Judul: Aplikasi Adsorben Dalam Proses Pemurnian   Biodiesel Jarak Pagar (Jatropha Curcas L.) Menggunakan Metode Kolom
Abstrak: Kebutuhan dunia akan bahan bakar terus meningkat sepanjang tahun. Salah satu jenis bahan bakar yang banyak digunakan di Indonesia adalah bahan bakar solar. Impor solar Indonesia mencapai sekitar 5-6 milyar liter atau sekitar 50 % dari total kebutuhan pada tahun 2006. Nilai ini akan terus bertambah, dan diperkirakan permintaan solar tahun 2010 akan mencapai 36 milyar liter. Oleh karena itu, diperlukan bahan bakar alternatif pengganti solar yang dapat diperbarui, seperti biodiesel. Biodiesel adalah bahan bakar yang ramah lingkungan dan dapat diperbarui, yang diproduksi dari minyak nabati seperti minyak jarak pagar. Dalam penggunaannya, biodiesel harus dimurnikan terlebih dahulu untuk menghilangkan bahan pengotor yang terdapat di dalam biodiesel seperti sabun, gliserol air, dan asam lemak bebas. Metode pemurnian biodiesel yang biasa digunakan adalah water washing, yaitu pemurnian menggunakan air hangat. Metode ini memiliki kelemahan, yaitu memerlukan banyak energi dan waktu. Oleh karena itu perlu adanya metode baru yang dapat menghemat energi dan waktu proses produksi biodiesel, seperti metode dry washing menggunakan adsorben. Adsorben yang digunakan adalah aluminium silikat dan magnesium silikat. Penelitian ini bertujuan untuk (1) menentukan adsorben terbaik antara aluminium silikat, magnesium silikat, dan kombinasi dari keduanya dengan berbagai perbandingan, (2) menentukan konsentrasi adsorben dalam pasir kuarsa yang akan digunakan dalam pemurnian biodiesel menggunakan kolom, dan (3) mengetahui pengaruh suhu pemurnian terhadap laju alir dan mutu biodiesel yang dihasilkan. Penelitian pendahuluan yang dilakukan adalah menentukan komposisi aluminium silikat dan magnesium silikat terbaik yang digunakan dalam proses pemurnian biodiesel. Komposisi yang digunakan adalah aluminium silikat 100%, magnesium silikat 100%, dan kombinasi aluminium silikat dan magnesium silikat dengan perbandingan 1:1, 1:2, 1:3, 2:3, 3:2, 3:1, dan 2:1. Pengamatan terhadap biodiesel hasil pemurnian meliputi bilangan asam, kadar sabun, kadar air, kadar gliserol total, bebas, dan terikat. Hasil analisa menunjukkan bahwa komposisi aluminium silikat dan magnesium silikat terbaik untuk memurnikan biodiesel adalah aluminium silikat 100%, dengan nilai bilangan asam 0,4373 mg KOH/g biodiesel, kadar sabun 53,37 ppm, kadar gliserol bebas 0,0054%, gliserol terikat 0,2490%, gliserol total 0,2544%, dan kadar air 0,01%. Penelitian selanjutnya adalah aplikasi aluminium silikat dalam pemurnian biodiesel menggunakan kolom. Proses pemurnian dilakukan dengan mengalirkan biodiesel melalui tumpukan aluminium silikat di dalam kolom dengan memanfaatkan gaya gravitasi, sehingga biodiesel yang keluar dari kolom telah dalam keadaan murni. Untuk memperlancar aliran biodiesel, aluminium silikat dicampur dengan pasir kuarsa dengan konsentrasi 5%, 10%, 15%, dan 20% (bobot aluminium silikat/bobot pasir kuarsa). Konsentrasi aluminium silikat yang terbaik adalah 10%, dengan tingkat kejernihan sebesar 84,1%, pH air pencuci biodiesel sebesar 7,422, dan waktu mengalir sebesar 14,10 detik/ml biodiesel. Metode kolom ini berhasil memurnikan biodiesel, dilihat dari kenaikan nilai kejernihan biodiesel mencapai >80% dan penurunan pH air pencuci biodiesel mencapai 7 (netral) yang cukup signifikan dari biodiesel kasar. Pada penelitian ini juga dilakukan uji coba pengaruh suhu pemurnian menggunakan kolom terhadap laju alir dan mutu biodiesel. Suhu pemurnian yang digunakan adalah 70 oC, 80 oC, dan 90 oC yang dibandingkan dengan suhu kamar (±25 oC). Waktu yang dibutuhkan untuk mengumpulkan 1 L biodiesel yang dimurnikan pada ketiga suhu tersebut lebih kecil daripada pada suhu kamar, yaitu 7,18 menit/L (70 oC), 6,91 menit/L (80 oC), dan 9,87 menit/L (90 oC), sedangkan
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Judul: Pengaruh Penggunaan Adsorben  Dan Penggunaan Ulang Adsorben Hasil  Recycling Pada Proses Pemurnian Biodiesel  Minyak Jarak Pagar (Jatropha Curcas L.)
