Performance of Pd and Pt noble metal impregnated on Lapindo mud-based mesoporous silica on hydrotreatment of waste cooking oil into biogasoline

Abstract

In the present work, an alternative pathway to produce liquid biogasoline with low aromatic value was done via catalytic hydrotreatment of waste cooking oil (WCO) over noble metal (Pd and Pt) loaded on cost-effective mesoporous silica (MS) synthesized from Lapindo mud. The implementation of 1.82 and 1.53 SiO₂/CTAB (cetyltrimethylammonium bromide) weight ratio successfully produced Lp-MS with average diameters of 5.1 (Lp-MS1) and 4.7 nm (Lp-MS2), respectively. The XRD analysis showed a better dispersion for Pt with a considerably smaller particle size and TEM image revealed that while Pt was shown to occupy both external and internal surface of Lp-MS1, Pd was only present on the outer part of Lp-MS2. During the hydrotreatment of WCO using a semi-batch reactor, Pd/Lp-MS2 exhibited a superior deoxygenation and hydrogenation capacity than Pt/Lp-MS1 by generating over 60.9% liquid biofuel with 86.75% selectivity towards gasoline-range hydrocarbon. The liquid product obtained from the catalytic hydrotreatment contained very low aromatic compound (<4%) which was known to be responsible in the emission of harmful gas during fuel combustion. This result can be maintained for at least 4 consecutive runs. This study offers another efficient pathway to produce a cleaner source of energy in the form of biogasoline fuel.