Loading...
Search for:
metal-ions
0.008 seconds
Total 150 records
Effect of Gd and Co contents on the microstructural, magneto-optical and electrical characteristics of cobalt ferrite (CoFe2O4) nanoparticles
, Article Ceramics International ; Volume 48, Issue 2 , 2022 , Pages 2782-2792 ; 02728842 (ISSN) ; Yousaf, M ; Akhtar, M. N ; Noor, A ; Akbar, M ; Shah, M. A. K. Y ; Yan, S ; Wang, F ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Rare earth oxides with a trivalent nature play a pivotal role in reinforcing the magneto-optical attributes of spinel ferrite nanoparticles by replacing Fe3+ ions. In this study, rare earth Gd oxide doped with CoFe2O4 NPs with a composition of Co1+xGdxFe2-2xO4 (x = 0, 0.05, 0.10, and 0.15) were synthesized using sol-gel auto-combustion. The outcome of Gd cations on the physical, magneto-optical and electrical characteristics of the cobalt ferrite NPs were reported. X-ray diffraction (XRD), and Fourier transform infrared (FTIR) investigations confirmed the single-phase cubic crystalline nature and metal ion stretching in the cobalt ferrite synthesized samples. Decreasing drift in the average...
Ethylenediamine-functionalized Zr-based MOF for efficient removal of heavy metal ions from water
, Article Chemosphere ; Volume 264 , 2021 ; 00456535 (ISSN) ; Tajahmadi, S ; Bahi, A ; Molavi, H ; Rezakazemi, M ; Ko, F ; Aminabhavi, T. M ; Arjmand, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Ethylenediamine-functionalized Zr-based metal-organic framework (MOF, UiO-66-EDA) was prepared via Michael addition reaction to investigate its potential for adsorption of heavy metal ions from water. Specifically, the influence of agitation time, solution pH, the dosage of the adsorbent, initial metal ion concentration, temperature, and coexistence of other metal ions was investigated on the removal efficiency of UiO-66-EDA towards Pb(II), Cd(II), and Cu(II) metal ions. The pseudo-second-order kinetic model governed the adsorption of these ions onto the UiO-66-EDA. Langmuir isotherm model matched the experimental isotherm of adsorption with a maximum adsorption capacity of 243.90, 217.39,...
Design of an Optoelectronic Tongue Based on Anti-Aggregation of Gold Nanoparticles for Detection and Classification of Heavy Metal Ions
, M.Sc. Thesis Sharif University of Technology ; Hormozi-Nezhad, Mohammad Reza (Supervisor)
Abstract
The first report of anti-aggregation-based sensor arrays is presented. The strategy is based on the competitive interaction of citrate-capped gold nanoparticles (AuNPs) and heavy metal ions (i.e., Hg(II), Ag(I), Fe(III), and Pb (II)) with three aggregation reagents (i.e., cysteine, melamine, and arginine). In the presence of aggregation reagent,the color and UV–vis spectra of AuNPs are changed indicating the aggregation ofAuNPs. Addition of the aggregation reagents which are firstly treated with the ions, causes AuNPs turn from the aggregation to the dispersion state. The anti-aggregation capability of ions towards various aggregation reagents is different because of distinct stability...
Developments of Fluorescence Sensor Arrays Using Nanostructured Sensor Elments and Nanocellulose Substrate for Identification and Discrimination of Biomolecules and Environmental pollutants
, Ph.D. Dissertation Sharif University of Technology ; Hormozi-Nezhad, Mohammad Reza (Supervisor) ; Golmohammadi Ghaneh, Hamed (Co-Supervisor)
Abstract
In the first part of this research, a ratiometric fluorescent sensor array has been developed on nanocellulose platform towards chemical discrimination applications. Bacterial nanocellulose (BC) was utilized for the first time as a novel, flexible and transparent substrate in optical sensor arrays for developing portable and high performance sensor array.. To fabricate this platform, the hydrophobic walls on BC nanopaper substrates were successfully created using laser printing technology. In addition, we have used the properties of immobilized ratiometric fluorescence sensor elements (Carbon Dots- Rhodamine B (CDs-RhB) nanohybrids) on nanopaper platform to improve the visual...
