Browsing by Author "Awitdrus"

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    Binderless Composite Electrode Monolith from Carbon Nanotube and Biomass Carbon Activated by H2SO4 and CO2 Gas for Supercapacitor
    (2015-09-07) Deraman, Mohamad; Ishak; Farma, Rakhmawati; Awitdrus; Taer, Erman; Talib; Omar, Ramli
    Binderless composite electrodes in the monolithic form prepared from carbon nanotubes (CNTs) and self‐adhesive carbon grains (SACG) from fibers of oil palm empty fruit bunch were studied as an electrode in a supercapacitor. The green monoliths (GMs) were prepared from three different types of precursors, SACG, SACG treated with 0.4 Molar H2SO4 and mixture of SACG and 5% CNTs (by weight) treated with 0.4 Molar H2SO4, respectively. These GMs were carbonized at 600 °C in N2 gas environment and activated by CO2 gas at 800 °C for 1 hour to produce activated carbon monoliths (ACMs). The properties of the ACMs (density, porosity, microstructure, structure and electrical conductivity) were found affected by CNTs addition and acid treatment. The acid treatment did not improve the electrochemical behavior of the ACMs used as electrodes (specific capacitance, specific energy and specific power of the supercapacitor) in the supercapacitor cells but CNTs addition improves the equivalent series resistance of the cell.
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    Binderless Composite Electrode Monolith from Carbon Nanotube and Biomass Carbon Activated by KOH and CO2 Gas for Supercapacitor
    (2015-09-07) Farma, Rakhmawati; Deraman, Mohamad; Omar, Ramli; Awitdrus; Ishak; Taer, Erman; Talib
    This paper presents a method to improve the performance of supercapacitors fabricated using binderless composite electrode monolith (BCMs) from self‐adhesive carbon grains (SACG) of fibers from oil palm empty fruit bunches. The BCMs were prepared from green monoliths (GMs) contain SACG, SACG treated with KOH (5 % by weight) and SACG mixed with carbon nanotubes (CNTs) (5% by weight) and KOH (5 % by weight), respectively. These GMs were carbonized at 800 °C under N2 environment and activated by CO2 gas at 800 °C for 1 hour. It was found that addition of KOH and CNTs produced BCMs with higher specific capacitance and smaller internal resistance, respectively. It was also found that supercapacitor cells using these BCMs as electrodes exhibited a better specific energy and specific power. The physical properties of BCMs (density, electrical conductivity, porosity, interlayer spacing, crystallite dimension and microstructure) were affected by the addition of KOH and CNTs.
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    DAYA KELUARAN PANEL SURYA SILIKON POLI KRISTALIN PADA CUACA NORMAL DAN CUACA BERASAP DENGAN SUSUNAN ARRAY PARALEL
    (2016-02-01) Pratomo, Andrian Budi; Erwin; Awitdrus
    The measurement of output power of silicon polycrystalline arrayduring normal and smoked days has been carried out. This array has an output tolerance about 3 %. The experiment was done for 6 days, started from 13 June until 14 June 2013 for the normal days and 24 June until 27 June 2013 for smoked days, at Department of Physics, Faculty of Mathematics and Natural Sciences, University of Riau. The result of the normal measurements show that average power output for normal days was greater than that for smoked days that was 46,6 Watt and 35,5 Watt respectively. The average output of voltage was 28,25 Volt while for smoked days, the voltage was 13,9 Volt. Higher values of the average output of voltage for normal days was due to the higher intensity of sunlight during the normal days compared to smoked days.
