Monday, 07 June 2010 Afternoon

Дата канвертавання24.04.2016
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Mustaffa Shamsuddin, Ng Yew Choo

Department of Chemistry, Faculty of Science,

Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia

Cadmium sulphide (CdS) nanoparticles have been known as few examples of visible-driven photocatalyst. The band gap of 2.3 eV corresponded well with the spectrum of sunlight. Therefore, it is expected that it could be fully utilize under solar energy conversion. Moreover, the conduction edge of CdS nanoparticles is more negative than the H+/H2 redox potential, which allows the evolution of hydrogen gas from water under sunlight or visible irradiation. In this study, CdS nanoparticles in the cubic phase have been successfully synthesized by both reverse micelle method and direct in-situ sulphur reduction. For reverse micelle method, CdS nanoparticles were prepared under an oil phase by using Triton-X100 as surfactant, whereas, for in-situ reduction method, an aqueous solution of DMF was used. The reflectance measurement of CdS nanoparticles prepared by both methods is apparently blue-shifted compared to bulk CdS. This phenomenon of blue shift of adsorption edge has been ascribed to an increase of band gap energy with the decrease in particle size. The XRD, FESEM, and EDAX data indicated that the physicochemical of CdS nanoparticles prepared by both methods were identical. Engelhard titanosilicate (ETS-10) that obtained from the hydrothermal synthesis, consists of molar ratio TiO2 : 3.75SiO2 : 1.5NaOH : 0.54KF : 21.25H2O. The fundamental vibration of octahedral TiO6 and tetrahedral SiO4 occurred at mid-infrared region of 450-1300 cm-1. The well dispersion of CdS nanoparticles on ETS-10 is expected to create a good morphology for photocatalytic reaction.


Catalytic Properties of Metallosalen supported on MCM-41 in Oxidation of Benzene

Salasiah Endud, Chin Tian Kae, Shajarahtunnur bt. Jamil and Wong Ka Lun

Department of Chemistry, Faculty of Science,

, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia

A series of metallosalen such as Fe(salen), Co(salen) and Cu(salen) supported on mesoporous molecular sieve MCM-41 have been synthesized by post synthesis modification method. These supported metallosalen were characterized by using Fourier transformed infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), diffuse reflectance ultraviolet-visible spectroscopy (UV-VIS DRS) and atomic absorption spectroscopy (AAS). The catalytic activity of the supported metallosalen was evaluated towards oxidation of benzene by using aqueous hydrogen peroxide 30% as the oxidant in acetonitrile at 70 oC. The reaction was monitored by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The results show that metallosalen supported on MCM-41 are active and selective in the formation of phenol. The catalytic activity of the metallosalen increases in the order: Fe(salen) > Co(salen) > Cu(salen).


μ-Oxo Bridged Dinuclear Iron(III) Complex Incorporated in MCM-48 as

Efficient Catalyst for Oxidation of Aromatic Alcohol

Salasiah Endud, Lau Su Chien, Wong Ka Lun

Department of Chemistry, Faculty of Science,

Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia

A series of μ-oxo bridged dinuclear iron 1,10-phenanthroline complex (Fe-phen) supported MCM-48 mesoporous molecular sieves with 0.1 mmol, 0.3 mmol, 0.5 mmol and 0.7 mmol loadings of the complex have been synthesized by post-synthesis modification method. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption measurement, thermogravimetric analysis (TGA), diffuse reflectance ultraviolet-visible spectroscopy (UV-VIS DRS), electron spin resonance (ESR), and atomic absorption spectrometry (AAS). The XRD results showed that the long range order of MCM-48 structure is maintained even after the incorporation of Fe-phen. The increase of unit cell parameter showed that encapsulation of Fe-phen in MCM-48 channel has caused the expansion of the unit cell. The UV-VIS-DRS spectra for Fe-phen-MCM-48 showed three peaks at 230 nm, 265 nm and 370 nm which correspond to the π → π* transitions of phenanthroline ligand, charge transfer from µ-oxo to Fe orbital and d-d transitions of Fe, respectively. The catalytic activity of Fe-phen-MCM-48 was tested in the oxidation of 1-naphthol with aqueous hydrogen peroxide as oxidant. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses showed that the only reaction product was 1,4-naphthoquinone after 20 hours of reaction at 80 oC. The conversion of 1-naphthol for the first use of catalyst was in the range of 65 – 75 %. Fe-phen-MCM-48 showed its reusability with 40 – 51 % conversion of 1-naphthol. This may be due to the leaching of Fe-phen into the solution during reaction.


MCNP for Neutron Radiography Simulation

Sumilah Marto*, Wan Muhamad Saridan Wan Hassan**

and Azali Muhamad***

* Department of Physics, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor.

** Ibnu Sina Institute for Fundamental Science Studies,

Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor.

*** Malaysian Nuclear Agency, Bangi, 43000 Kajang,Selangor.

The objective of the work is to use the MCNP simulation to investigate the contrast between a massive object and air in a simple canister in neutron radiography. The canisters used for spent fuel consist of copper and are filled with iron. The spent fuel bundles, which mostly consist of U-238, are placed inside the canisters. Four objects with the same shape but different elements of Fe, U-238, Pb and liquid hydrogen were investigated. The idea was to see whether it is possible to distinguish between different elements with 100 MeV neutrons. The result showed a clear contrast between the iron object and the air. The transmission through iron was about 2 × 10-5. The projection of the object on the detector implies that the shadow of the object should end at r = 4.13 cm. The resolution of the neutron radiography system was estimated as 1 mm or better.


