The effect of a nickel oxide supported silica oxide (NiO/SiO2) catalyst on temperature programmed... more The effect of a nickel oxide supported silica oxide (NiO/SiO2) catalyst on temperature programmed reduction (TPR) with 40% (v/v) carbon monoxide (CO) in nitrogen atmosphere as reductant agent was investigated. The conventional impregnation method was used to create the NiO/SiO2 catalysts. The reduction characteristics of NiO to Ni were investigated up to 700 °C, followed by isothermal reduction. The TPR profile of 9% NiO/SiO2 slightly shifted to lower temperature from 412 to 392 ºC. Whereas the undoped NiO was reduced at a lower temperature of 387 ºC. XRD diffractogram of the catalysts showed a complete reduction of NiO to Ni and have different intensities for each different loading of NiO catalyst on SiO2 support. The TEM images indicated that the carbon nanotubes were deposited on the NiO surfaces indicating some chemical reactions occur on NiO. It was found that the addition of 3% of NiO on SiO2 also exhibited a larger BET surface area (532.8 m 2 g-1) and insignificant pore diameter (5.9-6.0 nm). Based on these results, it is interesting to note that the addition of a small amount of NiO to SiO2 has a remarkable influence by reducing the temperature in the reduction process. The 9% NiO/SiO2 was found sufficient could enhance the reducibility of NiO at a lower temperature.
Virgin coconut oil (VCO) widely used in food industries, pharmaceuticals as well as beauty indust... more Virgin coconut oil (VCO) widely used in food industries, pharmaceuticals as well as beauty industries. Currently, the source of fossil fuels is facing extinction and is predicted to last for only another 50 years. Biodiesel produced by VCO has been indicated to be the perfect substitute for diesel. However, the methods for producing VCO such as heating cost a lot money, energy and time. The fermentation method has been shown to be the most convenient method for producing VCO. This research aims to find the best method for producing VCO for biodiesel production. Specifically, this research aims to determine the yield of VCO produced by the fermentation technique using four types of yeast namely bread yeast, tapai yeast, tempeh yeast and bread yeast with the addition of pineapple extract at different times of fermentation. The result of the organoleptic test, free fatty acids (FFA) test, and iodine test were compared, and VCO was then converted into biodiesel by transesterification using different amounts of catalyst to calculate its percentage yield. The results show that the highest yield percentage of VCO is 28.1% via the fermentation of tapai yeast for 18 hours with an FFA value of 0.8%. For biodiesel production, the transesterification of VCO produced using tapai yeast with 0.3 wt% potassium hydroxide (KOH) showed the highest yield percentage at 7 minutes (81.9%). In conclusion, the fermentation of coconut milk using 0.2 g of tapai yeast at 18 hours is the best method for producing VCO. Additionally, transesterification using 0.3 wt% KOH at 7 minutes is the best condition for biodiesel conversion.
The performance of nickel oxide catalysts was investigated using temperature programmed reduction... more The performance of nickel oxide catalysts was investigated using temperature programmed reduction (TPR) with promoter doping consisting of main group and transition metals in a mixture atmosphere of carbon monoxide (CO) and nitrogen (N2) (40:60 percent, vol/vol). The catalysts were prepared by wet-impregnation with a metal loading of 5 wt.% and characterized using X-ray diffraction (XRD) and N2-adsorption-desorption. TPR results revealed that metal doped Co improved NiO reduction (NiO →Ni 0) without intermediate phase during half of the reaction at 500 °C for 60 minutes. The promoter's physicochemical and textural properties influence metal-promoter interaction, crystallite size, and metal dispersion. Among these promoters, Co as a dopant has demonstrated superior performance in nickel oxide reduction behaviors, which was attributed to these elements' ability to prevent carbon accumulation on the active Ni components.
