Lia Harmelia - Academia.edu (original) (raw)
Papers by Lia Harmelia
Uji kompatibilitas antara membran datar perovskit La0,6Sr0,4Co0,2Fe0,8O3-δ (LSCF 6428), La0,7Sr0,... more Uji kompatibilitas antara membran datar perovskit La0,6Sr0,4Co0,2Fe0,8O3-δ (LSCF 6428), La0,7Sr0,3Co0,2Fe0,8O3-δ (LSCF 7328), dan La0,7Sr0,3Mn1,0O3±δ (LSM 7310) dengan lapisan campuran NiO-CeO2 serta CeO2 yang dibentuk menjadi membran lapis ganda dengan metode dry pressing telah dilakukan pada penelitian ini. Sebelumnya, dilakukan pembuatan dan karakterisasi membran tunggal LSCF 6428, LSCF 7328, LSM 7310 serta NiO-CeO2 dan CeO2. Hasil karakterisasi menunjukkan bahwa LSM 7310 memiliki nilai kerapatan tertinggi kemudian diikuti oleh LSCF 7328 dan LSCF 6428, sedangkan membran NiO-CeO2 dan CeO2 belum rapat. Nilai kerapatan membran tersebut berhubungan dengan nilai kekerasan dan koefisien muai panas membran, yaitu semakin rapat membran maka semakin tinggi nilai kekerasan membran namun semakin rendah nilai koefisien muai panasnya. Nilai koefisien muai panas LSCF 6428, LSCF 7328, LSM 7310, NiO-CeO2 dan CeO2 secara berurutan sebesar 22,16; 9,31; 10,14; 12,21 dan 21,11 ppm/°C. Perbedaan nilai koefisien muai panas antara material material tersebut menyebabkan delaminasi pada lapisan antarmuka perovskit dan NiO-CeO2 atau CeO2 ketika membran lapis ganda dibentuk Kata kunci: Membran lapis ganda, La1-xSrxCo1-yFeyO3-δ, La1-xSrxMnO3-δ, NiO, CeO2 , kompatibilitas, koefisien muai panas.
Archives of Metallurgy and Materials, Jul 26, 2023
Setting time and CompreSSive Strength of geopolymerS made of three indoneSian low CalCium fly aSh... more Setting time and CompreSSive Strength of geopolymerS made of three indoneSian low CalCium fly aSh with variation of Sodium SiliCate addition in this research, the effect of sodium silicate (na 2 Sio 3) on the geopolymerization of fly ash type F (low calcium) has been studied. the variations of na 2 Sio 3 used in the synthesized geopolymers were 19, 32, and 41wt%. the fly ash from three different power plant sources was characterized using X-Ray Fluorescence (XRF), X-Ray diffraction (XRd), Particle Size analyzer (PSa), and Scanning Electron microscopy (SEm). Fly ash-based geopolymers were tested for mechanical strength and setting time. the best geopolymer was obtained by adding 32% na 2 Sio 3 , produced a compressive strength of 21.62 mPa with a setting time of 30 hours. additions of 19wt% na 2 Sio 3 failed to form geopolymer paste while the addition of 41wt% na 2 Sio 3 decreased the mechanical strength of the geopolymer. Higher calcium content in low calcium fly ash produces stronger geopolymer and faster setting time.
Journal of Applied Membrane Science & Technology, Nov 21, 2018
The aim of this work is to study the effect of polyethylene glycol (PEG) on the modification of m... more The aim of this work is to study the effect of polyethylene glycol (PEG) on the modification of microstructure formation correlated with the mechanical strength properties of perovskitebased membrane in form of a flat sheet. LSCF 7328 flat membrane was potentially promoted as an oxygen separator and catalyst for partial oxidation of methane reaction at high temperature. In this study, the phase-inversion followed by sintering process was used as the membrane fabrication method using varied PEG concentration of 0.55, 1.00, and 3.00 wt% with different molecular weight, i.e., PEG 300, 600, 1500, and 4000 Da for each PEG concentration. The result of morphology observation shows that almost every membrane hasthe asymmetric structure with finger-like pores and thin dense layer. Increasing PEG concentration as well as molecular weight increases pore size and affects on porosity, pore's volume, and physical properties of membrane. The largest pore size, pore volume and porosity of the membrane after sintering were found in the addition of 3.00% PEG 4000 (Da) additive with the value of 110.45 μm, 81.34 ml.g-1 and 120.6%, respectively. In addition, the mechanical properties of membrane were tested using the Vickers micro hardness method with the greatest value found in the addition of 3.00% PEG 1500 (Da) additive with the value of 13.58 Hv and the lowest is 3.00% PEG 4000 (Da) with the value of 1.2 Hv.
