THE 7TH INTERNATIONAL CONFERENCE ON BASIC SCIENCES 2021 (ICBS 2021)
The calcination temperature effect on the crystallization and morphology of hydroxyapatite from b... more The calcination temperature effect on the crystallization and morphology of hydroxyapatite from bamboo shell (Sollen spp.
Artificial dyes such as methylene blue are commonly detected in textile industry wastewater. Clay... more Artificial dyes such as methylene blue are commonly detected in textile industry wastewater. Clay is commonly used as an economical and effective adsorbent for methylene blue in textile waste treatment. The addition of surfactants into the system is usually done to increase the adsorption capacity of the clay. In this study, we used a molecular dynamics simulation method to study the effect of tetrabutylammonium organic surfactant on the adsorption process of methylene blue on the clay surface. The modelled clays are pyrophyllite and montmorillonite which are hydrophobic and negatively charged, respectively. The simulation results show that the addition of tetrabutylammonium surfactant causes a 12 % and 40% decrease in the binding of methylene blue to the surfaces of pyrophyllite and montmorillonite, respectively. This is due to the occurrence of competitive adsorption in both systems. Therefore, the addition of tetrabutylammonium surfactant was considered ineffective in increasing ...
ABSTRAK: Fuel cell merupakan sumber energi alternatif pengganti minyak bumi yang bersifat dapat d... more ABSTRAK: Fuel cell merupakan sumber energi alternatif pengganti minyak bumi yang bersifat dapat diperbaharui, ramah lingkungan (bebas emisi CO2), dan mempunyai efisiensi tinggi. Fuel cell dapat langsung mengubah energi kimia bahan bakar menjadi energi listrik seperti halnya baterai. Untuk keperluan portable, jenis fuel cell yang sering digunakan antara lain Proton Exchange Membrane Fuel Cell (PEMFC) dan Direct Methanol Fuel Cell (DMFC). Salah satu komponen yang penting dalam PEMFC dan DMFC adalah polielektrolit. Hingga saat ini polielektrolit yang banyak digunakan adalah Nafion yang diproduksi oleh Du Pont. Nafion mempunyai konduktivitas penghantar ion yang tinggi, sifat mekanik, dan kestabilan kimia serta termal yang baik. Akan tetapi biaya produksi dan crossover metanol yang tinggi menjadi kendala penggunaan Nafion. Oleh karena itu, saat ini banyak dikembangkan material baru yang diharapkan dapat menggantikan fungsi Nafion dalam fuel cell. Salah satu material yang diduga dapat men...
Interfacial tension is an important parameter in enhanced oil recovery (EOR). The interaction bet... more Interfacial tension is an important parameter in enhanced oil recovery (EOR). The interaction between water and oil phase is a determinant factor of the interfacial tension. The interfacial tension changes if another component is added to the water-oil system. This study investigates the effect of adding nanocellulose to the water-oil system. To determine the molecular interactions that occur, a molecular dynamics simulation was carried out using the GROMACS-2018 software. The simulation shows that addition of nanocellulose slightly decreases the water-oil interface tension. Further, based on the density profile, nanocellulose may act as an emulsifier due to its geometric position in the water-oil interface. This is similar to asphaltene, which is a natural emulsifier in crude oil. The nanocellulose performs better in the presence of 1% NaCl as compared to pure water.
The important factors in petroleum production are the nature of the reservoir rock surface and th... more The important factors in petroleum production are the nature of the reservoir rock surface and the interaction between oil and water in the reservoir. Both of these factors can affect microscopic efficiency in increasing oil recovery. In this study, microcellulose (MCC) was tested as a potential agent to increase oil recovery. MCC is used to decrease interfacial tension between oil and water. MCC is a cellulose with particle size ranging from 30 nm to 20μm. This study aims to determine the effect of MCC on interfacial tension between oil and water. MCC is obtained through the process of cellulose hydrolysis isolated from corncob. The results of hydrolysis reaction were characterized using FTIR, Scanning Electron Microscope (SEM). The particle size was determined using Particle Size Analyzer, and interfacial tension measurements using du nouy tensiometer. The results of the study obtained MCC as a result of hydrolysis reaction with an average diameter particle size of 2.9 μm and 14 μm. The experimental results show that the addition of MCC with particle size 14 μm can reduce interfacial tension between oil and water from 11.3 mN/m to 6.85 mN/m, and the addition of MCC with particle size 2.9 μm can increase interfacial tension between oil and water from 11.3 mN/m to 21.74 mN/m. According to these data MCC has the potential to be used as an economic and environmentally friendly oil recovery agent.
Wettability is one factor that influences the enhanced oil recovery. Water-wet surfaces are predi... more Wettability is one factor that influences the enhanced oil recovery. Water-wet surfaces are predicted increasing the oil recovery from the reservoir. Microcellulose has the potential to produce water-wet surfaces. In this experiment, two types of microcellulose were used with different particle sizes of 2.9 μm and 14 μm. Both types of microcellulose are then applied to the reservoir rock surface model, i.e the surface of bentonite which has been soaked in crude oil for one week at 60 °C. Contact angle measurement shows that there is a decrease in water-the reservoir rock surface model contact angle from ~ 90 ° to ~ 80 ° when applied microcellulose solution 0.5% w/w. The difference in microcellulose size causes a difference in contact angle of about 5° at microcellulose solution 2.5%. This shows the application of microcellulose on the reservoir rock surface model causing the surface to be more water-wet.
