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"Since 2004, graphene has risen in popularity owing to its superior properties. However, limits to the scale of production methods have rendered graphene a costly material. Moreover, existing production methods require chemicals that are detrimental to the environment. This study uses Coconut Coir Dust (CCD) as a carbon precursor and an intermediate product in the manufacturing of graphene. Firstly, CCD sieved into a 100 mesh was carbonized using a hydrothermal method at temperatures of 235oC, 250oC, and 265oC, for 4 hours. Following this, the resulting solid residue was pyrolyzed at 1000oC for 2 hours under the protection of nitrogen (N2). The hydrothermal solid residue was labelled CHT (hydrothermal temperature) and the pyrolysis product was named as SP (hydrothermal temperature). Both samples were characterized using SEM, XRD and EDS. In addition, Raman characterization was conducted for SP samples. At the end of the process (SP), the XRD pattern showed two broad peaks centered around 2? ~24o and 44o corresponding to a (002) and (100) graphite plane. This pattern is similar to that of reduced-graphene oxide. SEM images showed a sheet-like microstructure is caused by undegraded lignin. A perforated and corrugated sheet formed after pyrolysis, which subsequently confirms the formation of reduced-graphene oxide. Furthermore, the Raman result indicates that higher hydrothermal temperatures lead to an increasing integrated ID/IG ratio. The ratios were 1.62, 1.71 and 1.77, for SP 235, SP 250, and SP 265, respectively. Research results conclude that the carbonaceous material formed through hydrothermal and pyrolytic processes contained a mixture of an amorphous-carbon form and a graphene-like cluster. Results additionally show a similar structure with reduced-graphene oxide."

"Penelitian ini bertujuan untuk membuat dan meng grafena oksida tereduksi (rGO) menggunakan glisina. Perbandingan massa grafena oksida (GO) dan glisina yang dipakai divariasikan dengan perbandingan 1:2 dan 2:3 (b/b). Grafit, GO dan rGO dicirikan menggunakan Fourier Transform Infrared Spectroscopy (FTIR). Hasil uji grafena oksida tereduksi (rGO) yang sudah dibuat melalui proses reduksi pakai glisina menunjukkan bahwa grafik FTIR tidak curam pada 3319 cm-1 yang menunjukkan ikatan -OH dan 694 cm-1 yang menunjukkan ikatan C-O.

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This study aims to prepare and prepare reduced graphene oxide (rGO) using glycine. The mass ratio of graphene oxide (GO) and glycine used was varied with a ratio of 1:2 and 2:3 (w/w). Graphite, GO and rGO were characterized using Fourier Transform Infrared Spectroscopy (FTIR). The test results of reduced graphene oxide (rGO) which has been prepared through the reduction process using glycine shows that the FTIR graph is not steep at 3319 cm-1 which indicates -OH bonds and 694 cm-1 which indicates C-O bonds."

"Karbon adalah atom yang diubah menjadi material yang sangat berlimpah di dunia. Karbon dapat digunakan menjadi material yang sangat berguna yaitu material pelapis yang digunakan untuk membangun bangunan, material komposit, material pengantar listrik, material penyerap (adsorben), dan lain-lain. Grafit adalah material yang mengandung alotrop karbon. Grafit merupakan material yang sangat berlimpah di dunia. Oleh karena itu, grafit dapat diolah menjadi material yang dipakai pada setiap saat. Oksida grafit memiliki struktur berlapis yang mirip dengan stuktur grafit. Hasil XRD menunjukkan bahwa lapisan grafit yang memiliki lapisan 109 lapisan dikupas menjadi 2 sampai 4 lapisan. Jika lembaran terkelupas yang mengakibatkan karbon hanya mengandung satu lapisan atau beberapa lapisan maka lembaran ini diberi nama menjadi grafena oksida (GO). GO dibuat melalui proses Hummers termodifikasi. GO mudah diproses menjadi grafena oksida tereduksi (rGO). Grafena oksida direduksi oleh glisina, asam askorbat, dan ekstrak lemon sebagai pereduksi hijau. Variasi penelitian grafena oksida tereduksi adalah massa grafena oksida dengan massa pereduksi. Hasil karakterisasi grafena oksida tereduksi adalah hasil ftir grafena oksida tereduksi tidak curam pada berkisar gelombang 3100 sampai 3500 cm-1 yang menunjukkan bahwa ikatan -OH, gelombang 1500-1600 cm-1 yang menunjukkan bahwa ikatan C=C, dan gelombang 1000 sampai 1300 cm-1 yang menunjukkan bahwa ikatan C-O; konsentrasi pereduksi hijau mempengaruhi unsur C yang dikandung di dalam rGO berkisar antara 82,81 sampai 85,33% dan unsur O yang dikandung di dalam rGO berkisar antara 8,60 sampai 14,85%.

