Encontrados 48 documentos, a visualizar página 1 de 5
Exploring the potential of a waste-derived bone char for pharmaceuticals adsorp...
Miranda, Catarina; Scalera, Francesca; Piancastelli, Andreana; Pullar, Robert C.; Tiritan, Maria Elizabeth; Piccirillo, Clara; Castro, Paula M. L.In this study, the effect of salinity in wastewater on the adsorption capacity of a bone char material prepared through pyrolysis of tuna bones at 1000 °C was investigated for two pharmaceuticals, tramadol (TRA) and venlafaxine (VNF), both contaminants of emerging concern. This is the first time that the adsorption efficiency of a bone char-type material was tested in such conditions. The Tuna Bone Char (TBC) w...
The ferromagnetic resonance (FMR) of SrZ hexaferrite (Sr3Co2Fe24O41), and the t...
Pullar, Robert C.; Galizia, Pietro; Migliano, Antonio C. C.; Amaral, João S.; Galassi, Carmen; Carvalho, Francisco E.The hexagonal Z-type ferrite Sr3Co2Fe24O41 (SrZ) was first synthesised in 2001 and reported as being a room temperature multiferroic material in 2010, with subsequent investigations into its multiferroic properties, but little into high frequency and microwave properties, and ferromagnetic resonance frequency (FMR), which determines its ability as an electromagnetic (EM) absorber and radar absorbing (RAM) steal...
Design and development of Ga-substituted Z-type hexaferrites for microwave abso...
Dhruv, Preksha N.; Pullar, Robert C.; Singh, Charanjeet; Carvalho, Francisco E.; Jotania, Rajshree B.; Meena, Sher Singh; Singh, JasbirGallium substituted Z-type Sr3GaxCo2-xFe24O41 (x = 0.0–2.0 in steps of 0.4) hexaferrites were synthesised by the sol-gel auto-combustion process, and sintered at 1150 °C. The structural, morphology, magnetic, Mössbauer, dielectric and microwave absorption properties were examined. XRD results of x = 0.0, 0.4, 0.8, and 1.2 samples show the formation of a single Z-type hexagonal phase. The samples x = 1.6 and 2.0...
Synthesis and characterisation of lead free BaFe12O19 –(K0.5Na0.5)NbO3 magnetoe...
Medeiros, Marco S. A.; Coondoo, Indrani; Oliveira, Filipe J. S.; Kholkin, Andrei L.; Amaral, João S.; Pullar, Robert C.Polycrystalline lead-free (1-x)BaFe12O19–x(K0.5Na0.5)NbO3 magnetoelectric ceramic composites (x = 10, 20 and 30 wt%) were fabricated for the first time, comparing various synthesis techniques, namely solid state reaction, sol-gel, co-precipitation and citrate combustion methods for the synthesis of the ferrite phase. As well as the four synthesis routes, comparisons were made between uniaxial pressing and cold ...
High performance cork-templated ceria for solar thermochemical hydrogen product...
Oliveira, Fernando Almeida Costa; Barreiros, M. Alexandra; Haeussler, Anita; Caetano, Ana P. F.; Mouquinho, Ana; Silva, P. Oliveira e; Novais, Rui M.ABSTRACT: Water splitting by solar energy-driven two-step thermochemical cycles is a promising approach for large-scale production of renewable fuels (e.g. hydrogen). The key challenge is developing materials capable of withstanding the harsh environmental conditions and to ensure high reliability in use, particularly in terms of redox kinetics and better activity at low operation temperatures. In this work, we...
Solar redox cycling of ceria structures based on fiber boards, foams, and biomi...
Haeussler, Anita; Abanades, Stéphane; Oliveira, Fernando Almeida Costa; Barreiros, M. Alexandra; Caetano, Ana P. F.; Novais, Rui M.; Pullar, Robert C.ABSTRACT: Solar thermochemical conversion of H2O and captured CO2 is considered for the production of high-value solar fuels and CO2 valorization, using nonstoichiometric oxygen-exchange redox materials. This work aims to compare the thermochemical cycle performance of different ceria structures, including biomimetic cork-templated ceria (CTCe), ceria foams (CeF), and ceria bulk fiber boards (CeFB), to study th...
Films of chitosan and natural modified hydroxyapatite as effective UV-protectin...
Cunha, Carla S.; Castro, Pedro J.; Sousa, Sérgio C.; Pullar, Robert C.; Tobaldi, David M.; Piccirillo, Clara; Pintado, Maria M.Chitosan is a natural polysaccharide widely used in biomedicine, for instance for wound dressing. Hydroxyapatite is a very bioactive calcium phosphate which, if modified with an appropriate element (iron Fe), can also have UV-absorbing properties. In this work, we report the study of films of chitosan incorporated with iron-modified hydroxyapatite of natural origin (from cod fish bones); this combination led to...
Biomimetic calcium carbonate with hierarchical porosity produced using cork as ...
Scalera, Francesca; Carbone, Luigi; Bettini, Simona; Pullar, Robert C.; Piccirillo, ClaraCalcium carbonate has many applications in different fields; its use in environment remediation is particularly considered, due to its non-toxicity and potentially high efficiency. The structure, morphology and surface features of calcium carbonate can greatly affect its performance. Hierarchical porosity, in particular, can be beneficial for several functional properties. In this study, we report the synthesis...
Studies of structural, magnetic and dielectric properties of X-type Barium Zinc...
Kagdi, Amrin R.; Pullar, Robert C.; Meena, Sher Singh; Jotania, Rajshree B.; Mujasam Batoo, KhalidVarious quantities of ginger (Zingiber officinale) root extract were used to prepare X-type Barium–Zinc hexaferrite with the chemical composition Ba2Zn2Fe28O46. The powders were prepared using a combustion treatment method, being pre-heated at 550 °C for 4 h with the ginger as a fuel, followed by final heating to 900 °C for 5 h and natural cooling to room temperature to obtain Ba2Zn2Fe28O46 hexagonal ferrite po...
Synthesis of red mud derived M-type barium hexaferrites with tuneable coercivity
Carvalheiras, João; Novais, Rui M.; Mohseni, Farzin; Amaral, João S.; Seabra, Maria P.; Labrincha, João A.; Pullar, Robert C.Hexagonal ferrites can be employed in a multitude of applications, the most common hexaferrites are the M ferrites such as BaFe12O19 (barium hexaferrite, BaM). It is known that if Fe3+ is substituted with a combination of Ti4+/Co2+ the coercivity of BaM can be reduced to produce soft M ferrites with easily switchable magnetisation. They can be utilised as powders, films or bulk ceramics, and can be manufactured...