Wahyu Widayatno | Indonesian Institute of Sciences (original) (raw)

Papers by Wahyu Widayatno

This study is an effort to increase ionic conductivity of electrolyte polymer membranes in Lithiu... more This study is an effort to increase ionic conductivity of electrolyte polymer membranes in Lithium ion battery applications by combining electrolyte salts. An electrolyte polymer membrane functions as electrolytes and a separator. Such a membrane is made using a solution casting method at room temperature and consists of Polyvinylidene fluoride co-hexaflouropropylene (PVDF-HFP) as the polymer, titanium oxide (TiO2) as a filler, and combinations of Lithium bis(oxalate) borat (LiBOB) and Lithium bis-trifluoromethanesulfonimide (LiTFSI) as electrolyte salts. The electrolyte polymer membrane was characterized using Electrochemical Impedance Spectroscopy (EIS) for conductivity, X-Ray Diffractometer (XRD) for material crystallinity, and Scanning Electron Microscope (SEM) for surface morphology. The results of EIS tests show that the sample containing 23% LiTFSI and 5% LiBOB has the highest conductivity (2,35 x 10 -6 S/cm) compared to the other samples. This finding is supported by the res...

P-54 Modification of zeolite acidity and its effect on the upgrading of biomass-derived oil

Kinetic study of methylene blue photocatalytic decolorization using zinc oxide under UV-LED irradiation

THE 14TH JOINT CONFERENCE ON CHEMISTRY 2019, 2020

Kinetic study of methylene blue photocatalytic decolorization using zinc oxide was carried out un... more Kinetic study of methylene blue photocatalytic decolorization using zinc oxide was carried out under UV-LED lamp irradiation. Zinc oxide was prepared by precipitation method. Zinc oxide was characterized by XRD, FESEM, and N2 adsorption-desorption. Characterization results show that zinc oxide has a hexagonal crystal face, particle size between 0.125-0.3 µm, specific surface area (SBET), micropore volume, and mesopore volume are 60.20 m2/g, 0.541 cm3/g, and 0.02 cm3/g, respectively. The variations of pH and concentration of methylene blue solution were observed. The results show that the alkaline conditions had the highest methylene blue photocatalytic decolorization rate. At initial low concentration, the methylene blue photocatalytic decolorization is very high and decrease when the initial concentration of methylene blue increase. Photocatalytic decolorization reaction kinetics follow the first-order kinetic. The Langmuir-Hinshelwood kinetic analysis results show that photocatalytic reaction constant and Langmuir-Hinshelwood constant value are 2.2621 L.mg−1.min−1 and 0.0144 L.mg-1, respectively.

Decolourization of methylene blue by NiO/ZSM-5 photocatalyst under UV-LED irradiation

THE 14TH JOINT CONFERENCE ON CHEMISTRY 2019, 2020

Crystals, 2020

The oxidation and hardness of thermally exposed titanium (Ti) prepared using inductive sintering-... more The oxidation and hardness of thermally exposed titanium (Ti) prepared using inductive sintering-assisted powder metallurgy was evaluated through cyclic tests in air at 700–900 °C for 100 h (5 cycles). In general, the oxidation kinetics of the Ti samples followed the parabolic law and their oxidation rates increased with increasing oxidation temperatures. The rutile form of titanium dioxide (TiO2) was detected by X-ray diffraction in the oxide scales after oxidation at 700 °C and 900 °C. Furthermore, the TiO2 grain size and thickness were significantly influenced by an increase in the oxidation temperature. Lastly, the formation of rutile as a single-phase on the surface of oxidized Ti enhanced the hardness of the oxide scales, whereas the substrate had lower hardness values than the oxide scales due to diffusion of Ti atoms at the surface to form the TiO2 oxide scales.

Jurnal Riset Kimia, 2019

The comparison of photocatalytic decolorization of Methylene Blue and Methyl Orange using ZnO Sem... more The comparison of photocatalytic decolorization of Methylene Blue and Methyl Orange using ZnO Semiconductor under UV-LED radiation has been studied at varied pH. ZnO have been synthesized using co-precipitation method. The Scanning Electron Microscopy (SEM) result showed that the synthesized ZnO has a hexagonal structure with the particle size range 0.125 to 0.5 µm. The BET isotherm characterization showed the synthesized ZnO has a specific surface area (SBET), mesoporous volume and micropore volume of 60.20 m2/g, 0.541 cm3/g and 0.02 cm3/g, respectively. The observation of the effect of pH to the photocatalytic activity showed that the highest removal percentage occurred at pH 9 with the value of 95.64% for methylene blue and occurred at pH 3 with the value of 6.236% for methyl orange.