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Carbon is an atom that is transformed into the most abundant material in the world. Carbon can be used as a very useful material, namely coating materials used to build buildings, composite materials, electrical delivery materials, absorbent materials, and others. Graphite is a material that contains allotropes of carbon. Graphite is the most abundant material in the world. Therefore, graphite can be processed into materials that are used at any time. Graphite oxide has a layered structure similar to that of graphite. XRD results show that the graphite layer which has a layer of 109 layers is peeled off into 2 to 4 layers. If the sheet peels off causing the carbon to contain only one layer or several layers then this sheet is named graphene oxide (GO). GO is made through a modified Hummers process. GO is easily processed into reduced graphene oxide (rGO). Graphene oxide was reduced by glycine, ascorbic acid, and lemon extract as a green reducing agent. The results of the characterization of reduced graphene oxide showed that the results of the reduced graphene oxide were not steep in the wave range of 3100 to 3500 cm^-1 which indicated that the -OH bond was present, the wave was 1500-1600 cm^-1 which indicated that the bond was C=C, and the wave was 1000 to 1300 cm^-1 which indicates that the C-O bond; The green reducing concentration affects the C elements contained in rGO ranging from 82.81 to 85.33% and the O elements contained in rGO ranging from 8.60 to 14.85%."

"Bambu merupakan sumber daya alam terbarukan yang dapat menyediakan banyak hal seperti sumber energi apabila siklus penanaman dan penggunaannya dijadwalkan dengan benar. Dalam penelitian ini, bambu digunakan sebagai sumber daya alam untuk proses preparasi grafit yang selanjutnya digunakan dalam sintesis oksida grafena tereduksi dengan metode hummer. Metode Hummer mengoksidasi grafit dengan cara mereaksikan grafit dengan kalium permanganat, sodium nitrat dalam larutan asam. Oksida grafena tereduksi (rGO) ini telah menarik minat yang besar karena banyaknya penggunaannya dalam berbagai aplikasi. Salah satu aplikasinya adalah lapisan anti korosi yang sangat baik untuk baja ringan yang digunakan dalam air laut. Dalam penelitian ini, hasil sintesis oksida grafena tereduksi dikarakterisasi menggunakan difraksi sinar-X (XRD) untuk menganalisis struktur kristal dan mikroskop elektron (SEM) untuk melihat morfologi permukaan. Selanjutnya, kinerja oksida grafena tereduksi sebagai pelapis anti korosi pada baja ST41 di lingkungan air laut diuji menggunakan uji polarisasi dan uji kehilangan berat. Hasil uji polarisasi pada baja ST41 yang dilapisi oksida grafena tereduksi hasil sintesis memiliki densitas arus korosi lebih rendah, icor, 3,08960 µA/cm2 jika dibandingkan dengan baja ST41 yang tidak dilapisi dengan densitas arus korosi, icor, 10,4270 µA/cm2. Ini menunjukkan bahwa lapisan rGO pada baja ST41 meningkatkan ketahanan korosi. Efisiensi proteksi korosi dari baja ST41 yang dilapisi rGO hasil sintesis adalah 70,36%, dan laju korosinya adalah 0,03589 mm/tahun dibandingkan dengan 0,12110 mm/tahun untuk baja ST41 tanpa dilapisi rGO. Hasil uji kehilangan berat menunjukan efisiensi proteksi baja ST41 dilapisi rGO hasil sintesis adalah 70,73%.