The effect of a nickel oxide supported silica oxide (NiO/SiO2) catalyst on temperature programmed... more The effect of a nickel oxide supported silica oxide (NiO/SiO2) catalyst on temperature programmed reduction (TPR) with 40% (v/v) carbon monoxide (CO) in nitrogen atmosphere as reductant agent was investigated. The conventional impregnation method was used to create the NiO/SiO2 catalysts. The reduction characteristics of NiO to Ni were investigated up to 700 °C, followed by isothermal reduction. The TPR profile of 9% NiO/SiO2 slightly shifted to lower temperature from 412 to 392 ºC. Whereas the undoped NiO was reduced at a lower temperature of 387 ºC. XRD diffractogram of the catalysts showed a complete reduction of NiO to Ni and have different intensities for each different loading of NiO catalyst on SiO2 support. The TEM images indicated that the carbon nanotubes were deposited on the NiO surfaces indicating some chemical reactions occur on NiO. It was found that the addition of 3% of NiO on SiO2 also exhibited a larger BET surface area (532.8 m 2 g-1) and insignificant pore diameter (5.9-6.0 nm). Based on these results, it is interesting to note that the addition of a small amount of NiO to SiO2 has a remarkable influence by reducing the temperature in the reduction process. The 9% NiO/SiO2 was found sufficient could enhance the reducibility of NiO at a lower temperature.
The α-Fe2O3 was synthesized using the hydrolysis method to obtain the nano coral-shaped morpholog... more The α-Fe2O3 was synthesized using the hydrolysis method to obtain the nano coral-shaped morphology. The adsorption isotherm and surface analysis upon CO2 adsorption were identified. The adsorption capacity for nano coral-shaped α-Fe2O3 was measured at 8.66 cm3/g (17.00 mg/g). Experimental data from CO2 adsorption isotherm at 25 ℃ best fits with the Freundlich isotherm model which implies the adsorption process is favorable and the multilayer adsorption on the heterogeneous surface. A decrease in the α-Fe2O3 crystallite peaks in the X-ray diffractogram after the CO2adsorption was associated with the carbonate complexes species formation. IR spectra indicate higher intensities over the CO2 exposure time of 4, 12 and 24 h, especially at absorption bands 1041 and 1627 cm-1 that corresponded to C-O and asymmetry O-C-O stretches, respectively, for carbonate. The morphology of the carbonate formation on nano coral-shaped α-Fe2O3 over the CO2 exposure time was analyzed using FESEM-EDX. Alth...
The chemical reduction progression behaviour of transition metals (Mo, Zr, W, Ce, and Co) doped o... more The chemical reduction progression behaviour of transition metals (Mo, Zr, W, Ce, and Co) doped on NiO was studied using temperature programmed reduction (TPR) analysis. A wet impregnation method was applied to synthesise the doped NiO series catalysts. The reduction progress of the catalysts was attained by using a reductant gas at the concentration of 40% v/v CO/N2. X-ray diffraction (XRD) was employed to determine the composition of the reduced phases. Undoped NiO was reduced at 384℃ to obtain a cubic phase of NiO. It was observed that Ce/NiO exhibited the lowest reduction temperature of 370℃ among all catalysts. This phenomenon might be due to a higher surface area of Ce/NiO compared to undoped NiO, which facilitated a faster reduction reaction. The rest of the doped NiO series catalysts (Co/NiO, Mo/NiO, W/NiO and Zr/NiO) demonstrated a higher reduction temperature compared to undoped NiO. New peaks in the XRD pattern were observed only for the reduced catalysts of Mo/NiO and W/...
