Papers by Author: Zahira Yaakob

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Authors: Samaneh Shahgaldi, Zahira Yaakob, Dariush Jafar Khadem, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: In recent years, one dimensional nanostructure, nanowires, nanofibers with unique properties have been a subject of intense research due to reduction of devise dimension, potential properties from the re-arrangement at the molecular level and high surface area. There are many methods for synthesize such as laser ablation, chemical vapour deposition, solution method micro pulling down method but all these method faced to the major disadvantages of being complicated with long wasting time and relatively high expense . The electrospinning recently used for producing ceramic, metal, and carbon nanofibers. In this report, we incorporate palladium into silica nanofibers for the first time, and the effect of doping of palladium into the silica nanofibers is investigated. The different ratio of palladium to silica and comparing with silica nanofibers is also reported. The composition, morphology, structure and surface area of silica, and silica palladium nanofibers were investigated by thermo gravimetric analysis (TGA), x-ray diffraction (XRD), scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FT-IR), and Micromeriics. To the best of our knowledge, investigation on characteristic on Silica palladium nanofibers has not been reported up to now. The result reveal that the silica nanofibers compare to silica doped with palladium have lower diameter, and also by increasing the temperature above 600 °C, the reduction in length of nanofibers happened. High surface area of silica palladium nanofibers can be one of the promising materials for hydrogen storage.
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Authors: Dariush Jafar Khadem, Zahira Yaakob, Samaneh Shahgaldi, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: Metal and Metal oxide nanofibers have different potential to play an essential role in a series of application, among them copper and copper oxide nanostructures is a promising semiconductor material with potential applications in many field. In this paper, electrospinning method via sol-gel was used to fabricate copper and copper oxide nanofibers. Synthesize of copper and copper oxide nanofibers and also effect of calcinations temperature on morphology investigated by thermal gravimetric analysis, scanning electron microscopy (SEM), Transmission electron microscopy, x-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer Emmett and Teller (BET).
1884
Authors: Naraya Nan Binitha, Zahira Yaakob, P.P. Silija, P.V. Suraja, S.M Tasirin
Abstract: Co-doping of nanosilver, carbon and nitrogen is done on titania to get improved photodegradation of pollutants when compared to single doping. Anion doping extends the absorption of TiO2 to the visible region; whereas noble metal NP doping prevents the recombination of photoinduced electrons and holes. Doped TiO2 prepared using sol gel method allows efficient dispersion of nano silver and thus enhances the photodegradability. X-ray Diffraction analysis shows the efficient dispersion of incorporated nano silver over anatase TiO2. The visible light absorption is confirmed from UV-Vis Diffuse Reflectance spectral studies. Photocatalytic activity is investigated by the degradation of methyl orange as a model pollutant. Efficient degradation in visible light shows the synergetic effect of carbon and nitrogen doping as well as nano silver loading on the performance of TiO2.
776
Authors: Hakim Lukman, Zahira Yaakob, Ismail Manal, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: The need and development of cleaner and greener alternative technologies using the heterogeneous catalytic system in the synthesis of fuel is very important. In this work hydrogen production via steam reforming of glycerol (C3H8O3) was carried out over nickel supported on hydroxyapatite [Ca5(PO4)3(OH)] as a biomaterial catalyst. The time reaction is carried out for 240 minutes in a fixed-bed reactor fixed at 600 oC and atmospheric pressure with the water-to-glycerol feed ratio of 8:1. Catalysts were prepared by mean of impregnation and sol-gel method with varied nickel loadings (3, 6, 9, 12 %) on hydroxyapatite. The catalysts were characterized by BET surface area, X-ray diffraction, and SEM-EDX techniques. It is found that 3 wt% of nickel loading prepared via sol-gel method exhibit the higher hydrogen production rates (63.62 % - 74.16 %) in comparison to the other nickel loadings.
1046
Authors: Ibrahim Yakub, Masita Mohammad, Zahira Yaakob
Abstract: Activated carbon was developed from physic nut seed hull through chemical activation using zinc chloride. The characteristics of raw physic nut seed hull as well as char and activated carbon from physic nut seed hull were obtained to study the effects of ZnCl2 impregnation. The comparisons of the characteristics that included elemental composition, surface morphology, surface area, surface functional groups and zeta potential were made on the three samples. The study found that ZnCl2 had positive effects towards developing activated carbon including increasing the carbon content, surface area and pore volume besides improving the microporosity and surface charge distribution of the carbon.
