Hydroprocessing of fatty carboxylic acids from waste oil feedstocks, via hydrodeoxygenation (HDO), hydrodecarbonylation (HDC) or decarboxylation (DCX), is a promising route to produce hydrocarbon fuels. Bifunctional metal doped solid acids show potential for low temperature hydroprocessing, however few studies systematically explore the role of support acidity on catalyst performance. Here we report the liquid phase hydroprocessing of octanoic acid, a model aliphatic carboxylic acid, over bifunctional 5 wt% Ni/Al-SBA-15 mesoporous solid acids with Si : Al molar ratios spanning 5 to 75. The different hydroprocessing pathways show a strong dependence on support acidity at 13–20% iso-conversion, with selectivity to C8 alkane production by HDO increasing with support Brønsted acidity, whereas competing HDC or DCX to C7 alkanes decreases. 5 wt% Ni/Al-SBA-15 with a Si : Al ratio of 5 exhibits the highest Brønsted : Lewis ratio and selectivity to HDO products, but shows a low activity attributed to coking. In contrast, catalysts with intermediate acidity (Si : Al = 54) are more stable, exhibiting 95% conversion and 74% selectivity to C8 alkanes after 5 h reaction.

Solid acid catalyzed cracking of waste oil-derived fatty acids is an attractive route to hydrocarbon fuels. HZSM-5 is an effective acid catalyst for fatty acid cracking; however, its microporous nature is susceptible to rapid deactivation by coking. We report the synthesis and application of hierarchical HZSM-5 (h-HZSM-5) in which silanization of pre-crystallized zeolite seeds is employed to introduce mesoporosity during the aggregation of growing crystallites. The resulting h-HZSM-5 comprises a disordered array of fused 10–20 nm crystallites and mesopores with a mean diameter of 13 nm, which maintain the high surface area and acidity of a conventional HZSM-5. Mesopores increase the yield of diesel range hydrocarbons obtained from oleic acid deoxygenation from ~20% to 65%, attributed to improved acid site accessibility within the hierarchical network.

Invasive plants can grow rampantly and spread fast in large amount, which can be economically invoked for generating value-added products. In this study, lignocellulosic fiber was extracted from the leaf waste of a luxuriant invasive plant, Mikania micrantha Kunth-ex H.B.K. by mercerization process. After the alkaline treatment, the lignocellulosic biomass remained at 38.54% resulting from the large removal of extractive impurities. The lignocellulosic fraction in the mercerized leaf fiber was improved from 56.59% to 83.96%. The chemical composition analysis showed the cellulose fraction was increased by 11.17% while the hemicellulose and lignin fractions were found to be decreased by 4.89% and 6.28%, respectively. The FT-IR and TGA results further affirmed the change in chemical composition of the lignocellulosic fiber. Furthermore, an increase in cellulose fraction raised the fiber crystallinity index from 11.0% to 36.7%. The SEM study revealed that the surface morphology of lignocellulosic fiber changed from smooth surface into rough corrugated ridges, which affirmed the increase in crystallinity, resulting from the removal of wrapped cementing materials. In subsequent, the lignocellulosic fiber exhibited more pervious to water attack with an increase in moisture absorption from 119.22% to 410.19%.