The barium oxide impregnated iron(III) oxide (BaO/Fe2O3) adsorbent was synthesized by an ultrason... more The barium oxide impregnated iron(III) oxide (BaO/Fe2O3) adsorbent was synthesized by an ultrasonic-assisted method. The adsorbent was calcined at 200-500 °C and its adsorption capacity was measured. The ultrasonic-assisted synthesis generated well-dispersed of BaO on Fe2O3 by giving none of the BaO peaks were observed through the XRD pattern. The most efficient adsorbent of BaO/Fe2O3200 was calcined at 200 °C with adsorption capacity for physisorption and chemisorption of 5.01 and 88.81 mg/g respectively. Besides other carbonate species, it was believed the presence of the hydroxyl group could enhance the sorption by forming bicarbonate upon CO2 chemisorption. It is also possessed a lower desorption range compared to BaO and Fe2O3 alone. The experimental CO2 adsorption isotherm at 25 °C fit better with the Freundlich isotherm model. It implies a favorable adsorption process with multilayer adsorption occurs onto the heterogeneous surface.
The reduction behaviour of cobalt doped with nickel oxide and undoped nickel oxide (NiO) by hydro... more The reduction behaviour of cobalt doped with nickel oxide and undoped nickel oxide (NiO) by hydrogen (H2) in nitrogen (20%, v/v) and carbon monoxide (CO) in nitrogen (40%, v/v) atmospheres have been investigated by temperature programmed reduction (TPR). The phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD). TPR results indicate that the reduction of Co doped and undoped nickel oxide in both reductants proceed in one step reduction (NiO → Ni) without intermediate. TPR results also suggested that by adding Co metal into NiO, the reduction to metallic Ni by both reductant gaseous give different intensity of the peak. The reduction process of Co and undoped NiO become faster when H2 was used as a reductant. Furthermore, in H2 atmosphere, Co-NiO give complete reduction to metallic Ni at 700 °C. Meanwhile, XRD analysis indicated that NiO without Co composed better crystallite phases of NiO with higher intensity.
Porous surface of silica gel (SG) have been modified with alkyl fatty amine compounds (octadecyla... more Porous surface of silica gel (SG) have been modified with alkyl fatty amine compounds (octadecylamine, ODA) via wet impregnation process. The ODA-based adsorbents were physically characterized by XRD. The presence of crystalline peaks on ODA/SG diffractograms were ascertained the well-dispersion of ODA on the SG surface. XRD analysis displayed the increasing intensity of crystalline ODA with higher percent amine loaded and shifting of the several crystalline peaks of ODA verified the interaction of SG600-ODA. Capacity of CO2 capture by prepared solid adsorbents were evaluated using CO2 adsorption-desorption isotherms. This study shows that increasing percentage of ODA were improved the amount of CO2 uptake by following this trend: 35ODA/SG > 25ODA/SG > 15ODA/SG > SG > 5ODA/SG. However, promotion of 5 wt.% ODA unabled to enhance the capacity of CO2 captured due to pore blockage and reduction in SG pore surface, thus hindered the physisorption between CO2 and SG.
This study was to detect the heavy metal and xanthones contain in mangosteen leaves. The heavy me... more This study was to detect the heavy metal and xanthones contain in mangosteen leaves. The heavy metal that being detect were lead (Pb), nickel (Ni), iron (Fe) and copper (Cu). The leaves were taken from top, middle and bottom of the tree. For xanthones, the leaves was extracted using methanol in soxhlet extraction process. For detection of heavy metal, Atomic Absorption Spectroscopy (AAS). Fe was the highest concentration which are 1.153 mg·L at the top, 1.493 mg·L -1 at the middle and 1.763 mg·L -1 at the bottom because Fe was the most abundant metal in earth’s crust and the most important heavy metal in plant growth. Pb shows the lowest concentration which are 0.028 mg·L -1 at the top, 0.040 mg·L -1 at the middle and 0.078 mg·L -1 at the bottom which showed that the soil is not contaminated by Pb. For the detection of concentration of xanthones, Ultraviolet-Visible spectroscopy (UVVis) was used. From the UV-Vis results, there were xanthones peak observed in the range of 306 nm to 3...