Investigation of Amyloid-Beta Inhibition using Multifunctional Peptide Drugs Associated with Metal Ions
, Ph.D. Dissertation Sharif University of Technology ; Shamloo, Amir (Supervisor)
Abstract
Many experimental and theoretical studies have suggested that zinc binding to Aβ could promote amyloid-β aggregation and reactive oxygen species (ROS) production induced by AD disease. Therefore, the introduction of multifunctional drugs capable of chelating zinc metal ion and inhibiting Aβ aggregation is a promising strategy in the development of AD treatment. In present study molecular docking and molecular dynamics (MD) simulations were used to evaluate the efficacy of two new bifunctional peptide drug, composed of two different domains: C-terminal hydrophobic region of Aβ and Zn2+ chelator region. To evaluate the multifunctionality of the ligands, a comprehensive set of MD simulations up...
A sensitive and selective colorimetric method for detection of copper ions based on anti-aggregation of unmodified gold nanoparticles
, Article Talanta ; Vol. 129, issue , 2014 , pp. 227-232 ; ISSN: 00399140 ; Abbasi-Moayed, S ; Sharif University of Technology
Abstract
A highly sensitive and selective colorimetric method for detection of copper ions, based on anti-aggregation of D-penicillamine (D-PC) induced aggregated gold nanoparticles (AuNPs) was developed. Copper ions can hinder the aggregation of AuNPs induced by D-PC, through formation of mixed-valence complex with D-PC that is a selective copper chelator. In the presence of a fixed amount of D-PC, the aggregation of AuNPs decreases with increasing concentrations of Cu2+ along with a color change from blue to red in AuNPs solution and an increase in the absorption ratio (A520/A 650). Under the optimum experimental conditions (pH 7, [AuNPs] =3.0 nmol L-1 and [NaCl]=25 mmol L-1), a linear calibration...
Core-shell γ-Fe2O3/SiO2/PCA/Ag-NPs hybrid nanomaterials as a new candidate for future cancer therapy
, Article International Journal of Nanoscience ; Vol. 13, issue. 1 , February , 2014 ; Pourjavadi, A ; Masoud, N ; Varamesh, A ; Sharif University of Technology
Abstract
In the current study, γ-Fe2O3/SiO 2/PCA/Ag-NPs hybrid nanomaterials were successfully synthesized and characterized. At first, prepared γ-Fe2O3 core nanoparticles were modified by SiO2 layer. Then they were covered by poly citric acid (PCA) via melting esterification method as well. PCA shell acts as an effective linker, and provides vacancies for conveying drugs. Moreover, this shell as an effective capping agent directs synthesis of silver nanoparticles (Ag-NPs) via in situ photo-reduction of silver ions by sunlight-UV irradiation. This system has several benefits as a suitable cancer therapy nanomaterial. Magnetic nanoparticles (MNPs) can guide Ag-NPs and drugs to cancer cells and then...
Separation of rhenium and molybdenum from molybdenite leach liquor by the solvent extraction method
, Article Minerals and Metallurgical Processing ; Volume 30, Issue 1 , February , 2013 , Pages 53-58 ; 07479182 (ISSN) ; Yoozbashizadeh, H ; Mohammadi, M ; Abazarpoor, A ; Maarefvand, M ; Sharif University of Technology
2013
Abstract
Molybdenum resources around the world are mainly associated with porphyry copper ores. Molybdenite (MoS2) is the main Mo mineral that has rhenium in its crystal lattice. This paper investigates the recovery of rhenium and molybdenum from a molybdenite concentrate using a hydrometallurgical treatment method. The molybdenite concentrate is leached with nitric acid and subjected to solvent extraction to recover and separate rhenium and molybdenum from the leached liquor. The effects of pH and the chemicals' concentration on extraction characteristics of Mo and Re are investigated to define the best condition for selective extraction of these metals. The tested leached liquor contained of 8.2...