The interfacial structure of heptane and toluene at oil-silica interfaces has previously been stu... more The interfacial structure of heptane and toluene at oil-silica interfaces has previously been studied by sum frequency generation [Z. Yang et al., J. Phys. Chem. C. 113, 20355 (2009)]. It was found that the toluene molecule is almost perpendicular to the silica surface with a tilt angle of about 25°. Here, we have investigated the structural properties of toluene and heptane at oil-silica interfaces using molecular dynamics simulations for two different surfaces: the oxygen-bridging (hydrophobic) and hydroxyl-terminated (hydrophilic) surfaces of quartz (silica). Based on the density profile, it was found that both heptane and toluene oscillate on silica surfaces, with heptane showing more oscillation peaks. Furthermore, the toluene molecules of the first layer were found to have an asymmetric distribution of orientations, with more CH(3) groups pointed away from the silica surface than towards the silica surface. These findings are generally consistent with previous experiments, and reveal enhanced molecular structures of liquids at oil-silica interfaces.
The recent discovery that molecular CO(2) transforms under compression into carbon four-coordinat... more The recent discovery that molecular CO(2) transforms under compression into carbon four-coordinated, 3-dimensional network solid phases has generated considerable interests on possible new phases in the fourth-main-group elemental oxides. Based on density-functional theory calculations, we have investigated the thermodynamic stability, mechanical properties and electronic structure of proposed guest-free clathrates, quartz and cristobalite phases for CO(2), SiO(2), and GeO(2), and the dry ice phase for CO(2). It was predicted that a GeO(2) clathrate, likely a semiconductor, could be synthesized presumably with some suitable guest molecules. The hypothetical CO(2) guest-free clathrate phase was found hardly to be formed due to the large energy difference with respect to the other polymorphs. This phase is unstable at all pressures, which is also implied by its different electronic structure in comparison with SiO(2) and GeO(2). Finally, the SiO(2) clathrate presents a uniquely high bulk modulus, which is higher than that of quartz and three times of the experimental data, might not be a weak point of ab-initio calculations such as pseudopotentials, correlation functional etc., instead it can be readily understood by the constraint as imposed by the high symmetry. Either temperature or an "exhausted" relaxation (without any symmetry constraint) can remedy this problem.
THE 7TH INTERNATIONAL CONFERENCE ON BASIC SCIENCES 2021 (ICBS 2021)
The calcination temperature effect on the crystallization and morphology of hydroxyapatite from b... more The calcination temperature effect on the crystallization and morphology of hydroxyapatite from bamboo shell (Sollen spp.
Artificial dyes such as methylene blue are commonly detected in textile industry wastewater. Clay... more Artificial dyes such as methylene blue are commonly detected in textile industry wastewater. Clay is commonly used as an economical and effective adsorbent for methylene blue in textile waste treatment. The addition of surfactants into the system is usually done to increase the adsorption capacity of the clay. In this study, we used a molecular dynamics simulation method to study the effect of tetrabutylammonium organic surfactant on the adsorption process of methylene blue on the clay surface. The modelled clays are pyrophyllite and montmorillonite which are hydrophobic and negatively charged, respectively. The simulation results show that the addition of tetrabutylammonium surfactant causes a 12 % and 40% decrease in the binding of methylene blue to the surfaces of pyrophyllite and montmorillonite, respectively. This is due to the occurrence of competitive adsorption in both systems. Therefore, the addition of tetrabutylammonium surfactant was considered ineffective in increasing ...
ABSTRAK: Fuel cell merupakan sumber energi alternatif pengganti minyak bumi yang bersifat dapat d... more ABSTRAK: Fuel cell merupakan sumber energi alternatif pengganti minyak bumi yang bersifat dapat diperbaharui, ramah lingkungan (bebas emisi CO2), dan mempunyai efisiensi tinggi. Fuel cell dapat langsung mengubah energi kimia bahan bakar menjadi energi listrik seperti halnya baterai. Untuk keperluan portable, jenis fuel cell yang sering digunakan antara lain Proton Exchange Membrane Fuel Cell (PEMFC) dan Direct Methanol Fuel Cell (DMFC). Salah satu komponen yang penting dalam PEMFC dan DMFC adalah polielektrolit. Hingga saat ini polielektrolit yang banyak digunakan adalah Nafion yang diproduksi oleh Du Pont. Nafion mempunyai konduktivitas penghantar ion yang tinggi, sifat mekanik, dan kestabilan kimia serta termal yang baik. Akan tetapi biaya produksi dan crossover metanol yang tinggi menjadi kendala penggunaan Nafion. Oleh karena itu, saat ini banyak dikembangkan material baru yang diharapkan dapat menggantikan fungsi Nafion dalam fuel cell. Salah satu material yang diduga dapat men...