Catalysis Communications, 2018

In this work, the selective conversion of hexanoic acid to hydrocarbons using Cu/βzeolite-EG prep... more In this work, the selective conversion of hexanoic acid to hydrocarbons using Cu/βzeolite-EG prepared by the ethylene glycol (EG) assisted impregnation method was investigated. It was found that Cu/βzeolite-EG shows higher selectivity towards benzene, toluene and xylenes (BTXs) as well as higher resistance to coke deposition when compared to Cu/βzeolite prepared by a conventional impregnation method. This should be attributed to the better dispersion and stronger interaction between the active Cu species and the β-zeolite surface in the Cu/β-zeolite-EG solid. This catalytic system shows potential practical application in the upgrading of bio-oil.

Journal of Physics: Conference Series, 2018

View the article online for updates and enhancements.

The number of vehicles in Jakarta increased by 5.66% from 2016. Vehicles have the highest contrib... more The number of vehicles in Jakarta increased by 5.66% from 2016. Vehicles have the highest contribution to air pollution, which is 70% of other activities. The purpose of this study was to determine the reduction of CO with zeolite pellets. This type of research is a quasi-experimental design with a non-equivalent control group design pre-test post-test design. The emission test instrument uses the automotive gas analyzer HESBOHN, a tachometer to measure engine speed, laptops, and stopwatches. The material used is activated natural zeolite pellets. Data were analyzed by univariate in the form of CO adsorption power efficiency, average, minimum, and maximum. The variables used are pellet drying time (3 hours and 24 hours) and engine speed (idle and 1250 rpm). The result of CO adsorption power efficiency using the most optimal zeolite pellets is Pellet I with 3 hours drying at 1250 rpm by 52%. While the lowest yield is Pellet II with 24-hour drying at idle conditions of 22%. The most e...

Journal of Metals, Materials and Minerals, Mar 29, 2022

Aluminum-based metal matrix nanocomposites have been extensively researched and developed for aer... more Aluminum-based metal matrix nanocomposites have been extensively researched and developed for aerospace and automotive applications. Al-4.5Cu-1.5Mg with 0.5 wt% graphite were milled for 2 h, 4 h, 6 h, and 8 h using shaker mill under argon gas. The phenomena of deformation, fracturing, and cold welding during shaker mill were investigated to observe how the shaker mill effects on their morphology and formation of intermetallic phases due to its very high speed. Sintering under ultrahigh purity argon gas for 99.9999% was done to produce high density materials. Intermetallic phase Al4C3 was found as a result reaction between aluminum and graphite during milling. Formation of Al4C3 is very important to the alloy as an interface between matrix and reinforcement particle in order to have higher hardness. A decrease in Peaks Cu and followed by an increase in Al2Cu precipitation in the XRD pattern occurred with increasing milling time. The role of Al2Cu precipitation is very important in improving mechanical properties, resulting in the highest hardness value reaching 97 HV and a density value of 83% at 8 h of milling.

CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN R... more CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN RECYCLE PROCESS. In general, during its fabrication, 2-5 % of total products of Ba-Sr hexaferrite permanent magnet will be rejected. Accordingly, an increase in rejected product of permanent magnet needs to be considered. It is expected that the re-utilization of rejected product can increase the production efficiency in order to achieve zero waste-production. In the present work, the recycling process of Ba-Sr hexaferrite permanent magnet was studied by applying 1 T magnetic field (anisotropic) to align the powder. The rejected products were milled using shaker mill PPF-UG for 10-40 min and then sintered at 1200 ºC for 60 min. The results show that the remanence of original powder was increased by 50% after the particle orientation. However, the recycled sample doesn't show a significant different. SEM and XRD analysis show the crystalline structure transformation from symmetrical he...

