Sharif Digital Repository

An anion-selective electrode based on rhodium(II) phthalocyanine (RhPc) as a neutral carrier is reported. The prepared electrode displays an anti-Hofmeister behavior with a high selectivity for thiocyanate. The potentiometric response characteristics and selectivities of the membrane electrodes with various ratios of cationic additive to ion-carrier indicate that the observed potentiometric response is based on the formation of a 1:1 complex between RhPc and thiocyanate as an axial ligand. The membrane electrodes containing ∼60 mol percent of cationic additive (relative to ionophore) exhibit a near-Nernstian response in a concentration range of thiocyanate between 1 × 10-6 M to 1 × 10-1 M, a... 

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... 

A metallophthalocyanine complex with zirconium(IV) ion in the center (as an oxo-zirconium, Zr=O, group) was used in poly vinyl chloride (PVC) membranes for the selective detection of 5-sulfosalicylic acid (SSA). The resulting electrodes demonstrate Nernstian responses over a wide range of sulfosalicylic acid concentration (10-6 to 10-1 mol dm-3) with a slope of about -29 mV per decade. The influence of lipophilic ion-exchanger sites on the response properties of the electrodes was investigated. The optimal potentiometric response was observed for the electrode in the presence of about 150 mol% of cationic additive (relative to ionophore) in the phase membrane. The electrodes have a fast... 

The mean spherical approximation (MSA) has been applied to accurately correlate the activity coefficients of individual ions in aqueòus solutions of single 1:1 electrolytes. In order to account for changes in the hydration of the ions, the size parameters of the ions are considered to be composition dependent. The values of the size parameters show that the hydration of the ions decreases as the electrolyte concentration increases. Results obtained from the full MSA and from a simplified version of MSA (SMSA), were compared. The use of the simplified version had a small effect on the final results and dramatically reduced the computation of the effort  

Under experimental conditions in which the self-association of the adenine phosphates (AP), that is, of adenosine 5′-monophosphate (AMP2-) and adenosine 5′-diphosphate (ADP3-), is negligible, potentiometric pH titrations were carried out to determine the stabilities of the M(H;AP) and M(AP) complexes where M2+=Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, or Cd2+ (25°C; I = 0.1m, NaNO3). It is concluded that in the M(H;AMP)+ species M2+ is bound at the adenine moiety and in the M(H;ADP) complexes at the diphosphate unit; however, the proton resides in both types of monoprotonated complexes at the phosphate residue. The stabilities of nearly all the M(AMP) and M(ADP)- complexes are... 

Electrochemical cells with two ion-selective electrodes, a cation ion-selective electrode against an anion ion-selective electrode, were used to measure the activity coefficient of amino acids in aqueous electrolyte solutions. Activity coefficient data were measured for (H2O + NaBr + glycine) and (H2O + NaBr + L-valine) at T = 298.15 K. The maximum concentrations of sodium bromide, glycine, and L-valine were (1.0, 2.4, and 0.4) mol · kg-1, respectively. The results show that the presence of an electrolyte and the nature of both the cation and the anion of the electrolyte have significant effects on the activity coefficients of amino acid in aqueous electrolyte solutions  

The activity coefficient data were reported for (water + potassium chloride + DL-valine) at T = 298.15 K and (water + sodium chloride + L-valine) at T = 308.15 K. The measurements were performed in an electrochemical cell using ion-selective electrodes. The maximum concentrations of the electrolytes and the amino acids studied were 1.0 molality and 0.4 molality, respectively. The results of the activity coefficients of DL-valine are compared with the activity coefficients of DL-valine in (water + sodium chloride + DL-valine) system obtained from the previous study. The results show that the presence of an electrolyte and the nature of its cation have a significant effect on the activity... 

Salicylate selective electrodes based on oxo(phthalocyanato)-vanadium(IV) [VO(Pc), vanadyl phthalocyanine] and oxo(phthalocyanato)molybdenum(IV) [MoO(Pc), molybdenyl phthalocyanine] are described. The electrodes were prepared by incorporating the ionophores into plasticized poly(vinyl chloride) membranes, which were directly coated on the surface of graphite electrodes. The resulting electrodes demonstrate Nernstian responses over a wide linear range (10-7-10-1 M) salicylate. The electrodes have a fast response time, submicromolar detection limit, and could be used over the pH range of 6-9. The proposed sensors revealed selectivity for salicylate over a number of common inorganic and organic... 

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  

Precise modelling of the interaction of ions with materials is important for many applications including material characterization, ion implantation in devices, thermonuclear fusion, hadron therapy, secondary particle production (e.g. neutron), etc. In this study, a new approach using the Geant4 toolkit in combination with the Bayesian regularization (BR) learning algorithm of the feed-forward neural network (FFNN) is developed to estimate the range of ions in materials accurately and quickly. The different incident ions at different energies are interacted with the target materials. The Geant4 is utilized to model the interactions and to calculate the range of the ions. Afterward, the... 

A cavity resonator containing graphene nanopores (GNPs), along with a metallic layer (Ag, as a reflector) and a dielectric layer (SiO2, as a spacer), has been proposed for broadband wide-angle absorption of light. The GNP/SiO2/Ag multilayers showed high significant increase in the absorption efficiency (with respect to the G/SiO2/Ag multilayer) in a broad spectral range (from ultra-violet (UV) and visible range to near-infrared (NIR)), due to the cavity resonance and absorptions induced by the oxygen-containing functional groups formed around the nanopores of graphene. The dependences of the cavity resonance absorption on the quality of the GNP layer, dimension of the cavity and the incident... 