Abstrak: Biodiesel is an alkyl esther which potentially as renewable alternative energy. It could be produced from plant oil derivates such as jathropa pagar oil. Jathropha biodiesel is produced by estrans (esterification-transesterification) reaction. But, in the end of its making, there would be produced dirty biodiesel and another contaminants such as; residue of glycerol, non-reacted methanol, KOH residue and soap produced from the reaction between alkali and free fatty acid during the transesterification. That contaminant will impact the quality of its fuel and has been loosen from the product. Because of that, biodiesel has to be purified in order to have standardized quality that approximately with SNI 04- 7182-2006. The biodiesel purification is commonly used water (water washing method), but this washing method is still having so many weakness that in this research was done the biodiesel purification using adsorbent (dry washing method). This research was aimed to know the impact of adsorbent using and regenerated adsorbent reusing in jathropa biodiesel purification. This research is divided into two stage; introduction and main research. The introduction research was done to know the best adsorbent formulation between silica alumina and silica magnesium. The adsorbent formulation decision was done by some biodiesel characteristic analysis such as acid value, catalyst percentage, soap percentage, free glycerol, total glycerol and bounded glycerol. The experimental designed used in this stage was completely randomized design with one factor, that is adsorbent formulation (Z). The factor (Z) consisted of 8 treatment level, include silica alumina 100%, silica magnesium 100%, and the combination of those two with various comparation; that was 1:1, 1:2, 1:3, 2:3, 2:1, 3:1, and 3:2. In the main research, variety and adsorbent comparation that chose in the former research used for several times and looked the impact of quality characteristic of biodiesel. Before reused, the chosen adsorbent regenerated with water in the temperature of 65-70oC and recovery methanol. The characteristic biodiesel parameter that tested includes acid value, soap value, free glycerol, total glycerol and bounded glycerol. The process of adsorbent activation in biodiesel was significantly reduced the impurities of biodiesel. Based on previous research, best performance was the variety and comparation of 100% silica alumina. The characteristic of purified biodiesel which has been purified by the 100% silica alumina was having the acid value 0.4373 mg KOH/g biodiesel, undetected catalyst, soap contain 53,37 ppm, free glycerol 0,0054%, bounded glycerol 0.2490%, total glycerol 0.2544% and water contain. The result of the main research showed that silica alumina could be used for several times but there was reduction to the quality of the biodiesel. The reduction of biodiesel was significant until the third reuse but it still accomplish the SNI standards. The regeneration process of silica alumina with water 65-70oC produced better methanol compared with recovery methanol. The characteristic of purified biodiesel using first regenerated silica alumina with water in the temperature of 65-70oC was acid value 0.4211 mg KOH/ g biodiesel, undetected catalyst contain, soap contain 1034.5 ppm, free glycerol 0,0079%, bounded glycerol 0.0842%, and total glycerol 0.0921%. The characteristic of the biodiesel in second stage was having the acid
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Judul: Phylogeography and Species Limits in the Papuan White Snake (Micropechis ikaheka) (Reptilia: Serpentes: Elapidae)
Abstrak: Papua white snake, Micropechis ikaheka, has been distingushed into two subspecies M.i. ikaheka and M.i. fasciatus. However, due to lack of data on their morphology, distribution and ecology, both subspecies often ignored in scintific discussions and refers only byas , Micropechis ikaheka. This study was designed to document the differences between M.i. ikaheka and M.i fasciatus by using scales characteristics and reproductive organ or hemipenes. The study also examine, zoogeography, habitat, diet and cannibalism of both subspecies to better understanding the the ecology of one of the most venomous snakes in the world. This study consists of three topics with method and also different in the size samples, respectively. The first study is the histology and microtopography of the skin were studied using paraffin method and Scanning Electron Microscope (SEM). The second is the hemipenis were examined by following Myers and Cadle (2003), and Zaher and Prudente (2003). The third is the abdominal surgery was carried out to document diet type and the investigate phenomenon of cannibalism in the snake. Specimens for this study came from the collection from Museum Zoologicum Bogoriense (MZB) and Universitas Negeri Papua’s Laboratory (LZU). The research result also indicated that the markers of skin and hemipenis described the same structure and microornamentation in all M. ikaheka groups being compared. Based specimens examined morphological descriptions do not s support the further differentiation in Micropechis. In short, two markers that used in this study could not sufficiently indicate the differences in the level of species and subspecies of M. ikaheka. The study, however, were able to delineate zoogeography and skin color patterns, which fall into four groups: M. i. ikaheka; M. i. fasciatus. M. i. ssp. “intermediate”; and M. i. ssp “black”. This study also revealed that color variations did not overlap in their geographic distribution. It is therefore, it suggested that environmental factors may contribute to the skin color variations. It also assumed that habitat discontinuous and biogeography factors may also cause the loss of the connection between the original populations (vicarians) or follow colonization events (dispersal). The examined of 22 stomach contents of M. ikaheka shows this species is carnivorous, and prey on vertebrates such as amphibians, fish, reptiles, and Mammals. These snakes are opportunistic predators since they prey on all that can be captured, but mainly reptiles (61.5%), followed by mammals and fish (both 15.4%), and amphibians (7.7%). Although categorized as terrestrial animal, the diet study showed that M. ikaheka snakes often go into the water to hunt for fish (the sample from Yapen island), including eel (the sample from Aru island). Based on prey items indentified, there is evidence that M. ikaheka is cannibal. At this time, there still no record on reason for cannibalism, but it is assumed that cannibalism was due to competition between populations and means to control population.
Keyword: geographic variation, white snake, papua