IOP conference series, May 1, 2018
Metal oxides and perovskites have got tremendous attention as a good catalyst for partial oxidati... more Metal oxides and perovskites have got tremendous attention as a good catalyst for partial oxidation of methane (POM). In the present work, the materials were cast into a double layer planar membrane using the dry pressing method in order to enhance its' catalytic activity. Unfortunately, the majority of metal oxides and perovskites have different thermal expansion coefficient (TEC). Therefore, this work was aimed to study the compatibility between catalyst metal oxides (NiO, CeO2) and perovskite oxides La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF 6428), La0.7Sr0.3Co0.2Fe0.8O3-δ (LSCF 7328) and La0.7Sr0.3MnO3-δ (LSM 73) when they were made as double layer membranes. The result shows that the density and volume shrinkage of LSCF 7328 was the highest, followed by LSM 73 and LSCF 6428. It was also found that the trends of hardness and density in the perovskites and metal oxides follows their thermal expansion trends. According to thermomechanical analysis (TMA) results,
Uji kompatibilitas antara membran datar perovskit La0,6Sr0,4Co0,2Fe0,8O3-δ (LSCF 6428), La0,7Sr0,... more Uji kompatibilitas antara membran datar perovskit La0,6Sr0,4Co0,2Fe0,8O3-δ (LSCF 6428), La0,7Sr0,3Co0,2Fe0,8O3 δ (LSCF 7328), dan La0,7Sr0,3Mn1,0O3±δ (LSM 7310) dengan lapisan campuran NiO-CeO2 serta CeO2 yang dibentuk menjadi membran lapis ganda dengan metode dry pressing telah dilakukan pada penelitian ini. Sebelumnya, dilakukan pembuatan dan karakterisasi membran tunggal LSCF 6428, LSCF 7328, LSM 7310 serta NiO CeO2 dan CeO¬2. Hasil karakterisasi menunjukkan bahwa LSM 7310 memiliki nilai kerapatan tertinggi kemudian diikuti oleh LSCF 7328 dan LSCF 6428, sedangkan membran NiO-CeO2 dan CeO2 belum rapat. Nilai kerapatan membran tersebut berhubungan dengan nilai kekerasan dan koefisien muai panas membran, yaitu semakin rapat membran maka semakin tinggi nilai kekerasan membran namun semakin rendah nilai koefisien muai panasnya. Nilai koefisien muai panas LSCF 6428, LSCF 7328, LSM 7310, NiO-CeO2 dan CeO2 secara berurutan sebesar 22,16; 9,31; 10,14; 12,21 dan 21,11 ppm/°C. Perbedaan nil...
IOP Conference Series: Materials Science and Engineering, 2018
Metal oxides and perovskites have got tremendous attention as a good catalyst for partial oxidati... more Metal oxides and perovskites have got tremendous attention as a good catalyst for partial oxidation of methane (POM). In the present work, the materials were cast into a double layer planar membrane using the dry pressing method in order to enhance its' catalytic activity. Unfortunately, the majority of metal oxides and perovskites have different thermal expansion coefficient (TEC). Therefore, this work was aimed to study the compatibility between catalyst metal oxides (NiO, CeO2) and perovskite oxides La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF 6428), La0.7Sr0.3Co0.2Fe0.8O3-δ (LSCF 7328) and La0.7Sr0.3MnO3-δ (LSM 73) when they were made as double layer membranes. The result shows that the density and volume shrinkage of LSCF 7328 was the highest, followed by LSM 73 and LSCF 6428. It was also found that the trends of hardness and density in the perovskites and metal oxides follows their thermal expansion trends. According to thermomechanical analysis (TMA) results,
Journal of Applied Membrane Science & Technology, 2018
The aim of this work is to study the effect of polyethylene glycol (PEG) on the modification of m... more The aim of this work is to study the effect of polyethylene glycol (PEG) on the modification of microstructure formation correlated with the mechanical strength properties of perovskite-based membrane in form of a flat sheet. LSCF 7328 flat membrane was potentially promoted as an oxygen separator and catalyst for partial oxidation of methane reaction at high temperature. In this study, the phase-inversion followed by sintering process was used as the membrane fabrication method using varied PEG concentration of 0.55, 1.00, and 3.00 wt% with different molecular weight, i.e., PEG 300, 600, 1500, and 4000 Da for each PEG concentration. The result of morphology observation shows that almost every membrane hasthe asymmetric structure with finger-like pores and thin dense layer. Increasing PEG concentration as well as molecular weight increases pore size and affects on porosity, pore's volume, and physical properties of membrane. The largest pore size, pore volume and porosity of the ...