Because of the recent frequent observations of major dust storms in southwestern cities in Iran such as Ahvaz, and the importance of the ionic composition of particulate matters regarding their health effects, source apportionment, etc., the present work was conducted aiming at characterizing the ionic composition of total suspended particles (TSP) and particles on the order of ∼10 μm or less (PM10) during dust storms in Ahvaz in April-September 2010. TSP and PM10 samples were collected and their ionic compositions were determined using an ion chromatography. Mean concentrations of TSP and PM10 were 1,481.5 and 1,072.9 μg/m 3, respectively. Particle concentrations during the Middle Eastern... 

We have compared the gas phase thermochemical properties of aspartame (artificial sweetener) and α- and β-glucose. These parameters include metal ion affinities with Li+-, Na+-, K+-, Mg+2-, Ca+2-, Fe+2-, Zn+2-ions, and chloride ion affinity by using DFT calculations. For example, for aspartame, the affinity values for the above described metal ions are, respectively, 86.5, 63.2, 44.2, 255.4, 178.4, 235.4, and 300.4, and for β-glucose are 65.2, 47.3 32.9, 212.9, 140.2, 190.1, and 250.0 kcal mol-1, respectively. The study shows differences between the intrinsic chemistry of aspartame and glucose. © 2008 Elsevier Ltd. All rights reserved  

The derivatives of glucose such as glucosamine (β-D-GlcN) and N-acetyl-D-β-glucosamine (GlcNAc) are significant in several biological systems. D-GlcN has been used widely to treat osteoarthritis in humans and animal models as well as GlcNAc has been proposed as a treatment for autoimmune diseases. The DFT/B3LYP/6–311++G (d,p) method as well as QTAIM and NBO analyses were used to the acidity values of D-GlcN and GlcNAc sugars and their complexes with alkali ions in the gas phase. The Li+, Na+ and K+ prefer bi-dentate chelate in these complexes. The computed results indicate that metal ion affinity (MIA) in GlcNAc is higher than that in D-GlcN. There are direct correlations between the MIA... 

Single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) were synthesized in aqueous solutions containing FeCl2, FeCl3, FeSO4 and Fe2(SO4) 3. The effects of iron charge and the counter ions on the formation of carbon nanotubes (CNTs) were investigated. Thermogravimetric (TG) analysis indicated that carbon multilayer structures including CNTs and multishell graphite particles were formed in deionized (DI) water without the iron precursor. SWCNTs were also synthesized in the presence of the iron ions. It was also found that the mole ratio of [Fe2+]/[Fe3+] in the solution has a significant influence on the purity of CNTs and the process yield. The highest yield was... 

This paper concentrates on degradation of electric vehicle (EV) lithium-ion batteries in vehicle-to-grid (V2G) programs and proposes a practical wear cost model for EVs charge scheduling applications. As the first step, all the factors affecting the cycle life of lithium-ion batteries are identified and their impacts on degradation process are investigated. Subsequently, a general model for battery loss of cycle life is devised incorporating all the pertinent factors associated with charging and discharging activities in V2G applications. Modeling the battery wear cost as a series of equal-payments over the cycle life, a mechanism for calculating the cost incurred by EV users due to... 

In this research, a continuous microsolvent extraction-reaction was developed for the efficient separation of calcium ion. This study gives a preliminary possible practical application of microfluidic devices in chemical exchange reaction for enrichment of 48Ca stable isotope. For this purpose, in the first stage, the hydrodynamic behavior of two immiscible liquids in a simple Y-shaped microfluidic junction is experimentally investigated, and then ion-pair extraction-reaction of Ca2+ using picric acid as a counter-ion and dicyclohexano-18-crown-6 (DC18C6) as a lipophilic ionophore is studied in this microfluidic and conventional batch method. The impact of main process parameters, including... 

The prepared colloidal silica via ion exchange was modified by adding Mg+2 ions in the surface growth process of colloidal silica. The particle size of the modified colloidal silica was decreased by increasing the seed concentration, whereas that of colloidal silica was slightly increased as the seeds concentration exceed 15 wt%. But the trend of changes in surface area was completely reversed. Magnesium ions on surface of the modified colloidal silica were identified by the measurement of energy-dispersive X-ray spectrometry (EDS). After modifying with Mg+2 ions, the iso-electric point (IEP) of colloidal silica in pH ∼ 2 without modification, disappears over the whole pH range. © 2008... 

Lithium ions play a crucial role in the energy storage industry. Finding suitable lithium-ion-conductive membranes is one of the important issues of energy storage studies. Hence, a perovskite-based membrane, Lithium Lanthanum Titanate (LLTO), was innovatively implemented in the presence and absence of solvents to precisely understand the mechanism of lithium ion separation. The ion-selective membrane’s mechanism and the perovskite-based membrane’s efficiency were investigated using Molecular Dynamic (MD) simulation. The results specified that the change in the ambient condition, pH, and temperature led to a shift in LLTO pore sizes. Based on the results, pH plays an undeniable role in...