Surface modification of Fe2O3 by adding BeO was synthesized and calcined at different temperature... more Surface modification of Fe2O3 by adding BeO was synthesized and calcined at different temperatures of 200-600 °C. The adsorbents were characterized by using XRD, N2 adsorption-desorption isotherm prior to performing CO2 adsorption and desorption studies. The CO2 adsorption data were analyzed using adsorption isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. BeO/Fe2O3-300 that calcined at 300 °C showed the most efficient adsorbent with physisorption and chemisorption were measured at 5.85 and 45.88 mg/g respectively. The CO2 adsorption notably best fitted with Freundlich isotherm with R2 = 0.9897 and calculated adsorption capacity closest to experimental data. This implies the CO2 adsorption process was governed by multilayer adsorption on the heterogeneous surface of the adsorbent. The mean free energy of adsorption (E=3.536 kJ/mol) from Dubinin-Radushkevich and heat of adsorption (bT=3.219 kJ/mol) from the Temkin model support that the adsorption proce...
The barium oxide impregnated iron(III) oxide (BaO/Fe2O3) adsorbent was synthesized by an ultrason... more The barium oxide impregnated iron(III) oxide (BaO/Fe2O3) adsorbent was synthesized by an ultrasonic-assisted method. The adsorbent was calcined at 200-500 °C and its adsorption capacity was measured. The ultrasonic-assisted synthesis generated well-dispersed of BaO on Fe2O3 by giving none of the BaO peaks were observed through the XRD pattern. The most efficient adsorbent of BaO/Fe2O3200 was calcined at 200 °C with adsorption capacity for physisorption and chemisorption of 5.01 and 88.81 mg/g respectively. Besides other carbonate species, it was believed the presence of the hydroxyl group could enhance the sorption by forming bicarbonate upon CO2 chemisorption. It is also possessed a lower desorption range compared to BaO and Fe2O3 alone. The experimental CO2 adsorption isotherm at 25 °C fit better with the Freundlich isotherm model. It implies a favorable adsorption process with multilayer adsorption occurs onto the heterogeneous surface.
The depletion of petroleum sources and global warming issues has increased awareness among scient... more The depletion of petroleum sources and global warming issues has increased awareness among scientists to produce alternative energy other than the one that we always depend on, which is petroleum. Hydrogen (H2) energy is one of the alternatives that was promising as an efficient and green fuel. Meanwhile, formic acid has been detected as one of the convenient H2 source/storage material. Here, we introduce two heterogeneous catalysts for H2 generation from formic acid. Fe0.1 Zn0.9 and Fe0.5 Zn0.5 were synthesized by a modified microwave method. In this study, we report the result of a detailed study undertaken to investigate the decomposition of formic acid to H2 and carbon dioxide (CO2) using gas chromatography with thermal conductivity detector (GC-TCD). The catalyst used to decompose the formic acid was characterized by x-ray diffraction (XRD) to determine their physicochemical properties. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TE...
Octadecylsilylated silica (ODS-Silica) stationary phases were developed and examined for solid ph... more Octadecylsilylated silica (ODS-Silica) stationary phases were developed and examined for solid phase extraction (SPE) analysis. The ODS-silica phases were endcapped using two different methods, namely by refluxing at 106 °C and stirring at room temperature. The effect of the reaction time was also investigated by performing the reactions for 6 and 16 h. Thermogravimetric analysis performed on the phases indicated that the capped ODS-silicas showed a decrease in weight loss in the temperature range of 25-125 °C, suggesting that the silanol groups decreased with endcapping. The thermograms for all the adsorbents showed a weight loss in the temperature range of 300-600 °C indicating the presence of methyl groups in the adsorbents. Abstrak: Oktadekilsilil-silika (ODS-silika) telah disediakan dan dikaji dalam analisis pengekstrakan fasa pepejal (SPE). Penutupan hujung fasa tersebut telah dilakukan menggunakan dua kaedah yang berbeza: refluks pada 106 °C dan pengacauan pada suhu bilik. Ke...