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Bamboo is a renewable natural resource that can provide many things such as source of energy, if the plantation cycles and its usage is properly managed. In this research, the use of bamboo as a natural resource for graphite preparation process, which then can be used as a precursor for synthesizing reduced graphene oxide (rGO) via Hummer’s method. The Hummer’s method oxidizes graphite by reacting graphite with potassium permanganate and sodium nitrate in an acid solution. This rGO has attracted intense interest for its many uses in various applications. One of the applications is its excellent potential anti-corrosion prevention for mild steel used in saline water. In this work, the results of reduced graphene synthesis were characterized using X-ray diffraction (XRD) for crystal structure analysis and electron microscopy (SEM) for surface morphology. Furthermore, the performance of reduced graphene as an anti-corrosion coating on mild steel ST41 in the seawater environment was tested using electrochemical measurement and weight loss. Reduced graphene oxide (rGO) coated on ST41 mild steel showed much lower corrosion current, Icorr, 3.08960 µA/cm2, when compared to 10.4270 µA/cm2 for bare ST41 mild steel indicating that rGO film on ST41 mild steel exhibits enhanced corrosion resistance. The corrosion protection efficiency of synthetic rGO-coated ST41 mild steel was 70.36%, and the corrosion rate was 0,03589 mm/year compared to 0,12110 mm/year for ST41 mild steel without rGO-coated. The results of the weight loss test showed that the protection efficiency of rGO-coated ST41 mild steel was 70.73%. "

"The gas diffusion layer (GDL) is one of the critical components of a proton exchange membrane fuel cell (PEMFC). It is generally made of a fossil-fuel-based carbon material. In this study, carbon composite paper (CCP) for GDL was prepared by using carbon material obtained from coconut coir. To obtain the CCP, 80 wt% carbon material from the coconut coir and 20 wt% polymer binder (ethylene vinyl acetate and polyethylene glycol) were mixed in xylene solvent at 100°C, cast on molded glass, and then rolled. The carbon material consists of a mixture of carbon fibers (length: 2 mm) and powders (size: 74 µm). Subsequently, the CCP was treated with polytetrafluoroethylene solution (10 wt%). The physical properties of the CCPs, such as through-plane electrical conductivity, porosity, density, and hydrophobic properties, were investigated. Scanning electron microscopy and energy-dispersive spectroscopy mapping were used to analyze the morphology and polytetrafluoroethylene (PTFE) distribution in the CCP. The through-plane conductivity test showed that CCP with 70 wt% carbon fiber, 10 wt% carbon powder, and 20 wt% polymer was the optimum sample, and it showed the highest electrical conductivity of 2.22 S cm-1. The physical properties of PTFE-treated CCP, such as porosity, density, and contact angle, were almost similar to that of commercial carbon paper used as a GDL. Therefore, the CCP prepared from coconut coir can be applied as a GDL in a PEMFC."

"The gas diffusion layer (GDL) is one of the critical components of a proton exchange membrane fuel cell (PEMFC). It is generally made of a fossil-fuel-based carbon material. In this study, carbon composite paper (CCP) for GDL was prepared by using carbon material obtained from coconut coir. To obtain the CCP, 80 wt% carbon material from the coconut coir and 20 wt% polymer binder (ethylene vinyl acetate and polyethylene glycol) were mixed in xylene solvent at 100°C, cast on molded glass, and then rolled. The carbon material consists of a mixture of carbon fibers (length: 2 mm) and powders (size: 74 µm). Subsequently, the CCP was treated with polytetrafluoroethylene solution (10 wt%). The physical properties of the CCPs, such as through-plane electrical conductivity, porosity, density, and hydrophobic properties, were investigated. Scanning electron microscopy and energy-dispersive spectroscopy mapping were used to analyze the morphology and polytetrafluoroethylene (PTFE) distribution in the CCP. The through-plane conductivity test showed that CCP with 70 wt% carbon fiber, 10 wt% carbon powder, and 20 wt% polymer was the optimum sample, and it showed the highest electrical conductivity of 2.22 S cm-1. The physical properties of PTFE-treated CCP, such as porosity, density, and contact angle, were almost similar to that of commercial carbon paper used as a GDL. Therefore, the CCP prepared from coconut coir can be applied as a GDL in a PEMFC."

