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Papers by Abdolraouf samadi

AIP Conference Proceedings, 2012

ABSTRACT A very simple, environmental friendly and sensitive method based on the cloud point extr... more ABSTRACT A very simple, environmental friendly and sensitive method based on the cloud point extraction (CPE) separation and spectrophotometric detection has been developed for the determination of antimony. The method is founded on the color reaction of Sb (III) with iodide in acidic medium and subsequent micelle-mediated extraction of the product using the non-ionic surfactant, Triton X-114, in the absence of any chelating agent. The Effects of reaction and extraction parameters were studied and optimum conditions were established. The calibration graph was linear in the range of 0.80-95 ng mL-1 of antimony in the initial solution with r = 0.9994 (n = 9). Detection limit based on three times the standard deviation of the blank (3Sb) was 0.23 ng mL-1 and the relative standard deviation (R.S.D.) for 10 and 70 ng mL-1 of antimony were 3.32 and 1.85% (n = 8), respectively. The proposed method was compared with other methods and favorably applied to evaluate this metal in some real samples, including seawater, antileishmanial drug (glucantime) and human serum.

Studies in Surface Science and Catalysis, 1994

The aluminophosphate glasses were prepared by the melting-quenching technique and their optical a... more The aluminophosphate glasses were prepared by the melting-quenching technique and their optical and structural properties were investigated. The 56P2O5-20Al2O3 glass exhibits unique blue emission at 406 nm due to the phosphorus defect in the glass matrix. Addition of SiO2, ZnF2, or Li2O to 56P2O5-20Al2O3 glass matrix has different influence on formation of phosphorus defect resulting in different intensities of blue emission at 406 nm, though SiO2, ZnF2 or Li2O mostly enters the glass network as modifier. Structural analysis of P2O5-Al2O3 based aluminophosphate glasses by positron annihilation lifetime spectroscopy indicates that values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects. Under excitation of 251 nm, a broad blue emission band and a red emission band were observed in the Mn-doped 56P2O5-20Al2O3-15SiO2-10ZnF2 glass, indicating the operation of energy transfer from the phosphorus defect to octahedrally coordinated Mn in the glass host.

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013

This paper presents distribution of phosphorus (total P, organic and inorganic P) in the southern... more This paper presents distribution of phosphorus (total P, organic and inorganic P) in the southern of Caspian Sea sediments where collected from four sampling stations in the summer 2009. Several forms of the phosphorus in sediment were separated and extracted according to sequential extraction method. Then extracted phosphorus in each fraction was determined by UV-Vis spectrophotometery. Five forms of phosphorus were studied (i) loosely sorbed phosphorus, (ii) ferric-iron-bound phosphorus, (iii) authigenic phosphorus, (iv) detrital phosphorus, and (v) organic phosphorus. The total P contents were ranged from 124.5 to 328.2 µgg-1. It was found that more than 98% of the total P is inorganic phosphorous (IP). Among the four forms of IP, loosely bound P, P-Fe, P-detrital and P-authigenic distribution ranges were 2.70-17.31%, 10.00-44.79%, 0.40-1.70% and 48.35-83.48%, respectively. Result also showed that the most abundant forms of phosphorus were authigenic phosphorus. Relative abundances of other forms of phosphorus follow the order: P-Fe > loosely bound-P > organic P > detrital P.

In this work, a novel in-situ synthesis route was applied for preparation of an adsorbent, i.e. p... more In this work, a novel in-situ synthesis route was applied for preparation of an adsorbent, i.e. palladium containing MCM-41. At first, a hydrophobic palladium precursor was added to the ethanolic micellar solution followed by vacuum distillation of ethanol which decreases the hydrophobic characteristic of the solution. Distillation caused diffusion of hydrophobic palladium precursor into the hydrophobic core of the micelles. Then, tetraethyl orthosilicate was added to the above solution and the silicate spices arranged around the palladium containing micelles. The XRD, N 2 physisorption and TEM studies revealed that 4 wt.% palladium loading was achieved without considerable loss of pore ordering. H 2-TPR showed that the palladium nanoparticles were accessible for hydrogen molecules. Ad-sorptive desulfurization of low sulfur diesel fuel was then investigated using synthesized samples. The effect of three valuable parameters, i.e., temperature (25, 75, 150 and 200 °C), concentration of palladium (2, 4 and 5 wt.%) and feed flow rate (0.3 and 1 mL/min) were tested using a fixed-bed flowing device. The highest sulfur break through adsorption capacity and total sulfur adsorption capacity obtained at 200 °C, 0.3 mL/min of feed flow rate and 4 wt.% of palladium concentration were 1.67 and 2.35 mg sulfur/g adsorbent, respectively.