The effect of a nickel oxide supported silica oxide (NiO/SiO2) catalyst on temperature programmed... more The effect of a nickel oxide supported silica oxide (NiO/SiO2) catalyst on temperature programmed reduction (TPR) with 40% (v/v) carbon monoxide (CO) in nitrogen atmosphere as reductant agent was investigated. The conventional impregnation method was used to create the NiO/SiO2 catalysts. The reduction characteristics of NiO to Ni were investigated up to 700 °C, followed by isothermal reduction. The TPR profile of 9% NiO/SiO2 slightly shifted to lower temperature from 412 to 392 ºC. Whereas the undoped NiO was reduced at a lower temperature of 387 ºC. XRD diffractogram of the catalysts showed a complete reduction of NiO to Ni and have different intensities for each different loading of NiO catalyst on SiO2 support. The TEM images indicated that the carbon nanotubes were deposited on the NiO surfaces indicating some chemical reactions occur on NiO. It was found that the addition of 3% of NiO on SiO2 also exhibited a larger BET surface area (532.8 m 2 g-1) and insignificant pore diameter (5.9-6.0 nm). Based on these results, it is interesting to note that the addition of a small amount of NiO to SiO2 has a remarkable influence by reducing the temperature in the reduction process. The 9% NiO/SiO2 was found sufficient could enhance the reducibility of NiO at a lower temperature.
Virgin coconut oil (VCO) widely used in food industries, pharmaceuticals as well as beauty indust... more Virgin coconut oil (VCO) widely used in food industries, pharmaceuticals as well as beauty industries. Currently, the source of fossil fuels is facing extinction and is predicted to last for only another 50 years. Biodiesel produced by VCO has been indicated to be the perfect substitute for diesel. However, the methods for producing VCO such as heating cost a lot money, energy and time. The fermentation method has been shown to be the most convenient method for producing VCO. This research aims to find the best method for producing VCO for biodiesel production. Specifically, this research aims to determine the yield of VCO produced by the fermentation technique using four types of yeast namely bread yeast, tapai yeast, tempeh yeast and bread yeast with the addition of pineapple extract at different times of fermentation. The result of the organoleptic test, free fatty acids (FFA) test, and iodine test were compared, and VCO was then converted into biodiesel by transesterification using different amounts of catalyst to calculate its percentage yield. The results show that the highest yield percentage of VCO is 28.1% via the fermentation of tapai yeast for 18 hours with an FFA value of 0.8%. For biodiesel production, the transesterification of VCO produced using tapai yeast with 0.3 wt% potassium hydroxide (KOH) showed the highest yield percentage at 7 minutes (81.9%). In conclusion, the fermentation of coconut milk using 0.2 g of tapai yeast at 18 hours is the best method for producing VCO. Additionally, transesterification using 0.3 wt% KOH at 7 minutes is the best condition for biodiesel conversion.
The performance of nickel oxide catalysts was investigated using temperature programmed reduction... more The performance of nickel oxide catalysts was investigated using temperature programmed reduction (TPR) with promoter doping consisting of main group and transition metals in a mixture atmosphere of carbon monoxide (CO) and nitrogen (N2) (40:60 percent, vol/vol). The catalysts were prepared by wet-impregnation with a metal loading of 5 wt.% and characterized using X-ray diffraction (XRD) and N2-adsorption-desorption. TPR results revealed that metal doped Co improved NiO reduction (NiO →Ni 0) without intermediate phase during half of the reaction at 500 °C for 60 minutes. The promoter's physicochemical and textural properties influence metal-promoter interaction, crystallite size, and metal dispersion. Among these promoters, Co as a dopant has demonstrated superior performance in nickel oxide reduction behaviors, which was attributed to these elements' ability to prevent carbon accumulation on the active Ni components.