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    Effect of carbonization temperature on the physical and electrochemical properties of supercapacitor electrode from fibers of oil palm empty fruit bunches
    (2015-09-07) Ishak; Deraman, Mohamad; Talib; Basri, Nur Hamizah; Awitdrus; Farma, Rakhmawati; Taer, Erman; Omar, Ramli; Dollah, Besek Nurdiana Mohd
    Self-adhesive carbon grains (SACG) was prepared from fibers of oil palm empty fruit bunches. The SACG green monoliths were carbonized in N2 environment at 400, 500, 600 and 700°C to produce carbon monoliths labeled as CM1, CM2, CM3 and CM4 respectively. The CMs were activated in CO2 surrounding at 800°C for 1 hour to produce activated carbon monolith electrodes (ACM1, ACM2, ACM3 and ACM4). The physical properties of the CMs and ACMs were investigated using X-ray diffraction, field emission scanning electron microscopy (FESEM) and N2 adsorption-desorption isotherm techniques. ACMs were used as electrode to fabricate symmetry supercapacitor cells and the cells’ performances were investigated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) standard techniques. In this paper we report the physical and electrochemical properties of the ACM electrodes by analyzing the influence of the carbonization temperature on these properties
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    Effect of Compression Pressure on the Physical and Electrochemical Properties of Activated Carbon Monoliths Electrodes for Supercapacitor Application
    (2015-08-18) Awitdrus; Deraman; Talib; Farma, Rakhmawati; Omar; Ishak; Basri; Dolah
    Green Monoliths (GMs) of self-adhesive carbon grain from fibers of oil palm empty fruit bunches were prepared by compression pressure at 1.43 × 107, 1.91 × 107 and 2.39 × 107 kg/m2, respectively. Activated carbon monoliths ACM-A, ACM-B and ACM-C prepared by CO2 activation from these GMs, respectively, were used as electrodes in supercapacitor cells which employed stainless steel 316L current collector and H2SO4 electrolyte. Evaluation of the electrochemical properties showed that ACM-A, ACM-B and ACM-C cells had specific capacitance of 30, 9 and 5 F/g, total ESR of 3.21, 4.95 and 7.33 Ω, specific power (maximum) of 173.41, 107.58 and 33.82 W/kg, and specific energy (maximum) of 0.67, 0.15 and 0.09 Wh/kg. These properties are directly associated with the surface area of the ACMs, i.e. 419, 336 and 302 m2/g for the ACM-A, ACM-B and ACM-C, respectively, indicating a direct effect of compression pressure on the physical and electrochemical properties of ACMs electrodes.
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    Effect of electrolyte concentration on performance of supercapacitor carbon electrode from fibers of oil palm empty fruit bunches
    (2015-09-07) Farma, Rakhmawati; Deraman, Mohamad; Talib; Awitdrus; Omar, Ramli; Ishak; Taer, Erman; Basri, Nur Hamizah; Dollah, Besek Nurdiana Mohd
    Fibers of oil palm empty fruit bunches were used to produce self-adhesive carbon grains (SACG). The SACG green monoliths were carbonized in N2 environment at 800°C to produce carbon monoliths (CM) and the CM was CO2 activated at 800°C for 4 hour to produce activated carbon monolith electrodes (ACM). The physical properties of the CMs and ACMs were investigated using X-ray diffraction, field emission scanning electron microscopy and nitrogen adsorption-desorption. ACMs were used as electrode to fabricate symmetry supercapacitor cells and the cells which used H2SO4 electrolyte at 0.5, 1.0 and 1.5 M were investigated using electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic charge-discharge standard techniques. In this paper we report the physical properties of the ACM electrodes and the effect of electrolyte concentration on the electrochemical properties the ACM electrodes
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    Effects of Activation Time on the Performance of Supercapacitor Binderless Activated Carbon Electrodes Derived from Fibers of Oil Palm Empty Fruit Bunches
    (2015-09-07) Ishak; Deraman, Mohamad; Dollah, Besek Nurdiana Mohd; Othman; Omar, Ramli; Basri, Nur Hamizah; Nor, Najah Syahirah Mohd; Taer, Erman; Awitdrus; Farma, Rakhmawati; Aziz
    Green monoliths (GMs) with different composition, labelled as GM1, GM2 and GM3, were prepared from self-adhesive carbon grains (SACG) produced from fibers of oil palm empty fruit bunches, SACG treated with 0.4 M H2SO4 and mixtures of SACG and carbon nanotubes (5 wt.%) treated with 0.4 M H2SO4, respectively. Each GMs was carbonized and then activated with holding time of 1 h and 2 h, respectively, to produce their respective activated carbon monoliths (ACMs). These ACMs were used as electrodes to fabricate supercapacitor cells using H2SO4 electrolytes, Teflon separator and stainless steel 316L current collector. The porosity of the ACMs, examined by nitrogen adsorption-desorption isotherm method were found affected after prolonging the activation time. From the electrochemical characterization of the ACMs electrodes using galvanic charge-discharge methods, it was found that supercapacitor cells fabricated using the ACMs produced by longer activation time (2 h) showed better performance, which had higher specific capacitance (113 F/g), specific power (159 W/kg) and specific energy (3.35 W h/kg), compared to the cells using ACMs produced by shorter activation time (1 h).