Garcinia mangostana, commonly known as mangosteen is a tropical fruit that grows in Asian region.... more Garcinia mangostana, commonly known as mangosteen is a tropical fruit that grows in Asian region. Nano Mangosteen's Pericarp have successfully been made by ball milling method with variations in milling time (30, 90, 150, 210 minutes), and non milling as a comparison. Mangosteen pericarp was dried in an oven at 70 ˚C for 12 hours, then continued by grinding and sieving using mesh 80, then milled. The effect of variations in milling time on the functional groups of nano mangosteen pericarp, also the correlation on total phenolic content and antioxidant activity in previous research were investigated. The morphology of the mangosteen pericarp shows that the grain size of mangosteen pericarp is getting finer along with increasing milling time. It can provide a clear reason for explaining the increasing solubility value of the samples. The zeta potential data shows that after being milled the mangosteen pericarp becomes unstable, thus it is easy to agglomerate. It was obtained that the total phenolic content and the antioxidant activity increased followed by longer milling times. The FTIR analysis indicated that the enhancement in total phenolic content is not due to transformation in functional groups of phenolic compounds.

Journal of Applied Materials and Technology, 2020

The LaMnO3 perovskite catalyst was successfully synthesized using a simple solid-state reaction m... more The LaMnO3 perovskite catalyst was successfully synthesized using a simple solid-state reaction method. This catalyst is used to activate PMS in the organic content's degradation process in the secondary effluent palm oil mill (POMSE). The organic content in POMSE is equivalent to the COD value; thus the COD value is used as a parameter for the process's success. The catalyst performance test shows that the catalyst effectively reduces COD, and the waste meets the maximum threshold allowed by government regulations. The variables that affect the catalyst's effectiveness were the calcination temperature of the catalyst, catalyst loading, PMS concentration, and temperature. The temperature of calcination affects the perovskite crystal formation; the higher the temperature, the more active catalyst obtained. The catalyst loading and PMS concentration variables affect the degradation process of organic levels in POMSE; at low levels, the higher the catalyst loading and PMS c...

ALCHEMY Jurnal Penelitian Kimia, 2020

ABSTRACT. The present research studied about decolorization of methylene blue dye using photocata... more ABSTRACT. The present research studied about decolorization of methylene blue dye using photocatalyst ZnO/ZSM-5 under UV-LED lamp. ZnO/ZSM-5 was synthesized using the impregnation method by adding two grams ZSM-5 to Zn solution 0.3 M 10 mL. Photocatalyst was characterized using X-ray diffractometer (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy-energy dispersive X-Ray (FESEM-EDX), and surface area analyzer (SAA). Analysis using XRD show addition characteristic peaks of ZnO at 2θ 31.60°, 34.21°, 36.08°, 47.35°, 56.50°, 62.73°, 67.83°, that indicates a successful impregnation process. The photocatalysis activity test was done on methylene blue dye 100 mg L-1. ZSM-5 and ZnO activities were tested under UV-LED irradiation and dark conditions. Data showed that percent removal of dye occurred on ZnO/ZSM-5 under 15 minutes irradiation is 78.32%.

Serbuk timah merupakan komponen utama dalam pembuatan pasta solder. Salah satu requirement dari s... more Serbuk timah merupakan komponen utama dalam pembuatan pasta solder. Salah satu requirement dari serbuk yang diperlukan adalah ukuran partikel serbuk maksimal 45 mikron. Dimana semakin kecil ukuran dari partikel serbuk timah dalam komposisi pasta solder tersebut, maka harga dari pasta solder akan semakin meningkat. Salah satu metode yang dapat dilakukan untuk menghasilkan serbuk timah adalah atomisasi gas. Tujuan dari penelitian ini untuk menambah pengetahuan tentang pengaruh dari tekanan dan suhu dari ruang peleburan terhadap ukuran dari output serbuk timah yang dihasilkan. Eksperimen dari penelitian ini menggunakan desain sistem atomisasi gas panas, dengan media gas berupa argon. Hasil penelitian dengan menggunakan desain sistem atomisasi gas ini, menunjukkan bahwa suhu ruang peleburan timah dan tekanan gas alir saat atomisasi mempengaruhi distribusi ukuran dari partikel serbuk timah yang dihasilkan, semakin tinggi suhu ruang peleburan dan tekanan gas alir yang digunakan, maka ukuran partikel serbuk timah yang dihasilkan akan semakin kecil.

