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Mashhadizadeh, Mohammad Hossein,Moatafavi, Ali,Allah-Abadi, Hossein,Zadmehr, Mohammad Reza Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.9
A simple and reliable method has been developed to selectively separate and concentrate trace amounts of thallium ion from real samples for the subsequent measurement by flame atomic absorption spectrometry (FAAS). Thallium ions are absorbed quantitatively during passage of aqueous real samples through an octadecyl bonded silica membrane disk modified by 4-(4-Chloro-phenylazo)-2-[(4-hydroxy-phenylamino)-methyl]-phenol. The retained $Tl^+$ ions are then stripped from the disk quantitatively with a minimal amount of thiosulfate solution as eluent. The proposed method permitted large enrichment factors of about 130 and higher. The relative standard deviation for ten replicate extraction of thallium from 1 L samples containing 5 ${\mu}g$ thallium is 1.2%. The break through volume for 5 ${\mu}g$ thallium is 1000 mL. The limit of detection of the proposed method is 11.2 ng of $Tl^+$ per 1000 mL. The effects of various cationic interferences on the recovery of thallium in binary mixtures were studied. The method was applied to the recovery of $Tl^+$ ions from natural water and human hair samples.
Taher Yousefi,Ahmad Nozad Golikand,Mohammad Hossein Mashhadizadeh,Mustafa Aghazadeh 한국물리학회 2012 Current Applied Physics Vol.12 No.1
Manganese dioxide (MnO2) nanowires with diameter about 30e70 nm is achieved via a two-step process: first, template-free cathodic electrodeposition from aqueous solution of Mn(NO3)2 on steel substrate and followed by heat treatment. The temperature-annealed sample was studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM)methods and Fourier transform infrared (FT-IR) spectroscopy. The electrochemical performance of the MnO2 sample was studied by cyclic voltammetry (CV) and chronopotentiometry in Na2SO4 solutions. The sample showed excellent supercapacitive behavior. The specific capacitance (SC) of 237 F g-1 in a potential window of 0e0.9V was obtained at the scan rate of 2 mV s-1. The SC calculated from the chronopotentiometry data is about 246 F g-1. The SC was decreased by 16% after 1000 cycles. Manganese dioxide (MnO2) nanowires with diameter about 30e70 nm is achieved via a two-step process: first, template-free cathodic electrodeposition from aqueous solution of Mn(NO3)2 on steel substrate and followed by heat treatment. The temperature-annealed sample was studied by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM)methods and Fourier transform infrared (FT-IR) spectroscopy. The electrochemical performance of the MnO2 sample was studied by cyclic voltammetry (CV) and chronopotentiometry in Na2SO4 solutions. The sample showed excellent supercapacitive behavior. The specific capacitance (SC) of 237 F g-1 in a potential window of 0e0.9V was obtained at the scan rate of 2 mV s-1. The SC calculated from the chronopotentiometry data is about 246 F g-1. The SC was decreased by 16% after 1000 cycles.