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    Electrical Conductivity Of Carbon Pellets Prepared From Mixtures Of Pyropolymers From Oil Palm Bunches and Petroleum Green Coke
    (2015-09-07) Deraman, Mohamad; Awitdrus; Talib; Omar, Ramli; Jumali; Ishak; Saad; Taer, Erman; Saman; Farma, Rakhmawati; Yunus
    reen pellets (GPs), prepared at different compression pressures (cs = 6, 7.5 and 12 metric tonne) from mixtures containing self‐adhesive carbon grains (sacg) from the oil palm empty fruit bunch (EFB) and different percentages (pr = 0 to 90%) of a non self‐adhesive powder of petroleum green coke (ppgc), were carbonized (800° C) and activated with CO2 to produce carbon pellets (CPs). The measured electrical conductivity (σ) of the CP for all cs showed a curve having a minimum value at pr around 50%, indicating that the conducting phase displays a nonlinear σ‐ pr relationship. A significant increase in the σ due to CO2 activation was observed. For a sufficienctly high cs, an existence of a pr range in which the σ varies linearly with the density was also observed. These results provide some new information for modifying the electrical conductivity of carbon derived from the sacg from EFB or other types of biomass.
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    Impedance spectroscopic analysis of composite electrode from activated carbon/conductive materials/ruthenium oxide for supercapacitor applications
    (2015-09-07) Taer, Erman; Deraman, Mohamad; Talib; Awitdrus; Farma, Rakhmawati; Ishak; Omar, Ramli; Dollah, Besek Nurdiana Mohd; Basri, Nur Hamizah; Othman; Kanwal
    Activated carbon powders (ACP) were produced from the KOH treated pre-carbonized rubber wood sawdust. Different conductive materials (graphite, carbon black and carbon nanotubes (CNTs)) were added with a binder (polivinylidene fluoride (PVDF)) into ACP to improve the supercapacitive performance of the activated carbon (AC) electrodes. Symmetric supercapacitor cells, fabricated using these AC electrodes and 1 molar H2SO4 electrolyte, were analyzed using a standard electrochemical impedance spectroscopy technique. The addition of graphite, carbon black and CNTs was found effective in reducing the cell resistance from 165 to 68, 23 and 49 Ohm respectively, and increasing the specific capacitance of the AC electrodes from 3 to 7, 17, 32 F g-1 respectively. Since the addition of CNTs can produce the highest specific capacitance, CNTs were chosen as a conductive material to produce AC composite electrodes that were added with 2.5 %, 5 % and 10 % (by weight) electro-active material namely ruthenium oxide; PVDF binder and CNTs contents were kept at 5 % by weight in each AC composite produced. The highest specific capacitance of the cells obtained in this study was 86 F g-1, i.e. for the cell with the resistance of 15 Ohm and composite electrode consists of 5 % ruthenium oxide.