The effect of a nickel oxide supported silica oxide (NiO/SiO2) catalyst on temperature programmed... more The effect of a nickel oxide supported silica oxide (NiO/SiO2) catalyst on temperature programmed reduction (TPR) with 40% (v/v) carbon monoxide (CO) in nitrogen atmosphere as reductant agent was investigated. The conventional impregnation method was used to create the NiO/SiO2 catalysts. The reduction characteristics of NiO to Ni were investigated up to 700 °C, followed by isothermal reduction. The TPR profile of 9% NiO/SiO2 slightly shifted to lower temperature from 412 to 392 ºC. Whereas the undoped NiO was reduced at a lower temperature of 387 ºC. XRD diffractogram of the catalysts showed a complete reduction of NiO to Ni and have different intensities for each different loading of NiO catalyst on SiO2 support. The TEM images indicated that the carbon nanotubes were deposited on the NiO surfaces indicating some chemical reactions occur on NiO. It was found that the addition of 3% of NiO on SiO2 also exhibited a larger BET surface area (532.8 m 2 g-1) and insignificant pore diameter (5.9-6.0 nm). Based on these results, it is interesting to note that the addition of a small amount of NiO to SiO2 has a remarkable influence by reducing the temperature in the reduction process. The 9% NiO/SiO2 was found sufficient could enhance the reducibility of NiO at a lower temperature.
The α-Fe2O3 was synthesized using the hydrolysis method to obtain the nano coral-shaped morpholog... more The α-Fe2O3 was synthesized using the hydrolysis method to obtain the nano coral-shaped morphology. The adsorption isotherm and surface analysis upon CO2 adsorption were identified. The adsorption capacity for nano coral-shaped α-Fe2O3 was measured at 8.66 cm3/g (17.00 mg/g). Experimental data from CO2 adsorption isotherm at 25 ℃ best fits with the Freundlich isotherm model which implies the adsorption process is favorable and the multilayer adsorption on the heterogeneous surface. A decrease in the α-Fe2O3 crystallite peaks in the X-ray diffractogram after the CO2adsorption was associated with the carbonate complexes species formation. IR spectra indicate higher intensities over the CO2 exposure time of 4, 12 and 24 h, especially at absorption bands 1041 and 1627 cm-1 that corresponded to C-O and asymmetry O-C-O stretches, respectively, for carbonate. The morphology of the carbonate formation on nano coral-shaped α-Fe2O3 over the CO2 exposure time was analyzed using FESEM-EDX. Alth...
The chemical reduction progression behaviour of transition metals (Mo, Zr, W, Ce, and Co) doped o... more The chemical reduction progression behaviour of transition metals (Mo, Zr, W, Ce, and Co) doped on NiO was studied using temperature programmed reduction (TPR) analysis. A wet impregnation method was applied to synthesise the doped NiO series catalysts. The reduction progress of the catalysts was attained by using a reductant gas at the concentration of 40% v/v CO/N2. X-ray diffraction (XRD) was employed to determine the composition of the reduced phases. Undoped NiO was reduced at 384℃ to obtain a cubic phase of NiO. It was observed that Ce/NiO exhibited the lowest reduction temperature of 370℃ among all catalysts. This phenomenon might be due to a higher surface area of Ce/NiO compared to undoped NiO, which facilitated a faster reduction reaction. The rest of the doped NiO series catalysts (Co/NiO, Mo/NiO, W/NiO and Zr/NiO) demonstrated a higher reduction temperature compared to undoped NiO. New peaks in the XRD pattern were observed only for the reduced catalysts of Mo/NiO and W/...
