120 documents found, page 1 of 12
The potential of almonds, hazelnuts, and walnuts SFE-CO2 extracts as sources of...
Júlia C. Kessler; Vanessa Vieira; Isabel M. Martins; Yaidelin A. Manrique; Patrícia Ferreira; Ricardo C. Calhelha; Ricardo C. Calhelha; Andreia AfonsoNuts have been part of the human diet since our early ancestors, and their use goes beyond nutritional purposes, for example, as aromatic sources for dairy products. This work explores the potential of almond (Prunus dulcis (Mill.) DA Webb), hazelnut (Corylus avellana L.), and walnut (Juglans regia L.) extracts as sources of food flavouring agents, suggesting a new added-value application for lower quality or e...
Visible-light-induced self-cleaning functional fabrics using graphene oxide/car...
Marta Pedrosa; Sampaio, M.J.; Tajana Horvat; Olga C. Nunes; Goran Dražic; Alírio E. Rodrigues; José L. Figueiredo; Cláudia G Silva; Adrián M. T. SilvaFunctional cotton fabrics consisting of neat polymeric carbon nitride (CN) combined with graphene oxide (GO) were prepared by a simple impregnation route. The CN-based coated fabrics were characterized by several techniques. The self-cleaning efficiency of these hybrid fabrics was assessed in the photocatalytic degradation of caffeine and rhodamine B (RhB) in aqueous solutions under visible light-emitting diode...
Supercritical CO2 assisted process for the production of high-purity and steril...
G. Ruphuy; M. Souto Lopes; Diana Paiva; P. Costa; Alírio E. Rodrigues; Fernando Mendes Monteiro; C. L. Salgado; Maria Helena FernandesHybrid scaffolds composed of hydroxyapatite (HAp), in particular in its nanometric form (n-HAp), and chitosan (CS) are promising materials for non-load-bearing bone graft applications. The main constraints of their production concern the successful implementation of the final purification/neutralization and sterilization steps. Often, the used purification strategies can compromise scaffold structural features,...
Cryogenic pressure temperature swing adsorption process for natural gas upgrade
Mariana A. Moreira; Ana M. Ribeiro; Alexandre F. P. Ferreira; Alírio E. RodriguesRemoval of carbon dioxide from natural gas for LNG production, can be carried out by cryogenic distillation using a multicolumn sequence to obtain a product stream with less than 50 ppm of CO2. Cryogenic adsorption-based processes, particularly pressure thermal swing adsorption, arise as a reliable and innovative alternative to replace the distillation columns, in particular the last one. In this work, the impl...
Biogas upgrading by selective adsorption onto CO2 activated carbon from wood pe...
Jose F. Vivo-Vilches; Agustín F. Pérez-Cadenas; Francisco J. Maldonado-Hódar; Francisco Carrasco-Marín; Rui P. V. Faria; Ana M. RibeiroAn activated carbon from commercial pine wood pellets was obtained by means of physical activation with carbon dioxide. Carbonized sample was also prepared in order to compare both samples. Carbonization lead to a material with very low micropore volume, which was increased when physical activation was performed (W-0(N-2) from 0.00 to 0.22 cm(3)g (1) and W-0(CO2) from 0.21 to 0.31 cm(3) g (1)). After characteri...
Fractionation of acid lime essential oil using ethanol/water mixtures: Effect o...
Daniel Gonçalves; Patrícia Costa; Christianne E. C. Rodrigues; Alírio E. RodriguesThis study aims to separate aroma-active components of the crude Citrus latifolia essential oil (EO) from the unstable terpene hydrocarbons using ethanol/water mixtures through liqUid-liquid equilibrium (LLE) and to evaluate the aroma profiles of the crude EO and the LLE phases. For this purpose, the liquid compositions of the crude EOs and the LLE phases were found by gas chromatography analysis. The compositi...
Dynamic response to process disturbances-A comparison between TMB/SMB models in...
Ildefonso B. R Nogueira; Ana M. Ribeiro; Alírio E. Rodrigues; José M. LoureiroThe modelling and design of Simulated moving bed (SMB) processes is normally done using the True moving bed (TMB) approximation. Several studies show that average values obtained at cyclic steady state for SMB units approach the TMB unit at steady state and that this approach is better as the number of columns in the SMB increases. However, studies that evaluate this equivalence under dynamic conditions are sca...
Predicting Vapor-Phase Concentrations for the Assessment of the Odor Perception...
Patrícia Costa; Miguel A. Teixeira; Gabriel Mestre; Luísa Carneiro; José Miguel Loureiro; Alírio E. RodriguesIn this study, the Henrys law methodology is applied to predict the release of odorants present in single and multicomponent fragrance mixtures diluted in mineral oil, a simplified matrix used in cosmetic products. To attain this goal, the experimental Henrys law constant (H) of each odorant in each studied fragrance system (containing one, two, three, or four odorants) was first evaluated by plotting their liq...
Effect of Dead Volumes on the Performance of an Industrial-Scale Simulated Movi...
Marta S. P. Silva; Alírio E. Rodrigues; José P. B. MotaThe cyclic steady state (CSS) of the industrial-scale, seven-zone, simulated moving-bed (SMB) unit for p-xylene (p-x) purification (Parex unit) with three types of dead volumes-bed lines, push-around and pump-around circulation lines, and bed heads-is analyzed. In particular, the effects of the size and level of hydrodynamic dispersion of each dead volume on process performance and on its CSS are studied in det...
Xylene Isomerization in the Liquid Phase Using Large-Pore Zeolites
Jonathan C. Gonçalves; Alírio E. RodriguesThree large-pore zeolites, Beta with Si/Al ratios of 25 and 35 and Mordenite with an Si/Al ratio of 30, were studied in the conversion of o-xylene at 493K. Maximum conversion was achieved by the catalyst with the highest Si/Al ratio due to faster diffusion of the isomer inside the zeolite channels because of the lower acidity of the solid even with larger crystal size. A kinetic study was then carried out over ...