1-2-2 Production and Characterization of bio oil from fast copyrolysis of low rank coal and biomass

Microstructure and oxidation behavior of an Al–Ni–Cr–Cu–MoO3–SiO2 composite coating on low-carbon steel

Materials Chemistry and Physics, 2021

In the present study, an Al–Ni–Cr–Cu–MoO3–SiO2 composite coating with varying elemental compositi... more In the present study, an Al–Ni–Cr–Cu–MoO3–SiO2 composite coating with varying elemental compositions was deposited using the mechanical alloying technique. The composite coating structure before and after an oxidation test was studied using X-ray diffraction (XRD), three-dimensional optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). A cyclic oxidation test was conducted in an 800 °C air atmosphere for 10 cycles (200 h). Based on the XRD, SEM, and EDX analyses, the coating comprised composite-refined Al, Ni, Cr, and Cu particles as well as coarse SiO2 particles. The composite coating had a thickness in the range of 36–59 μm, with good and continuous adherence to the substrate. The cyclic oxidation curve of the composite coating followed a parabolic rate law. The sample that contained 5.3 wt% MoO3 showed the best oxidation resistance after 10 oxidation cycles at 800 °C. This sample had a lower mass gain than the other samples. Moreo...

CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN R... more CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN RECYCLE PROCESS . In general, during its fabrication, 2-5%of total products of Ba-Sr hexaferrite permanent magnet will be rejected.Accordingly, an increase in rejected product of permanent magnet needs to be considered. It is expected that the re-utilization of rejected product can increase the production efficiency in order to achieve zero waste-production. In the present work, the recycling process of Ba-Sr hexaferrite permanent magnet was studied by applying 1 T magnetic field (anisotropic) to align the powder. The rejected products were milled using shaker mill PPF-UG for 10-40 min and then sintered at 1200 oC for 60 min. The results show that the remanence of original powder was increased by 50% after the particle orientation. However, the recycled sample doesn’t show a significant different. SEM and XRD analysis show the crystalline structure transformation from symmetrical hexagona...

Dental cement based on zinc phosphate (Zinc Phosphate Cement) is the oldest dental cement that is... more Dental cement based on zinc phosphate (Zinc Phosphate Cement) is the oldest dental cement that is still widely used today. One disadvantage of zinc phosphate-based dental cement is its low mechanical properties. In this study, ZnO nanoparticles are added to the zinc phosphate dental cement with the hypothesis that there will be the strengthening of the mechanical properties of dental cement. The fraction of ZnO nanoparticles were variedly added from 0.1 g, 0.5 g, 1 g and 1.5 g to the zinc phosphate dental cement which is then compared to the dental cement without the addition of ZnO nanoparticles. The materials were manually mixed and mold to form dental cement pellets (4 mm thick and 4 mm in diameter). Characterization of pellet hardness and strength result in a linear value to the addition of ZnO nanoparticles in which the value of hardness and strength increases as increasing of ZnO nanoparticles fractions. XRD analysis results indicate the appearance of peaks Zn 3 (PO 4 ) 2 .4H2...

The tin powder was used in some applications and technology such as for part manufacture through ... more The tin powder was used in some applications and technology such as for part manufacture through alloying, pressing, and sintering process, mixing material for the pyrotechnic application, the main material for solder pasta, mixing material on tin chemical, and others. Therefore, the demand for tin powder with a small size, spherical shape, and high purity is increasing severely. Indonesia (PT. Timah Tbk.) is one of the world’s largest producers of tin raw materials. This raw material can be processed be as powder by the atomization method. In this research, hot argon gas atomization system was used to generated tin powder. Raw tin was melted in a melting chamber with temperature variations of 600, 700, 800, and 900 °C. This experiment generates powder with a dominant size of 37 – 150 mm. Meanwhile, for size powder of 0 – 30 mm, dominated by size range of 0 – 10 mm. Furthermore, the size powder of 0 – 30 mm is composed of tin phase, without tin oxide. The tin powder of melting chamb...

