Journal of Applied Research in Chemistry
Year:2013 | Volume:7 | Issue:1|Papers Count:8

In this study, MWCNT-SiO2 nanohybrides were prepared with sol-gel and hydrothermal methods. Hybride formation was occurred in situ of SiO2 nanostrutures synthesis. Spherical and hexagonal morphologies can be obtained for SiO2 nanostrutures with sol-gel and hydrothermal methods, respectively. Both of the as-prepared nanohybrides were used for emulsion preparation. These emulsions consists of water, MWCNT-SiO2 nanohybrid, Sodium dodecyl benzene sulfonic acid (SDBS), and 2-propanol and n-hexane. The samples were characterized with X-ray diffraction (XRD), surface area measurment by BET method, and field emission scanning electron microscopy FE-SEM. According to the contact angle and interfacial tension experimental results of MWCNT-SiO2 nanohybrides nanofluid that were prepared with sol-gel method, the product will be suitable for enhanced oil recovery because of increasing the reservoir stone wettability.

In this investigation, novel multidentate symmetric cores containing tetrabromine, tetrazide and tetramine compounds were synthesized by using of diethyl malonate as reactant in a five-step synthetic route. All intermediates and final products were fully characterized by FT-IR, 1H NMR, 13C NMR and Elemental Analysis. Synthesized multidendate symmetric compounds can be used as important cores for preparing new dendrimers, star-polymers, hyperbranched polymers, complexes and so on. Tetramine compound can be used as central core at the preparation of new polyamidoamine and polyamine dendrimers and as chelating ligand at preparation of new complexes.

The objective of this study is to develop and evaluate the static headspace in combination with GC equipped with electrolytic conductivity detector (ELCD) for the analysis of trihalomethanes (THMs) in drinking water. The effects of experimental parameters such as water temperature, ionic strength of solution, agitation time and sample volume on the system performance were investigated. The quantification was based on the internal standard 1-chloro-2-bromopropane. The response for all THMs was linear in the concentration range of 0.5 to 40 mg/l. The limits of detection (LOD) are 0.09, 0.13, 0.21 and 0.34 mg/l for chloroform, bromodichloromethane, dibromochloromethane and bromoform, respectively. The relative standard deviations for analysis were less than 4.8%. The proposed method was applied to the analysis of THMs in spiked drinking water and well water samples.

Tetrahydropyranylation of a variety of alcohols and phenols in excellent yields in solvent-free conditions at room temperature was performed in the presence of environmentally friendly, hydrophobic, highly thermal stable and completely heterogeneous propylsulfonic acid functionalized nanostructured SBA-15. The absence of solvent, simple experimental procedure, and reusability of the catalyst (at least 7 reaction cycles) characterize the present procedure as green method.

This study aims to assess the absorption of copper and lead by using buttonwood fruit as a cheap absorbent. Extraction of Pb and Cu were performed by buttonwood fruit powder. The extraction conditions such as pH, absorbent dose, contact time and size of buttonwood fruit powders were optimized by experimental design method. Thus, 30 experiments were designed by Box-Behnken method and absorption of Pb and Cu were measured in the solutions by Atomic Absorption Spectrometer (AAS). these results showed that the pH and absorbent dose are effective parameters on the extraction efficiency. Elimination efficiency was achieved 95.34% and 92.22% for Cu and Pb respectively. These results shows the buttonwood fruit is a promising sorbent for economy elimination of heavy metals in environment.

In this study, in order to remove the lead contamination from silicon and chromium industrial surfaces, a novel cleaning solution containing hydrogen peroxide (as oxidizing agent) and EDTA disodium salt (as chelating agent) was used. After the removal of lead contamination, the UV spectra of the cleaning solutions were examined. The results showed that the prepared Pb (EDTA) complex in the solution can play an important role in the prevention of lead re-absorption on the surface of the basic metals in industrial surfaces. Scanning electron microscopy (SEM) study illustrated that by using the suggested solution at optimized condition, the lead contamination can be removed properly with no damage to the surface of the basic metals.

In this work, topics such as the geometry, structure electronic configuration, and electronic absorption spectrum in order to investigate the effect of the fluorine substitution into organic dyes (H-P, F-P, FF-P), has been studied by the computation method of the density functional theory (DFT) and the time-dependent density functional theory (TDDFT). In this regard, the calculated bond length and the angle between nitrogen atoms in aniline and the carbon atom in carboxylic acid, indicating that the efficiency of conversion of light into the current in F-P dye is greater than FF-P and H-P which this statement is consistent with the experimental results. On the other hand, electronic absorption spectroscopy and HOMO and LUMO diagrams, verify experimental parameters.

In this study, nitrile rubber (NBR)/CaCO3 nanocomposites were prepared by melt mixing method. The effect of calcium carbonate nanoparticles as an effective agent in reinforcement of swelling resistance of nitrile rubber was investigated. Transport of aromatic solvents through prepared nanocomposites were investigated by equilibrium swelling test at different temperatures. The Diffusion of benzene and toluene through these nanocomposites were studied with respect to the effect of the nano particles concentration and temperature on transport process. The transport parameters such as diffusion coefficient, permeation and sorption coefficients and mechanism of solvent transport and also thermodynamic parameters such as Gibbs free energy, entropy, enthalpy and activation energy of diffusion and permeation were calculated from the equilibrium swelling test information. The microstructure and dispersion of calcium carbonate nanoparticles in nitrile rubber matrix was studied by scanning Electron Microscopy (SEM). The results showed that there was a consistency between microstructure of nanocomposite and experimental results. The results showed that the concentration of nanoparticles in nanocomposites had an important role in determination of the values of diffusion coefficient, sorption and permeation. By increasing the amount of nanoparticles, final swelling of nanocomposite and the rate of solvent diffusion decreased. It seems that improvements in swelling resistance of nitrile rubber is possible by an optimum concentration of calcium carbonate nanoparticles.