Preparasi Membran Elektrolit Berbasis Poliaromatik Untukaplikasi Sel Bahan Bakar Metanol Langsung Suhu Tinggi

PREPARASI MEMBRAN ELEKTROLIT BERBASIS POLIAROMATIK UNTUKAPLIKASI SEL BAHAN BAKAR METANOL LANGSUNG SUHU TINGGI. Operasi sel bahan bakar metanol langsung (Direct Methanol Fuel Cell / DMFC) suhu tinggi (>120 oC) mempunyai keuntungan yaitu meningkatkan reaksi baik di anoda maupun di katoda. Saat ini membran yang banyak digunakan untuk aplikasi DMFC adalah Nafion. Kelebihan dari membran Nafion memiliki konduktivitas ionik yang tinggi tetapi kelemahannya adalah permeabilitas metanol yang tinggi, termasuk membran yang mahal dan kinerja membran menurun jika digunakan pada suhu >80 oC. Untuk hal tersebut perlu pengembangan polimer pengganti Nafion diantaranya adalah polimer aromatik yaitu polisulfon (PSf) dan polieter-eterketon (PEEK). PEEK dan PSf adalah polimer yang bersifat hidrofobik, untuk menjadi elektrolit perlu diberikan gugus sulfonat melalui proses sulfonasi. Sulfonasi PSf dilakukan setelah membuat membran terlebih dahulu, dengan memvariasikan konsentrasi asam sulfat (0,5 M dan 1 M) dan waktu sulfonasi (2 jam, 3 jam dan 4 jam) pada suhu tetap 80 oC. Sedangkan sulfonasi PEEK menggunakan asam sulfat pekat dengan variasi suhu (50 oC , 60 oC dan 70 oC) pada waktu tetap 3 jam, yang kemudian dibuat membran. Karakteristik membran elektrolit polisulfon yang tersulfonasi (sPSf) menghasilkan swelling air pada membran 10 % hingga 25 %, konduktivitas ionik sebesar 10-4 S/cm hingga 10-3 S/cm, permeabilitas metanol sebesar 10-7 cm2/detik hingga 10-6 cm2/detik dan suhu transisi glass membran PSf dan sPSf sebesar 220 oC dan 237 oC. Karakteristik membran elektrolit polieter eter keton yang tersulfonasi (sPEEK) menghasilkan swelling air pada membran 8 % hingga 28 %, konduktivitas ionik sebesar 10-2 S/cm, permeabilitas metanol sebesar 10-7 cm2/detik hingga 10-6 cm2/detik dan suhu transisi glass membran PEEK dan sPEEK sebesar 187 oC dan 266 oC. Kedua polimer tersebut berpeluang untuk aplikasi DMFC suhu tinggi, walaupun konduktivitas ionik dari sPSf perlu ditingkatkan

Effect of Photoperiodicity on Co2 Fixation by Chlorella Vulgaris Buitenzorg in Bubble Column Photobioreactor for Food Supplement Production

To reduce the level of CO2 content in air, effort on converting CO2 to useful products is required. One of thealternatives includes CO2 fixation to produce biomass using Chlorella vulgaris Buitenzorg. Chlorella vulgarisBuitenzorg is applied for production of food supplement. Chlorella vulgaris Buitenzorg is also easy to handle due to itssuperior adaptation. Currently, Chlorella vulgaris Buitenzorg has been analyzed by some experts for its cellularcomposition, its ability to produce high quality biomass and the content of essential nutrition. A series of experimentswas conducted by culturing Chlorella vulgaris Buitenzorg using Beneck medium in bubbling column photobioreactor.The main variation in this experiment was photoperiodicity, where growth of Chlorella vulgaris Buitenzorg wasexamined during photoperiodicity condition. The difference between CO2 gas concentration of inlet and outlet of thereactor during operational period, was compared to the same experiment under continuous illumination. Underphotoperiodicity of 8 and 9 h/d, the culture cell densities (N) were approximately 40 % higher than under continuousillumination. Final biomass density of Chlorella vulgaris Buitenzorg at 9 h/d illumination was 1.43 g/dm3, around 46%higher than under continuous illumination. Specific carbon dioxide transfer rate (qCO2) in photoperiodicity was 50-80%higher than under continuous illumination. These experiments showed that photoperiodicity affects the growth ofChlorella vulgaris Buitenzorg The specific growth rate (μ) by photoperiodicity was higher than that by continuousilumination while the growth period was two times longer. Based on the experiments, it can be concluded thatphotoperiodicity might save light energy consumption. The prediction of kinetic model under continuous illuminationas well as under photoperiodicity illumination showed that Haldane model became the fitted kinetic model

Effects of Ph on Calcium Carbonate Precipitation Under Magnetic Field

Magnetic field effect on CaCO3 precipitation is the key parameter in evaluating the effectiveness of Anti-scale MagneticTreatment (AMT). The purpose of this study was to investigate magnetic fields influence on CaCO3 precipitation inhigh and low super-saturated CaCO3 solution by varied pH CaCO3 solution using circulation flow fluid system. Theobservation results in the high super saturated solution (pH 8.5) showed the increase of precipited CaCO3 in magnetizedsolutions compared to those in non-magnetic solution during circulation process. In the low super-saturated CaCO3solution (pH 6.4) it was found that magnetic treatment increased CaCO3 precipitation after circulation process. In highsuper-saturated solution, magnetic field strengthens ion interactions, which reduce precipitation during circulationprocess. However, in low super-saturated CaCO3 solution, magnetic field weakens hydrate ion interaction whichindicated by decreasing of the conductivity of solution. It increases the precipitation of CaCO3 after the circulation ofmagnetization process has completed