This study is an effort to increase ionic conductivity of electrolyte polymer membranes in Lithiu... more This study is an effort to increase ionic conductivity of electrolyte polymer membranes in Lithium ion battery applications by combining electrolyte salts. An electrolyte polymer membrane functions as electrolytes and a separator. Such a membrane is made using a solution casting method at room temperature and consists of Polyvinylidene fluoride co-hexaflouropropylene (PVDF-HFP) as the polymer, titanium oxide (TiO2) as a filler, and combinations of Lithium bis(oxalate) borat (LiBOB) and Lithium bis-trifluoromethanesulfonimide (LiTFSI) as electrolyte salts. The electrolyte polymer membrane was characterized using Electrochemical Impedance Spectroscopy (EIS) for conductivity, X-Ray Diffractometer (XRD) for material crystallinity, and Scanning Electron Microscope (SEM) for surface morphology. The results of EIS tests show that the sample containing 23% LiTFSI and 5% LiBOB has the highest conductivity (2,35 x 10 -6 S/cm) compared to the other samples. This finding is supported by the res...

P-54 Modification of zeolite acidity and its effect on the upgrading of biomass-derived oil

Kinetic study of methylene blue photocatalytic decolorization using zinc oxide under UV-LED irradiation

THE 14TH JOINT CONFERENCE ON CHEMISTRY 2019, 2020

Kinetic study of methylene blue photocatalytic decolorization using zinc oxide was carried out un... more Kinetic study of methylene blue photocatalytic decolorization using zinc oxide was carried out under UV-LED lamp irradiation. Zinc oxide was prepared by precipitation method. Zinc oxide was characterized by XRD, FESEM, and N2 adsorption-desorption. Characterization results show that zinc oxide has a hexagonal crystal face, particle size between 0.125-0.3 µm, specific surface area (SBET), micropore volume, and mesopore volume are 60.20 m2/g, 0.541 cm3/g, and 0.02 cm3/g, respectively. The variations of pH and concentration of methylene blue solution were observed. The results show that the alkaline conditions had the highest methylene blue photocatalytic decolorization rate. At initial low concentration, the methylene blue photocatalytic decolorization is very high and decrease when the initial concentration of methylene blue increase. Photocatalytic decolorization reaction kinetics follow the first-order kinetic. The Langmuir-Hinshelwood kinetic analysis results show that photocatalytic reaction constant and Langmuir-Hinshelwood constant value are 2.2621 L.mg−1.min−1 and 0.0144 L.mg-1, respectively.

Decolourization of methylene blue by NiO/ZSM-5 photocatalyst under UV-LED irradiation

THE 14TH JOINT CONFERENCE ON CHEMISTRY 2019, 2020

Crystals, 2020

The oxidation and hardness of thermally exposed titanium (Ti) prepared using inductive sintering-... more The oxidation and hardness of thermally exposed titanium (Ti) prepared using inductive sintering-assisted powder metallurgy was evaluated through cyclic tests in air at 700–900 °C for 100 h (5 cycles). In general, the oxidation kinetics of the Ti samples followed the parabolic law and their oxidation rates increased with increasing oxidation temperatures. The rutile form of titanium dioxide (TiO2) was detected by X-ray diffraction in the oxide scales after oxidation at 700 °C and 900 °C. Furthermore, the TiO2 grain size and thickness were significantly influenced by an increase in the oxidation temperature. Lastly, the formation of rutile as a single-phase on the surface of oxidized Ti enhanced the hardness of the oxide scales, whereas the substrate had lower hardness values than the oxide scales due to diffusion of Ti atoms at the surface to form the TiO2 oxide scales.

Jurnal Riset Kimia, 2019

The comparison of photocatalytic decolorization of Methylene Blue and Methyl Orange using ZnO Sem... more The comparison of photocatalytic decolorization of Methylene Blue and Methyl Orange using ZnO Semiconductor under UV-LED radiation has been studied at varied pH. ZnO have been synthesized using co-precipitation method. The Scanning Electron Microscopy (SEM) result showed that the synthesized ZnO has a hexagonal structure with the particle size range 0.125 to 0.5 µm. The BET isotherm characterization showed the synthesized ZnO has a specific surface area (SBET), mesoporous volume and micropore volume of 60.20 m2/g, 0.541 cm3/g and 0.02 cm3/g, respectively. The observation of the effect of pH to the photocatalytic activity showed that the highest removal percentage occurred at pH 9 with the value of 95.64% for methylene blue and occurred at pH 3 with the value of 6.236% for methyl orange.