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    Influence of gamma irradiation exposure on the performance of supercapacitor electrodes made from oil palm empty fruit bunches
    (2015-08-18) Nor, Najah Syahirah Mohd; Deraman, Mohamad; Omar, Ramli; Awitdrus; Farma, Rakhmawati; Basri, Nur Hamizah; Dolah, Besek Nurdiana Mohd; Mamat, Nurul Fatin; Yatim, Baharudin; Daud, Mohd Norizam Md
    Carbon-monolith electrodes for supercapacitors were prepared from GMs (green monoliths) made from pre-carbonized fibers of oil palm EFB (empty fruit bunches) and GMs of pre-carbonized EFB fibers exposed to gamma radiation at 5 kGy, 15 kGy, and 20 kGy. GMs and irradiated GMs were carbonized and activated to prepare ACM (activated-carbon-monolith) electrodes. The gamma radiation affected the pore structure of the ACM electrodes and the electrochemical performance of the supercapacitors; irradiation doses of 0 kGy, 5 kGy, 15 kGy and 20 kGy produced specific capacitances of 121 F g 1, 196 F g 1, 11 F g 1, and 12 F g 1, respectively. The irradiation dose of 5 kGy appears to be optimum and produces a specific power and specific energy of 236 W kg 1 and 5.45 W h kg 1, respectively, representing 34% and 60% increases over ACM electrodes prepared from non-irradiated GMs.
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    KOMPUTER ANALOG DALAM PREDIKSI KONSENTRASl GLUKOSA PLASMA DARAH HOMOSTATIS ABNORMAL
    (2013-02-27) Hamdi, Muhammad; Awitdrus
    Telah dilakukan kajian replika dari sistem sirkulasi regulasi fluks insulin-glukosa darah dalam tubuh yang dikonstruksi dengan menggunakan prinsip feedback negatif analog. Secara umum disain sistem ini melibatkan fungsi-fungsi organ utama yang dominan dalam merespon regulasi insulin-glukosa, antara lain: hati, pankreas dan ginjal. Sedangkan sistem lain yang disertakan adalah sistem syaraf otak, otot-otot, sel-sel dan jaringan-jaringan utama dalam daerah ekstraseluler. Integritas dari respon fungsi masingmasing bagian membentuk loop-loop tertutup yang bisa dianalogikan dengan rangkaian listrik, sehingga dikenal dengan nama komputer analog elektronik. Sistem ini dirancang oleh derivasi persamaan diferensial konsentrasi insulin-glukosa dengan prinsip persamaan keseimbangan masa, pendekatan syarat awal dan batas. Untuk tujuan validasi model dipergunakan hasil dari data klinik yang diperlakukan kepada pasien dengan keadaan konsentrasi insulin-glukosa tak normal, seperti glukosa darah tinggi. Hasil pemodelan yang mewakili untuk kategori 2 model pasien diperoleh sebagai berikut: • Model pasien pertama untuk kondisi glukosa rendah dalam pemodelan diperoleh harga Kp dari 4.1 s' menjadi 8.7 s"\ perubahan harga ini membuat level konsentrasi glukosa berubah dari 65 mg/ml.menjadi 71 mg/ml. • Model pasien ke lima untuk kondisi glukosa tinggi dalam pemodelan diperoleh harga Kp dari 31.9 s'* menjadi 24.4 s'\ perubahan harga ini membuat level konsentrasi glukosa berubah dari 162 mg/ml.menjadi 128 mg/ml. Pengaruh perubahan level konsenterasi glukosa abnormal baik yang rendah maupun yang tinggi mendekati konsentrasi normal dikarenakan peranan metabolisme pankreas dalam pengaturan konsentrasi insulin. Hasil pengukuran perubahan dari level konsentrasi ini dikaji dengan menggunakan pemodelan diperoleh perubahan harga parameter konstanta laju transpot organ pankreas (Kp) untuk kedua keadaan. Baik yang abnormal dengan konsentrasi glukosa rendah maupun yang tinggi. Hal ini dikarenakan adanya perlakuan terapi terhadap pasien oleh medis setelah periode 2 bulan. Besar dan kecilnya harga Kp dapat diasumsikan menunjukkan minimum dan maksimumnya glukosa yang didisipasi atau ditransformasikan kedalam bentuk energi selama proses sirkulasi glukosa dan juga regulasi metabolisme glukosa dalam tubuh. Hasil keseluruhan dari level konsentrasi glukosa abnormal homostatis menunjukkan hasil cukup baik dalam tahap penyelidikan awal
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    A method to produce binderless supercapacitor electrode monoliths from biomass carbon and carbon nanotubes
    (2015-08-18) Dolah; Deraman; Othman; Farma, Rakhmawati; Awitdrus
    Binderless supercapacitor electrode monoliths (BSEM), prepared via the carbonization and activation of green monoliths from (a) self-adhesive carbon grains (SACG) from oil palm empty fruit bunch fibers, (b) SACG mixed with KOH, and (c) mixtures of SACG, KOH, and varying percentages of carbon nanotubes (CNTs), were characterized and evaluated in symmetrical supercapacitor cells. The porosity and the structural and microstructural characteristics of the electrodes are influenced by KOH and CNTs. The electrodes containing CNTs have a relatively lower specific capacitance but exhibit lower equivalent series resistance values and hence can sustain or improve the specific power of the cells, suggesting the need to optimize the quantity of CNTs used to sustain higher specific capacitance above 100 F/g. This innovative process uses inexpensive SACG with relatively small quantities of CNTs and KOH with no binder, and it directly combines both chemical (KOH) and physical (CO2) activation during the production of BSEM.
