EFFECT OF COBALT CONCENTRATION SUPPORTED ON MESOPOROUS SILICA TOWARD CHARACTERS AND ACTIVITIES OF CATALYST FOR CONVERSION OF WASTE COCONUT OIL INTO BIOGASOLINE AND BIODIESEL

NUGROHO RAKA SANTOSO, Prof. Dr. Triyono, S.U. ; Prof. Dra. Wega Trisunaryanti, M.Si., Ph.D.Eng.

2019 | Skripsi | S1 KIMIA

Telah dilakukan analisis pengaruh konsentrasi logam kobalt yang terembankan pada silika mesopori terhadap karakter dan aktivitas katalis untuk konversi minyak kelapa bekas menjadi biogasolin dan biodiesel. Silika mesopori (SM) disintesis menggunakan metode hidrotermal dari silika lumpur Lapindo dan cetakan CTAB dengan rasio berat silica dan CTAB adalah 2. SM yang dihasilkan dikarakterisasi menggunakan FTIR dan SEM. Pengembanan logam kobalt ke dalam SM dilakukan menggunakan metode impregnasi basah dengan variasi logam kobalt awal 1, 3, dan 5% yang menghasilkan Co(1)/SM, Co(2)/SM, dan Co(3)/SM. Katalis yang dihasilkan kemudian dikarakterisasi dengan Atomic Absorption Spectroscopy (AAS), X-Ray Diffractometer (XRD), Surface Area Analyzer (SAA), Scanning Electron Microscopy (SEM), dan uji total keasaman dengan adsorpsi uap basa NH3. Uji aktivitas katalitik serta perengkahan termal (tanpa katalis) pada hidrorengkah katalitik minyak kelapa bekas dilakukan pada suhu 450 derajat C dengan aliran gas H2 sebesar 20 mL min pangkat negatif 1. Rasio berat umpan minyak kelapa bekas dan katalis adalah 50. Hasil produk hidrorengkah yang dihasilkan dianalisis dengan GC-MS. Hasil penelitian menunjukan bahwa penambahan logam kobalt juga meningkatkan total sisi aktif yaitu dari 13,24 mmol g pangkat negatif 1 sampai 17,94; 13,91; 15,36 mmol g pangkat negatif 1 dengan urutan MS, Co(1)/MS, Co(2)/MS, dan Co(3)/MS. Berdasarkan hasil uji aktivitas katalitik dapat disimpulkan bahwa katalis Co(1)/MS merupakan katalis dengan performa terbaik dibandingkan katalis lainnya dengan konversi produk cair sebesar 75,97%, dan menghasilkan biogasolin sebesar 43,11% dan biodiesel sebesar 21,74% . Meningkatnya kosentrasi logam Co menunjukan penurunan aktivitas dari katalis. Korelasi linear antara keasaman katalis dengan produksi fraksi gas, kandungan kobalt dengan pembentukan kokas, dan luas permukaan katalis dengan produksi fraksi bensin berturut-berturut adalah 0,9434; 0,9776; 0,8058.

Analysis of cobalt concentration effect supported on mesoporous silica toward characters and activities of catalyst for conversion of waste coconut oil into biogasoline and biodiesel had been evaluated. Mesoporous silica (MS) was synthesized from Lapindo silica mud and CTAB template with the weight ratio of silica to CTAB of 2 using hydrothermal method. The resulting MS was characterized using FTIR and SEM. The impregnation of cobalt into the MS was carried out using wet impregnation method under variations of initial cobalt metal content of 1, 3, and 5 wt % that produced Co(1)/MS, Co(2)/MS, and Co(3)/MS catalyst respectively. The catalysts were then characterized by atomic absorption spectrophotometer (AAS), X-Ray Diffractometer (XRD), Surface Area Analyzer (SAA), Scanning Electron Microscopy (SEM), and total acidity test using NH3 base vapor adsorption. The catalytic activity test in catalytic hydrocracking as well as thermal cracking (without catalyst) of waste coconut oil were carried out at a temperature of 450 degree C and under the H2 stream of 20 mL min to the power of negative 1 for 2h. The weight ratio of the oil feed to catalyst was 50 and the resulting hydrocracking products were analyzed by GC-MS. The results showed that the addition of cobalt metal also increases the total active site, from 13.24 mmole g to the power of negative 1 to 17.94; 13.91; 15.36 mmole g to the power of -1 for Co(1)/MS, Co(2)/MS, and Co(3)/MS respectively. Based on the results of the catalytic activity test it was concluded that the Co(1)/MS catalyst showed the best performance catalyst compared to other catalysts with the conversion of liquid products of 75.97%, and produces 43.11% of biogasoline and 21.74% of biodiesel. The higher Co concentration showed lower activities of the catalyst. Positive linear correlation value between catalyst acidity with gas fraction production, cobalt content with coke formation, and surface area of the catalyst with the gasoline fraction production were 0.9434; 0.9776; 0.8058 respectively.

Kata Kunci : Cobalt, hydrocracking, Lapindo mud, mesoporous silica, waste coconut oil.