Hydrothermal Liquefaction of Sinapis Arvensis Biomass Using TiO2-Supported Metal Catalysts: A Study on Bio-Oil Yield and Composition

Abstract

The development of catalytic systems for hydrothermal liquefaction (HTL) is crucial for transforming lignocellulosic biomass into biofuels with high energy density. This research investigates the HTL process of Sinapis arvensis biomass using TiO2-supported catalysts, specifically Fe, Al, and Fe-Al, at temperatures from 275-325 degrees C. The catalysts were synthesized through incipient wetness impregnation and characterized using techniques like X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), and inductively coupled plasma optical emission spectrometry (ICP-OES) to evaluate element distribution and surface chemistry. Findings show that the Al/TiO2 catalyst boosted lighter bio-oil production via acid-catalyzed dehydration and decarboxylation, while the Fe/TiO2 catalyst favored heavier oils through redox-assisted depolymerization. The Fe-Al/TiO2 bifunctional catalyst exhibited superior biomass conversion, yielding more aliphatic hydrocarbons. Gas chromatography-mass spectrometry (GC-MS) revealed how catalysts influenced product distributions, increasing monoaromatic and aliphatic compounds and reducing oxygenated entities. Elemental analysis confirmed higher carbon content, lower oxygen levels, and improved higher heating values (HHVs) in catalyzed bio-oils, indicating enhanced fuel quality.