Supercritical ethanol liquefaction of rice husk to bio-fuel over modified graphene oxide

Abstract

An increase in the energy system used promote new renewable source produced to improve human well-being quality. The objective of this work is to study the supercritical ethanol liquefaction reaction using rice husk as a feedstock and graphene oxide as catalyst. Characterization of the catalyst was conducted using thermal gravimetry analysis technique and N2 Sorption. Results revealed that graphene oxide treated with 1.5 M sulfuric acid solution gave the largest surface area of 110.5 m2/g. This research promised to optimize bio-fuel production using Box–Behnken method with 15 experimental data. The significant of the 3 parameters (catalyst amount, temperature and reaction time) was demonstrated using the ANOVA method. These statistical data were employed to illustrate contour data and response surface. A polynomial equation was also derived from the experimental data and used to valid with calculated data from the equation. Optimization was discussed in term of yield and operating cost. Optimum conditions were of 51.8% bio-fuel yield were derived from supercritical ethanol liquefaction at reaction time of 298 °C, 60 min reaction time, and 3.4 grams of SO4(1.5)/GO catalyst. Bio-fuel derived the optimum condition gave a high heating value as high as 30.15 MJ/kg, which is in the range of transportation fuel.