Measurement of Diamagnetic Susceptibility of Crude Oils
Mr. Abd. Aziz Abd. Kadir1, Hasrul Afendi Ahmad Khonif1, Rashdi Shah Ahmad2
1Petroleum Engineering Department

Faculty of Chemical and Natural Resources Engineering

2Department of Physics, Faculty of Science

University Technologi Malaysia,

81310 Skudai, Johor, Malaysia.

Diamagnetism is a fundamental property of all matter. However because it is so weak it can only be observed in materials that do not exhibit other forms of magnetism. Diamagnetic materials give a value of magnetic susceptibility, K range about 10-6. The objective of this study is to determine the value of diamagnetic susceptibility of crude oils by utilizing Quincke method. It is believed that paraffin deposition can be solved by using magnetic technique. So by doing this study we can have initial knowledge about the magnetic characteristic in the crude oil. This study had been conducted on four crude oils samples from Malaysian oilfields under the influenced of the magnetic field, names Talisman, Corelab, GNPOC and sample A. These samples are different in their properties such as density, viscosity and others. The apparatus was verified by using known values materials as n-Hexane, n-Pentane and water. The percentage of error from the measurement of known values materials was calculated and gave the error between 3-7%. The value of diamagnetic susceptibility showed that Corelab have the highest value which is 0.644 x 10-6, followed by GNPOC (0.584 x 10-6), Talisman (0.567 x 10-6) sample A (0.482 x 10-6).


Growth and Characterization of Gallium Oxide Thin Films Deposited By DC Magnetron Sputtering
Putut Marwoto, Sugianto and Wiyanto
Material Laboratory, Physics Department, Faculty of Science

Universitas Negeri Semarang

Indonesia 50229

Gallium oxide (Ga2O3) films were successfully fabricated by DC magnetron sputtering. The films were grown on silicon (100) substrate at temperature of 600oC with plasma power between 40 – 50 watt. Crystal structure, morphology and optic properties have been investigated. It is found that the properties of the films are affected by growth conditions.


Mechanical Properties of Talc and Calcium Carbonate Filled PVC
Bee Soo Tueen, Azman Hassan and Aznziam Abu Bakar
Department of Polymer Engineering, Faculty of Chemical and Natural Resources Engineering,

Universiti Teknologi Malaysia

The main aim of this work was to compare the mechanical properties of calcium carbonate (CaCO3) and talc filled PVC. Talc and CaCO3 are common fillers in plastics such as PVC to reduce cost and modify mechanical properties. The PVC resin and additives were blended by using high speed laboratory mixer to produce a homogenized PVC formulation. Then, the dry blended samples were melted and sheeted on the two roll mill machine. The sheeted PVC compounds were compression moulded into impact and flexural test specimens. Flexural and impact tests were then performed to determine and compare the mechanical properties of both PVC composites. Talc filled PVC composite gave the highest flexural modulus but the lowest impact strength compared to all grades of CaCO3 filled PVC composites. The SM90 CaCO3 gave the most optimum properties in terms of impact strength and flexural modulus compared to all grades of CaCO3.


Effect of Na Loading On the Properties of Catalysts And N-Heptane Isomerization Over Pt/SO42--Zro2 Catalyst
Sugeng Triwahyono1 and Aishah Abdul Jalil2

1Ibnu Sina Institute for Fundamental Science Studies,

2Faculty of Chemical & Natural Resources Engineering

Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia.

The acidic properties of Pt/SO42--ZrO2 (PSZ) have been characterized by a combined study using temperature-programmed desorption (TPD) of ammonia and infrared (IR) spectroscopy. PSZ samples were prepared by impregnation of Zr(OH)4 with 1.0N of sulfate ion and calcined at 873 K, followed by addition of 0.5wt% Pt. Then 0.1 and 0.5wt% of Na were loaded in order to change the acidity of PSZ. The ammonia TPD spectra confirmed the existence of peaks at 443 and 623 K corresponding to the weak and medium acid sites, respectively. The TPD plot did not change much by addition of 0.1wt% Na, but changed considerably by addition of 0.5wt% Na which the intensity of peak at 623 K decreased and the intensity of peak at 443 K increased. It is indicated the conversion of strong into weak acid sites by addition of Na. IR spectra of pyridine adsorbed on samples showed the presence of Na decreased the intensities of bands at 1450, 1490 and 1540 cm-1 which corresponding to pyridine adsorbed on Lewis, Lewis-Bronsted and Bronsted acid sites. The addition of Na caused a more extensive decrease in the number of strong Bronsted acid sites than in the number of strong Lewis acid sites. The activity of PSZ samples were examined by isotherm hydrogen adsorption and n-heptane isomerization. The presence of Na decreased the hydrogen uptake due to the reducing of the number and strong acid sites. The hydrogen uptakes in 8 h for the samples unmodified and modified with 0.1 wt% Na and 0.5 wt% Na were 6.19 x1017, 3.62x1017 and 2.66x1017 atom/m2-cat, respectively. These numbers correspond to H/Pt ratios of 4.79, 2.75 and 2.01, respectively. The presence of Na decreased the conversion of n-heptane and increased the isomerization selectivity of n-heptane due to the weakening the acidity of catalyst.


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