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Authors: Norliza Abd. Rahman, N.T. Kofli, Zahira Yaakob, S. Gauri
Abstract: Fossil fuel is one of the main energy sources for almost all country in the world. However, it is non-renewable energy source, not environmental friendly and the limited supply of the fossil fuel encouraged the scientist to discover other alternative way of new renewable energy supply. New alternative source should be considered for prolonged lifetime. Thus, non-conventional energy sources should be placed in the prior consideration, for instant bioethanol. Jatropha curcas seed is a toxic substance; however, it has a very high oil content which is approximately 3545%. After the extraction of oil from the seed, Jatropha seed cake is formed. In the pressed seed cake, it is found that it contains cellulose and glucose that can be used as substrate in bioethanol production. The production of bioethanol can be estimated by neural network using data from previous research. A programme using MATLAB 7.8 was used to develop the neural network. The software consists of Neural Network Toolbox which functions to train the input data and estimate the production of glucose and bioethanol as output data. An input layer represents the criteria of the production properties of glucose and bioethanol concentration. The hidden layer determines either the input data can be proceed to further production of glucose and bioethanol, whereas the output layer gives the estimation values of glucose and bioethanol production. Back propagation algorithm with TANSIG transfer function was used to accomplish the estimation of production of bioethanol. The error value given by the network was 0.0390. Thus, training sessions were considered successful. Therefore, the users could determine and estimate the production of glucose and bioethanol concentration in just a short period of time.
943
Authors: Samaneh Shahgaldi, Zahira Yaakob, Norazrina Mat Jali, Dariush Jafar Khadem, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: Electrospun Poly (vinylidene fluoride) (PVdF) fine fiber of 100-300 nm in diameter in ribbon shape was synthesized through the electrospinning process via sol-gel. In order to synthesize infusible nanofibers all processing of dehydrofluorination and carbonization was investigated. Iron nanoparticles was doped with PVDF nanofibers in order to be effective in surface area, and porosity to increase the hydrogen storage. The composition, morphology, structure and surface area of PVDF/Iron Oxide nanofibers were investigated by thermo gravimetric analysis (TGA) to determinate the temperature of possible decomposition and crystallinity, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Micromeritics (ASAP2020) used to study the textural properties of the sample, like surface area, total pore volume, and micro pore volume. The result shows that the PVDF without dehydrofluorination treatment for infusibility become melt at around 160 °C. By adding the iron oxide nanoparticles as a catalyst it can improve the characteristic of the carbon fiber for hydrogen storage. In best of our knowledge, PVDF doping with iron oxide investigated for first time.
1184
Authors: Dariush Jafar Khadem, Zahira Yaakob, Samaneh Shahgaldi, Wan Ramli Wan Daud, Edy Herianto Majlan
Abstract: One-dimensional nanostructures, like nanofibers, nanobelts, nanotubes, nanorods have been regarded as a new class of nanomaterials that have been attracted as the most promising building blocks for verity applications in the last few years. As one type of important structures with intensive research efforts have been devoted to the production and investigation of the metal oxides. Metal oxide nanofibers have different potential to play an essential role in a series of application such as optics, nanoelectronics, catalysts, sensors, storage, optoelectonics, and full cell. Copper oxide nanostructures is a promising semiconductor material with potential applications in photochemical, electrochemical, electrochromic especially in water splitting, catalysts, and fabrication of photovoltaic devices. In this paper electrospinning method via sol-gel was used to fabricate copper oxide nanofibers. Copper oxide nanofibers with different morphology were synthesized by different calcinations temperature. In this paper, effective parameters such as voltage, concentration of precursor and different calcinations temperature were characterized by thermal gravimetric analysis, scanning electron microscopy (SEM), Transmission electron microscopy, x-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer Emmett and Teller (BET).
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Authors: Samaneh Shahgaldi, Zahira Yaakob, Mostafa Ghasemi, Wan Ramli Wan Daud, Dariush Jafar Khadem
Abstract: One dimensional (1D) nanostructure materials such as nanowires, nanofibers, and nanorods with porous structures have potential for use in various applications. Electrospinning is one of the versatile techniques with the ability of producing cost-effective, large production, highly porous nanofibers and membrane with large surface to volume ratios. Poly ether sulfone (PES) is a kind of special engineering plastic with good processing characteristics. In this paper, synthesis of PES membrane was investigated by two main methods, i.e. phase inversion and electrospiing. For electrospining, the main effective parameters such as concentration of polymer and solvent, for finding the optimized condition of electrospun PES membrane was studied. The produced membranes were characterized by SEM for morphology and BET observation of surface area, permeability, flux, and mechanical propertise for different applications.
607
Authors: Hakim Lukman, Zahira Yaakob, Ismail Manal, Wan Ramli Wan Daud
Abstract: Nickel-hydroxyapatite as biomaterial catalysts exhibited high activity and selectivity in glycerol steam reforming. The catalytic steam reforming of glycerol (C3H8O3) for the production of hydrogen is carried out over nickel supported on hydroxyapatite [Ca5(PO4)3(OH)] catalyst at 600 oC with atmospheric pressure and 120 minute time reaction. The catalysts were prepared by mean of wet impregnation method and varied nickel loadings (3, 6, 12 %) on hydroxyapatite. It is found that the 3% wt% Ni/HAP show higher hydrogen production rate over the other nickel loadings on hydroxyapatite, which is correlated with Ni/HAP catalyst surface area measured by BET adsorbtion and morphology of catalysts. Glycerol steam reforming with water-to-glycerol feed ratio 8/1 much more hydrogen production (77-82%) compared feed ratio 4/1. The catalysts were characterised by BET surface area and SEM-EDX techniques.
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