Equilibrium Journal of Chemical Engineering
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Penentuan Pelarut untuk Adsorpsi Oryzanol dari Minyak Bekatul dengan Investigasi Kromatografi Lapis Tipis (Thin Layer Chromatography)
Get PDFOryzanol yang terkandung dalam minyak bekatul mempunyai kekuatan antioksidan lebih tinggi daripada vitamin E dan terbukti mempunyai efek hipokolesteromik sehingga berguna untuk kesehatan jantung dan pembuluh darah. Metode adsorpsi menggunakan adsorben silika merupakan salah satu metode isolasi oryzanol yang menjanjikan. Keberhasilan proses pemungutan oryzanol sangat ditentukan oleh pemilihan pelarut yang digunakan karena oryzanol merupakan senyawa ester sehingga sifatnya mirip dengan sifat trigliserida minyak bekatul yang ingin dipisahkan darinya. Oleh karena itu perlu ditentukan pemodifikasi pelarut sehingga diperoleh campuran pelarut yang cocok untuk proses tersebut. Modifikasi dilakukan terhadap pelarut utama n-heksana dan pemodifikasi potensial yang digunakan adalah etil asetat, diklorometana, kloroform, dan aseton. Performa campuran pelarut diuji menggunakan metode kromatografi lapis tipis (thin layer chromatography - TLC) menggunakan plat TLC silika gel grade 60. Hasil penelitian menunjukkan kombinasi n-heksana/aseton = 85/15 memberikan hasil pemisahan oryzanol terbaik, sedangkan kombinasi n-heksana/etil asetat = 90/10 patut dipertimbangkan apabila elusi secara gradien dipilih dalam proses pemisahan
Smart-Urea-Controlled-Release-Nitrogen-Fertilizer Menggunakan Plastik Biodegradable Poli Asam Laktat Sebagai Carrier
Get PDFPoly lactic acid is a polymer that has been developed as an alternative to substitution of conventional polymers. The properties of this polymer are biodegradable in nature and non-toxic substances. These polymers potentially can be used as a matrix for urea carries. The aim of this research was to synthesize poly lactic acid in a low molecular weight. This product can be used as a matrix that urea release controller during the process of fertilization. The methodology consisted of two stages. The first stage was polycondensation of lactic acid and degradability test. Lactic acid was mixed with SnCl2 catalyst 0.1% and heated to 138oC for 24 hours. The second stage was producing in the form of Smart Urea Controlled Release Nitrogen Fertilizer (CRNF). Urea was dissolved in poly lactic acid through a heating process at 150°C to dissolve urea with variation in urea concentration weight of 0.5%; 0.1%; 0.15%; 0.2%; 0.25%; 0.3% and CRNF granulation processes. Finally, the mixture was granulated in ambient temperature. Chemical analysis was done the molecular weight of poly lactic acid. The relationship between intrinsic viscosity and molecular weight was used. The IR spectra (FTIR) was used to fine molecular structure. The release testing of urea from the matrix of poly lactic acid uses UV-VIS Spectrophotometer. The results showed that the average molecular weight of poly lactic acid is 1149.49 g /gmol. FTIR spectra of CRNF with variation in urea concentration weight showed the presence of groups owned by poly lactic acid and urea. The peaks are1627.03 to 1629.92 cm-1 for the -NH group and 3478.77 to 3498.06 cm-1 for group -OH. The existence of these groups proves the existence of urea in CRNF. The release of urea from poly lactic acid occurs by diffusion. It can be seen, when urea in CRNF form immersed in water, the concentration of urea in water increase as well as the increasing immersed time
Kinetika Slow Release Pupuk Urea Berlapis Chitosan Termodifikasi
Get PDFDuring this time, the use of urea is not efficient, because about 40-70% of nitrogen in the fertilizer is not absorbed by plants. In order to increase the effectivity of nitrogen release in urea fertilizer, it needs to be coated with modified chitosan as slow releasing agent to form a hydrogel material by forming a cross linking with glutaraldehyde cross-linker.The aims of this research is to study the mechanism and the appropriate kinetic model of nitrogen release in slow releasing fertilizer of modified chitosan. This research was conducted by analyzing the ability of bio-hydrogel by calculating the percentage of swelling ratio and water retention of hydrogel and the nitrogen release in slow releasing fertilizer both in the soil and water. The experiments were conducted by varying the amount of urea used which 30 gram, 40 gram, 50 gram, 60 gram and 70 gram of urea fertilizer. The The release profile is then plotted on several models of diffusion kinetic such as zero order, first order, higuchi and korsmeyer peppas. The appropriate model of diffusion kinetic is chosen by the largest correction factor (R2).The results showed that nitrogen release of the slow releasing fertilizer in the soil with 50% urea content and the water followed korsmeyer peppas model with fickian mechanism. Nitrogen release in the soil with urea content of 30%, 40%, 60%, and 70% followed the korsmeyer peppas model with nonfickian mechanism