Konversi lemak ayam menjadi biodiesel dengan katalis zeolit alam teraktivasi H2SO4 dan NaOH

HADI, Kuncoro, Prof. DR.rer.nat. Karna Wijaya, M.Eng

2009 | Tesis | S2 Ilmu Kimia

Telah dipelajari konversi lemak ayam menjadi biodiesel dengan menggunakan katalis zeolit alam teraktivasi H2SO4. Zeolit alam diaktivasi asam dengan Asam Sulfat 1 M. Karakterisasi H-Zeolit antara lain penentuan keasaman dengan metode gravimetri, difraksi sinar-X, FT-IR dan Scanning Electron Microscopy (SEM). Sebelum reaksi transesterifikasi, dilakukan reaksi esterifikasi lemak ayam dalam media metanol dengan katalis H-Zeolit sebagai perlakuan awal untuk mengurangi asam lemak bebas. Rasio berat H-Zeolit terhadap lemak dan metanol divariasi, yaitu 1,25%; 2,50%; 3,75%; dan 5,00%. Reaksi transesterifikasi dilakukan dengan katalis basa (NaOH teknis) dalam media metanol. Sebagai pembanding perlakuan awal lemak ayam digunakan katalis cair (asam sulfat) dengan rasio 1,25% terhadap berat lemak dan metanol, sebelum reaksi transesterifikasi katalis basa dengan metode yang sama. Proses esterifikasi dan transesterifikasi dilakukan pada temperatur 40 °C selama 4 jam dengan menggunakan reaktor. Biodiesel yang diperoleh dianalisis dengan Gas Chromatography-Mass Spectroscopy (GC-MS), 1H-NMR dan analisis sifat fisiknya dengan metode ASTM. Hasil penelitian menunjukkan bahwa aktivasi asam tidak merusak struktur zeolit dan meningkatkan keasamannya. Prototipe reaktor biodiesel dapat digunakan untuk sintesis biodiesel dari lemak ayam. Semakin tinggi rasio H-Zeolit dalam reaksi esterifikasi lemak ayam, persentase biodiesel yang dihasilkan semakin tinggi sampai batas optimum. Konversi terbesar diperoleh pada H-Zeolit 3,75% (b/b) sebesar 47,84%. Berdasarkan data ASTM, biodiesel yang diperoleh memiliki kualifikasi sebagai bahan bakar biodiesel dan diesel dan memenuhi karakter SNI Biodiesel dan minyak solar.

Conversion of chicken’s fat into biodiesel by using H2SO4 activated natural zeolite catalyst has been carried out. Natural Zeolite was activated by sulfuric acid 1 M. The characterization of H-Zeolit included the acidity was determined by a gravimetric method, X-ray diffractometry, FT-IR and Scanning Electron Microscopy (SEM). Before transesterification reaction, chicken’s fat was esterified over H-Zeolite catalyst in methanol medium as a pretreatment for reducing free fatty acid content. H-Zeolit ratio by weight towards fat and methanol was varied; there were 1.25%, 2.50%, 3.75% and 5.00%. The reaction was continued by constant ratio of base catalyst (technical NaOH) in the methanol medium. As comparison, pretreatment of chicken’s fat also has been done over 1.25% liquid catalyst used (sulfuric acid), before base catalytic transesterifikasi reaction by the similar method. Esterification and transesterification processes were done in the reactor conducted at temperature 40 °C for 4 hours. Biodiesel was analyzed with Gas Chromatography-Mass Spectroscopy (GC-MS), and 1H-NMR and their physical properties was analyzed using ASTM methods. The research results showed that acidification gave no destruction of zeolite structure and increased its acidity. The prototype biodiesel reactor could be used for biodiesel synthesis from chicken’s fat. The highest conversion of biodiesel was 47.84% achieved by H-Zeolite catalyst 3.75% (w/w). Based on the ASTM data, the biodiesel was qualified as diesel fuel and has characters of SNI Biodiesel and automotive diesel fuel.

Kata Kunci : Aktivasi zeolit alam,Biodiesel,Asam lemak bebas,Lemak ayam, Activated Natural Zeolite; Biodiesel; free fatty acid, chicken’s fat