A new chemically modified electrode was constructed based on nickel phosphate nanoparticles modif... more A new chemically modified electrode was constructed based on nickel phosphate nanoparticles modified carbon paste electrode that immersed in NiCl 2 solution (Ni-NP/CPE). The modified electrode was employed as a sensor for electrocatalytic oxidation of paracetamol (PAR), phenylephrine hydrochloride (PHE), chlorpheniramine maleate (CLP) in aqueous solutions using differential pulse voltammetry (DPV) method in Tris-HCl buffer solution with pH 7.0. The Ni(II) ion adsorbed in nickel phosphate nanoparticles can act as catalyst to oxidize above drugs. The prepared electrode showed voltammetric responses with high sensitivity and selectivity for PAR, PHE and CLP in optimal conditions, which makes it very suitable for determination of these compounds. A linear calibration graph was obtained with concentration ranges of 0.75–7.0, 0.02–10.0 and 0.05–10.0 mM for PAR, PHE and CLP, respectively. The detection limits of PAR, PHE and CLP were obtained 0.24, 0.0064 and 0.016 mM, respectively. The pr...

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2008

Resolution of binary mixtures of vitamin B12, methylcobalamin and B12 coenzyme with minimum sampl... more Resolution of binary mixtures of vitamin B12, methylcobalamin and B12 coenzyme with minimum sample pre-treatment and without analyte separation has been successfully achieved by methods of partial least squares algorithm with one dependent variable (PLS1), orthogonal signal correction/partial least squares (OSC/PLS), principal component regression (PCR) and hybrid linear analysis (HLA). Data of analysis were obtained from UV-vis spectra. The UV-vis spectra of the vitamin B12, methylcobalamin and B12 coenzyme were recorded in the same spectral conditions. The method of central composite design was used in the ranges of 10-80 mg L(-1) for vitamin B12 and methylcobalamin and 20-130 mg L(-1) for B12 coenzyme. The models refinement procedure and validation were performed by cross-validation. The minimum root mean square error of prediction (RMSEP) was 2.26 mg L(-1) for vitamin B12 with PLS1, 1.33 mg L(-1) for methylcobalamin with OSC/PLS and 3.24 mg L(-1) for B12 coenzyme with HLA techniques. Figures of merit such as selectivity, sensitivity, analytical sensitivity and LOD were determined for three compounds. The procedure was successfully applied to simultaneous determination of three compounds in synthetic mixtures and in a pharmaceutical formulation.

Defect and Diffusion Forum, 2010

Zinc phosphate molecular sieve were synthesized using zinc chloride, phosphoric acid as a zinc an... more Zinc phosphate molecular sieve were synthesized using zinc chloride, phosphoric acid as a zinc and phosphor source, respectively. Different types of zinc phosphates zeolites were synthesized by conventional hydrothermal (using (2-hydroxyethyl) trimethylammonium hydroxide (2-HETMAOH) as new template. Also, ethylene glycol (EG) was utilized as co-solvent and ultrasonic tool was applied as mixer. The influence of the chemical composition of the starting sol-gel and the other parameters such as, Zn/P mole ratio, time of microwave irradiation were studied.

Journal of the Chemical Society, Dalton Transactions, 2001

... Highly resolved 27 Al NMR spectra of aluminosilicate solutions. Abdolraouf Samadi-Maybodi, S.... more ... Highly resolved 27 Al NMR spectra of aluminosilicate solutions. Abdolraouf Samadi-Maybodi, S. Naser Azizi, Hossein Naderi-Manesh, Hamidreza Bijanzadeh, Ian H. McKeag and Robin K. Harris J. Chem. Soc., Dalton Trans ...

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2009

Phosphorus-31 and aluminum-27 nuclear magnetic resonance techniques have been used to characteriz... more Phosphorus-31 and aluminum-27 nuclear magnetic resonance techniques have been used to characterize the distribution of soluble aluminophosphate species in aqueous solutions of (2-hydroxyethyl) trimethylammonium chloride (2-HETMACl), phosphoric acid, and aluminum sulfate. Soluble aluminophosphate cations obtain from reactions of hexaaqua aluminum cations [A1(H(2)O)(6)](3+), with phosphate ligands (i.e., H(3)PO(4), H(2)PO(4)(-), and acid dimers H(6)P(2)O(8) and H(5)P(2)O(7)(-)). (31)P NMR and (27)Al NMR spectroscopies are very powerful techniques for characterization of the species present in the solution. A number of solutions containing different mole ratio of Al/P were prepared. The assignment of the peaks to aluminate connectivities is attempted, clarifying earlier works and producing information on the equilibrium between various aluminum-containing species (different aluminophosphate complexes). At least seven separated resonances were observed by (31)P NMR spectroscopy indicating presence of different complexes in aluminum phosphate solutions.