The barium oxide impregnated iron(III) oxide (BaO/Fe2O3) adsorbent was synthesized by an ultrason... more The barium oxide impregnated iron(III) oxide (BaO/Fe2O3) adsorbent was synthesized by an ultrasonic-assisted method. The adsorbent was calcined at 200-500 °C and its adsorption capacity was measured. The ultrasonic-assisted synthesis generated well-dispersed of BaO on Fe2O3 by giving none of the BaO peaks were observed through the XRD pattern. The most efficient adsorbent of BaO/Fe2O3200 was calcined at 200 °C with adsorption capacity for physisorption and chemisorption of 5.01 and 88.81 mg/g respectively. Besides other carbonate species, it was believed the presence of the hydroxyl group could enhance the sorption by forming bicarbonate upon CO2 chemisorption. It is also possessed a lower desorption range compared to BaO and Fe2O3 alone. The experimental CO2 adsorption isotherm at 25 °C fit better with the Freundlich isotherm model. It implies a favorable adsorption process with multilayer adsorption occurs onto the heterogeneous surface.
The reduction behaviour of cobalt doped with nickel oxide and undoped nickel oxide (NiO) by hydro... more The reduction behaviour of cobalt doped with nickel oxide and undoped nickel oxide (NiO) by hydrogen (H2) in nitrogen (20%, v/v) and carbon monoxide (CO) in nitrogen (40%, v/v) atmospheres have been investigated by temperature programmed reduction (TPR). The phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD). TPR results indicate that the reduction of Co doped and undoped nickel oxide in both reductants proceed in one step reduction (NiO → Ni) without intermediate. TPR results also suggested that by adding Co metal into NiO, the reduction to metallic Ni by both reductant gaseous give different intensity of the peak. The reduction process of Co and undoped NiO become faster when H2 was used as a reductant. Furthermore, in H2 atmosphere, Co-NiO give complete reduction to metallic Ni at 700 °C. Meanwhile, XRD analysis indicated that NiO without Co composed better crystallite phases of NiO with higher intensity.
Porous surface of silica gel (SG) have been modified with alkyl fatty amine compounds (octadecyla... more Porous surface of silica gel (SG) have been modified with alkyl fatty amine compounds (octadecylamine, ODA) via wet impregnation process. The ODA-based adsorbents were physically characterized by XRD. The presence of crystalline peaks on ODA/SG diffractograms were ascertained the well-dispersion of ODA on the SG surface. XRD analysis displayed the increasing intensity of crystalline ODA with higher percent amine loaded and shifting of the several crystalline peaks of ODA verified the interaction of SG600-ODA. Capacity of CO2 capture by prepared solid adsorbents were evaluated using CO2 adsorption-desorption isotherms. This study shows that increasing percentage of ODA were improved the amount of CO2 uptake by following this trend: 35ODA/SG > 25ODA/SG > 15ODA/SG > SG > 5ODA/SG. However, promotion of 5 wt.% ODA unabled to enhance the capacity of CO2 captured due to pore blockage and reduction in SG pore surface, thus hindered the physisorption between CO2 and SG.
This study was to detect the heavy metal and xanthones contain in mangosteen leaves. The heavy me... more This study was to detect the heavy metal and xanthones contain in mangosteen leaves. The heavy metal that being detect were lead (Pb), nickel (Ni), iron (Fe) and copper (Cu). The leaves were taken from top, middle and bottom of the tree. For xanthones, the leaves was extracted using methanol in soxhlet extraction process. For detection of heavy metal, Atomic Absorption Spectroscopy (AAS). Fe was the highest concentration which are 1.153 mg·L at the top, 1.493 mg·L -1 at the middle and 1.763 mg·L -1 at the bottom because Fe was the most abundant metal in earth’s crust and the most important heavy metal in plant growth. Pb shows the lowest concentration which are 0.028 mg·L -1 at the top, 0.040 mg·L -1 at the middle and 0.078 mg·L -1 at the bottom which showed that the soil is not contaminated by Pb. For the detection of concentration of xanthones, Ultraviolet-Visible spectroscopy (UVVis) was used. From the UV-Vis results, there were xanthones peak observed in the range of 306 nm to 3...
