Papers by Keyword: Surface Area

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Authors: Yong Gang Luo, Linda Zou, Eric Hu
Abstract: The porous TiO2 pellets were prepared based on pigment grade titaina, P25 titania powder and titanium(IV) butoxide. The characterization was done with X-Ray diffraction, scanning electron microscopy and BET measurements. The result shows that TiO2 pellets by using titanium(IV) butoxide with some addictive have the best surface porosity, with specific surface area of 196.9m2/g. For pigment grade titania and P25 titania powder, it is still effective to enhance the surface area after reassembling. The surface area increased from 11.6 to 29.2 m2/g for pigment grade titania and from 50 to 84.4 m2/g for P25 titania powder. Furthermore, it has been investigated on how to optimize and get the highest surface area by controlling the sintering temperature, reaction temperature, pH of solution, and the amount of alcohol and addictive of surfactant during preparation. The experimental photocatalytic degradation of acetone and toluene was performed using titania pellets made from P25 titania powder.
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Authors: Takaharu Watanabe, Shun Fukutomi, Kozo Taguchi
Abstract: This study examines two things about a dye sensitized solar cell (DSSC) to improve power conversion efficiency. One is how to make ZnO-coated TiO2 electrode. The other is how to make carbon nanotube (CNT) electrode. First, we considered the process of making the ZnO-coated TiO2 electrode of the DSSC. This ZnO coating of the DSSC is important for the increase of power conversion efficiency. The fabrication method of the ZnO-coated TiO2 electrode was simple dip coating. This method uses the immerse of the zinc acetate dehydrate [Zn (CH3COO2)・2H2O] solution. This method can make the cheap ZnO-coated TiO2 electrode. However, this method has a slightly negative effect, which is filling in holes of the porous TiO2 layer. We tried to improve this negative effect. We changed the concentration of a zinc acetate dehydrate solution from low to high. Also, we changed the immersing time of the zinc acetate dehydrate solution. We did the control of the band gap of ZnO-coated TiO2 electrode of DSSC for increasing power conversion efficiency. Second, we substituted CNT for counter electrodes to improve the performance of DSSC. As a manufacture method of CNT electrode, we used electrophoretic deposition (EPD). After that, we baked this CNT electrode and measured its specific surface area. We tried to improve specific surface area by changing baking temperature.
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Authors: Sung Yong Choi, Young Hwan Park, Woo Tai Jung
Abstract: Fiber Reinforced Concrete (FRC) is a representative strengthening method adopted to improve the sudden brittle failure of concrete under tension and dynamic loadings and to control the generation and propagation of cracks occurring during the curing process. The strengthening performance provided by the fiber is sensitively influenced by the physical properties of the fiber itself as well as by its volume ratio but is also varying according to the difference in the bond performance at the interface between the fiber and concrete. Even if the fiber exhibits outstanding physical performance, if the bond performance does not reach similar level, the fiber will not be able to develop fully its performance. Currently, the methods improving the fiber bond performance are essentially focusing on the improvement of the mechanical bond performance by changing the longitudinal shape of the fiber such as the application of crimped and hooked fibers. A very few methods intend to improve the bond performance by increasing the bond area of the fiber itself. Therefore, this study increases the surface area of the fiber by changing its section while preserving its volume during the fabrication process, conducts tests on the bond performance between the cement paste and the fiber with changed surface area, and examines the changes in the bond performance according to the increase of the surface area.
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Authors: Man Cheng Zhang, Wei Wang, Cong Jian Huang, Ai Min Li
Abstract: The adsorption behaviors of chlortetracycline on two kinds of granular activated carbons with different BET surface area and average pore width have been studied. The results show that larger BET surface area is beneficial for the adsorption capacity, and wider pore structure can enhance the adsorption rate. Initial solution pH has great effect on the adsorption behavior, and the suitable pH for the effective adsorption is from 4 to 8.
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Authors: Meng Qiao Wang, Xiao Han Liu, Liu Yan Wu, Ai Min Li
Abstract: Three commercial resins (NDA150, NDA88 and NDA77) with different physicochemical properties were selected to investigate the adsorption behavior and primary factors controlling the adsorption of oxytetracycline (OTC) onto the resins. The adsorption kinetics of OTC onto all resins were fitted well to pseudo-second-order model. NDA150 had the largest adsorption capacity due to its higher surface area and larger total pore volume. Moreover, all of the three resins exhibited nearly the same equilibrium time because of their nearly the same particle size. The suitable pH for the effective adsorption of NDA150 and NDA77 is from 4 to 7, while the ideal pH for NDA88 is 10. OTC adsorption on all of the three resins increased with the increasing ionic concentration.
