Kajian Pengaruh Konsentrasi Katalis Nb2O5-ZAA terhadap Konversi Biodiesel Total Pada Transesterifikasi Minyak Goreng Bekas
ABSTRACT: Study on the
concentration effect of Nb2O5-ZAA catalyst towards total conversion of
biodiesel has been conducted. The natural zeolite (ZA) was activated by dipping
in NH4Cl solution and was calcined using N2 atmosphere at 500 °C for 5h to
produce the ZAA sample. The Nb2O5-ZAA catalyst was made by mixing the activated
natural zeolite (ZAA), Nb2O5 3 % (w/w) and oxalic acid 10 % (w/w) solution,
until the paste was formed, followed by drying and calcining the catalyst for 3
h at 500 °C under N2 atmosphere. Catalyst characterizations were conducted by
measuring acidity with NH3 gas using gravimetric method and porosimetric analysis
using N2 gas adsorption based on the BET equation by surface area analyzer
instrument. The Nb2O5-ZAA catalyst was then used as an acid catalyst in free
fatty acid esterification reaction of wasted cooking oil in methanol medium
with variation of catalyst concentration: 1.25%; 2.5%; 3.75% and 5% towards the
weight of oil+methanol. The reaction was continued by transesterification of
triglyceride in the used cooking oil using NaOH catalyst in methanol medium.
For comparison, the esterification reaction using H2SO4 catalyst 1.25% towards
the weight of oil+methanol has been conducted as well. Methyl ester (biodiesel)
product was analyzed using Gas Chromatography (GC) and Gas Chromatography-Mass
Spectrometry (GC-MS). The characters of biodiesel were analyzed using American
Society for Testing and Materials (ASTM) method. The results showed that
modification of ZAA by impregning Nb2O5 3% (w/w) increased the total catalyst
acidity from 5.00 mmol/g to 5.65 mmol/g. The Nb2O5-ZAA catalyst has specific
surface area of 60.61 m2/g, total pore volume of 37.62x10-3 cc/g and average
pore radius of 12.41 Å. The Nb2O5-ZAA catalyst with concentration of 1.25%-5%
produced higher total conversion of biodiesel than that of H2SO4 catalyst
1.25%. The Nb2O5-ZAA catalyst with concentration of 3.75% produced the highest
total conversion of biodiesel, i.e. 76.76 %. Based on the ASTM data analysis,
the product has a qualification as diesel fuel.
Penulis: Astuti Tri
Padmaningsih, Wega Trisunaryanti, Iqmal Tahir
Kode Jurnal: jpkimiadd060074
