Jurnal Reaktor

261-266

Authors: Erlyta Septa Rosa, Shobih Shobih

This research reports on a fabrication of polymer solar cells based on blends of two widely used polymeric semiconductors i.e. poly(2-methoxy-5-(3,7-dimethyloctyloxy)-para phenylene vinylene) (MDMO-PPV) and the soluble fullerene C60 derivative [6,6 phenyl C61-butyric acid methyl ester] (PCBM). The devices were fabricated on an indium tin oxide (ITO) coated glass substrate. After cleaned and dried, a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in H2O was spin coated onto the freshly prepared substrate and then dried in a vacuum oven at 120°C for 60 minutes. A blend of MDMO-PPV and PCBM in chlorobenzene was spin coated on the top and dried in a nitrogen ambient at room temperature for 24 hours. The devices were transferred to a sputtering system where an aluminum was coated. Some of the devices then were annealed in a vacuum oven at 60°C for 60 minutes. Finally, the devices were encapsulated by placing a sealant between the back of the devices and glass slides and then cured in a vacuum oven at temperature 100°C for 10 minutes. For characterization, the devices were illuminated with a xenon lamp at the intensity of 27 mW/cm2 and the temperature at approximately 25°C. The influence of the annealing treatment and polymer blends on the photovoltaic performance of the devices was also discussed here. The best performance was obtained from the device with a blend ratio of 1:1 MDMO-PPV/PCBM without annealing treatment. The typical power efficiency was 0.01% with open circuit voltage of 0.347 V, short circuit current of 0.064 mA, and maximum power of 0.006 mW.

272-276

Authors: Ery Susiany Retnoningtyas, Antaresti Antaresti, Aylianawati Aylianawati

Tongkol jagung yang melimpah sebagai produk samping dari hasil pengolahan industri jagung pipilan, memberikan peluang untuk dimanfaatkan sebagai substrat dalam produksi crude enzim selulase. Crude enzim selulase dari tongkol jagung selanjutnya diaplikasikan pada produksi etanol dengan memanfaatkan tongkol jagung juga dengan metode simultaneous saccharification and fermentation (SSF). Penelitian ini bertujuan untuk mempelajari pengaruh volume crude enzim selulase terhadap kadar etanol, kinerja crude enzim selulase dalam memproduksi etanol dan membandingkan kinerjanya dengan crude enzim komersial. Penelitian ini terbagi dalam dua tahap yaitu : pretreatment tongkol jagung, dan fermentasi. Tongkol jagung yang sudah dikeringkan, dihaluskan hingga menjadi serbuk dengan ukuran 12 mesh, dan diberi perlakuan hidrolisis dengan uap panas (steam explosion) selama 60 menit. Serbuk tongkol jagung difermentasi,dengan penambahan nutrisi, crude enzim selulase dan jamur Saccharomyces cerevisiae. Proses fermentasi dilakukan pada suhu 30oC selama 120 jam, sedangkan pengamatan dilakukan setiap 24 jam. Hasil penelitian menunjukkan produksi etanol yang dihasilkan dengan menggunakan crude enzim selulase dan crude enzim komersial berturut-turut adalah 1,28 dan 2,89 %.

284-290

Authors: Mubiar Purwasasmita, Petrus Benny Juwono, Aysha Mareta Karlina, Khoiruddin Khoiruddin, I Gede Wenten

Performance of polypropylene hollow fiber ultrafiltration membrane during non-dissolved solids (NDS) removal from palm kernel oil is investigated. The filtration is operated at difference feed temperature and pressure to study the effect of both parameters on membrane performance. From the experimental results, it can be concluded that polypropylene hydrophobic hollow fiber membrane can be used for palm kernel oil NDS removal. Temperature and trans-membrane pressure have proportional effect to permeate flux. In contrast, they have inverse effect to rejection of NDS. During the experiment, permeate fluxes and rejections of NDS varied from 3.4 to 8.7 L/m2.h and from 51% to 94%, respectively. The best operating conditions suggested are feed temperature of 30°C and TMP of 1 bar which produce the highest NDS rejection. In addition, the permeate quality can meet the requirement of standard NDS content even at its lowest rejection level which shows the remarkable performance of membrane filtration.

298-304

Authors: Syamsudin Syamsudin, Herri Susanto, Subagjo Subagjo

Kraft pulp mill sludge cake composed of rejected wood fibers and activated sludge microorganisms. With a heating value about 14 MJ/kg (dried basis), this type of biomass had a potential as an alternative energy source. Unfortunately, it had an ash content of 27.6% and a moisture content of 80%. For reducing moisture content with minimum energy consumption, a combination of mechanical dewatering and thermal drying was studied previously. Meanwhile, experiments on isothermal pyrolysis had been carried out for further improvement on ultimate and proximate analysis of solid fuel. Final mass of char obtained from pyrolysis at 500oC was not significantly different from that of 700oC, so pyrolysis was considered to be optimum at 500oC. A char obtained from pyrolysis at temperature of 500oC had a pore surface area of 77.049 m2/g (highest among other temperatures). Kinetic of isothermal pyrolysis was well represented with a first order modified volumetric model with a frequency factor of 0.782 1/s and an activation of 34.050 kJ/mol.