Surface modification of Fe2O3 by adding BeO was synthesized and calcined at different temperature... more Surface modification of Fe2O3 by adding BeO was synthesized and calcined at different temperatures of 200-600 °C. The adsorbents were characterized by using XRD, N2 adsorption-desorption isotherm prior to performing CO2 adsorption and desorption studies. The CO2 adsorption data were analyzed using adsorption isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. BeO/Fe2O3-300 that calcined at 300 °C showed the most efficient adsorbent with physisorption and chemisorption were measured at 5.85 and 45.88 mg/g respectively. The CO2 adsorption notably best fitted with Freundlich isotherm with R2 = 0.9897 and calculated adsorption capacity closest to experimental data. This implies the CO2 adsorption process was governed by multilayer adsorption on the heterogeneous surface of the adsorbent. The mean free energy of adsorption (E=3.536 kJ/mol) from Dubinin-Radushkevich and heat of adsorption (bT=3.219 kJ/mol) from the Temkin model support that the adsorption proce...
The barium oxide impregnated iron(III) oxide (BaO/Fe2O3) adsorbent was synthesized by an ultrason... more The barium oxide impregnated iron(III) oxide (BaO/Fe2O3) adsorbent was synthesized by an ultrasonic-assisted method. The adsorbent was calcined at 200-500 °C and its adsorption capacity was measured. The ultrasonic-assisted synthesis generated well-dispersed of BaO on Fe2O3 by giving none of the BaO peaks were observed through the XRD pattern. The most efficient adsorbent of BaO/Fe2O3200 was calcined at 200 °C with adsorption capacity for physisorption and chemisorption of 5.01 and 88.81 mg/g respectively. Besides other carbonate species, it was believed the presence of the hydroxyl group could enhance the sorption by forming bicarbonate upon CO2 chemisorption. It is also possessed a lower desorption range compared to BaO and Fe2O3 alone. The experimental CO2 adsorption isotherm at 25 °C fit better with the Freundlich isotherm model. It implies a favorable adsorption process with multilayer adsorption occurs onto the heterogeneous surface.
The depletion of petroleum sources and global warming issues has increased awareness among scient... more The depletion of petroleum sources and global warming issues has increased awareness among scientists to produce alternative energy other than the one that we always depend on, which is petroleum. Hydrogen (H2) energy is one of the alternatives that was promising as an efficient and green fuel. Meanwhile, formic acid has been detected as one of the convenient H2 source/storage material. Here, we introduce two heterogeneous catalysts for H2 generation from formic acid. Fe0.1 Zn0.9 and Fe0.5 Zn0.5 were synthesized by a modified microwave method. In this study, we report the result of a detailed study undertaken to investigate the decomposition of formic acid to H2 and carbon dioxide (CO2) using gas chromatography with thermal conductivity detector (GC-TCD). The catalyst used to decompose the formic acid was characterized by x-ray diffraction (XRD) to determine their physicochemical properties. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TE...
Octadecylsilylated silica (ODS-Silica) stationary phases were developed and examined for solid ph... more Octadecylsilylated silica (ODS-Silica) stationary phases were developed and examined for solid phase extraction (SPE) analysis. The ODS-silica phases were endcapped using two different methods, namely by refluxing at 106 °C and stirring at room temperature. The effect of the reaction time was also investigated by performing the reactions for 6 and 16 h. Thermogravimetric analysis performed on the phases indicated that the capped ODS-silicas showed a decrease in weight loss in the temperature range of 25-125 °C, suggesting that the silanol groups decreased with endcapping. The thermograms for all the adsorbents showed a weight loss in the temperature range of 300-600 °C indicating the presence of methyl groups in the adsorbents. Abstrak: Oktadekilsilil-silika (ODS-silika) telah disediakan dan dikaji dalam analisis pengekstrakan fasa pepejal (SPE). Penutupan hujung fasa tersebut telah dilakukan menggunakan dua kaedah yang berbeza: refluks pada 106 °C dan pengacauan pada suhu bilik. Ke...
Uploads