Adsorption of lead ions in aqueous solution using Yttrium oxide nanoparticles
, Article Journal of Nano Research ; Volume 16 , 2011 , Pages 83-87 ; 16625250 (ISSN) ; Ahmadi, S. J ; Hosseinpour, M ; Sharif University of Technology
2011
Abstract
By a single-step supercritical hydrothermal synthesis method, yttrium oxide nanoparticles were successfully prepared without additional treatment. Yttrium oxide nanoparticles were employed as an adsorbent to study the adsorption of some heavy metal ions. This study revealed that nano structure yttrium oxide was an effective adsorbent for removal of lead ions from aqueous solutions
Recovery of metals from spent refinery hydrocracking catalyst using adapted Aspergillus niger
, Article Hydrometallurgy ; Volume 109, Issue 1-2 , 2011 , Pages 65-71 ; 0304386X (ISSN) ; Yaghmaei, S ; Mousavi, S. M ; Sheibani, S ; Sharif University of Technology
2011
Abstract
This study was designed to compare one-step, two-step and spent medium bioleaching of spent catalyst by adapted Aspergillus niger in batch cultures. Aspergillus niger, which was adapted to heavy metal ions, Ni, Mo, Fe, and W, was grown in medium containing up to 5% (w/v) of spent catalyst. The main lixiviant in bioleaching was gluconic acid, which was produced at all pulp densities in the one-step bioleaching process. Gluconic acid was also produced in the two-step bioleaching process when the spent catalyst was present at pulp densities greater than 1% (w/v). In the spent medium leaching, however, the primary agent was citric acid. The pulp density of the spent catalyst was varied, and this...
Nano-scale modification of polysulfone membrane matrix and the surface for the separation of chromium ions from water
, Article Chemical Engineering Journal ; Volume 267 , May , 2015 , Pages 306-316 ; 13858947 (ISSN) ; Nematollahzadeh, A ; Mousavi, S. A ; Sharif University of Technology
Elsevier
2015
Abstract
In this study, aiming at hexavalent chromium removal from aqueous solutions, different strategies were proposed for developing hydrophilic and surface functional polysulfone (PSf) membrane. In addition to PSf membrane, three different types of membranes were prepared by addition of SiO2 nano-particles to the dope solution and/or by deposition of polydopamine (PDA) layer on the surface of the membranes. The membranes (i.e. PSf, PSf/PDA, PSf/SiO2 and PSf/SiO2/PDA) were characterized by different techniques. The membranes' transport properties and the separation performance were studied using a filtration unit operated at a continuous dead-end flow mode. The kinetics and the separation...
The advantage of spectrophotometric measurement for size-selective complexing of Cu(II) with O2N2-azacrown ligands
, Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 139 , March , 2015 , Pages 286-289 ; 13861425 (ISSN) ; Gholamnezhad, P ; Sharif University of Technology
Elsevier
2015
Abstract
A comparative investigation of the interaction of Cu(II) with a series of 15- to 19-membered mixed-donor dibenzo-substituted macrocyclic ligands, each incorporating an O2N2-donor set, has been carried out using UV-Visible studies in methanol. Although a ring size effect has been reported for a related series of Ni(II) complexes, no such metal ion discrimination has been reported for Cu(II) in terms of its binding constants with 14- to 17-membered macrocycles. Employing Job's method of continuous variation established 1:1 stoichiometry for the interaction between Cu(II) and 1-5. From UV-Visible studies applying the Benesi-Hildebrand equation, the binding constants (K) of Cu(II) with 1-5 were...