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    Microcrystallite Dimension and Total Active Surface Area of Carbon Electrode from Mixtures of Pre-Carbonized Oil Palm Empty Fruit Bunches and Green Petroleum Cokes
    (2015-09-07) Awitdrus; Deraman, Mohamad; Talib; Omar, Ramli; Jumali, Mohd Hafizuddin; Taer, Erman; Saman, Mansor mohd
    Carbon pellets (CP) were prepared from the green pellets (GP) containing mixtures of pre-carbonized oil palm empty fruit bunches (SACG) and Green Petroleum Cokes (GPC), with the weight percentages (x) of SACG in the samples at 10%, 30%, 50%, 70% and 90%. Carbonization process to produce the CP was conducted up to 900oC using a multi steps heating profile. The interlayer spacing (d200 and d100), stack height (Lc), stack width (La,) and effective dimension L of the turbostratic crystallites (microsrystallite) in the CPs were estimated from X-ray diffraction data; d200, d100, La, L increased and Lc decreased with increasing weight percentage of SACG. The total surface area of active material of the CP (Atot) with thickness, t, estimated from Lc was found to follow the equation, Atot = [4.8086 – 0.0083x]1010 t, indicating a significant influence of the SACG content in the mixture of the green body.
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    Nanoporous separators for supercapacitor using activated carbon monolith electrode from oil palm empty fruit bunches
    (2015-09-06) Nor, Najah Syahirah Mohd; Deraman, Mohamad; Omar, Ramli; Taer, Erman; Awitdrus; Farma, Rakhmawati; Basri, Nur Hamizah
    Activated porous carbon electrode prepared from fibres of oil palm empty fruit bunches was used for preparing the carbon based supercapacitor cells. The symmetrical supercapacitor cells were fabricated using carbon electrodes, stainless steel current collector, H2SO4 electrolyte, and three types of nanoporous separators. Cells A, B and C were fabricated using polypropylene, eggshell membrane, and filter paper, respectively. Electrochemical characterizations data from Electrochemical Impedance Spectroscopy, Cyclic Voltammetry, and Galvanic Charge Discharge techniques showed that specific capacitance, specific power and specific energy for cell A were 122 F g-1, 177 W kg-1, 3.42 Wh kg-1, cell B; 125 F g- 1, 179 W kg-1, and 3.64 Wh kg-1, and cell C; 180 F g-1, 178 W kg-1, 4.27 Wh kg-1. All the micrographs from Field Emission Scanning Electron Microscope showed that the different in nanoporous structure of the separators lead to a significant different in influencing the values of specific capacitance, power and energy of supercapacitors, which is associated with the mobility of ion into the pore network. These results indicated that the filter paper was superior than the eggshell membrane and polypropylene nanoporous separators. However, we found that in terms of acidic resistance, polypropylene was the best nanoporous separator for acidic medium.