Journal of the Indonesian Chemical Society
Crude oil spills pose a serious threat to the marine environment. This is due to crude oil, in la... more Crude oil spills pose a serious threat to the marine environment. This is due to crude oil, in large part, is composed of aromatic, aliphatic, and alicyclic hydrocarbons which are toxic, carcinogenic, and mutagenic to the marine life. However, the degradation of crude oil spills with bacteria in simulated seawater media is rarely reported. In this study, oil spill in the seawater, especially petroleum, had been successfully degraded by bacterium culture Bacillus subtilis in simulated seawater under 7 and 14 days incubation. Simulated seawater had synthesized based on ASTM D1141-98 for Standard Practice for the Preparation of Substitute Ocean Water. The petroleum recovery was analyzed using Gas chromatography-mass spectrometry. In this research, the optimum recovery value of crude oil degradation by the bacterial culture obtained by octadecadienoic acid compound gave a percentage recovery of 8.20% and 8.87% after 7 and 14 days of incubation, respectively. This result indicated that...
Malaysian Journal of Fundamental and Applied Sciences
Bacterium Ralstonia pickettii has ability to survive and thrive in low nutrient condition as well... more Bacterium Ralstonia pickettii has ability to survive and thrive in low nutrient condition as well as a capability to remediate some pollutants and using them as carbon and energy source. In this study, the ability of R. pickettii on biodegradation of crude oil under high salinity medium was investigated. R. pickettii was pre-incubated in nutrient broth (NB) medium and then, washed and transferred to artificial seawater medium. Crude oil was added to each culture and incubated for 7 and 14 days. The biodegradation of crude oil was analysed using Gas chromatography mass spectrometry (GC-MS). The result showed that R. pickettii had successfully degraded the crude oil in the high salinity artificial seawater. The incubation on 7 and 14 days did not show a significant effect on the number of the degraded compounds. The optimum recovery percent was obtained from the derivation of 2,6,10,14-tetramethyl hexadecane with the recovery percentage of 12.7% and 16.0% for 7 and 14 days respectivel...
Jurnal Sains dan Seni ITS
Abstrak-Oksida perovskit La1-xSrxCo1-yFeyO3 (LS CF) dan La1-xSrxMnO3-δ (LS M) dikenal sebagai mem... more Abstrak-Oksida perovskit La1-xSrxCo1-yFeyO3 (LS CF) dan La1-xSrxMnO3-δ (LS M) dikenal sebagai membran MIEC yang berpotensi sebagai membran penghantar ion oksigen karena fluks permeasi oksigen tinggi, dan telah terbukti kemampuannya baik sebagai katalis dalam reaksi oksidasi parsial metana (OPM). Pada penelitian ini untuk meningkatkan aktivitas katalis, materialmaterial tersebut dilapisi oksida logam NiO dan CeO2 menjadi membran planar lapis ganda dengan metode dry pressing. Oleh karena itu, penelitian ini bertujuan untuk megetahui preparasi membran dan kompatibilitas antara campuran NiO-CeO2, CeO2 dan perovskit LS CF 6428, LS CF 7328, dan LS M 7310. Hasil karakterisasi menunjukkan bahwa LS M 7310 memiliki nilai kerapatan tertinggi kemudian diikuti oleh LS CF 7328 dan LS CF 6428, sedangkan membran NiO-CeO2 dan CeO2 belum rapat. Kekerasan dan kerapatan berhubungan dengan pola muai panasnya, yaitu semakin rapat membran maka semakin tinggi nilai kekerasan membran namun semakin rendah nilai koefisien muai panasnya. Perbedaan nilai koefisien muai panas antara material material tersebut menyebabkan delaminasi pada lapisan antarmuka perovskit dan NiO-CeO2 atau CeO2, ketika membran lapis ganda dibentuk. S ementara itu, penambahan agen perekat berupa amilum pada lapisan NiO-CeO2 atau CeO2 berhasil menyebabkan NiO-CeO2 dapat melekat pada lapisan perovskit.
