Rare-earth doped TiO2 films for the visible light photocatalytic oxidation of ethanol in air

In the last decades, TiO2 has emerged for its excellent photocatalytic properties applicable to pollutant abatement. In particular, it is a promising material to remove small amounts of volatile organic compounds (VOCs) from contaminated indoor atmosphere. Most applications are limited to UV light irradiation because TiO2 only absorbs light with wavelengths shorter than 380nm. Much research has been prompted on modification procedures to extend its spectral sensitivity to visible light, which forms the largest part of solar radiation and is the main radiation emitted by lamps used in indoor illumination. In recent years, different approaches, such as coupling with visible-light activated semiconductors, the use of smaller band gap materials and doping of TiO2, have been proposed to achieve this goal. In this work thin films were doped with rare-earth metal ions showing transitions in the visible region. La, Ce, Nd, Sm, Eu, Gd, Dy and Ho doped TiO2 sols were prepared through a sol-gel method which allows to control the stoichiometry, work in mild and ambient atmospheric conditions and achieve high purity and homogeneity of the final product. The aim of the present study was to investigate the influence of these rare earth-metal dopants in different contents (1, 2 and 3% in weight, respectively) on the photocatalytic activity of TiO2 using ethanol as VOC molecule, under both UV and visible illumination. The films were deposited by spin coating on sodium free glass [1] and calcined at 450 C for 2 hours. The microstructure, optical and morphological properties of the films were investigated using SEM, UV-Vis spectroscopy, ellipsometry and photoluminescence (PL). The nature of the crystalline phases was ascertained by X-ray diffraction and the effective composition of the samples determined by X-ray photoelectron spectroscopy (XPS). The photocatalytic measurements were carried out in a stainless steel batch reactor in a controlled Ar/O2 atmosphere (ratio 80:20 to simulate air). The ethanol concentration was monitored by means of an atmospheric gas analyzer containing a mass spectrometer and a mercury high-pressure short arc lamp was used as light source. The initial reaction rate was determined from the slope of the first linear data points measured during the breakdown reaction of ethanol into CO2 and H2O. The doped TiO2 films show good photocatalytic activity in degradation of the tested VOC molecule, compared to titania films prepared using P25 Degussa. In particular, the addition of rare earth elements with 4f electron configuration, enhances the photoresponse in the visible region of the sol-gel derived catalyst. Among the developed catalysts, the Eu doped titania has the largest effect on the photocatalytic activity of TiO2 under visible light. (1) H. Tomaszewski, K. Eufinger, H. Poelman, D. Poelman, R. De Gryse, P.F.Smet, G.B. Marin, Int. J. Photoenergy 8, 1 (2007

Identification of specific demands on Feed in Dutch Organic Aquaculture

The evaluation of specific demands for organic feed focussed on feed demands for four fish species which can be cultured in Recirculation Aquaculture Systems (RAS), tilapia, African Catfish, shrimp and turbot. The evaluation of the various feed formulations indicates that there are several ingredients, which are common for the four species, and will therefore be used for further elaboration on the organic availability. These feed ingredients, are: fishmeal and oil, corn meal, wheat meal, blood meal, vitamin mix, mineral mix, and antioxidants. Besides the evaluation of the feed ingredients an inventory was made on the demands set by three key organic standards and legislation documents; European legislation (in prep), IFOAM and Naturland. A draft consensus standard containing a synthesis of all demands has been described. The implication of the demands, and the possibilities and bottlenecks for organic feed production were evaluated for the selected feed ingredients. It was concluded that organic feed production for RAS can meet the general criteria set for feed, on GMO material and organic composition. However, for the production of organic feed, a bottleneck will be the necessary requirement of synthetic amino acids for health improvement. The lack of these amino acids in organic feed can result in potential disadvantage for animal needs. This raw material restrictions will most likely also result in the lack of possibilities for fine tuning the feed for animal need

Pre-inspection Mauritania Bivalve Mollusks Food Safety April 20-24th 2008

Mauritania is working on the completion of a Food Safety Program for Bivalve Mollusks, in order to be obtain an export approval by the Europe Union for the last 4 years (and before). For the second semester 2008 the FVO has programmed a veterinary inspection for the on bivalve mollusks. In order to prepare themselves for the veterinary inspection the competent authority of Mauritania (ONISPA) has requested Wageningen IMARES for a pre-inspection of the Mauritanian system. The pre-inspection was performed during the period of 20-24 April in Mauritania (Nouakchott and Nouadhibou)

Travel report Mauritania bivalve Molluscs october 2008

During the last four years Mauritania has been working on the completion of a Food Safety Program of Bivalve Mollusks, in order to obtain an export approval by the Europe Union. During the preparations for an inspection by the FVO (Food and Veterinary Office) no fisheries or production activities for Bivalve Mollusks occurred in Mauritania. The aim of the mission was to perform a pre-assessment on the status of the Bivalve Food Safety program in Mauritania. The pre-inspection was carried out in order to prepare Mauritania for the upcoming Food and Veterinary Office (FVO) inspection, planned for the second semester of 2008 or the beginning of 2009