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    A New Empirical Equation for Estimating Specific Surface Area of Supercapacitor Carbon Electrode from X-ray Diffraction
    (2015-08-18) Deraman, Mohamad; Daik, Rusli; Soltaninejad, Sepideh; Nor, Najah Syahirah Mohd; Awitdrus; Farma, Rakhmawati; Mamat, Nurul Fatin; Basri, Nur Hamizah; Othman, Mohd Amir Radhi
    The current trend of increasing research interest in supercapacitor is due to high demands for an energy storage device that can work in systems that require either low or high power-energy usage. In a supercapacitor using porous carbon electrodes, the energy storage mechanism involves the electrolyte ions in electrode pores and electronic charges in electrodes to form electric double layers at the electrode-electrolyte interface without undergoes any chemical reaction. The specific surface area of porous electrodes, which affect the performance of supercapacitor, have been widely investigated by many researchers using the nitrogen adsorption-desorption measurement. However, despite its simplicity, the X-ray diffraction method is rarely found being used to determine the specific surface area of porous electrodes. Therefore, in the present paper, we propose a new equation which expressed the specific surface area of electrodes as a function the electrode structural parameters obtained from the X-ray diffraction data, and duration of activation time employed during the electrode preparation. This equation is found to produce a satisfactory result and is expected to be beneficial for studying supercapacitor electrode materials
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    Pemanfaatan Limbah Tandan Kosong Kelapa Sawit Dan Green Petroleum Coke Sebagai Elektroda Karbon Superkapasitor
    (2015-07-02) Awitdrus
    Dalam penelitian ini bahan baku dasar (raw materials) yang digunakan adalah serabut tandan kosong kelapa sawit (STKS) yang lerscdia dalam Junilah yang besar sebagai bahan sisa hasil induslri pengolahan minyak kelapa sawil {crude palm oil) dan green petroleum coke (GPC) yang merupakan hasil sampingan dari proses pengolahan minyak bunii oleh Pertamina UP I I Dumai. Sedangkan sebagai pengumpul arus (current collector) digunakan adalah stainless steel tipe 316L, pemisah (separator) antar karbon digunakan teflon dengan ketebalan 0.2 mm dan sebagai larutan elektrolit (electrolite solution) digunakan asam sulfat (H2SO4) 1 M. STKS dilakukan proses pra-karbonisasi dalam tungku pemanas (furnace) pada temperatur rendah. yaitu 280''C dalam ruang vakum selama 4 jam. Sebelum dilakukan pencampuran. masing-masing STKS dan GPC terlebih dahulu dihaluskan dengan menggunakan ball mill selama 36 jam dan diayak agar diperoleh butiran STKS dan GPC dengan ukuran < 53 urn. Selanjutnya kedua bahan dicampur dengan komposisi GPC yang berbeda yaitu 10% dan 30% berat dan diaduk agar kedua bahan campuran tercampur merata. Bahan campuran dimasukan ke dalam alat cetakan (mould) dan ditekan dengan gaya tekan sebesar 7.5 metrik ton agar membentuk pelet. Proses karbonisasi pelet jasad hijau dilakukan pada temperatur 800°C dengan menggunakan pemanasan multi step heating profile, dimana laju pemanasan sebesar 1°C per menit dari temperatur kamar ke temperatur 340°C dan pada temperatur ini ditahan selama 60 menit, dari 340''C ke 800°C laju pemanasannya 3"C per menil. Selama proses karbonisasi, tungku pemanas dialiri gas nitrogen dengan laju aliran 1,5 - 2 liter per menit.