Taher Yousefi,Ahmad Nozad Golikand,Mohammad Hossein Mashhadizadeh,Mustafa Aghazadeh 한국물리학회 2012 Current Applied Physics Vol.12 No.2
Uniform and single-crystalline Mn3O4 nano-spheres were synthesized by cathodic electrodeposition at high temperature (80 ℃) and low current density (0.25 mA cm-1) on steel electrode. Further the annealed samples were characterized for their structural and morphological properties by means of Xray diffraction (XRD), Fourier transform infrared spectrum (FTIR), Scanning electron microscopy (SEM),Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) studies. TEM and SEM images showed that particles have spherical shapes and the average diameter size was about 50 nm. Formation of Mn3O4 compound was confirmed from FTIR studies. The XRD pattern showed that the Mn3O4 exhibit tetragonal hausmannite structure. The results of N2 adsorption-desorption analysis indicated that Mn3O4 nanoesphere has BET surface area of about 177.6 m2 g-1 and average pore diameters of 3 and 4 nm. The possible formation mechanism of Mn3O4 nanostructures has been discussed. The supercapacitive properties of Mn3O4 sample in 0.5 M Na2SO4 electrolyte showed maximum supercapacitance of 235.4 Fg-1 at scan rate 10 mV s-1. Coulumbic efficiency could be kept about 90%during 1000 cycles at 10 mV s-1. Uniform and single-crystalline Mn3O4 nano-spheres were synthesized by cathodic electrodeposition at high temperature (80 ℃) and low current density (0.25 mA cm-1) on steel electrode. Further the annealed samples were characterized for their structural and morphological properties by means of Xray diffraction (XRD), Fourier transform infrared spectrum (FTIR), Scanning electron microscopy (SEM),Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) studies. TEM and SEM images showed that particles have spherical shapes and the average diameter size was about 50 nm. Formation of Mn3O4 compound was confirmed from FTIR studies. The XRD pattern showed that the Mn3O4 exhibit tetragonal hausmannite structure. The results of N2 adsorption-desorption analysis indicated that Mn3O4 nanoesphere has BET surface area of about 177.6 m2 g-1 and average pore diameters of 3 and 4 nm. The possible formation mechanism of Mn3O4 nanostructures has been discussed. The supercapacitive properties of Mn3O4 sample in 0.5 M Na2SO4 electrolyte showed maximum supercapacitance of 235.4 Fg-1 at scan rate 10 mV s-1. Coulumbic efficiency could be kept about 90%during 1000 cycles at 10 mV s-1.
Shamsipur, Mojtaba,Saeidi, Mahboubeh,Yari, Abdullah,Yaganeh-Faal, Ali,Mashhadizadeh, Mohammad Hossein,Azimi, Gholamhasan,Naeimi, Hossein,Sharghi, Hashem Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.5
A new PVC membrane electrode for $UO_2^{2+}$ ion based on 2,2'-[1,2-ethanediyl bis (nitriloethylidene)]bis(1-naphthalene) as a suitable ionophore was prepared. The electrode exhibites a Nernstian response for $UO_2^{2+}$ ion over a wide concentration range ($1.0{\times}10^{-1}-1.0{\times}10^{-7}$M) with a slope of 28.5 ${\pm}$ 0.8 mV/decade. The limit of detection is $7.0{\times}10^{-8}$M. The electrode has a response time of < 20 s and a useful working pH range of 3-4. The proposed membrane sensor shows good discriminating abilities towards $UO_2^{2+}$ ion with regard to several alkali, alkaline earth transition and heavy metal ions. It was successfully used to the recovery of uranyl ion from, tap water and, as an indicator electrode, in potentiometric titration of $UO_2^{2+}$ ion with Piroxycam.
Seyed Javad Ahmadi,Neda Akbari,Zahra Shiri-Yekta,Mohammad Hossein Mashhadizadeh,Morteza Hosseinpour 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.3
This study focuses mainly on the synthesis of MnO2-ZrO2 nano-composite as a new inorganic adsorbent. Supercritical water was used as a preparation medium for particle deposited materials. MnO2-ZrO2 was prepared frommetal nitrate solutions in supercritical region. The resulting sample was characterized by Fourier transform infrared(FTIR), X-ray fluorescence (XRF), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and transmissionelectron microscope (TEM). Analyses of the TEM images show the possibility for crystallizing nano-sized particles. The synthesized adsorbent was then used for the removal of strontium(II) from the nuclear waste. Moreover, anumber of factors such as aqueous phase pH, contact time and initial metal ions concentration in the adsorption processwere investigated. Comparison of the adsorption efficiency of the MnO2-ZrO2 nano-particles with those of thenon-nano particles shows a shift of uptake of the metal ions vs. pH curves towards lower pH values and a significantimprovement in adsorption of strontium ions was observed by using the nano-adsorbent. The kinetic data correspondswell to the pseudo-second-order equation. The adsorption data for strontium(II) were well fitted by the Langmuir isotherm. The synthesized nano-composite also showed a strong affinity toward the removal of Y(III), Ni(II), Pb(II) andCo(II) from the nuclear radioactive waste.