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Abstrak :
Untuk mengurangi kandungan NOx, SOx, HC, dan partikulat-partikulat yang dihasilkan dari penggunaan solar, dapat dilakukan dengan cara meningkatkan angka setana. Salah satu cara meningkatkan angka setana adalah penambahan aditif pada solar. Aditif yang telah komersial merupakan senyawa organik nitrat, yaitu 2-Ethyl Hexyl Nitrate (2-EHN). Pada penelitian ini dilakukan pembuatan aditif yang berasal dari minyak kelapa dengan metode nitrasi menggunakan HNO3 dan H2SO4. Hasil reaksi adalah metil ester nitrat yang strukturnya mirip 2-EHN. Spektra IR dari hasil reaksi menunjukkan adanya metil ester nitrat yang diindikasikan dengan munculnya spektrum NO2 pada 1635 cm-1. Hasil ini menunjukkan bahwa metil ester nitrat dapat disintesis dengan metode nitrasi, dan yield yang dihasilkan adalah 74,84% volume. Penambahan 1% metil ester nitrat ke dalam solar menyebabkan peningkatan CN (Cetane Number) dari 44,68 menjadi 47,49.

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To reduce NOx, SOx, HC, and particulates that produce because of using diesel fuel, can be done by increasing cetane number. One of methods is adding an additive to diesel fuel. 2-Ethyl Hexyl Nitrate (2-EHN) is a commercial additive that an organic nitrate. Making an additive in this research is used palm oil by nitration reaction that used HNO3 and H2SO4. Result of this reaction is methyl ester nitrate that has a structure looks like 2-EHN. IR spectra from research show that methyl ester nitrate is indicated by spectrum NO2 at 1635 cm-1. This result show that methyl ester nitrate can be synthesized by nitration reaction and yield is 74,84% volume. Loading 1% methyl ester nitrate to diesel fuel can increase cetane number from 44,68 to 47,49.

Abstrak :
Sintesis biodiesel menggunakan biokatalis merupakan proses alternatif yang banyak menarik perhatian untuk menggantikan proses konvensional yang menggunakan katalis alkali karena mempunyai keunggulan di proses separasi yang lebih mudah dan terhindarnya dari reaksi samping yang merugikan. Namun, biokatalis ini mudah terdeaktivasi oleh alkohol yang merupakan reaktan dalam reaksi sintesis biodiesel. Oleh karena itu, perlu dikembangkan metode baru yang mampu mempertahankan aktivitas dan stabilitas biokatalis selama reaksi berlangsung. Metode baru yang akan dikembangkan adalah dengan mengubah rute reaksi dari menggunakan alkohol ke rute reaksi yang tidak menggunakan alkohol. Rute reaksi non alkohol bisa dilakukan dengan cara mengganti alkil alkohol dengan alkil asetat yang sama-sama berfungsi sebagai pensuplai alkil. Pada makalah ini disajikan hasil penelitian sintesis biodiesel rute non alkohol menggunakan biokatalis Novozym 435. Dalam reaksi ini, metil asetat direaksikan dengan trigliserida dari minyak jelantah dalam reaktor batch. HPLC digunakan untuk menganalisa reaktan dan produk. Hasil penelitian ini menunjukan Novozym 435 mampu mengkonversi trioleat sebesar 93.24% pada kondisi konsentrasi biokatalis sebesar 4% wt substrat, rasio mol minyak/alkil sebesar 1/12 selama 50 jam reaksi. Uji stabilitas menunjukkan bahwa biokatalis terimobilisasi ini masih memiliki aktivitas untuk tiga kali siklus reaksi. Model Kinetika berbasis mekanisme Michaelis-Menten mampu menggambarkan reaksi ini dengan ditandai hasil fitting yang cukup memuaskan dengan hasil eksperimen.

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Synthetic biodiesel using biocatalyst is an emerging and attracting alternative process to replace the conventional process. However, biocatalyst is easy to be deactivated by alcohol, which is a reactant in biodiesel synthesis reaction. Therefore, it is needed to develop new method to maintain the activity and stability of the biocatalyst during reaction. New method to be developed is by changing the reaction route which is using alcohol to the reaction route which is not using alcohol. Route reaction of non alcohol can be done by changing the alkyl alcohol with alkyl acetate. Both have the same function as alkyl supply during the reaction. In this paper, the research results of the synthesis biodiesel via route of non alcohol using biocatalyst Novozym 435 are presented. In this reaction, methyl acetate is reacted with triglyceride from used fried oil in batch reactor. The reactants and products were analyzed using HPLC. The Results showed that Novozym 435 can convert trioleat up to 93.24% under the condition of 4% wt substrate of the biocatalyst concentration, oil/alkyl mole ratio equal to 1/12 in 50 hour reaction. Stability test indicate that the activity of the immobilized biocatalyst still remain after three reaction cycles.

Abstrak :
The microbial desalination cell (MDC) is a modification of the microbial fuel cell (MFC) system. The microbial desalination cell is a sustainable technology to desalinate saltwater by directly utilizing the electrical power generated by bacteria during the oxidation process of organic matter. In this study, tempe wastewater will be used as a substrate. Methylene blue (MB) at concentrations of 100 μM, 200 μM, and 400 μM in the anolyte is added as a redox mediator, and the effect on electricity production and desalination performance are evaluated. The average power density increases by 27.30% and 54.54% at MB concentrations of 100 μM and 200 μM, respectively. On the other hand, the increase of the MB concentration in the anolyte results in a decrease in the salt removal percentage. The observation made using a scanning electron microscope showed the presence of MB adsorption on the surface of the anion exchange membrane (AEM) and is suspected to be the cause of the disruption of anion transfer between MDC chambers causing a decrease in the salt removal percentage.

Abstrak :
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.