Catalysis Communications, 2018

In this work, the selective conversion of hexanoic acid to hydrocarbons using Cu/βzeolite-EG prep... more In this work, the selective conversion of hexanoic acid to hydrocarbons using Cu/βzeolite-EG prepared by the ethylene glycol (EG) assisted impregnation method was investigated. It was found that Cu/βzeolite-EG shows higher selectivity towards benzene, toluene and xylenes (BTXs) as well as higher resistance to coke deposition when compared to Cu/βzeolite prepared by a conventional impregnation method. This should be attributed to the better dispersion and stronger interaction between the active Cu species and the β-zeolite surface in the Cu/β-zeolite-EG solid. This catalytic system shows potential practical application in the upgrading of bio-oil.

Journal of Physics: Conference Series, 2018

View the article online for updates and enhancements.

The number of vehicles in Jakarta increased by 5.66% from 2016. Vehicles have the highest contrib... more The number of vehicles in Jakarta increased by 5.66% from 2016. Vehicles have the highest contribution to air pollution, which is 70% of other activities. The purpose of this study was to determine the reduction of CO with zeolite pellets. This type of research is a quasi-experimental design with a non-equivalent control group design pre-test post-test design. The emission test instrument uses the automotive gas analyzer HESBOHN, a tachometer to measure engine speed, laptops, and stopwatches. The material used is activated natural zeolite pellets. Data were analyzed by univariate in the form of CO adsorption power efficiency, average, minimum, and maximum. The variables used are pellet drying time (3 hours and 24 hours) and engine speed (idle and 1250 rpm). The result of CO adsorption power efficiency using the most optimal zeolite pellets is Pellet I with 3 hours drying at 1250 rpm by 52%. While the lowest yield is Pellet II with 24-hour drying at idle conditions of 22%. The most e...

Journal of Metals, Materials and Minerals, Mar 29, 2022

Aluminum-based metal matrix nanocomposites have been extensively researched and developed for aer... more Aluminum-based metal matrix nanocomposites have been extensively researched and developed for aerospace and automotive applications. Al-4.5Cu-1.5Mg with 0.5 wt% graphite were milled for 2 h, 4 h, 6 h, and 8 h using shaker mill under argon gas. The phenomena of deformation, fracturing, and cold welding during shaker mill were investigated to observe how the shaker mill effects on their morphology and formation of intermetallic phases due to its very high speed. Sintering under ultrahigh purity argon gas for 99.9999% was done to produce high density materials. Intermetallic phase Al4C3 was found as a result reaction between aluminum and graphite during milling. Formation of Al4C3 is very important to the alloy as an interface between matrix and reinforcement particle in order to have higher hardness. A decrease in Peaks Cu and followed by an increase in Al2Cu precipitation in the XRD pattern occurred with increasing milling time. The role of Al2Cu precipitation is very important in improving mechanical properties, resulting in the highest hardness value reaching 97 HV and a density value of 83% at 8 h of milling.

CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN R... more CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN RECYCLE PROCESS. In general, during its fabrication, 2-5 % of total products of Ba-Sr hexaferrite permanent magnet will be rejected. Accordingly, an increase in rejected product of permanent magnet needs to be considered. It is expected that the re-utilization of rejected product can increase the production efficiency in order to achieve zero waste-production. In the present work, the recycling process of Ba-Sr hexaferrite permanent magnet was studied by applying 1 T magnetic field (anisotropic) to align the powder. The rejected products were milled using shaker mill PPF-UG for 10-40 min and then sintered at 1200 ºC for 60 min. The results show that the remanence of original powder was increased by 50% after the particle orientation. However, the recycled sample doesn't show a significant different. SEM and XRD analysis show the crystalline structure transformation from symmetrical he...