Characterization of nanocrystalline CuCo2 O4 spinel prepared by sol–gel technique applicable to the SOFC interconnect coating
,
Article
Applied Physics A: Materials Science and Processing
;
Volume 119, Issue 2
,
May
,
2015
,
Pages 727-734
;
09478396 (ISSN)
; Askari, M
; Ghorbanzadeh, M
;
Sharif University of Technology
Springer Verlag
2015
Abstract
CuCo2 O4 spinel nanopowders were synthesized by sol–gel method. The optimal values of pH and molar ratio of citric acid to metal ions (RC), and the influence of the calcination temperature and time were investigated. As-prepared materials were characterized by XRD, TGA, DSC, FE-SEM and electrical and coefficient of thermal expansion (CTE) measurements. It was found that pH = 4.5 and RC = 1 are the optimum conditions to produce pure CuCo2 O4 nanopowders. The electrical conductivity was increased remarkably from 15.2 to 27.5 S cm−1 with an increase in temperature from 500 to 800 °C. Over the temperature range of 25–800 °C, the CTE of...
An ultrasensitive and selective turn-off fluorescent nanoprobe for the detection of copper ions
, Article Analytical Methods ; Volume 7, Issue 12 , 2015 , Pages 5067-5073 ; 17599660 (ISSN) ; Taghipour, M ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
In this study, a novel approach for sensitive and extremely selective detection of copper ions has been developed based on fluorescence resonance energy transfer (FRET) between AuNPs as an acceptor and fluorescein isothiocyanate (FITC) as a donor. Initially, the fluorescence of the FITC molecule turns-off due to adsorption to the AuNPs surface. However, the fluorescence of the FITC-AuNPs system was switched to turn-on by adding d-Pencillamine (d-PC) to the solution mixtures as FITC molecules are released upon displacement by d-PC on the NPs surface. The higher affinity of d-PC toward the surface of AuNPs was further evidenced by controlling the fluorescence intensity enhancement of the...
Copper immobilized onto a triazole functionalized magnetic nanoparticle: A robust magnetically recoverable catalyst for "click" reactions
, Article RSC Advances ; Volume 5, Issue 5 , 2015 , Pages 3894-3902 ; 20462069 (ISSN) ; Ayati, S. E ; Sharif University of Technology
Abstract
A novel magnetic heterogeneous copper catalyst was synthesized by immobilization of copper ions onto triazole functionalized Fe3O4. The catalyst was fully characterized by FT-IR, TGA, CHN, SEM, TEM, EDX and atomic adsorption spectroscopy. The resulting catalyst was used in the synthesis of 1,2,3-triazoles via a one-pot three component reaction of alkynes, alkyl halides, sodium azides under green conditions. The catalyst was reused ten times and no significant loss of activity was observed
An Fe3O4@SiO2@polypyrrole magnetic nanocomposite for the extraction and preconcentration of Cd(ii) and Ni(ii)
, Article Analytical Methods ; Volume 7, Issue 1 , Nov , 2015 , Pages 313-320 ; 17599660 (ISSN) ; Hosseinzadeh Khanmiri, R ; Ghorbani Kalhor, E ; Hassanpour, A ; Asgharinezhad, A. A ; Shekari, N ; Fathi, A ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
This work describes a novel Fe3O4@SiO2@polypyrrole magnetic nanocomposite and its application in the preconcentration of Cd(ii) and Ni(ii) ions. The parameters affecting the preconcentration procedure were optimised by a Box-Behnken design using response surface methodology. Three variables (extraction time, magnetic sorbent amount, and pH) were selected as the main factors affecting the sorption step, while four variables (type, volume and concentration of the eluent, and elution time) were selected as the main factors in the optimisation study of the elution step. Following the sorption and elution of analytes, the ions were quantified by FAAS. The limits of detection were 0.3 and 1.2 ng...