"ABSTRAKImplan biodegradable merupakan implan yang diharapkan dapat mengalamikorosi secara bertahap di in vivo dan dapat terlarut secara sempurna ketikajaringan yang disokong dapat berfungsi secara normal tanpa implant serta hasilkorosi tersebut tidak bersifat toksik. Magnesium (Mg) merupakan kandidat yangbaik untuk diaplikasikan sebagai implan biodegradable karena bersifat korosi danbiokompatibel dengan tubuh. Penambahan Hidroksi Apatit ke dalam Mg, menjadiimplant komposit Mg-HA dapat mengurangi tingkat korosi dari paduantersebutmasih bersifat toksik. Oleh sebab itu diperlukan Hidroksi apatit dari bahanalam yaitu tulang sapi karena memiliki karakteristik mekanik dan struktur yanghampir sama dengan tulang manusia. Penelitian ini bertujuan untuk mensintesaimplan biodegradable komposit Magnesium-Hidroksi Apatit (Mg-HA) dimanaHA bersumber dari bahan alam yaitu tulang sapi. Tahap pertama HA disintesadari tulang sapi yang dikalsinasi dengan variasi suhu 2000C, 3000C, 3500C,4000C, 5000C, 6000C, 7000C, 8000C, 8500C, 9000C dan 10000C. Secara kualitatiftulang sapi yang dikalsinasi mulai suhu 7000C ke atas terkristalisasi dengan lebihbaik dan menunjukkan karakteristik yang sesuai dengan karakteristik HA referensidi mana hasil analisis didukung dengan menggunakan Karakterisasi FTIR, XRD,BET, SEM-EDX. Derajat Kristalinitas Hidroksi apatit dari tulang sapi meningkatseiring dengan peningkatan suhu sinter. Hasil yang optimal di dapat pada tulangsapi yang dikalsinasi pada suhu 850 0C di mana Ca/P yang di dapat yaitu sebesar1.651 variasi suhu (850 0C) dan variasi waktu (5 jam) sebesar 1.679 yangmendekati Ca/P HA referensi stoikiometri sebesar 1.67. HA dari tulang sapi yangdikalsinasi pada suhu 8500C dan waktu 5 jam ditambahkan pada komposit Mg-HA dari tulang sapi dengan 4 variasi komposisi. Penambahan Hidroksiapatit daritulang sapi pada komposit Mg-HA dapat menjadi material komposit dengan nilailaju korosi yang diizinkan sebagai material implant (0.235 MPY) dan jugamempercepat laju degradasi. Penambahan juga meningkatkan densitas sertakekerasan, hingga penambahan 5 % berat. Namun, ketika penambahan HA lebihbesar dari 5 % berat , densitas dan kekerasan menurun karena aglomerasi partikelHA. Penambahan HA dari tulang sapi pada komposit juga bersifat tidak toksiksehingga aman bila digunakan sebagai material implan

