Synthesis, Structural Characterization and Photocatalytic Activity of Iron-Doped Titanium Dioxide Nanopowders
Pages 1-9
Jordana H. Castillo, Francisco J. Rodriguez, Aurelio López-Malo, Enrique Sanchez-Mora, Marco A. Quiroz and Erick R. Bandala

DOI: http://dx.doi.org/10.6000/1929-6002.2015.04.01.1

Published: 11 March 2015

Abstract: Iron-doped TiO₂ nanopowders with different doping amounts have been prepared by co-precipitation method followed by heat treatment. The obtained materials were structurally, morphologically and analytically characterized by X-ray diffraction (XRD), FT-Raman spectroscopy, diffuse reflectance spectroscopy (DRS) and energy dispersive X-ray spectroscopy (EDX) coupled to scanning electron microscopy (SEM). XRD analysis revealed the major presence of the anatasa crystalline phase for iron-doped and undoped TiO₂. SEM confirmed particles sizes among the nanometer scale along with XRD data. The presence of iron ions was validated by EDX-SEM. Diffuse reflectance techniques were carried out to validate the shift of the band edge absorption spectrum of doped TiO₂ nanoparticles towards the visible region and to confirm the presence of iron atoms in the TiO₂ crystal lattice by the resulting variation of the band gap value of the doped materials. Photocatalytic activity of the nanoparticles under UV and visible radiation was evaluated by means of hydroxyl radicals production through indirect estimation using N,N-dimethyl-p-nitrosoaniline (PNDA)photo-discoloration experiments in aqueous dispersion. Samples containing 1.2 and 5.6 weight % Fe exhibited the highest activities in this study for both conditions..

Techno-Economic Investigation of a Thermal Cure Center Excess Heat Recovery System for Producing Hot Water for a Hotel in Antsirabe Madagascar
Pages 10-20
Hery Tiana Rakotondramiarana, Mamy Harimisa Radanielina and Andriamaholisoa Yvan Ramananjatovo

DOI: http://dx.doi.org/10.6000/1929-6002.2015.04.01.2

Published: 11 March 2015

Abstract: Energy saving is a significant feature to take in account in the choice of renewable energy technologies to use. This paper techno-economically investigates an excess heat recovery system that is proposed to be installed in a thermal cure center geothermal source for producing domestic hot water to be conveyed through piping to a nearby three star hotel located in Antsirabe Madagascar. For that purpose, the hotel hot water needs were determined by using an available online free code, called Solo, and the effectiveness-NTU method was used to size the plate heat exchanger to be used to recover the geothermal heat. The proposed hybrid geothermal solution performance was compared with that of hybrid solar energy water-heaters in terms of electricity consumption related to water temperature adjustment. It follows from comparison results that the proposed hybrid geothermal solution is more profitable and allows about 73.2 (%) of electric energy saving while it is 54.9 (%) for hybrid solar option. Besides, economic evaluation confirmed that the geothermal installation allows a shorter return on investment more favorably.