JOURNAL OF PHYSICAL AND THEORETICAL CHEMISTRY
Year:2012 | Volume:9 | Issue:3|Papers Count:8

The modified surface of Typha latifolia L. root (MSTL), as an alternative economical adsorbent, was used for the removal of Ni (II) and Cd (II) ions from aqueous solutions. The effect of initial pH, initial concentration of metal ion, and contact time was investigated in a batch system at room temperature. The kinetics data could be fitted well by pseudo-second-order model with correlation coefficient values greater than 0.99. The mechanism of adsorption process was tested by fitting the experimental data by intraparticle diffusion kinetic and Boyd kinetic equations. The adsorption data could be fitted well by Langmuir and Freundlich adsorption isotherms. The maximum adsorption capacity of MSTL was determined to be 37.31 mg g-1 for Ni2+ and 28.90 mg g-1 for Cd2+ at room temperature when the initial concentration of both metal ion was 100 mg/L, and the pH of the solution was 5.00 and 4.00 for Ni2+ and Cd2+, respectively. It has been suggested that the MSTL can be successfully applied for the removal of toxic heavy metal ions such as Ni2+ and Cd2+ from aqueous solutions.

Vanillin offers interesting possibilities for corrosion inhibition because of its safe use and high solubility in water. The effect of vanillin on the corrosion inhibition of AISI 304 stainless steel in 0.5M H2SO4 solution has been studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Furthermore, this paper demonstrates that the electrochemical noise (EN) technique under open circuit conditions as the only truly noninvasive electrochemical method can be applied to investigate the corrosion inhibition. According to calculation of the total amount of noise charges due to all partial signals resulted from wavelet analysis of EN current data, it is possible to obtain the inhibition efficiency (IE) of an inhibitor. These IE values show a reasonable agreement with those obtained from potentiodynamic polarization and EIS measurements.

This study is about Complexes of Li doped silicon carbide nanotube with Thymine and Cytosine in gas phase and aqueous solutions. Li doped silicon carbide nanotube and its pyrimidine nucleobase compounds were first modeled by Quantum mechanical calculations in gas phase and in water. Calculated binding energies indicated the stronger ability of thymine to functionalize silicon carbide nanotube than Cytosine. After that, Monte Carlo simulation and Free Energy Perturbation method was utilized to calculate solvation free energies and complexation free energies to evaluate solvation behavior and stability of the related structures. The results indicated that Li doped silicon carbide nanotube-thymine has more stability in water.

In order to increase the water content and the oxygen permeability of hydrogels used in the manufacture of contact lenses, the polar monomer Silicon Hydrogel Contact Lenses (SHCL), and 2-hydroxyethyl methacrylate (HEMA) were copolymerized with the hydrogels. Due to the presence of polar monomers in the conventional contact lenses, the major component of the human tear, lysozyme is extensively adsorbed onto their surfaces. The adsorption of lysozyme onto the contact lens’ surface leads to limitations in its application. The present study concentration of lysozyme, adsorbed onto the surface of HEMA and SHCL hydrogels were measured by UV-Vis spectroscopy. The lysozyme employed was obtained from solutions with similar to concentration of artificial tear. The adsorption results were examined by the Langmuir adsorption isotherm and the constants of this isotherm were also evaluated.

In this research at the first, captopril drug (CA) and its fullerene connected form (FCA) were optimized. Natural Bond Orbital (NBO) calculations for these compounds were carried out at the B3LYP/6-31G quantum chemistry level, in the gas phase and the liquid phase. These calculations can be performed at different accuracy levels depending on the aim of the theoretical study [1]. For instance, Density Functional Theory (DFT) can be used to calculate an accurate electronic structure, HOMO and LUMO energies, Mulliken charge of atoms, energetic_orbital levels, chemical hardness, chemical potential and electrophilicity of systems, and finally chemical, physical, biological, pharmacological and industrial of fullerene and fullerene derivatives [4–7]. Theoretical calculations such as NBO are very important to understand the pathways of electron transfer in assemblies. Consequently, the obtained results showed that energy orbital levels decreased considerably by linking structure of Captopril to structure of fullerene C60. In the study some other characteristics such as chemical potential, chemical hardness, electrophilicity in these structures, it was found that they changed considerably. These changes show dependency of the results, on power of electron affinity of C60. In another part, the valence electrons populations for carbons, nitrogen, oxygens and hydrogens atoms in similar position for FCA and CA were compared. Finally the data were compared and discussed.

A PVC membrane Ni (II) ion selective electrode has been constructed using (1E, 2E) -bis (2-aminophenyl) N'1, N'2-dihydroxyethanebis as membrane carrier. The electrode exhibited a good potentiometric response for Ni (II) over a wide concentration range 1.0×10-4 to 1.0×10-1M with a slope of 29.4±0.5 mV/decade a and a working pH range of 6.5-9.0. It had a fast response time of£20s. The best performance was observed with the membrane having 30.5% PVC, 3.0% ligand, 61.0% acetophenone and 5.5% oleic acid composition.In this work, the ligand structure studied by ab initio HF calculations using a standard 6-31G* basis set and LanL2DZ.

Carbon activated powdered was prepared from activated carbon derived from olive stone. Then by using the surface methodology, many parameters such as pH, furnace temperature (T), acid ratio, time of activation that affect on the qualities prepared activated carbon produced and its efficiency were investigated. In addition, the adsorption of Congo Red onto the activated olive stone carbon active was studied and removal or adsorption percent as response was reported. By applying surface methodology we obtained optimum conditions, at the other hand next researches can use these conditions to produce activated carbon by high efficiency from Olive stone as natural adsorbent.

A PVC membrane Fe (III) ion selective electrode has been constructed using a new macrocyclic as membrane carrier. The electrode exhibits a good potentiometric response for Fe (III) over a wide concentration range 1.0×10-4 to 1.0×10-1M with a slope 19.4±0.5 mV/decade a and a working pH range of 6.5-9.0. It has a fast response time£30s.The best performance was observed with the membrance having the 30.5% PVC, 3.0% ligand, 61.0% acetophenone and 5.5% oleic acid composition.