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ABSTRACTBiodegradable implant is an implant that is expected to corrosion gradually invivo and can be dissolved completely when the bone tissue can function normallywithout implants and the results are not toxic corrosion. Magnesium (Mg) is agood candidate to be applied as biodegradable implants because it is corrosive andbiocompatible with the body. The addition of HA into Mg, became implantcomposite Mg-HA can reduce the corrosion rate of these composites, but the rateof corrosion is still quite high (8 MPY) and they are toxic, therefore it is necessaryHydroxy Apatite from natural material. The material is cow bone because it hasthe mechanical and structural characteristics similar to human bone. This studyaims to synthesize the composite biodegradable implant Magnesium- HydroxyApatite (Mg-HA) where HA derived from natural materials are cow bone. Thefirst stage HA synthesized from cow bones calcined with temperature variationsare 2000C, 3000C, 3500C, 4000C, 5000C, 6000C, 7000C, 8000C, 8500C, 9000C and10000C. The qualitatively calcined cow bones start at temperature 7000C to thetop of the crystallized with better and show the characteristics corresponding tothe characteristics of HA commercial in which the analysis results are supportedby using FTIR characterization, XRD, BET, SEM-EDX. Hydroxy apatitecrystallinity degree from bovine bones increases with increasing sinteringtemperature. The natural HA obtained by calcining with temperature variationsshows the desired quality in which Ca/P was found 1.651 (at 850 °C) and withtime variations was found 1.679 (5 hours) were approaching the Ca/P HAcommercial stoichiometry of 1.67 HA from cow bones are calcined at atemperature of 8500C ( 5 hours) added to the Mg-HA composite with fourvariations of composition. The addition of hydroxyapatite from cow bone to thecomposite can be Mg-HA composite materials with a value of corrosion rateallowed as implant materials (0.235 MPY) and also accelerate the rate ofdegradation. The addition also increases the density and hardness, add up toadditional 5% by weight. However, when the addition of HA is greater than 5%by weight, density and hardness decreases due to the agglomeration of HA. Theaddition of HA from cow bones to composites also are not toxic so it is safe whenused as an implant material.;"

"Oil spill can contaminate the environment as a consequence of activities related to crude oil exploration, oil refinary, transporation, pipeline leaking, and industrial processes. This researchrelated with the characteristics of coir dust as oil sorbent material to remove oil from water. Hydrophobicity is an important parameter that determines the effectiveness of the oil sorbent. Some treatment were done in this research to increase the hydrophobicity of choir dust. Moreover, these treatments were expected to improve oil sorption capacity of coir dust. They are heating andacetylation prosess. The results showed both of heating and acetylation could increase hydrophobicity and oil sorption capacity onto coir dust."

"Telah dilakukan sintesis dan karakterisasi grafit oksida dari sabut kelapa dengan menggunakan metode Hummer termodifikasi dan diaplikasikan sebagai aditif pada NMC 811 komersil. Penambahan grafit oksida sebanyak 5 wt.% pada NMC 811 dilakukan dengan menggunakan metode solid state. Hasil pengujian NMC 811/grafit oksida dengan mikroskop elektron (SEM) memperlihatkan bahwa butiran grafit oksida telah melapisi NMC 811 secara merata. Fabrikasi sel baterai diawali dengan pembuatan slurry menggunakan NMP 811 yang sudah ditambahkan aditif, Super-P, dan PVDF dengan perbandingan 8:1:1. Slurry yang terbentuk dituangkan pada lembaran Al dan dilakukan proses coating dengan doctor blade dengan ketebalan 15 μm. Hasil coating dipotong dan dilakukan fabrikasi menggunakan coin cell tipe CR2032. Pengujian baterai dilakukan menggunakan cyclic voltammetry (CV) dan electrochemical impedance spectroscopy (EIS). Hasil uji EIS menunjukkan bahwa nilai koefisien difusi ion NMC 811/grafit oksida masih dibawah NMC 811 komersil namun lebih baik dibandingkan NMC 811/grafen oksida komersial dengan nilai masing-masing secara berturut-turut 4.31x10-13 cm2/s, 6.27x10-13 cm2/s, dan 2.49x10-13 cm2/s. Hasil uji performa baterai dengan CV menunjukkan sampel NMC 811/grafen oksida memiliki kestabilan reaksi oksidasi dan reduksi yang paling baik dengan ΔE sebesar 0.1 V, kemudian diikuti oleh NMC 811/grafit oksida dengan ΔE sebesar 0.49 V serta NMC 811 komersil dengan ΔE sebesar 0.95V. Hasil dari pengujian yang telah dilakukan menunjukkan bahwa sabut kelapa dapat diolah menjadi grafit oksida dan dapat digunakan untuk meningkatkan kestabilan NMC 811