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2010

Resolution of binary mixtures of paracetamol, phenylephrine hydrochloride and chlorpheniramine ma... more Resolution of binary mixtures of paracetamol, phenylephrine hydrochloride and chlorpheniramine maleate with minimum sample pre-treatment and without analyte separation has been successfully achieved by methods of partial least squares algorithm with one dependent variable, principal component regression and hybrid linear analysis. Data of analysis were obtained from UV-vis spectra of the above compounds. The method of central composite design was used in the ranges of 1-15 mg L −1 for both calibration and validation sets. The models refinement procedure and their validation were performed by cross-validation. Figures of merit such as selectivity, sensitivity, analytical sensitivity and limit of detection were determined for all three compounds. The procedure was successfully applied to simultaneous determination of the above compounds in pharmaceutical tablets.

Solid State Sciences, 2011

MCM-41material was synthesized using various ratios of (2-Hydroxyethyl)-trimethylammonium hydroxi... more MCM-41material was synthesized using various ratios of (2-Hydroxyethyl)-trimethylammonium hydroxide and sodium hydroxide. The calcined samples were characterized by powder XRD, scanning electron microscopy, nitrogen physisorption, 29 Si MAS NMR spectroscopy and transmission electron microscopy. The XRD pattern of all calcined samples shows at least four distinct peaks that indicates long range order of them. The nitrogen adsorption/desorption isotherm of all samples exhibits type IV isotherm which is the typical characteristic of mesoporous materials. When (2-Hydroxyethyl)-trimethylammonium hydroxide was used alone as a base for the synthesis of MCM-41, the highest value of surface area was obtained. Results also reveal that the pore size distribution of this sample is so narrow. The SEM images show that wiry MCM-41 samples were obtained when (2-Hidroxyethyl)-trimethylammonium hydroxide was used in the synthesis process. 29 Si MAS NMR spectroscopy proves that the presence of pure organic base in synthesis medium improves framework condensation of MCM-41. TEM images illustrate well-ordered hexagonal array of mesopores in all samples.

Magnetic Resonance in Chemistry, 2002

The effects of tetraalkylammonium (TAA) and alkali metal cations on the equilibrium distribution ... more The effects of tetraalkylammonium (TAA) and alkali metal cations on the equilibrium distribution of aluminosilicate oligomers in aqueous alkaline aluminosilicate solutions were investigated using 27 Al NMR spectra and their evolution with time. The results indicate that there are no differences in the initial equilibria involving solutions containing both TAA and alkali metal cations on the one hand and those containing alkali metal cations only. However, re-equilibration of the aluminosilicate species for TAA/Na aluminosilicates is slow (usually not detectable on the timescale of the experiments), whereas when purely alkali metal cations are used, the spectra alter over a period of ∼1 h, such that resolution is degraded substantially. In the latter case, it is suggested that the anions aggregate into larger systems, although the solutions are still clear. 29 Si NMR evidence for slow equilibration of silicate and aluminosilicate solutions at higher concentrations is also discussed.

Journal of the Iranian Chemical Society, 2012

Zinc phosphate molecular sieves were synthesized using zinc chloride, phosphoric acid and (2-hydr... more Zinc phosphate molecular sieves were synthesized using zinc chloride, phosphoric acid and (2-hydroxyethyl) trimethylammonium hydroxide as template, respectively. Synthesized samples were characterized by XRD, SEM and FT-IR techniques. The morphology and crystal size of the samples were investigated using ultrasonic during aging process. Large particle size (7.2 9 20.4 lm) was obtained by ultrasonication. Imperfect orthorhombic particles were obtained when the sample was mixed with magnetic stirrer; meanwhile, some rod-like particles were obtained when the mixture was stirred with ultrasonic. In addition, the rod-like b-Zn 3 (PO 4) 2 Á4H 2 O phase was prepared using ethylene glycol as co-solvent.

Journal of Solution Chemistry, 2012

ABSTRACT In this work, phosphorus-31 and aluminum-27 nuclear magnetic resonance techniques were u... more ABSTRACT In this work, phosphorus-31 and aluminum-27 nuclear magnetic resonance techniques were used to characterize the distribution of soluble aluminophosphate species in methanol + water and ethanol + water mixtures. The assignment of the peaks to aluminate species was attempted, clarifying earlier work and producing information on the different aluminophosphate complexes. Nine peaks were observed at −0.41, −6.4, −7.5, −7.9, −13.1, −13.9, −16.6, −18.1 and −20.6 ppm. Four new peaks appeared in the 31P NMR spectra of the alcoholic aluminophosphate solutions and their intensities changed with changes of the alcohol:water volume ratio. These new peaks were observed in the presence of methanol or ethanol but not in aqueous solutions.