Garcinia mangostana, commonly known as mangosteen is a tropical fruit that grows in Asian region.... more Garcinia mangostana, commonly known as mangosteen is a tropical fruit that grows in Asian region. Nano Mangosteen's Pericarp have successfully been made by ball milling method with variations in milling time (30, 90, 150, 210 minutes), and non milling as a comparison. Mangosteen pericarp was dried in an oven at 70 ˚C for 12 hours, then continued by grinding and sieving using mesh 80, then milled. The effect of variations in milling time on the functional groups of nano mangosteen pericarp, also the correlation on total phenolic content and antioxidant activity in previous research were investigated. The morphology of the mangosteen pericarp shows that the grain size of mangosteen pericarp is getting finer along with increasing milling time. It can provide a clear reason for explaining the increasing solubility value of the samples. The zeta potential data shows that after being milled the mangosteen pericarp becomes unstable, thus it is easy to agglomerate. It was obtained that the total phenolic content and the antioxidant activity increased followed by longer milling times. The FTIR analysis indicated that the enhancement in total phenolic content is not due to transformation in functional groups of phenolic compounds.

Journal of Applied Materials and Technology, 2020

The LaMnO3 perovskite catalyst was successfully synthesized using a simple solid-state reaction m... more The LaMnO3 perovskite catalyst was successfully synthesized using a simple solid-state reaction method. This catalyst is used to activate PMS in the organic content's degradation process in the secondary effluent palm oil mill (POMSE). The organic content in POMSE is equivalent to the COD value; thus the COD value is used as a parameter for the process's success. The catalyst performance test shows that the catalyst effectively reduces COD, and the waste meets the maximum threshold allowed by government regulations. The variables that affect the catalyst's effectiveness were the calcination temperature of the catalyst, catalyst loading, PMS concentration, and temperature. The temperature of calcination affects the perovskite crystal formation; the higher the temperature, the more active catalyst obtained. The catalyst loading and PMS concentration variables affect the degradation process of organic levels in POMSE; at low levels, the higher the catalyst loading and PMS c...

ALCHEMY Jurnal Penelitian Kimia, 2020

ABSTRACT. The present research studied about decolorization of methylene blue dye using photocata... more ABSTRACT. The present research studied about decolorization of methylene blue dye using photocatalyst ZnO/ZSM-5 under UV-LED lamp. ZnO/ZSM-5 was synthesized using the impregnation method by adding two grams ZSM-5 to Zn solution 0.3 M 10 mL. Photocatalyst was characterized using X-ray diffractometer (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy-energy dispersive X-Ray (FESEM-EDX), and surface area analyzer (SAA). Analysis using XRD show addition characteristic peaks of ZnO at 2θ 31.60°, 34.21°, 36.08°, 47.35°, 56.50°, 62.73°, 67.83°, that indicates a successful impregnation process. The photocatalysis activity test was done on methylene blue dye 100 mg L-1. ZSM-5 and ZnO activities were tested under UV-LED irradiation and dark conditions. Data showed that percent removal of dye occurred on ZnO/ZSM-5 under 15 minutes irradiation is 78.32%.

Serbuk timah merupakan komponen utama dalam pembuatan pasta solder. Salah satu requirement dari s... more Serbuk timah merupakan komponen utama dalam pembuatan pasta solder. Salah satu requirement dari serbuk yang diperlukan adalah ukuran partikel serbuk maksimal 45 mikron. Dimana semakin kecil ukuran dari partikel serbuk timah dalam komposisi pasta solder tersebut, maka harga dari pasta solder akan semakin meningkat. Salah satu metode yang dapat dilakukan untuk menghasilkan serbuk timah adalah atomisasi gas. Tujuan dari penelitian ini untuk menambah pengetahuan tentang pengaruh dari tekanan dan suhu dari ruang peleburan terhadap ukuran dari output serbuk timah yang dihasilkan. Eksperimen dari penelitian ini menggunakan desain sistem atomisasi gas panas, dengan media gas berupa argon. Hasil penelitian dengan menggunakan desain sistem atomisasi gas ini, menunjukkan bahwa suhu ruang peleburan timah dan tekanan gas alir saat atomisasi mempengaruhi distribusi ukuran dari partikel serbuk timah yang dihasilkan, semakin tinggi suhu ruang peleburan dan tekanan gas alir yang digunakan, maka ukuran partikel serbuk timah yang dihasilkan akan semakin kecil.

