Papers by Author: H. Manuspiya

Abstract: Inorganic Mesoporous Membrane is a new alternative to improve high-temperature fuel cell performance in proton exchange membrane fuel cells (PEMFCs) to substitute for Nafion. It possess high porosity and high specific surface areas, resulting in high proton conductivity. In this study, niobium-modified titania and antimony/niobium-modified titania ceramic were prepared via the sol-gel technique. The various contents of antimony, 0 to 3 wt%, and 3% niobium are incorporated into titania to improve the porous surface condition of the ceramic particles. The xerogels were heated at about 500°C. Inorganic membranes were prepared by using the spin-coating technique using epoxy resin as a binder. The physical, chemical, and electrical properties of these membranes were investigated. The XRD and Raman results showed that pure TiO2 and doped TiO2 nanoparticles obtained possess an anatase structure with mesoporosity. The specific surface area of the doped TiO2 was higher than that of pure TiO2 and it is worth pointing out that the doping of antimony affected the surface areas more than the doping of niobium in TiO2. Moreover, these membranes were also tested to evaluate their potential use as an electrolyte in PEMFC by using impedance spectroscopy, TGA, mechanical properties and water uptake.

Abstract: Inorganic Mesoporous Membrane is a new alternative to improve high-temperature fuel cell performance in proton exchange membrane fuel cells (PEMFCs) to substitute for Nafion. It possess high porosity and high specific surface areas, resulting in high proton conductivity. In this study, niobium-modified titania and antimony/niobium-modified titania ceramic were prepared via the sol-gel technique. The various contents of antimony, 0 to 3 wt%, and 3% niobium are incorporated into titania to improve the porous surface condition of the ceramic particles. The xerogels were heated at about 500°C. Inorganic membranes were prepared by using the spin-coating technique using epoxy resin as a binder. The physical, chemical, and electrical properties of these membranes were investigated. The XRD and Raman results showed that pure TiO2 and doped TiO2 nanoparticles obtained possess an anatase structure with mesoporosity. The specific surface area of the doped TiO2 was higher than that of pure TiO2 and it is worth pointing out that the doping of antimony affected the surface areas more than the doping of niobium in TiO2. Moreover, these membranes were also tested to evaluate their potential use as an electrolyte in PEMFC by using impedance spectroscopy, TGA, mechanical properties and water uptake.

Abstract: A wide variety of toxic metals and organic chemicals are discharged to the environment as industrial or laboratory wastes, causing serious water, air, and soil pollution. One of the interesting materials for using as the adsorbents to adsorb these pollutants in wastewater treatment is porous clay heterostructures (PCHs). These porous materials are obtained by the surfactant-directed assembly of mesostructured silica within clay layers. In the present work, the PCHs were synthesized within the galleries of Na-bentonite clay by the polymerization of tetraethoxysilane (TEOS) in surfactant templates (cetyltrimethylammonium ion and dodecylamine). These PCHs were functionalized with 3-mercaptopropyltrimethoxysilane (MPTMS) to obtain the MP-PCH utilizing as heavy metal adsorbent. According to N2 adsorption-desorption data, the results show that PCH has surface areas of 549.7 m2/g, an average pore diameter in the supermicropore to small mesopore range of 3.16 nm, and a pore volume of 0.45 cc/g, while MP-PCH shows pore parameters of 488.7 m2/g, 3.28 nm, and 0.48 cc/g, respectively. Moreover, the MP-PCH was investigated the adsorption properties which concerned with their function as adsorbents for aqueous solution. The results show that the adsorption capacity of MP-PCH was 0.22, 0.24, 0.50 , 0.48 and 0.11 mmol/g for Cd, Cu, Mn, Ni and Pb, respectively. They point out the potential for utilizing as the heavy metal adsorbents in wastewater treatment.

Abstract: Porous Clay Heterostructures (PCHs) have been prepared by the surfactant-directed assembly of mesostructured silica within the two-dimensional interlayer galleries of clays. The PCH is an interesting material to use as entrapping system such as ethylene scavenger, owing to its high surface area with uniform and specific pore size. In the present work, the PCH was synthesized within the galleries of Na-bentonite clay by the polymerization of tetraethoxysilane (TEOS) in the presence of surfactant micelles. In addition, a mesoporous clay with organic-inorganic hybrid (HPCH) is modified via co-condensation reaction of TEOS with methyltriethoxysilane (MTS) to enhance hydrophobicity of PCH material for entrapping system. According to pore characterization, PCHs have surface areas of 421-551 m2/g, an average pore diameter in the supermicropore to small mesopore range of 4.79-5.02 nm, and a pore volume of 0.57-0.66 cc/g while HPCHs have surface areas of 533-966 m2/g, an average pore diameter of 4.28-6.38 nm, and a pore volume of 0.42-0.77cc/g.

Abstract: This research proposed a novel nano barium strontium titanate (BST) powder- polybenzoxazine composite as a new dielectric material. In this work, the dielectric properties of a surface-treated BST powder-polybenzoxazine composite were studied. The surface of the BST powders were modified by using three different chemicals: 3-aminopropyl-trimethoxysilane, benzoxazine monomer and phthalocyanine. The distribution of the BST powders in the polybenzoxazine matrix was observed by SEM. The dielectric constants of the composites with a function of frequency (1 kHz–10 MHz) were investigated. It was found that the composites with modified BST powders showed good distribution in the polybenzoxazine matrix, and the dielectric constants were also much enhanced than those with untreated BST powders. In comparisons among the three modification methods, the composite with the silane coupling modified BST powder showed significantly in dielectric constant improvement while the composite with the benzoxazine and phthalocyanine modified BST powders displayed lower dielectric loss due to the modified powder dispersed well in the polybenzoxazine matrix.

Abstract: Poly (vinylidene fluoride), Piezoelectric, Dielectric constant, Microporous PVDF films, Bubble shapes.