Abstrak-Oksida perovskit La1-xSrxCo1-yFeyO3 (LS CF) dan La1-xSrxMnO3-δ (LS M) dikenal sebagai mem... more Abstrak-Oksida perovskit La1-xSrxCo1-yFeyO3 (LS CF) dan La1-xSrxMnO3-δ (LS M) dikenal sebagai membran MIEC yang berpotensi sebagai membran penghantar ion oksigen karena fluks permeasi oksigen tinggi, dan telah terbukti kemampuannya baik sebagai katalis dalam reaksi oksidasi parsial metana (OPM). Pada penelitian ini untuk meningkatkan aktivitas katalis, materialmaterial tersebut dilapisi oksida logam NiO dan CeO2 menjadi membran planar lapis ganda dengan metode dry pressing. Oleh karena itu, penelitian ini bertujuan untuk megetahui preparasi membran dan kompatibilitas antara campuran NiO-CeO2, CeO2 dan perovskit LS CF 6428, LS CF 7328, dan LS M 7310. Hasil karakterisasi menunjukkan bahwa LS M 7310 memiliki nilai kerapatan tertinggi kemudian diikuti oleh LS CF 7328 dan LS CF 6428, sedangkan membran NiO-CeO2 dan CeO2 belum rapat. Kekerasan dan kerapatan berhubungan dengan pola muai panasnya, yaitu semakin rapat membran maka semakin tinggi nilai kekerasan membran namun semakin rendah nilai koefisien muai panasnya. Perbedaan nilai koefisien muai panas antara material material tersebut menyebabkan delaminasi pada lapisan antarmuka perovskit dan NiO-CeO2 atau CeO2, ketika membran lapis ganda dibentuk. S ementara itu, penambahan agen perekat berupa amilum pada lapisan NiO-CeO2 atau CeO2 berhasil menyebabkan NiO-CeO2 dapat melekat pada lapisan perovskit.
Uji kompatibilitas antara membran datar perovskit La0,6Sr0,4Co0,2Fe0,8O3-δ (LSCF 6428), La0,7Sr0,... more Uji kompatibilitas antara membran datar perovskit La0,6Sr0,4Co0,2Fe0,8O3-δ (LSCF 6428), La0,7Sr0,3Co0,2Fe0,8O3-δ (LSCF 7328), dan La0,7Sr0,3Mn1,0O3±δ (LSM 7310) dengan lapisan campuran NiO-CeO2 serta CeO2 yang dibentuk menjadi membran lapis ganda dengan metode dry pressing telah dilakukan pada penelitian ini. Sebelumnya, dilakukan pembuatan dan karakterisasi membran tunggal LSCF 6428, LSCF 7328, LSM 7310 serta NiO-CeO2 dan CeO2. Hasil karakterisasi menunjukkan bahwa LSM 7310 memiliki nilai kerapatan tertinggi kemudian diikuti oleh LSCF 7328 dan LSCF 6428, sedangkan membran NiO-CeO2 dan CeO2 belum rapat. Nilai kerapatan membran tersebut berhubungan dengan nilai kekerasan dan koefisien muai panas membran, yaitu semakin rapat membran maka semakin tinggi nilai kekerasan membran namun semakin rendah nilai koefisien muai panasnya. Nilai koefisien muai panas LSCF 6428, LSCF 7328, LSM 7310, NiO-CeO2 dan CeO2 secara berurutan sebesar 22,16; 9,31; 10,14; 12,21 dan 21,11 ppm/°C. Perbedaan nilai koefisien muai panas antara material material tersebut menyebabkan delaminasi pada lapisan antarmuka perovskit dan NiO-CeO2 atau CeO2 ketika membran lapis ganda dibentuk Kata kunci: Membran lapis ganda, La1-xSrxCo1-yFeyO3-δ, La1-xSrxMnO3-δ, NiO, CeO2 , kompatibilitas, koefisien muai panas.