Journal of Solid State Electrochemistry, 2013

ABSTRACT Carbon paste electrodes were modified by nickel phosphate nanoparticles and nickel phosp... more ABSTRACT Carbon paste electrodes were modified by nickel phosphate nanoparticles and nickel phosphate Versailles Santa Barbara-5 molecular sieves. Then, transition metal ions of Ni (II) were incorporated to the nickel phosphate by immersion of the modified electrode in a 0.1-M nickel chloride solution. The electrochemical behaviors of the modified electrodes were studied using cyclic voltammetry. These modified elec-trodes were used as anode for the electrocatalytic oxidation of methanol in alkaline medium. The influence of some param-eters such as different molecular sieves, scan rate of potential, and methanol concentration was investigated on the anodic peak height of the methanol oxidation. The best result was obtained by nickel phosphate nanoparticles.

$Research paper thumbnail of A New Silicate Clathrate Hydrate: An X-Ray Diffraction and Nuclear Magnetic Resonance Study of a System with Octameric Silicate Anions and Trivalent Cations$

Journal of Solid State Chemistry, 1995

The first crystal structure is reported for a silicate clathrate hydrate involving a triply charg... more The first crystal structure is reported for a silicate clathrate hydrate involving a triply charged cation [C18H30N3]3+ and an octameric cubic silicate cage. The structure is essentially a host/guest system, with the silicate cages linked into a framework by hydrogen bonding to water molecules. The space group is P1̄ with Z = 2, and the asymmetric unit includes a complete cation and half the anion, plus 21 water molecules (4 of which are in disordered positions). Solid-state (CPMAS) 29Si and 13CNMR spectra are consistent with the diffraction-determined structure and indicate substantial distortion of the anion from cubic symmetry. Solution-state spectra of precursor solutions and of melted material are also presented and discussed.

Journal of Porous Materials, 2013

ABSTRACT In this research, a novel method was reported for the synthesis of ZSM-5 nanozeolite. Th... more ABSTRACT In this research, a novel method was reported for the synthesis of ZSM-5 nanozeolite. The ZSM-5 nanozeolite was modified by transition metals such as nickel, copper and iron. These nanozeolites were characterized using X-ray diffraction, scanning electronic microscopy, Fourier transform infrared and Energy-dispersive X-ray techniques. The synthesized Fe-ZSM-5 nanozeolite has been smaller average particle size than the other nanozeolites. Adsorption behavior of Acridine Orange (AO) onto nanozeolites has been studied in an aqueous medium using UV–VIS technique. The modified nanozeolites have more adsorption efficiency compared to the unmodified ZSM-5 nanozeolite for AO removal. Also, Fe-ZSM-5 nanozeolite was shown higher adsorption efficiency of AO than the other synthesized nanozeolites. Adsorption isotherms were fitted with the Langmuir, Freundlich and D–R models. The kinetic data were investigated using pseudo-first order and pseudo-second order models. The adsorption kinetics of AO on Fe-ZSM-5 nanozeolitewell matched with pseudo-second order kinetic model.

Journal of Non-Crystalline Solids, 2011

In the present work, mesoporous silica nanoparticles (MSNs) with well-ordered hexagonal structure... more In the present work, mesoporous silica nanoparticles (MSNs) with well-ordered hexagonal structure were synthesized using Sodium Carboxy Methyl Cellulose. The MSNs were characterized by scanning electron microscopy, dynamic light scattering, powder XRD, nitrogen physisorption and Transmission electron microscopy. The MSNs were also functionalized with thiol groups and its capacity toward adsorption of a large cation, i.e. lead was investigated. Scanning electron microscopy reveals that MSNs have semi-spherical shapes. The XRD pattern of the calcined sample shows at least five well-defined peaks which point out that silicate nanoparticles have hexagonal array of pores as MCM-41 structure. The nitrogen adsorption isotherm displays a type IV isotherm according to the IUPAC classification. A sharp inflection in capillary condensation/ evaporation step specifies that well-ordered MCM-41 nanoparticles were synthesized. TEM image shows the well-ordered hexagonal structure of MSNs. The adsorption capacity of functionalized MSNs was higher than functionalized MCM-41 in which one reason for such behavior might be explained by higher accessibility of pores of functionalized MSNs. This approach was carried out using relatively low-cost and nonhazardous reactants in concentrated reaction medium and also the yield of this approach was high up to 96% by weight.

Journal of Hazardous Materials, 2011

In situ incorporation of nickel nanoparticles into the mesopores of MCM-41 by manipulation of sol... more In situ incorporation of nickel nanoparticles into the mesopores of MCM-41 by manipulation of solvent-solute interaction and its activity toward adsorptive desulfurization of gas oil