314-323

Authors: Subagjo Subagjo, Maria Ulfah

Evaluasi kinetika reaksi hidrodesulfurisasi (HDS) dibenzothiophene dan simulasi nafta hydrotreater yang berada di PT. PERTAMINA Refinery Unit II Dumai menggunakan katalis NiMo/Al2O3 hasil pengembangan telah dilakukan. Kinetika reaksi HDS DBT dilakukan dalan sistem reaktor batch dengan variasi temperatur 280-320oC dan tekanan 30 bar. Data kinetika diolah dengan persamaan hukum pangkat (law power) dan persamaan kinetik mekanistik (Langmuir Hinshelwood, LH). Berdasarkan model hukum pangkat, kinetika HDS DBT menggunakan NiMo/Al2O3 hasil pengembangan merupakan orde satu terhadap DBT dengan konstanta Arhenius sebesar 165633 detik-1 dan energi aktivasi 69017 J/mol (16,56 kkal/mol). Model LH yang cocok untuk reaksi HDS DBT menggunakan NiMo/Al2O3 hasil pengembangan adalah model LH yang mengilustrasikan adanya kompetisi antara reaktan DBT dan H2 pada tipe pusat aktif yang sama, dengan DBT teradsorb secara kuat sedangkan H2 teradsorpsi secara lemah. Energi aktifasi dan konstanta Arhenius berdasarkan model LH ini ini berturut-turut adalah 81409 J/mol (19,34 kkal/mol) dan 1658133 s-1. Dengan menggunakan persamaan laju reaksi hukum pangkat, model memberikan hasil konversi sulfur yang sama dengan hasil keluaran reaktor nafta hydrotreater RU II-Dumai, yaitu mencapai 98%.

179-186

Authors: Opy Kurniasari, Tri Padmi, Edwan Kardena, Enri Damanhuri

Municipal solid waste (MSW) handling in Indonesia is currently highly dependent on landfilling at the final disposal facility (TPA), which generally operated in layer-by-layer basis, allowing the anaerobic (absent of oxygen) process. This condition will certainly generate biogas in the form of methane (CH4) and CO2. Methane is a greenhouse gas with a global warming potential greater than CO2, and can absorb infrared radiation 23 times more efficient than CO2 in the period of over 100 years. One way that can be done to reduce methane gas from landfills that escape into nature is to oxidize methane by utilizing landfill cover material (biocover) as methane-oxidizing microorganism media. Application of compost as landfill cover material is a low-cost approach to reduce emissions so are suitable for developing countries. The compost used in this study was compost landfill mining, which is degraded naturally in landfill. The purpose of this study was to evaluate the ability of biocover to oxidize the methane on a certain layer thickness with a continuous flow conditions. Three column reactors were used, which were made of flexy glass measuring 70 cm in high and 15 cm in diameter. The methane flowed from the bottom of the reactor continuously at a flow rate of 5 ml/minute. The columns were filled with biocover compost landfill mining with layer thickness of 5, 25, 35 and 60 cm. The results showed that the thicker layer of biocover, the higher the efficiency of methane oxidation. The oxidation efficiency obtained in each layer thickness of 15, 25, 35 and 60 cm was 56.43%, 63.69%, 74.58% and 80, 03% respectively, with the rate of oxidation of 0.29 mol m-2 d-1 and the fraction of oxidation of 99%. The oxidation result was supported by the identification of bacteria isolated in this experiment, namely metanotrophic bacteria that have the ability to oxidize methane through the form of methanol metabolite.

193-198

Authors: Luqman Buchori, Mohamad Djaeni, Laeli Kurniasari

The main problem in corn drying process is the low of energy efficiency (50%) and quality products. Consequently, operating costs in large for fuel consumption and the short shelf life of corn. Zeolite adsorption dryers have the potential to overcome this problem. This research aims to study composition of corn-zeolite and the effect of temperature on drying speed and protein and fat content in corn. Research variables are the ratio of corn and zeolite (1:0, 1:3, 1:1, 3:1) and intake air temperature (room temperature, 30oC, 40oC, 50oC). Sampling for moisture testing performed every 15 minutes. For energy purposes also calculated the energy efficiency (h) based on the amount of heat used to evaporate water from the corn (Qevap) divided by the total heat requirement to regenerate the zeolite and raising the air temperature (Qintr). Profiles of temperature and water in the mixed adsorption dryer are also studied. The results showed that the greater number of zeolite used, the water content of the final outcome a little more drying, protein and fat content of the final result of drying is relatively constant. The larger intake air temperature, the water content of the less drying results, protein content decreases, and the fat content does not change/relatively constant. The best variable was a ratio of corn: zeolite is 1:3 and air temperature was 50oC. While the variables that are suitable and in accordance with ISO standards for dry foods (14%) are air temperature of between 40oC and 50oC with a ratio of corn:zeolite is 1:3. The energy efficiency of 81.23% is obtained. Modeling done with FEMLAB (COMSOL) can describe the moisture content and temperature profiles in the corn and zeolite