Archives of Metallurgy and Materials, Jul 26, 2023
Setting time and CompreSSive Strength of geopolymerS made of three indoneSian low CalCium fly aSh... more Setting time and CompreSSive Strength of geopolymerS made of three indoneSian low CalCium fly aSh with variation of Sodium SiliCate addition in this research, the effect of sodium silicate (na 2 Sio 3) on the geopolymerization of fly ash type F (low calcium) has been studied. the variations of na 2 Sio 3 used in the synthesized geopolymers were 19, 32, and 41wt%. the fly ash from three different power plant sources was characterized using X-Ray Fluorescence (XRF), X-Ray diffraction (XRd), Particle Size analyzer (PSa), and Scanning Electron microscopy (SEm). Fly ash-based geopolymers were tested for mechanical strength and setting time. the best geopolymer was obtained by adding 32% na 2 Sio 3 , produced a compressive strength of 21.62 mPa with a setting time of 30 hours. additions of 19wt% na 2 Sio 3 failed to form geopolymer paste while the addition of 41wt% na 2 Sio 3 decreased the mechanical strength of the geopolymer. Higher calcium content in low calcium fly ash produces stronger geopolymer and faster setting time.
Journal of Applied Membrane Science & Technology, Nov 21, 2018
The aim of this work is to study the effect of polyethylene glycol (PEG) on the modification of m... more The aim of this work is to study the effect of polyethylene glycol (PEG) on the modification of microstructure formation correlated with the mechanical strength properties of perovskitebased membrane in form of a flat sheet. LSCF 7328 flat membrane was potentially promoted as an oxygen separator and catalyst for partial oxidation of methane reaction at high temperature. In this study, the phase-inversion followed by sintering process was used as the membrane fabrication method using varied PEG concentration of 0.55, 1.00, and 3.00 wt% with different molecular weight, i.e., PEG 300, 600, 1500, and 4000 Da for each PEG concentration. The result of morphology observation shows that almost every membrane hasthe asymmetric structure with finger-like pores and thin dense layer. Increasing PEG concentration as well as molecular weight increases pore size and affects on porosity, pore's volume, and physical properties of membrane. The largest pore size, pore volume and porosity of the membrane after sintering were found in the addition of 3.00% PEG 4000 (Da) additive with the value of 110.45 μm, 81.34 ml.g-1 and 120.6%, respectively. In addition, the mechanical properties of membrane were tested using the Vickers micro hardness method with the greatest value found in the addition of 3.00% PEG 1500 (Da) additive with the value of 13.58 Hv and the lowest is 3.00% PEG 4000 (Da) with the value of 1.2 Hv.
IOP conference series, May 1, 2018
Metal oxides and perovskites have got tremendous attention as a good catalyst for partial oxidati... more Metal oxides and perovskites have got tremendous attention as a good catalyst for partial oxidation of methane (POM). In the present work, the materials were cast into a double layer planar membrane using the dry pressing method in order to enhance its' catalytic activity. Unfortunately, the majority of metal oxides and perovskites have different thermal expansion coefficient (TEC). Therefore, this work was aimed to study the compatibility between catalyst metal oxides (NiO, CeO2) and perovskite oxides La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF 6428), La0.7Sr0.3Co0.2Fe0.8O3-δ (LSCF 7328) and La0.7Sr0.3MnO3-δ (LSM 73) when they were made as double layer membranes. The result shows that the density and volume shrinkage of LSCF 7328 was the highest, followed by LSM 73 and LSCF 6428. It was also found that the trends of hardness and density in the perovskites and metal oxides follows their thermal expansion trends. According to thermomechanical analysis (TMA) results,
Uji kompatibilitas antara membran datar perovskit La0,6Sr0,4Co0,2Fe0,8O3-δ (LSCF 6428), La0,7Sr0,... more Uji kompatibilitas antara membran datar perovskit La0,6Sr0,4Co0,2Fe0,8O3-δ (LSCF 6428), La0,7Sr0,3Co0,2Fe0,8O3 δ (LSCF 7328), dan La0,7Sr0,3Mn1,0O3±δ (LSM 7310) dengan lapisan campuran NiO-CeO2 serta CeO2 yang dibentuk menjadi membran lapis ganda dengan metode dry pressing telah dilakukan pada penelitian ini. Sebelumnya, dilakukan pembuatan dan karakterisasi membran tunggal LSCF 6428, LSCF 7328, LSM 7310 serta NiO CeO2 dan CeO¬2. Hasil karakterisasi menunjukkan bahwa LSM 7310 memiliki nilai kerapatan tertinggi kemudian diikuti oleh LSCF 7328 dan LSCF 6428, sedangkan membran NiO-CeO2 dan CeO2 belum rapat. Nilai kerapatan membran tersebut berhubungan dengan nilai kekerasan dan koefisien muai panas membran, yaitu semakin rapat membran maka semakin tinggi nilai kekerasan membran namun semakin rendah nilai koefisien muai panasnya. Nilai koefisien muai panas LSCF 6428, LSCF 7328, LSM 7310, NiO-CeO2 dan CeO2 secara berurutan sebesar 22,16; 9,31; 10,14; 12,21 dan 21,11 ppm/°C. Perbedaan nil...