Biomass Production Chlorella Vulgaris Buitenzorg Using Series of Bubble Column Photo Bioreactor with a Periodic Illumination

Chlorella vulgaris Buitenzorg cultivation using three bubble column photo bioreactors arranged in series with a volume of 200 mL for 130 hours shows an increase of biomass production of Chlorella vulgaris Buitenzorg up to 1.20 times and a decrease of the ability of CO2 fixation compared to single reactor at a periodic sun illumination cycle. The operation conditions on cultivation are as following: T, 29.0oC; P,1 atm.; UG, 2.40 m/h; CO2, 10%; Benneck medium; and illumination source by Phillip Halogen Lamp 20W /12V/ 50Hz. Other research parameters such as microbial carbon dioxide transferred rate (qco2), CO2 transferred rate (CTR), energy consumption for cellular formation (Ex), and cultural bicarbonate species concentration [HCO3] also give better results on series of reactor

Kinetic Model for Triglyceride Hydrolysis Using Lipase: Review

Triglyceride hydrolysis using lipase has been proposed as a novel method to produce raw materials in food andcosmetic industries such as diacylglycerol, monoacylglycerol, glycerol and fatty acid. In order to design a reactor forutilizing this reaction on industrial scale, constructing a kinetic model is important. Since the substrates are oil andwater, the hydrolysis takes place at oil-water interface. Furthermore, the triglyceride has three ester bonds, so that thehydrolysis stepwise proceeds. Thus, the reaction mechanism is very complicated. The difference between theinterfacial and bulk concentrations of the enzyme, substrates and products, and the interfacial enzymatic reactionmechanism should be considered in the model

KINETIC MODEL FOR TRIGLYCERIDE HYDROLYSIS USING LIPASE: REVIEW

Triglyceride hydrolysis using lipase has been proposed as a novel method to produce raw materials in food andcosmetic industries such as diacylglycerol, monoacylglycerol, glycerol and fatty acid. In order to design a reactor forutilizing this reaction on industrial scale, constructing a kinetic model is important. Since the substrates are oil andwater, the hydrolysis takes place at oil-water interface. Furthermore, the triglyceride has three ester bonds, so that thehydrolysis stepwise proceeds. Thus, the reaction mechanism is very complicated. The difference between theinterfacial and bulk concentrations of the enzyme, substrates and products, and the interfacial enzymatic reactionmechanism should be considered in the model.Keywords: Lipase, kinetic model, enzymatic reaction mechanism, hydrolysis, triglycerid

KINETIC MODEL FOR TRIGLYCERIDE HYDROLYSIS USING LIPASE: REVIEW

Abstract Triglyceride hydrolysis using lipase has been proposed as a novel method to produce raw materials in food and cosmetic industries such as diacylglycerol, monoacylglycerol, glycerol and fatty acid. In order to design a reactor for utilizing this reaction on industrial scale, constructing a kinetic model is important. Since the substrates are oil and water, the hydrolysis takes place at oil-water interface. Furthermore, the triglyceride has three ester bonds, so that the hydrolysis stepwise proceeds. Thus, the reaction mechanism is very complicated. The difference between the interfacial and bulk concentrations of the enzyme, substrates and products, and the interfacial enzymatic reaction mechanism should be considered in the model

Pengelolaan Air Limbah Rumah Potong Hewan Di Rph X, Kota Bogor, Provinsi Jawa Barat (Wastewater Management of Slaughterhouse in Slaughterhouse X, Bogor City, West Java Province)

Air limbah Rumah Potong Hewan (RPH) yang tidak dikelola dengan baik dapat menimbulkan masalah lingkungan dan gangguan pada masyarakat yang bertempat tinggal di sekitar RPH. Sejak RPH X beroperasi pada tahun 2009, pengelolaan air limbah RPH X masih belum berjalan optimal. Hal ini dikarenakan air limbah RPH X masih dilihat sebagai materi yang tidak berguna dan dibuang. Saat ini, praktik pengelolaan air limbah RPH X dilakukan dengan menggabungkan semua air limbah kemudian air limbah tersebut diolah dengan Instalasi Pengolahan Air Limbah (IPAL). Riset ini mencoba menganalisis praktik pemotongan sapi, Fasilitas RPH, pengelolaan air limbah RPH, kualitas air limbah RPH, dan dampak limbah RPH pada masyarakat. Riset ini menggunakan pendekatan metode kuantitatif dan kualitatif, melalui observasi, wawancara, kuesioner, dan uji laboratorium. Hasil riset menunjukkan bahwa praktik pemotongan sapi di RPH X termasuk kategori baik, Fasilitas RPH X termasuk kategori kurang sesuai dengan persyaratan, pengelolaan air limbah RPH X belum berjalan optimal, kualitas air outlet IPAL telah memenuhi baku mutu, dan dampak limbah RPH X pada masyarakat berupa gangguan bau yang dirasakan oleh 100% responden dan gangguan kesehatan berupa mual yang dirasakan oleh 41% responden. Alternatif peningkatan dalam pengelolaan air limbah RPH yang dapat dilakukan adalah minimisasi air limbah melalui segregasi dan pemanfaatan air limbah RPH