Enhanced liquid yield and upgrading of almond shell pyrolysis over sonochemically synthesized Metal-ZnO catalysts
JOURNAL OF THE ENERGY INSTITUTE, cilt.128, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 128
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.joei.2026.102652
- Dergi Adı: JOURNAL OF THE ENERGY INSTITUTE
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, INSPEC
- Anahtar Kelimeler: Almond shell, Catalytic pyrolysis, Liquid yield enhancement, Metal–ZnO catalysts, Sonochemical synthesis
- Ankara Üniversitesi Adresli: Evet
Özet
In this study, sonochemically synthesized metal-ZnO catalysts (M = Cd, Co, Cu) were evaluated for catalytic pyrolysis of almond shell, a lignocellulosic biomass, with the aim of enhancing liquid yields and improving the chemical quality of the liquid products. The catalysts were prepared via an ultrasound-assisted synthesis route and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) surface area analysis in order to elucidate their crystallinity, morphology and textural properties. Pyrolysis experiments were performed in a tubular fixed-bed reactor at different temperatures to determine the optimum operating conditions, and the obtained liquid products were analyzed using Fourier-transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), and elemental analysis. Based on temperature-dependent product distributions, 600 degrees C was identified as the optimum temperature, yielding the highest liquid fraction. Catalyst-assisted experiments conducted at catalyst-to-biomass ratios of 1 wt% and 2 wt% demonstrated that metal modification significantly influenced both product yield and composition. Compared with non-catalytic pyrolysis (maximum liquid yield of 38.34%), the use of a 1% metal-ZnO catalyst increased the maximum liquid yield to 49.21%. GC-MS analysis further revealed a pronounced compositional change characterized by a decrease in aliphatic oxygenated compounds and organic acids, accompanied by an increased fraction of aromatic and phenolic derivatives, indicating selective deoxygenation and structural upgrading of the liquid phase. Among the synthesized catalysts, Cu-ZnO exhibited the most pronounced catalytic performance, which can be attributed to its enhanced ability to promote controlled secondary reactions and selective vapor-phase transformation pathways. Overall, the results demonstrate that sonochemically synthesized metal-ZnO catalysts provide an effective catalytic route for simultaneously increasing liquid yield and promoting selective structural upgrading of biomass-derived pyrolysis liquids, thereby producing an upgraded bio-oil with potential use as a fuel precursor or as a feedstock for further upgrading.