204-210

Authors: Darmawan Darmawan, Dyah Tjahyandari Suryaningtyas, Juniska Muria Sariningpuri

Wastewater treatment produces semi-solid residue (sludge) that must be handled carefully during dumping and discharge to avoid polluting the environment. A low cost and easy treatment of dewatering is needed. This research aimed to apply electroosmosis technique for dewatering sludge in order to seek for parameters that can efficiently reduce water content of sludge, including range of voltage, type of electrodes, and distance between electrodes; and to determine the effect of electroosmosis processes on changes of chemical characteristics of sludge. The results showed that: (1) electroosmosis dewatering occurred on the sludge taken from waste water treatment of landfill but not on sludge from water purification plant (PDAM), (2) direct current voltage of 30 volts was the optimum voltage, (3) copper rod cathode provided electroosmosis process as good as stainless steel cathode and both were better than the woven stainless steel cathode, (4) the dewatering time to reduce 1200% (w/w) water content to about 400% was about 40 hours for sludge of 2500 cm3 in volume (laboratory bench scale), (5) the anode need to reinserted gradually approaching the cathode due to current lost when the water content at the anode point reached 400% and sludge at the point shrink, and (6) some chemical elements in the sludge decreased significantly after treatment.

218-224

Authors: Mariana Mariana, Farid Muluna, Purwana Satriyo

Gases produced by garbage burning consist of dangerous gases such as CO, SO2 and other gases. Technology for reducing dangerous gases from incinerator outlet can be done by using a dry or wet process. The dry process is more economical process because of simple process, easy maintenance and no liquid waste as product. However, the weakness of the dry process is low absorption conversion and low gas removal efficiency. One way to overcome these problems is to use sorbent which has high reactivity. An inexpensive sorbent that commonly used is Ca(OH)2. The aim of this research was to increase the reactivity of Ca(OH)2 sorbent by using diatomaceous earth and compost as a source of silica and biosorbent, respectively. Diatomaceous earth contains CaO, SiO2 and Al2O3 and compost contains bacteria as a biosorbent that can convert CO to CO2 and CH4. The reaction between SiO2 and Ca(OH)2 would form calcium silicate hydrate (CaO.SiO2.2H2O) that has a high porosity and reactivity. The results showed that the reactivity of Ca(OH)2 sorbent increased by addition of diatomaceous earth and compost. The results also showed that the sorption of CO gas increases with increasing of height of sorbent bed and temperature. The highest CO gas sorption was obtained at temperature of 150oC and sorbent bed height of 6 cm using the modified sorbent with Ca(OH)2/DE/compost ratio of 3:1:1.

234-241

Authors: Tutuk Djoko Kusworo, Desmile Yusufina, Atyaforsa Atyaforsa

Carbon Nanotubes (CNTs) is one of the most well known nano-technology applications which the most of attracting the attention of researchers, because it has more advantages than other materials. The application of the CNT has extended into various aspects, such as electronics, materials, biology and chemistry. This research uses a system of Catalytic Chemical Vapour Deposition (CCVD), which aims to determine the influence of Co and Fe as a catalyst and zeolite 4A as a support catalyst with acetylene gas (C2H2) as carbon source in the synthesis of Carbon Nanotubes (CNTs). In this experiment, used the ratio of acetylene gas and flow rate of N2 gas is 1:1 by weight of the catalyst Co/Zeolite and Fe/Zeolite amounted to 0.5 grams at the operating temperature of 700oC for 20 minutes. N2 gas serves to minimize the occurrence of oxidation reaction (explosion) when operating. From analysis result by Scanning Electron Microscopy (SEM) shows the CNTs formed a type of MWNT with different of diameter size and product weight, depending on the size of the active component concentration on the catalyst. The larger of active components produced CNTs with larger diameter, whereas product weight syntheses result smaller. Use of the catalyst Fe/Zeolite produce CNTs with a diameter larger than the catalyst Co/Zeolite.

247-254

Authors: Nyoman Jaya Wistara, Gokma Silaban, Gustan Pari

The main goal of the present works was to determine chemical changes, thermal decomposition, and the content of moisture, ash, volatile, fixed carbon and calorific value of soda pulping black liquor of the rice straw. Neutralized black liquor was dried to a moisture content of 10% and then pyrolized at 106oC-750oC. It was found that calorific value, fixed carbon, volatile mater, and moisture content were in the range of 2782-4716 cal/g, 49.2-81.6%, 15.5-47.5%, and 0.2-3.5%, respectively. Ash content was not influenced by the temperature of pyrolysis and was thought to depend on its initial silicate content. The weight loss of pulp was higher than that of black liquor. Extreme weight loss has been found in the temperature of 200-400oC. Noticeable functional groups changes were found with the increasing temperature of pyrolysis. Hydroxyl group completely disappeared at 300oC and above. Carbonyl related groups were also disappeared at 300-500oC, but it was reformed at 650 and 750oC. It might be brought about by the deformation of chemical bonding of oxygen ring in lignin structures.