Journal of Applied Research in Chemistry
Year:2012 | Volume:6 | Issue:1|Papers Count:9

A new magnetic nanoadsorbent was prepared by treating Fe3O4 nanoparticles with 3-aminopropyltriethoxysilane and 4-mercaptobenzoic acid was added to remove excessive mercury from aqueous solutions. 4-mercaptobenzoic acid was attached to Fe3O4 via the interaction between the carboxylic groups of 4-mercaptobenzoic acid and the amine groups of APTES. Fourier Transform Infrared Spectroscopy (FT-IR), elemental analysis, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermo gravimetric Analysis (TGA) were used to characterize the synthesized nanoparticles. The effect of pH, contact time, and some co-existing cations present in aqueous solutions, were investigated. Regeneration of adsorbed mercury could be possible up to 99.3 % by 1 M HCl and the modified magnetic nanoparticles can be re-used.

A new technique of combining the gel-casting and polymer sponge methods is introduced in this study to prepare macroporous hydroxyapatite/titania scaffolds, which provides a better control over the microstructures of scaffolds and enhances their mechanical properties. The phase compositions, porous structure, mechanical properties and bioactivity of the hydroxyapatite/titania scaffolds were studied by X-ray diffractometry analysis (XRD), scanning electron microscopy (SEM), mechanical and In vitro tests respectively. XRD results indicated that hydroxyapatite (HAp), a-TCP, b-TCP, rutile (TiO2) and titanat calcium were the main crystal phases of porous HAp/TiO2 scaffolds. SEM observations of HAp/TiO2 scaffolds showed open, uniform and interconnected porous structure with a pore size of 200–400 mm. By increasing the amount of titania, mechanical results revealed that compressive strength of scaffolds decreased. The results of In vitro test indicated that the bioactivity of the HAp/TiO2 scaffolds was related to the addition of titania by inducing apatite nucleation on the sample’s surface after being immersed in simulated body fluid (SBF).

The electrocatalysis of the oxidation of D-glucose on Pt/TiO2/Ti electrodes was investigated, where Pt/TiO2/Ti electrodes were prepared by galvanic deposition of Platinum particles from an acidic bath containing H2PtCl6 onto anodized titanium, in 1 M NaOH solution. The morphology and surface characteristics of Pt/TiO2/Ti electrodes were investigated using scanning electron microscopy. The results indicated that platinum particles were homogeneously deposited on the surface of anodized titanium. The electro-catalytic behavior of Pt/TiO2/Ti electrodes for the electro-oxidation D-glucose was studied by cyclic voltammetry. The results showed that the used electroplating method for preparation Pt/TiO2/Ti electrodes led to the elimination of oxide layer. There is also a good electric connection between deposited platinum and under layer. Pt/TiO2/Ti electrodes in comparison with pure platinum electrodes exhibit a considerably higher electro-catalytic activity toward the oxidation of D-glucose. These electrodes also have higher catalytic surface in comparison with pure platinum electrodes. Because of the anodizing and constructing holes on titanium surface followed by electroplating inside these holes. Higher catalytic surface causes the increase of catalytic activity and oxidation peak. The catalytic oxidation peak current showed a linear dependence on D-glucose concentration and a linear calibration curve was obtained in the concentration range of 0.1-0.5 M of D-glucose.

Two new dioxo molybdenum (VI) complexes were obtained from interaction of MoO2 (acac)2 (I) {acac=acetylacetonato} and 1,8 and 1,5- naphthalenediamine in MeOH solvent. Reaction of MoO2(acac)2 (I) with 1,8-naphthalenediamine gave [MoO2(C10H6(NH)2)2](CH3)2 (II) (83%yiehd) where metal centers have octahedral arrangement with cis naphthalenediamine groups. The reaction of MoO2 (acac)2 with 1,5-naphthalenediamine in MeOH yielded the bimetallic compound [MoO2(acac)(H2O)]2[m-C10H6(NH)2] (III) (71%yield) with cis dioxo groups in the around Mo (VI) centers and bridging naphthalenediamine bitween two molybdenum (VI) complexes with octahedral geometry. These compounds characterized by elemental analysis, IR, 1H and 13C NMR. The catalytic activitives of the complexes in the reaction of epoxidation of cyclohexene and 1-octene with tert-butyl hydroperoxide (TBPH) as oxidant were studied. The epoxide yield was higher for cyclohexene (92% yield for compound II and 98% for compound III) than that for 1-octene (23% yield for compound II and 38% for compound III). The catalytic activity of the two synthesized complexes II and III in the reaction of cyclohexene epoxidation was nearly similar.

Heavy metals are major pollutants in the environment due to their toxicity threaten creatures and human being. In this study, the adsorption of lead (II) and copper (II) onto treated self-growing plant, Onopordon Leptolepis (OL), was investigated. Fresh OL was collected from the hills of Tehran, and it was modified using Mg, Ag, Fe and Al nanoparticles at the presence of H2O2. The morphology of the modified samples was studied by scanning electron microscopy (SEM) and elemental analysis of the deposited nanoparticles on the plant was performed by EDX. The removal of Pb (II) and Cu (II) from the solution was determined by atomic absorption spectroscopy. The SEM images of the modified samples showed that the particles which were deposited on the sample surface were in nano scale. The results showed that the Onopordon Leptolepis plant, removed 97% of lead and 81% of copper from the 500 ppm solution, respectively.

TiO2/SiO2 and V2O5/ TiO2/SiO2 nano photocatalyst have been synthesized by sol-gel method. X-ray diffraction, SEM, FT-IR, and UV-VIS methods were used to characterize the structures and properties of these photo catalysts. The particle size was determined to be 7 nm using the Scheerer,s equation. The results of XRD and FT-IR confirmed the existence of V2O5, TiO2 and SiO2. In order to investigate and compare the photocatalytic activity of TiO2/SiO2 and V2O5/TiO2/SiO2, photodegradation of monochlorobenzene and dichlorobenzene in water under the ultraviolet and visible lights was studied. The decrease in concentration of monochlorobenzene and dichlorobenzene was monitored by UV-vis spectroscopy. Our results show that in the visible light, the V2O5/ TiO2/SiO2 have better photocatalytic activity in comparison with the TiO2/SiO2.

Fluid catalytic cracking (FCC) is an industrial process to convert heavy petroleum cuts into light products, such as gasoline and light olefins. In this research, a steady state one dimensional model of FCC riser using a four-lump kinetic model was presented. Equations for mass, momentum, and energy balances were written and coded by MATLAB. It is assumed that the catalyst particles in the riser are moving upward as clusters. Using the model, product yield, temperature profile in the riser, gas and solid velocity and catalyst decay rate along the riser were investigated. Obtained results are in good agreement with published industrial data.

Fe3O4@SiO2 incorporated as a super magnetic nanoparticle into Polyurethane rigid foams in order to preparation of new corresponded magnetic Nano composite foams via one-shot method. The core-shell structured nanoparticles were prepared by sol-gel method and characterized by TEM, XRD as well as FTIR techniques. Magnetic nanoparticles were used up to 3 % in the foam formulations and the samples prepared successfully. Thermal properties of Nano composites studied and the results showed superior properties in comparison with unfilled foams. Magnetic properties of prepared foams showed improvements in magnetic properties by applying 2% of prepared nanoparticles.