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    Pembangunan Superkapasitor Menggunakan Elektroda Karbon
    (2015-07-02) Taer, Erman; Awitdrus; Farma, Rakhmawati; Anita, Sofia
    Sel Superkapasitor terdiri dari pengumpul arus {current collector), elektroda, pemisah (Separator) dan elektroiit. Elektroda karbon biasa diguneikan karena mempunyai sifat surface area yang tinggi, sifat listrik yang baik dan harga yang relatif murah. Sel superkapasitor mempunyai nilai kapasitan yang sangat tinggi bila dibandingkan dengan kapasitor konvensional. Elektroda karbon dapat dibuat dari bahan yang kaya akan lignoselulose. Serbuk gergaji kayu karet merupakan bahan pemula yang baik untuk sumber karbon. Serbuk pengergajian kayu karet akan mengalami proses pra-karbonisasi, pengilingan, pencetakan, karbonisasi, aktivasi, kemudian dilakukan penumbuhan nano partikel. Variasi tekanan, suhu karbonisasi dan aktivasi dilakukan untuk memporoleh optimasi sifat listrik yang baik (nilai tahanan yang rendah) untuk menjamin electrik series resistance (ESR) sel yang rendah dan sifat fisik yang sesuai (surface area) yang tinggi. Karakterisasi XRD, SEM dan BET dilakukan untuk mendukung sifat-sifat yang dikehendaki dapat diketahui. Hasil optimasi elektroda karbon akan digunakan untuk membangun sel supercapasitor dengan struktur Stainlesstel Current Colector/Elektroda karbon+Aguas Elektrolyte+Separator+Electroda karbon/ Stainlesstel Current Colector. Karakterisasi impedance dan Siklus Galvanic akan dilakukan sebagai investigasi nilai ESR dan prestasi cas dan discas sel.
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    PEMBUATAN KARBON AKTIF DARI KULIT JERUK (CITRUS SINENSIS (L) OSBECK) DENGAN AKTIVASI KOH BERBANTUAN GELOMBANG MIKRO
    (2020-05) Siregar, Gladys May Grace; Awitdrus
    Orange peel based activated carbon by microwave assisted potassium hydroxide chemical activation has succesfully been made. Pre-carbonized of activated carbon was conducted for 1 hour at temperature of 150˚C and followed by chemical activation using KOH with variation of molarity of 2 M, 3 M, and 4 M. The microwave pyrolisis was carried out using output power of 630 Watt for 15 minutes. The molarity of KOH was influenced by of the physical properties of activated carbon. Higher of output of activator concentration shows bigger of carbon content produced. The data of energi dispersive X-ray show the activated carbon of KJ4M has the highest of carbon content of 66,55%
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    PENGARUH PERSENTASE KALIUM HIDROKSIDA TERHADAP SIFAT FISIS KARBON AKTIF KAYU EUCALYPTUS PELLITA
    (2016-10-12) Harini, Resti; Awitdrus; Farma, Rakhmawati
    research has been conducted on activated carbon of Eucalyptus pellita wood with various ratios of charcoal and potassium hydroxide of 1:0.25, 1:0.5, and 1:0.75 respectively. Chemical activation was conducted using the potassium hydroxide for 20 hours and microwave irradiation with output power of 630 Watt for 20 minutes. The aim of this research is to know the effects of potassium hydroxide on the physical properties of activated carbon i.e yield of activated carbon, micro structures, surface morfology, elements of activated carbon, and methylene blue adsorption. X-ray diffraction patterns of the activated carbon showed semicrystalline structure and SEM images showed porous activated carbon. Weigh percentages of carbon (C), oxygen (O), and potassium (K) elements of activated carbon were 67.87%, 30.63%, and 1.50%, respectively. Adsorptive power of activated carbon on methylene blue was 97.45 mg/g and surface area was 361.67 m2/g respectively
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    PENGARUH WAKTU IRADIASI GELOMBANG MIKRO TERHADAP KUALITAS KARBON AKTIF DARI CANGKANG BUAH KETAPANG SEBAGAI ADSORBEN
    (2016-10-12) Annur, Al; Awitdrus
    The fabrication of activated carbon made from shell of Terminalia Catappa L has been carried out using chemical activation methods assisted by microwave irradiation. The irradiation times was varied of 15, 20 and 25 minutes. The aims of this study is to determine the morphological characteristics, microstructure, surface area and the adsorption of activated carbon to the methylene blue, and to know the influence of microwave irradiation time variations to the quality of activated carbon as adsorbent. The results showed that the best characteristic was the activated carbon with microwave irradiation time of 15 minutes resulted microcrystallite dimension with Lc and La were 3.3494 and 1.0239 respectively, surface area of 304.82 m2 / g and the methylene blue adsorption of 82.46 mg / g. The result of methylene blue adsorption test exhibited that the time variation of microwave irradiation affected the quality of the adsorption of activated carbon that has been produced