Comparison of different methods in bioleaching of tungsten- rich spent hydro-cracking catalyst using adapted Penecillum simplicissimum BBRC-20019
, Article Chemical Engineering Transactions ; Volume 21 , 2010 , Pages 1483-1488 ; 19749791 (ISSN) ; 9788895608051 (ISBN) ; Yaghmaei, S ; Mousavi, S. M ; Sharif University of Technology
Italian Association of Chemical Engineering - AIDIC
2010
Abstract
This study was designed to compare one-step, two-step and spent medium bioleaching of spent catalyst by adapted Penecillum simplicissimum in batch cultures. Penecillum simplicissimum which was adapted to heavy metal ions Ni, Mo, Fe, and W grew in the presence of up to 5 %w/v of spent catalyst in the medium. The main lixiviant in bioleaching was gluconic acid which was produced mainly in present and absence of spent catalyst. A total of 3 %w/v spent catalyst generally gave maximum extraction yields in two-step bioleaching process, which the amounts of leached metals were 100 % of W, 100 % of Fe, 92.7 % of Mo, 66.43 % of Ni, and 25 % of Al. The red pigment produced by fungus could also...
Magnetic starch nanocomposite as a green heterogeneous support for immobilization of large amounts of copper ions: Heterogeneous catalyst for click synthesis of 1,2,3-triazoles
, Article RSC Advances ; Volume 6, Issue 23 , 2016 , Pages 19128-19135 ; 20462069 (ISSN) ; Motamedi, A ; Hosseini, S. H ; Nazari, M ; Sharif University of Technology
Royal Society of Chemistry
Abstract
A new magnetic heterogeneous copper catalyst was prepared by immobilization of copper ions onto a cross-linked polymeric nanocomposite composed of starch grafted polyacrylamide and functionalized Fe3O4 magnetic nanoparticles. The resulting support was loaded with large amounts of copper ions (1.6 mmol g-1). The prepared catalyst is highly active in Huisgen 1,3-dipolar cycloaddition reactions of different azides and alkynes at low catalyst amounts. Various corresponding 1,2,3-triazoles were produced with high yields in mild conditions. The catalyst was easily recovered and reused for ten cycles of reaction and no significant loss of catalytic activity was observed
Synthesis, crystal structures and Hirshfeld surface analyses of two new Salen type nickel/sodium heteronuclear complexes
, Article Journal of Molecular Structure ; Volume 1110 , 2016 , Pages 119-127 ; 00222860 (ISSN) ; Behzad, M ; Tarahhomi, A ; Maroney, M ; Rudbari, H. A ; Bruno, G ; Ghanbari, B ; Sharif University of Technology
Elsevier
Abstract
Two new heteronuclear Nickel(II)/Sodium(I) complexes of a side-off compartmental Schiff base ligand were synthesized and characterized by spectroscopic methods. Crystal structures of both of the complexes were also obtained. The Schiff base ligand was synthesized from the condensation of meso-1,2-diphenyl-1,2-ethylenediamine with 2-hydroxy-3-methoxybenzaldehyde. In both of the complexes the Ni(II) ion is coordinated to the inner N2O2 coordination sphere with square-planar geometry and the Na(I) ion is coordinated to the outer O2O2′ coordination sphere. In Complex (1) with general formula [Ni(L)Na(CH3OH)(ClO4)] the sodium ion is seven coordinated while in (2) with general formula...
A unique sensitive and highly selective fluorescent naphthodiaza-crown macrocyclic ligand chemosensor for Hg2+ in water
, Article Journal of Fluorescence ; Volume 27, Issue 4 , 2017 , Pages 1385-1398 ; 10530509 (ISSN) ; Zarepour jevinani, M ; Sharif University of Technology
Springer New York LLC
2017
Abstract
The noticeable enhancement in fluorescence emission of O2N2-donor naphthodiaza-crown macrocyclic ligand (L) in the presence of Hg2+ was observed in which the fluorescence quantum yield of free ligand L as well as L/Hg2+ complex were found to be as 0.29 and 0.49, respectively. The observed ultra-low limit of detection (LOD) for Hg2+ by L was determined as low as 1.0 × 10−11 M in water. A 1:1 stoichiometry was also established for L/Hg2+ together with a binding constant KBH = 66,543 by employing fluorescence spectrophotometry. The competition experiments on L/Hg2+ demonstrated highly selective detection of Hg2+ in the presence of the library cations. A two path mechanism for detection of metal...