1-2-2 Production and Characterization of bio oil from fast copyrolysis of low rank coal and biomass

Microstructure and oxidation behavior of an Al–Ni–Cr–Cu–MoO3–SiO2 composite coating on low-carbon steel

Materials Chemistry and Physics, 2021

In the present study, an Al–Ni–Cr–Cu–MoO3–SiO2 composite coating with varying elemental compositi... more In the present study, an Al–Ni–Cr–Cu–MoO3–SiO2 composite coating with varying elemental compositions was deposited using the mechanical alloying technique. The composite coating structure before and after an oxidation test was studied using X-ray diffraction (XRD), three-dimensional optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). A cyclic oxidation test was conducted in an 800 °C air atmosphere for 10 cycles (200 h). Based on the XRD, SEM, and EDX analyses, the coating comprised composite-refined Al, Ni, Cr, and Cu particles as well as coarse SiO2 particles. The composite coating had a thickness in the range of 36–59 μm, with good and continuous adherence to the substrate. The cyclic oxidation curve of the composite coating followed a parabolic rate law. The sample that contained 5.3 wt% MoO3 showed the best oxidation resistance after 10 oxidation cycles at 800 °C. This sample had a lower mass gain than the other samples. Moreo...

CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN R... more CRYSTAL STRUCTURE TRANSFORMATION OF Ba-Sr HEXAFERRITE AND ITS EFFECT ON PARTICLE ORIENTATION IN RECYCLE PROCESS . In general, during its fabrication, 2-5%of total products of Ba-Sr hexaferrite permanent magnet will be rejected.Accordingly, an increase in rejected product of permanent magnet needs to be considered. It is expected that the re-utilization of rejected product can increase the production efficiency in order to achieve zero waste-production. In the present work, the recycling process of Ba-Sr hexaferrite permanent magnet was studied by applying 1 T magnetic field (anisotropic) to align the powder. The rejected products were milled using shaker mill PPF-UG for 10-40 min and then sintered at 1200 oC for 60 min. The results show that the remanence of original powder was increased by 50% after the particle orientation. However, the recycled sample doesn’t show a significant different. SEM and XRD analysis show the crystalline structure transformation from symmetrical hexagona...

Dental cement based on zinc phosphate (Zinc Phosphate Cement) is the oldest dental cement that is... more Dental cement based on zinc phosphate (Zinc Phosphate Cement) is the oldest dental cement that is still widely used today. One disadvantage of zinc phosphate-based dental cement is its low mechanical properties. In this study, ZnO nanoparticles are added to the zinc phosphate dental cement with the hypothesis that there will be the strengthening of the mechanical properties of dental cement. The fraction of ZnO nanoparticles were variedly added from 0.1 g, 0.5 g, 1 g and 1.5 g to the zinc phosphate dental cement which is then compared to the dental cement without the addition of ZnO nanoparticles. The materials were manually mixed and mold to form dental cement pellets (4 mm thick and 4 mm in diameter). Characterization of pellet hardness and strength result in a linear value to the addition of ZnO nanoparticles in which the value of hardness and strength increases as increasing of ZnO nanoparticles fractions. XRD analysis results indicate the appearance of peaks Zn 3 (PO 4 ) 2 .4H2...

The tin powder was used in some applications and technology such as for part manufacture through ... more The tin powder was used in some applications and technology such as for part manufacture through alloying, pressing, and sintering process, mixing material for the pyrotechnic application, the main material for solder pasta, mixing material on tin chemical, and others. Therefore, the demand for tin powder with a small size, spherical shape, and high purity is increasing severely. Indonesia (PT. Timah Tbk.) is one of the world’s largest producers of tin raw materials. This raw material can be processed be as powder by the atomization method. In this research, hot argon gas atomization system was used to generated tin powder. Raw tin was melted in a melting chamber with temperature variations of 600, 700, 800, and 900 °C. This experiment generates powder with a dominant size of 37 – 150 mm. Meanwhile, for size powder of 0 – 30 mm, dominated by size range of 0 – 10 mm. Furthermore, the size powder of 0 – 30 mm is composed of tin phase, without tin oxide. The tin powder of melting chamb...