VO x /SBA-15 catalysts with five different vanadium loadings were prepared by a modified wet impregnation method, characterized using N 2 adsorption, XRD, EDX, SEM, Raman and UV-vis spectroscopies and H 2 -TPR techniques, and tested in the oxidative dehydrogenation of propane in the temperature range 450-600 • C. For all the catalysts the propane conversion increases with both reaction temperature and vanadium loading, while the selectivity for propene decreases mainly to the benefit of carbon oxides. Several types of VO x species coexist on the catalyst surface, with monomeric and low-polymerized ones leading mainly to propene, while V 2 O 5 crystallites at high vanadium loadings producing more carbon oxides. Propene was determined to be the only primary product irrespective of the vanadium content.

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Nowadays, the transformation of biomass into valuable chemicals and fuels through thermochemical, biochemical or even mixed technologies, is becoming increasingly popular and challenging. A promising solution for the near future is the substitution of non-renewable fossil fuels with a sustainable liquid feedstock for biofuel (biodiesel) production. The cost of conventional biodiesel production is higher than that of petroleum-based diesel production since it is produced mostly from expensive high-quality virgin oil. Conventionally, commercial biodiesel is produced via liquid base-catalyzed transesterification of triglycerides components of oil/fat with short-chain alcohols. It is that about 70–80% of the overall biodiesel production cost is associated with the cost of raw materials. Brown grease (with free fatty acid levels > 15%) is created from rendered trap waste and is known as Fats, Oils, and Greases (FOGs), it is a potential source of biodiesel feedstocks and is available at no cost. Many researchers are interested in using low-cost high Free Fatty Acid (FFA) oils as the feedstock for biodiesel production. This paper reviews the effect of feedstock pre-treatment and process parameters on the conversion of FOGs-wastewater to biodiesel by esterification-transesterification process.

A unique process for transesterification at low temperatures using a novel functionalised polyacrylonitrile polymer mesh acting as a strong heterogeneous base in the production of biodiesel. A promising solution for energy minimisation and the sustainable use of waste fats and oils.

Supported nickel catalysts have been prepared by coating mesoporous silica with nickel oxide through a sol-gel coating technology, other than the conventional impregnation procedure. Sol-gel nickel oxide coatings were first synthesized using nickel nitrate and lactic acid as precursors and then, deposited on the support of mesoporous silica SBA-15. Various synthetic parameters, such as the nickel/lactic acid molar ratio for the synthesis of the sol-gel coatings and the nickel/SBA-15 ratio for the preparation of the catalysts, were investigated. Scanning electron microscopy and energy-dispersive X-ray analysis, X-ray diffraction, thermal analysis and attenuated total reflection fourier transform infrared spectroscopy were used to characterise the nickel oxide sol-gel coatings and the resulting supported catalysts. The catalytic activity was tested using the Catlab integrated system. Results showed that this sol-gel coating route produces uniform nickel oxide thin films and leads to a good distribution of the nickel oxide on the mesopore surface of SBA-15. Compared with the catalyst prepared by impregnation with nickel nitrate salt solutions, the catalysts prepared through the sol-gel coating route are superb in nickel loading and distribution. The mesostructure of the supported catalysts remain unchanged after calcinations at elevated temperatures. Moreover, their catalytic activity towards the dry reforming of methane reaction is higher at temperatures lower than 700°C.

Although catalytic dry reforming of methane has recently attracted considerable attention from both environmental and economical points of view, due to the simultaneous utilization of two greenhouses with a high environmental impact, CO 2 and CH 4 , and to the production of syngas (CO and H 2 mixtures), a building block used for the synthesis of valuable chemicals and synthetic fuels, it has not yet been commercialized. Low-cost Ni-based catalysts with high activity have been developed. However, due to their major drawbacks (such as carbon formation and Ni particles sintering at high temperatures, which is required by the endothermic reaction), their industrial applicability is limited. What is more, access to advanced characterization techniques is needed to monitor coke deposition and to assess the efficiency of the dry reforming process, access which can be challenging for small and on-site laboratories. The focus of this current study is on the development and testing of a simple carbon deposition prediction method, which is easily accessible, based on the comparison of the gas composition measured at the exit of the reactor with the theoretical one, and calculated based on the process thermodynamics. Trustworthy results, confirmed by SEM and TGA/DSC measurements, were obtained when the method was applied for the monometallic, Ni/SBA-15, prepared by wet impregnation, and bimetallic, Ni-Co/SBA-15, and Ni-La/SBA-15 samples, prepared by both impregnation and co-impregnation, with different metal loading. The dry reforming process was performed at four temperatures: 550, 600, 650, and 700 • C.