-eter of series solutions controllable, and increases the convergence, and...
Adsorptive behavior of an amberlite anion exchanger resin for uranium (VI) sorption in the presence of sulfate anions
, Article International Journal of Engineering, Transactions B: Applications ; Volume 29, Issue 2 , 2016 , Pages 170-175 ; 1728144X (ISSN) ; Sepehrian, H ; Fasihi, J ; Arabieh, M ; Mahani, M ; Sharif University of Technology
Materials and Energy Research Center
Abstract
Uranium (VI) sorption using an anionic exchanger resin, namely Amberlite IRA910, in the presence of sulfate anions was the subject of current study. Batch sorption experiments were carried out to evaluate the influence of operational parameters such as pH, contact time, initial concentration and existence of various anions (including phosphate, sulfate, chloride, fluoride, and nitrate) in the solution on Amberlite IRA910 sorption behavior. Experiments revealed that uranium adsorption was fulfiled at pH>3 and 50 min to amount of 80%. Kinetics study revealed that the pseudo-second-order model showed better curve-fitting regression of the experimental data than the pseudo-first-order one....
Theoretical aspects of the enhancement of metal binding affinity by intramolecular hydrogen bonding and modulating p: K a values
, Article New Journal of Chemistry ; Volume 41, Issue 24 , 2017 , Pages 15110-15119 ; 11440546 (ISSN) ; Fattahi, A ; Sharif University of Technology
Royal Society of Chemistry
2017
Abstract
Polyols were used as model ligands for Mg2+, Ca2+, and Zn2+ complexes to study the role of the hydrogen bond network on the metal binding affinity and modulation of successive pKa values using density functional theory. The results confirm that the acidity of polyols dramatically increases upon metal complexation in the order Zn2+ > Mg2+ > Ca2+. For example, the three H-site positions in the hydroxyl groups of the heptaol, bound to Zn2+, are 11.2, 29.9, and 30.9 pKa units (in methanol) more acidic than those of pure heptaol. This acidity enhancement leads to making polyols as good ligands toward complexation. For instance, the formation constants of the heptaol in the presence of Zn2+, Mg2+,...
The synergistic effect of dimethyl sulfoxide vapor treatment and C60 electron transporting layer towards enhancing current collection in mixed-ion inverted perovskite solar cells
, Article Journal of Power Sources ; Volume 405 , 2018 , Pages 70-79 ; 03787753 (ISSN) ; Aitola, K ; Sveinbjörnsson, K ; Yang, W ; Svanström, S ; Cappel, U. B ; Rensmo, H ; Johansson, E. M. J ; Taghavinia, N ; Boschloo, G ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Inverted perovskite solar cells (PSCs) have been introduced as better candidate for roll-to-roll printing and scale-up than their conventional configuration counterparts, while their fabrication is technically more demanding. The common light absorbing layer in inverted PSCs is the single cation methylammonium lead iodide (MAPbI3) perovskite, whereas mixed-ion perovskites are chemically more stable. In mixed-ion perovskites, where FA (formamidinium) is the main replacement for MA, the electron affinity is larger than in MAPbI3 perovskites, leading to possible barriers against photoelectron collection by the electron transporting layer (ETL). In this paper we report on a mixed-ion...