IOP Conference Series: Materials Science and Engineering, 2018
Metal oxides and perovskites have got tremendous attention as a good catalyst for partial oxidati... more Metal oxides and perovskites have got tremendous attention as a good catalyst for partial oxidation of methane (POM). In the present work, the materials were cast into a double layer planar membrane using the dry pressing method in order to enhance its' catalytic activity. Unfortunately, the majority of metal oxides and perovskites have different thermal expansion coefficient (TEC). Therefore, this work was aimed to study the compatibility between catalyst metal oxides (NiO, CeO2) and perovskite oxides La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF 6428), La0.7Sr0.3Co0.2Fe0.8O3-δ (LSCF 7328) and La0.7Sr0.3MnO3-δ (LSM 73) when they were made as double layer membranes. The result shows that the density and volume shrinkage of LSCF 7328 was the highest, followed by LSM 73 and LSCF 6428. It was also found that the trends of hardness and density in the perovskites and metal oxides follows their thermal expansion trends. According to thermomechanical analysis (TMA) results,
Journal of Applied Membrane Science & Technology, 2018
The aim of this work is to study the effect of polyethylene glycol (PEG) on the modification of m... more The aim of this work is to study the effect of polyethylene glycol (PEG) on the modification of microstructure formation correlated with the mechanical strength properties of perovskite-based membrane in form of a flat sheet. LSCF 7328 flat membrane was potentially promoted as an oxygen separator and catalyst for partial oxidation of methane reaction at high temperature. In this study, the phase-inversion followed by sintering process was used as the membrane fabrication method using varied PEG concentration of 0.55, 1.00, and 3.00 wt% with different molecular weight, i.e., PEG 300, 600, 1500, and 4000 Da for each PEG concentration. The result of morphology observation shows that almost every membrane hasthe asymmetric structure with finger-like pores and thin dense layer. Increasing PEG concentration as well as molecular weight increases pore size and affects on porosity, pore's volume, and physical properties of membrane. The largest pore size, pore volume and porosity of the ...
Journal of the Indonesian Chemical Society
Crude oil spills pose a serious threat to the marine environment. This is due to crude oil, in la... more Crude oil spills pose a serious threat to the marine environment. This is due to crude oil, in large part, is composed of aromatic, aliphatic, and alicyclic hydrocarbons which are toxic, carcinogenic, and mutagenic to the marine life. However, the degradation of crude oil spills with bacteria in simulated seawater media is rarely reported. In this study, oil spill in the seawater, especially petroleum, had been successfully degraded by bacterium culture Bacillus subtilis in simulated seawater under 7 and 14 days incubation. Simulated seawater had synthesized based on ASTM D1141-98 for Standard Practice for the Preparation of Substitute Ocean Water. The petroleum recovery was analyzed using Gas chromatography-mass spectrometry. In this research, the optimum recovery value of crude oil degradation by the bacterial culture obtained by octadecadienoic acid compound gave a percentage recovery of 8.20% and 8.87% after 7 and 14 days of incubation, respectively. This result indicated that...
Malaysian Journal of Fundamental and Applied Sciences
Bacterium Ralstonia pickettii has ability to survive and thrive in low nutrient condition as well... more Bacterium Ralstonia pickettii has ability to survive and thrive in low nutrient condition as well as a capability to remediate some pollutants and using them as carbon and energy source. In this study, the ability of R. pickettii on biodegradation of crude oil under high salinity medium was investigated. R. pickettii was pre-incubated in nutrient broth (NB) medium and then, washed and transferred to artificial seawater medium. Crude oil was added to each culture and incubated for 7 and 14 days. The biodegradation of crude oil was analysed using Gas chromatography mass spectrometry (GC-MS). The result showed that R. pickettii had successfully degraded the crude oil in the high salinity artificial seawater. The incubation on 7 and 14 days did not show a significant effect on the number of the degraded compounds. The optimum recovery percent was obtained from the derivation of 2,6,10,14-tetramethyl hexadecane with the recovery percentage of 12.7% and 16.0% for 7 and 14 days respectivel...
