Judul: The design process of cellulose acetate ultrafiltration membrane production by phase inversion method of cellulose pulp from wood of sengon (Paraserianthes falcataria.)
Abstrak: Cellulose acetate ultrafiltration membrane has been utilized in a variety of separation and purification processes, including in agro-industry sector. In general, cellulose acetate is obtained from acetylation of cotton cellulose and wood pulp (abaca, straw, sawdust). In this study, cellulose from wood pulp of Sengon (Paraserianthes falcataria) was used. This plant is fast growing species and has potential as a raw material from its high cellulose content. The purpose of this study was to find a cellulose acetate manufacturing process conditions, to characterize cellulose diacetate and its performance on ultrafiltration process. There are three steps of cellulose diacetate manufacturing process. They are: (1) activation of cellulose using acetic acid, (2) acetylation, cellulose in acetic acid solvent is reacted with acetic anhydride reactant using sulfuric acid as catalyst, (3) hydrolysis to obtain cellulose diacetate. At each operating processes acetyl content was observed at temperature 50oC. In addition, effect of variation of anhydride acetate reactant and cellulose ratio, namely (3.35:1), (4:1) (5:1), and (6:1) were also investigated. Asymmetric cellulose diacetate membrane preparation by phase inversion method was carried out by the addition of cellulose diacetate (SDA) as a polymer, N, N-Dimethil formaida (DMF) as solvent, water as a non-solvent, and polyethylene glycol (PEG) as additive. At this stage, effect of PEG / SDA ratio (10%, 20%, 30%), PEG molecular weight variation (1450, 4000, and 6000 Da), and coagulation temperature (15oC, room temperature, and 50oC) were also investigated. Membrane pore size was determined by by measuring Molecular Weight Cut Off ( MWCO) using a standard solution of dextran (12 kDa) and Bovin Serum Albumin (67 kDa). Membrane morphology was observed by Scanning Electron Microscope (SEM). Cellulose acetate of acetyl content of 39.66% and number average molecular weight 130,221 Da was obtained at the activation time 30 minutes; one hour acetylation process for acetic anhydride to cellulose ratio 3.35:1; and 15 hours hydrolysis process. The addition of PEG produced a thicker layer and greater tensile strength membranes and suppress the formation of macrovoid. SEM analysis shows a denser structure of membrane morphology with better regularity of pore shape, so has a better pore density (porosity) distribution of large and visible pores. The addition of PEG with higher molecular weight produces a denser morphological structure with larger pore size, but smaller porosity with large pore distribution. The addition of PEG with the increasing of PEG / SDA ratio resulted in a denser pore structure and greater number of pores with a greater porosity and large pore distribution. Coagulation at higher temperatures produced a thinner layer and low tensile strength membrane. The structure of membrane morphology is more tenuous with a bigger pore size and greater number of pores so large porosity and pore distribution. Flux (water, dextran, and BSA) and rejection (dextran and BSA) are determined by the porosity and pore distribution of the membrane. High flux and rejection generated by large porosity and small pore distribution membrane. Membrane having small porosity and pore distribution produces low flux but high rejection. Conversely, high flux with low rejection obtained from the membrane with greater porosity and pore distribution.
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Judul: Pengembangan Membran Selulosa Asetat Menggunakan Natrium Dodesil Sulfat
Abstrak: Development of membrane technology is waste treatment unit is growing rapidly and widely used in separation process. Membrane technology is chosen because the process is simple, low energy use, nondestructive, and do not generate new waste, thus classified as a green good technology. The production of membrane was started by preparing polymeric mixture solution of cellulose acetate (CA) and sodium dodecyl sulfate (SDS) in acetone. Composition of CA was 15% w/v and composition of SDS were varied from 0; 0.05; 0.01; to 0.125% w/v. The solution was stirred by ultrasonic for 3 hours and casted on the glass plate surface then immersed in warm water at 60 oC. The membranes were characterized by their rejection index. Rejection index was applied to detergent solution with concentration of 1600 ppm. When compared with values below the critical micelle concentration (CMC), the best average value of rejection index was resulted at the initiation of CMC, with SDS concentration of 0.125%. At that concentration, a quite high average values was obtained for the rejection index (77%). While, at the SDS concentration below CMC, 0.05% and 0.01%, the average index rejection values were 17% and 37%, repectively. The best CMC value was reached at the initiation (0.125%).
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Judul: Penyebaran Sarang Komodo di Pulau Longos dan Perilaku Bersarang Komodo di Pulau Rinca, Nusa Tenggara Timur.
Abstrak: Komodo tersebar di dalam kawasan Taman Nasional Komodo (TNK) dan di pulau-pulau kecil di luar TNK. Penelitian ini bertujuan untuk memetakan sebaran sarang komodo di Pulau Longos dan mendeskprisikan perilaku bersarang komodo di Pulau Rinca. Survei menggunakan peta grid 300x300 m dilakukan untuk mencari sarang komodo di Pulau Longos. Pengamatan perilaku bersarang komodo di Pulau Rinca dilakukan terhadap empat individu komodo dengan metode focal animal sampling. Ditemukan 86 sarang yang menyebar secara berkelompok di Pulau Longos. Di sebagian besar dari sarang yang ditemukan terdapat jerat untuk menangkap burung gosong, yang bisa menjadi ancaman bagi populasi komodo. Teridentifikasi lima kategori perilaku bersarang betina komodo di Pulau Rinca, yakni berjalan, pemeliharaan diri, menjaga, menggali, dan kawin. Perilaku pemeliharaan diri merupakan perilaku yang paling sering dilakukan (41,67%) dan perilaku menjaga merupakan satu-satunya perilaku penjagaan anak oleh komodo.
Keyword: komodo, Longos, perilaku, Rinca, sarang