Interfacial tension is an important parameter in enhanced oil recovery (EOR). The interaction bet... more Interfacial tension is an important parameter in enhanced oil recovery (EOR). The interaction between water and oil phase is a determinant factor of the interfacial tension. The interfacial tension changes if another component is added to the water-oil system. This study investigates the effect of adding nanocellulose to the water-oil system. To determine the molecular interactions that occur, a molecular dynamics simulation was carried out using the GROMACS-2018 software. The simulation shows that addition of nanocellulose slightly decreases the water-oil interface tension. Further, based on the density profile, nanocellulose may act as an emulsifier due to its geometric position in the water-oil interface. This is similar to asphaltene, which is a natural emulsifier in crude oil. The nanocellulose performs better in the presence of 1% NaCl as compared to pure water.
The important factors in petroleum production are the nature of the reservoir rock surface and th... more The important factors in petroleum production are the nature of the reservoir rock surface and the interaction between oil and water in the reservoir. Both of these factors can affect microscopic efficiency in increasing oil recovery. In this study, microcellulose (MCC) was tested as a potential agent to increase oil recovery. MCC is used to decrease interfacial tension between oil and water. MCC is a cellulose with particle size ranging from 30 nm to 20μm. This study aims to determine the effect of MCC on interfacial tension between oil and water. MCC is obtained through the process of cellulose hydrolysis isolated from corncob. The results of hydrolysis reaction were characterized using FTIR, Scanning Electron Microscope (SEM). The particle size was determined using Particle Size Analyzer, and interfacial tension measurements using du nouy tensiometer. The results of the study obtained MCC as a result of hydrolysis reaction with an average diameter particle size of 2.9 μm and 14 μm. The experimental results show that the addition of MCC with particle size 14 μm can reduce interfacial tension between oil and water from 11.3 mN/m to 6.85 mN/m, and the addition of MCC with particle size 2.9 μm can increase interfacial tension between oil and water from 11.3 mN/m to 21.74 mN/m. According to these data MCC has the potential to be used as an economic and environmentally friendly oil recovery agent.
Wettability is one factor that influences the enhanced oil recovery. Water-wet surfaces are predi... more Wettability is one factor that influences the enhanced oil recovery. Water-wet surfaces are predicted increasing the oil recovery from the reservoir. Microcellulose has the potential to produce water-wet surfaces. In this experiment, two types of microcellulose were used with different particle sizes of 2.9 μm and 14 μm. Both types of microcellulose are then applied to the reservoir rock surface model, i.e the surface of bentonite which has been soaked in crude oil for one week at 60 °C. Contact angle measurement shows that there is a decrease in water-the reservoir rock surface model contact angle from ~ 90 ° to ~ 80 ° when applied microcellulose solution 0.5% w/w. The difference in microcellulose size causes a difference in contact angle of about 5° at microcellulose solution 2.5%. This shows the application of microcellulose on the reservoir rock surface model causing the surface to be more water-wet.
The interfacial structure of heptane and toluene at oil-silica interfaces has previously been stu... more The interfacial structure of heptane and toluene at oil-silica interfaces has previously been studied by sum frequency generation [Z. Yang et al., J. Phys. Chem. C. 113, 20355 (2009)]. It was found that the toluene molecule is almost perpendicular to the silica surface with a tilt angle of about 25°. Here, we have investigated the structural properties of toluene and heptane at oil-silica interfaces using molecular dynamics simulations for two different surfaces: the oxygen-bridging (hydrophobic) and hydroxyl-terminated (hydrophilic) surfaces of quartz (silica). Based on the density profile, it was found that both heptane and toluene oscillate on silica surfaces, with heptane showing more oscillation peaks. Furthermore, the toluene molecules of the first layer were found to have an asymmetric distribution of orientations, with more CH(3) groups pointed away from the silica surface than towards the silica surface. These findings are generally consistent with previous experiments, and reveal enhanced molecular structures of liquids at oil-silica interfaces.
The recent discovery that molecular CO(2) transforms under compression into carbon four-coordinat... more The recent discovery that molecular CO(2) transforms under compression into carbon four-coordinated, 3-dimensional network solid phases has generated considerable interests on possible new phases in the fourth-main-group elemental oxides. Based on density-functional theory calculations, we have investigated the thermodynamic stability, mechanical properties and electronic structure of proposed guest-free clathrates, quartz and cristobalite phases for CO(2), SiO(2), and GeO(2), and the dry ice phase for CO(2). It was predicted that a GeO(2) clathrate, likely a semiconductor, could be synthesized presumably with some suitable guest molecules. The hypothetical CO(2) guest-free clathrate phase was found hardly to be formed due to the large energy difference with respect to the other polymorphs. This phase is unstable at all pressures, which is also implied by its different electronic structure in comparison with SiO(2) and GeO(2). Finally, the SiO(2) clathrate presents a uniquely high bulk modulus, which is higher than that of quartz and three times of the experimental data, might not be a weak point of ab-initio calculations such as pseudopotentials, correlation functional etc., instead it can be readily understood by the constraint as imposed by the high symmetry. Either temperature or an "exhausted" relaxation (without any symmetry constraint) can remedy this problem.
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