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Synthesis and characterization of graphite oxide from coconut coir via modified Hummer method have been carried out and applied as an additive to commercial NMC 811. The addition of 5 wt.% graphite oxide to NMC 811 was carried out via the solid-state reaction. Examination of NMC 811/graphite oxide using electron microscope (SEM) showed that the graphite oxide had coated NMC 811 homogeneously. Battery cell fabrication begins with the manufacture of slurry NMP 811/graphite oxide, Super-P, and PVDF with a ratio of 8:1:1. The slurry was coated onto Al sheets using a doctor's blade method with a thickness of 15 μm. The obtained result was cut and fabricated using a CR2032 coin cell. The performance of battery was tested using cyclic voltammetry (CV) dan electrochemical impedance spectroscopy (EIS). The EIS test results showed that the ion diffusion coefficient of NMC 811/graphite oxide was still below the commercial NMC 811 but better than that of NMC 811/graphene oxide with the values of 4.31x10-13 cm2/s, 6.27x10-13 cm2/s, and 2.49x10-13 cm2/s, respectively. Battery performance test using CV showed that the NMC 811/graphene oxide sample had the best oxidation and reduction reaction stability with ΔE of 0.1 V, followed by NMC 811/graphite oxide with ΔE of 0.49 V and commercial NMC 811 with ΔE of 0.95 V. These results indicate that coconut coir can be processed into graphite oxide and can be used to increase the stability of NMC 811."

"Biogas adalah salah satu jenis energi alternatif yang memiliki potensi tinggi untuk mengurangi ketergantungan kebutuhan energi dunia terhadap bahan bakar fosil. Namun, kandungan CO₂ yang tinggi dalam biogas dapat menimbulkan masalah dalam penggunaannya. CO₂ dapat dipisahkan dari biogas melalui metode adsorpsi. Oleh karena itu, pada penelitian ini disintesis zeolit NaY dan Ni-MOF terkarbonisasi (Ni-MOFC) sebagai prekursor untuk sintesis suatu komposit zeolit NaY/Ni-MOFC. Dengan NaY yang dapat menyerap uap air dan Ni-MOFC yang memiliki afinitas tinggi terhadap CO₂, diharapkan bahwa material komposit dapat menjadi adsorben bagi CO₂, H2O, dan pengotor polar lainnya dalam satu tahap untuk digunakan dalam purifikasi biogas. Pada penelitian ini, setiap material dikarakterisasi dengan XRD, FTIR, BET, SEM-EDX, TGA, dan TEM. Dilakukan juga optimasi dengan RSM-BBD untuk digunakan untuk uji adsorpsi CO₂ dari model biogas oleh NaY/Ni-MOFC, yang kemudian diolah menjadi kapasitas adsorpsi dan selektivitas. Diperoleh kesimpulan bahwa kondisi optimal adsorpsi CO2 adalah adsorpsi yang dilakukan dengan NaY/Ni-MOFC dengan komposisi NaY:Ni MOFC = 5:1, suhu 25°C, dan %CO2 sebesar 40%. Dengan keadaan tersebut, diperoleh kapasitas adsorpsi CO2 sebesar 50,108 mmol/g dan selektivitas terhadap CO2 sebesar 4,925.

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Biogas is an up and coming class of alternative energy that has high potential to redunce the dependence of the world’s energy needs on fossil fuels. However, the high CO₂ content in biogas can cause problems when biogas is used as an energy source. CO₂ can be separated from biogas through adsorption. Therefore, in this study, NaY zeolite and carbonized Ni-MOF (Ni-MOFC) will be synthesized as precursors for the synthesis of a NaY/Ni-MOFC composite material. With NaY’s ability for water vapor adsorption and Ni-MOFC’s high affinity for CO₂ among other things, it is predicted that the resulting composite material will be able to adsorb CO₂, H2O, and other polar impurities within one stage to be used in biogas purification. In this study, every material is characterized by XRD, FTIR, BET, SEM-EDX, TGA, and TEM. Optimization with RSM-BBD is also conducted to be used as a basis for the CO₂ adsorption test, from which was calculated adsorption capacity and selectivity. It is concluded that the optimal condition of CO2 adsorption was adsorption conducted with NaY/Ni-MOFC with NaY:Ni-MOFC composition of 5:1, temperature of 25°C, and %CO2 of 40%. Under these conditions, the CO2 adsorption capacity of 50.108 mmol/g and selectivity to CO2 of 4.925 were obtained."