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Authors: S. Azat, Rosa Busquets, V.V. Pavlenko, A.R. Kerimkulova, Raymond L.D. Whitby, Z.A. Mansurov
Abstract: This article presents the results of the synthesis of carbon nanomaterials: Nanoscale materials obtained by carbonization of waste agricultural products (apricot kernel, Greek walnut (GW), rice husk). The results of physico-chemical characteristics of the obtained nanomaterials. Physico-chemical parameters of the synthesis of carbonized sorbents based on plant raw material are investigated along with the properties of these sorbents. The data of FTIR, ESR spectroscopy & BET-method, as well as electron microscopy are reported. It is stated that carbonized sorbents possess high specific surface area and porosity. Carboxylic, carbonyl, hydroxyl groups are detected on the surface of the synthesized sorbents. Separate fusicoccine and similar biostimulators effectively; remove LPS-endotoxines from blood plasma selectively. They may be used as carriers to introduce probiotics into intestine thanks to formation of stable colonies on their developed surface. A method of preparation of honeycomb monoliths from carbonized rice husk with developed mesoporous structure via modification of the porous structure by silica leaching has been developed.
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Authors: Hanna Yoon, Yong Keun Lee, Bum Soon Lim, Sang Hoon Rhee
Abstract: Non-woven silica fabric was made by electro-spinning method for the application as a bone grafting material. The silica gel, the source material for electro-spinning, was prepared by the hydrolysis of tetraethyl orthosilicate in the presence of water, hydrochloric acid and ethanol. It was transferred to a syringe (spinneret), which was connected to the high voltage supply generating a high electric field between the spinneret and the ground collecting drum. The silica fibers were spun under the electric field of 2 KV/cm. Their diameters were in the range from about 100 nm to 5 µm. After soaking in the SBF for 4 week, low crystalline apatite crystals were observed to occur partly on their surfaces. From the results, it can be concluded that the non-woven silica fabric made by electro-spinning method has the apatite forming ability in the SBF and it means it has a potential to be used as a bone grafting material because of its apatite-forming ability, high surface area to volume ratio and high porosity.
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Authors: Nurul’ Ain binti Jamion, Siti Mazleena binti Mohamed
Abstract: Interface adsorption of gases and liquid on a clean solid surface could be due to the physical or chemical adsorption. In this study, the activated carbon was prepared from sugar cane husk (powder and granular form) using phosphoric acid (H3PO4) as activating agent. Sample was activated at 500°C for two hours in the furnace and washed using vacuum method. Besides, surface area of activated carbon was defined using Single Point Brunauer-Emmett-Teller (BET) Nitrogen Gas. The physico-chemical characteristics of the prepared activated carbon were characterized by Fourier-Transformed Infrared Spectroscopy (FTIR), gravimetric method, and Field Emission Scanning Electron Microscopy (FESEM). The adsorption study by surfactants, namely CTAB (cationic) and TX-100 (non-ionic) were investigated. The experimental results showed that a good activated carbon was prepared from sugar cane husk granular (SCH-G) gave the highest BET surface area of 860.18 m2/g and the adsorption capacity of SCH-G activated carbon at 25°C using TX-100 (205.81 mg g-1) was greater compared to the CTAB (108.20 mg g-1). This study has shown that the sugar cane husk was a good activated carbon and has potential to be used as adsorbent for the removal of surfactants from aqueous solutions.
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Authors: Luis F. Herrera, Duong D. Do, Greg R. Birkett
Abstract: The determination of the properties of porous solids remains an integral element to the understanding of adsorption, transport and reaction processes in new and novel materials. The advent of molecular simulation has led to an improved understanding and prediction of adsorption processes using molecular models. These molecular models have removed the constraints of traditional adsorption theories, which require rigid assumptions about the structure of a material. However, even if we possess a full molecular model of a solid, it is still desirable to define the properties of this solid in a standard manner with quantities such as the accessible volume, surface area and pore size distribution. This talk will present Monte Carlo integration methods for calculating these quantities in a physically meaningful and unambiguous way. The proposed methods for calculating the surface area and pore size distribution were tested on an array of idealised solid configurations including cylindrical and cubic pores. The method presented is adequate for all configurations tested giving confidence to its applicability to disordered solids. The method is further tested by using several different noble gas probe molecules. Finally, the results of this technique are compared against those obtained by applying the BET equation for a range of novel materials.
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Authors: Wan Norasiah Wan Mahmood, Rusnah Samsuddin, Raja Razuan Raja Deris
Abstract: Selection of suitable activation agent is important in order to produce high surface area of activated carbon. The present study was undertaken to develop high surface area of durian shell activated carbon (DSAC) using different chemical activation agents which were potassium hydroxide (KOH) and phosphoric acid (H3PO4). Surface porosity and surface area were directly measured from scanning electron microscopy (SEM) and surface area analyzer, respectively. For the optimum condition, it showed that H3PO4 treated DSAC had the highest surface area which was 257.50 m2/g compared to KOH treated DSAC which was 13.10 m2/g. H3PO4 treated DSAC also showed the highest micropore surface area, external surface area and total pore volume with 191.22 m2/g, 66.28 m2/g and 0.149 cm3/g, respectively. SEM result showed that H3PO4 treated DSAC had a well pronounce porosity than durian shell char. Surface area and surface porosity were important in an adsorption process.
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