Design of TiO2 nanomaterials for the photodegradation of formic acid - Adsorption isotherms and kinetics study

AIR:EAU:RAFFINAGE:MATERIAUX+ATR:CGU:FDA:GBE:HKO1D-TiO2 nanomaterials (nanotubes, nanorods, nanoplates, nanospheres and nanoparticles) with tuned structural and textural properties have been evaluated in the photocatalytic degradation of formic acid (FA) under UV conditions. The FA adsorption isotherms follow the model of Langmuir and the kinetic of FA photodegradation shows Langmuir-Hinshelwood model whatever the TiO2 morphologies. TiO2 nanotubes (HTNT-400), nanoplates (HTNW-700) and nanoparticles (HTNT-500 and HTNT-600) show an interesting photocatalytic activities compared to TiO2 nanospheres (P25) and nanorods (TNR). The nanotubular TiO2 (HTNT-400) has a photocatalytic activity 4 times higher than TiO2 P25. The enhanced activity is attributed to the smaller crystallite size of anatase and tuned surface area of the photocatalyst. The pH study showed that the coexistence of HCOO- and HCOOH species at natural pH (ca. 3.5) is favourable for better adsorption on active sites of titanium oxide nanomaterials and consequently to a better photocatalytic activity. (C) 2014 Elsevier B.V. All rights reserved

Phenol photocatalytic degradation over anisotropic TiO2 nanomaterials: Kinetic study, adsorption isotherms and formal mechanisms

SSCI-VIDE+CARE:ECI2D+ATR:CGU:FDA:GBE:HKOInternational audienceAnisotropic TiO2 nanomaterials (nanotubes, nanorods, nanoplates, nanospheres, and nanoparticles) with controlled structural and textural properties have been evaluated in the photocatalytic degradation of phenol under UV conditions. The kinetic study of phenol adsorption fits well to a quasi-second-order model whereas the adsorption isotherms of phenol over the different TiO2 nanomaterials follow the Langmuir model and the degradation kinetics the Langmuir-Hinshelwood (L-H) model. TiO2 nanomaterials exposing (001) or (101) anatase facets are less active than TiO2 P25 for the phenol degradation. This is related to their tendency to degrade faster intermediates products (organic acids) rather than phenol itself. A good compromise between anatase crystallinity, crystallites sizes, and specific surface area can however improve the photocatalytic activity of the TiO2 nanomaterials. Results also showed that the degradation mechanism follows pseudo-first order kinetics. Pseudo-rate constants were therefore determined and formal mechanism schemes proposed. (C) 2014 Elsevier B.V. All rights reserved

The performance of Fraxinus angustifolia as a helper for metal phytoremediation programs and its relation to the endophytic bacterial communities

Soil contamination with metals is a serious problem requiring urgent measures to counteract their impacts. The conventional soil remediation techniques are often inefficient and expensive. In this work, we studied the potential of the species Fraxinus angustifolia for the phytoremediation of metal contaminated soils from the Cunha Baixa uranium mine (Mangualde, Portugal). The plants were exposed to a contaminated, a reference and a control soil, for a period of about 3months, during which metal accumulation and a set of physiologic parameters (shoot height, potential maximum efficiency of PSII (Fv/Fm) and quantum yield of PSII (ΦPSII), leaf area, specific leaf area, leaf relative water content, leaf chlorophyll a, chlorophyll b and carotenoid content, leaf malondialdehyde (MDA) content and leaf proline content) were measured. The genetic profiles of the endophytic communities from the roots of the plants were also analyzed, via PCR-Denaturing Gradient Gel Electrophoresis (DGGE) targeted for a conserved region of 16S rDNA, pre- and post-exposure. Only the shoot height was a suitable indicator of the negative effects of the contamination with metals on the plants. The remaining parameters indicated good physiologic fitness and recovery. The trees did not hyperaccumulate metals but extracted Sr at a higher rate. The bacterial profiles from the control and reference soils showed more similarity with each other and with the pre-exposure profiles than with those from the contaminated soil. We showed that F. angustifolia has the ability to resist and adapt to the adverse conditions of contamination, revealing a potential which can be exploited for phytoremediation, specifically phytostabilization. It also revealed that changes exerted on the bacterial root communities exposed to contamination, resulted in profiles considerably different from those of the remaining communities.This work was carried out under a project funded by the North Atlantic Treaty Organization (NATO), within the Program Science for Peace (Ref. SfP. 983311). This study was also partially funded by FSE and POPH funds (Programa Ciência 2007).publishe

The use of fishers' Local Ecological Knowledge to reconstruct fish behavioral traits and fishers' perception of conservation relevance of elasmobranchs in the Mediterranean Sea

The Mediterranean Sea has a long-lasting history of fishery exploitation that, together with other anthropogenic impacts, has led to declines in several marine organisms. In particular, elasmobranch populations have been severely impacted, with drastic decreases in abundance and species diversity. Based on their experience, fishers can provide information on marine species oc- currence, abundance and behavioural traits on a long-term scale, therefore contributing to research on the poorly studied biolog- ical aspects of elusive or rare elasmobranch species. In this study, for the first time, the Local Ecological Knowledge (LEK) of fishers was applied to study the behavioural traits of sharks, rays and skates in 12 FAO-GFCM geographical sub-areas (GSAs) of the Mediterranean Sea. This study found both new insight and proved the reliability of LEK-based catch seasonality, reflect- ing seasonal movements, by comparing LEK-based findings and available literature on five elasmobranch taxa (Mustelus spp., Squalus acanthias, Raja spp., Myliobatis aquila and Scyliorhinus stellaris) in the Adriatic Sea and 7 taxa (Mustelus spp., Raja spp., Prionace glauca, Scyliorhinus canicula, Torpedo spp., Pteroplatytrygon violacea and Isurus oxyrinchus) in the remaining Mediterranean GSAs. In addition, LEK provided new insights into a novel comprehensive representation of species aggregations (Mustelus spp., S. acanthias, M. aquila and S. canicula) in the sampled GSAs and supplied the first descriptions of the size, num- ber of individuals and sex composition of the aggregations. When the limits and shortcomings of LEK-based research are consid- ered, this methodology can be a complementary and cost-effective tool used to study elasmobranchs in either a data-poor scenario or a scenario in which a baseline is missing. LEK can also be useful for the evaluation and inclusion of fishers’ perceptions of bottom-up management and to provide important evidence for conservation plans