Artículos SCI

Catalytic hydrodeoxygenation (HDO) is a critical technique for upgrading biomass derivatives to deoxygenated fuels or other high-value compounds. Phenol, guaiacol, anisole, p-cresol, m-cresol and vanillin are all monomeric phenolics produced from lignin. Guaiacol is often utilised as a model lignin compound to deduce mechanistic information about the bio-oil upgrading process. Typically, a source of H2 is supplied as reactant for the HDO reaction. However, the H2 supply, due to the high cost of production and additional safety precautions needed for storage and transportation, imposes significant economic infeasibilities on the HDO process's scaling up. We investigated a novel H2-free hydrodeoxygenation (HDO) reaction of guaiacol at low temperatures and pressures, using water as both a reaction medium and hydrogen source. A variety of Ni catalysts supported on zirconia/ graphene/with/without nitrogen doping were synthesised and evaluated at 250 degrees C and 300 degrees C in a batch reactor, with the goal of performing a multi-step tandem reaction including water splitting followed by HDO. The catalysts were characterised using H2-TPR, XRD, TEM and XPS to better understand the physicochemical properties and their correlation with catalytic performance of the samples in the HDO process. Indeed, our NiZr2O/Gr-n present the best activity/selectivity balance and it is deemed as a promising catalyst to conduct the H2-free HDO reaction. The catalyst reached commendable conversion levels and selectivity to mono-oxygenated compounds considering the very challenging reaction conditions. This innovative HDO approach provides a new avenue for cost-effective biomass upgrading.

The development of effective and environmentally friendly methods for separating hazardous radionuclides from waste poses a significant technological challenge. 137Cs and 131I are among the most important radionuclides discharged into the environment by nuclear power plants. One of the best ways to eliminate them involves adsorption on clay minerals. In this regard, studies have demonstrated that organofunctionalized clay minerals are effective adsorbents. Thus, this study investigates the capability of organofunctionalized synthetic design clay minerals to jointly eliminate cesium and iodine. The adsorbents studied are a range of organofunctionalized clay minerals with alkylammonium cations of different alkyl chain lengths (2, 3 and 18) and some physical mixtures of raw clay minerals and octadecylammonium compounds. Organofunctionalized synthetic swelling highly charged micas are effective adsorbents for the simultaneous adsorption of cesium and iodine. In addition, the optimal system is a mixture of Na-M4 with octadecylammonium (50% w/w).