Jurnal Sains dan Seni ITS
Abstrak-Oksida perovskit La1-xSrxCo1-yFeyO3 (LS CF) dan La1-xSrxMnO3-δ (LS M) dikenal sebagai mem... more Abstrak-Oksida perovskit La1-xSrxCo1-yFeyO3 (LS CF) dan La1-xSrxMnO3-δ (LS M) dikenal sebagai membran MIEC yang berpotensi sebagai membran penghantar ion oksigen karena fluks permeasi oksigen tinggi, dan telah terbukti kemampuannya baik sebagai katalis dalam reaksi oksidasi parsial metana (OPM). Pada penelitian ini untuk meningkatkan aktivitas katalis, materialmaterial tersebut dilapisi oksida logam NiO dan CeO2 menjadi membran planar lapis ganda dengan metode dry pressing. Oleh karena itu, penelitian ini bertujuan untuk megetahui preparasi membran dan kompatibilitas antara campuran NiO-CeO2, CeO2 dan perovskit LS CF 6428, LS CF 7328, dan LS M 7310. Hasil karakterisasi menunjukkan bahwa LS M 7310 memiliki nilai kerapatan tertinggi kemudian diikuti oleh LS CF 7328 dan LS CF 6428, sedangkan membran NiO-CeO2 dan CeO2 belum rapat. Kekerasan dan kerapatan berhubungan dengan pola muai panasnya, yaitu semakin rapat membran maka semakin tinggi nilai kekerasan membran namun semakin rendah nilai koefisien muai panasnya. Perbedaan nilai koefisien muai panas antara material material tersebut menyebabkan delaminasi pada lapisan antarmuka perovskit dan NiO-CeO2 atau CeO2, ketika membran lapis ganda dibentuk. S ementara itu, penambahan agen perekat berupa amilum pada lapisan NiO-CeO2 atau CeO2 berhasil menyebabkan NiO-CeO2 dapat melekat pada lapisan perovskit.
Abstrak-Oksida perovskit La1-xSrxCo1-yFeyO3 (LS CF) dan La1-xSrxMnO3-δ (LS M) dikenal sebagai mem... more Abstrak-Oksida perovskit La1-xSrxCo1-yFeyO3 (LS CF) dan La1-xSrxMnO3-δ (LS M) dikenal sebagai membran MIEC yang berpotensi sebagai membran penghantar ion oksigen karena fluks permeasi oksigen tinggi, dan telah terbukti kemampuannya baik sebagai katalis dalam reaksi oksidasi parsial metana (OPM). Pada penelitian ini untuk meningkatkan aktivitas katalis, materialmaterial tersebut dilapisi oksida logam NiO dan CeO2 menjadi membran planar lapis ganda dengan metode dry pressing. Oleh karena itu, penelitian ini bertujuan untuk megetahui preparasi membran dan kompatibilitas antara campuran NiO-CeO2, CeO2 dan perovskit LS CF 6428, LS CF 7328, dan LS M 7310. Hasil karakterisasi menunjukkan bahwa LS M 7310 memiliki nilai kerapatan tertinggi kemudian diikuti oleh LS CF 7328 dan LS CF 6428, sedangkan membran NiO-CeO2 dan CeO2 belum rapat. Kekerasan dan kerapatan berhubungan dengan pola muai panasnya, yaitu semakin rapat membran maka semakin tinggi nilai kekerasan membran namun semakin rendah nilai koefisien muai panasnya. Perbedaan nilai koefisien muai panas antara material material tersebut menyebabkan delaminasi pada lapisan antarmuka perovskit dan NiO-CeO2 atau CeO2, ketika membran lapis ganda dibentuk. S ementara itu, penambahan agen perekat berupa amilum pada lapisan NiO-CeO2 atau CeO2 berhasil menyebabkan NiO-CeO2 dapat melekat pada lapisan perovskit.