Source control options for reducing emission of priority pollutants from urban areas.

The overall aim of the ScorePP project is to develop comprehensive and appropriate source control strategies that authorities, cities, water utilities and the chemical industry can employ to reduce emissions of priority pollutants (PPs) from urban areas into the receiving water environment. Focus is on the 33 priority and priority hazardous substances and substance groups identified in the European Water Framework Directive. However, this list may be expanded to include emerging pollutants or reduced if appropriate model compounds can be identified. The initial work focuses on 67 substances, including substances identified in the proposed European environmental quality standard (EQS) directive as well as the defined example compounds and several organometallic derivatives. Information on inherent properties, environmental presence and fate, and legislative issues is made available in open database format, and a data management system combining chemical identification (CAS#), NACE economic activity classifications and NOSE-P emission source classifications has been developed as a basis for spatial characterisation of PP sources using GIS. Further work will focus on dynamic urban scale source-flux models, identifying emission patterns and optimising monitoring programmes in case studies and multi-criteria comparison of source control versus end-of-pipe mitigation options in relation to their economic, social and environmental impacts

A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor

[EN] The aim of this work is to study the activity for the nitrate catalytic reduction in natural water, using a continuous stirred tank reactor, of Pd/Cu and Pd/Sn catalysts supported on different materials. The studied supports are: -Al2O3 (commercial), active carbon, graphite, hydrotalcite and alumina synthesized in our laboratory with a high surface area. The activity and selectivity of the catalysts supported on these materials have been compared. The best results have been obtained with the Pd/Sn catalysts supported on alumina. These results show thatthe surface area ofthe supportis notthe only important characteristic for an active catalyst in this reaction, but also its acid–base properties, electrical conductivity and interaction with the metallic active sites are very significant. The adequate combination of these characteristics is necessary to obtain an active catalyst. The influence of the Pd/Sn content on the activity of the alumina supported catalysts was studied, observing that the best activity was obtained when the Pd/Sn ratio was higher than 1. This result clearly indicates that it is necessary to have both Pd and Pd–Sn centers in order to obtain an active catalyst.The authors thank the Spanish Government(projects MAT2009-14528-C02-01 and CONSOLIDER INGENIO 2010) and the European Union (European Community’s Seventh Framework Programme FP7/2007-2013 under Grant Agreement No. 226347 Project)for the financial support.Franch Martí, C.; Palomares Gimeno, AE.; Corma Canós, A. (2011). A study of different supports for the catalytic reduction of nitrates from natural water with a continuous reactor. Catalysis Today. 172(1):90-94. https://doi.org/10.1016/j.cattod.2011.05.015S9094172

European survey on criteria of aesthetics for periodontal evaluation: The ESCAPE study

Objective: The ESCAPE multicentre survey was designed to (a) compare the agreement of three relevant aesthetic scoring systems among different centres, and (b) evaluate the reproducibility of each question of the questionnaires. / Materials and Methods: EFP centres (n = 14) were involved in an e‐survey. Forty‐two participants (28 teachers, 14 postgraduate students) were asked to score the one‐year aesthetic outcomes of photographs using the Before–After Scoring System (BASS), the Pink Esthetic Score (PES) and the Root coverage Esthetic Score (RES). Mean values of kappa statistics performed on each question were provided to resume global agreement of each method. / Results: Between teachers, a difference of kappa ≥ 0.41 (p = .01) was found for BASS (75%) and PES (57%). Similarly, RES (84%) and PES (57%) were different (p < .001). No difference was found between BASS (75%) and RES (84%). No difference was found between students, whatever the scoring system. Questions of each scoring system showed differences in their reproducibility. / Conclusions: The outcomes of this study indicate that BASS and RES scoring systems are reproducible tools to evaluate aesthetic after root coverage therapies between different centres. Among the various variables, lack of scar, degree of root coverage, colour match and gingival margin that follows the CEJ show the best reliability

Preparation of low-density xerogels through additives to TEOS-based alcogels

A new process for preparing silica xerogels with similar textural properties to silica aerogels by drying under vacuum has been studied. The xerogels are produced by adding, before gelation, 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) to tetraethylorthosilicate (TEOS)-based alcogels, synthesised in a single base-catalysed (NH3) step. It is hypothesized that EDAS acts as a nucleation agent leading to silica particles with a hydrolysed EDAS core and a shell principally made of hydrolysed TEOS. The EDAS concentration and the basicity of the aqueous NH3 solution are important parameters influencing the resistance of the gel to drying stress. A decreasing EDAS/TEOS ratio or an increasing concentration of NH3 at constant EDAS content leads to less shrinkage during drying and so the final pore volume is larger. Gels prepared with a low EDAS/TEOS ratio (about 0.03) contain large particles (similar to 20 nm) due to the nucleation process by EDAS, thus the pores between those particles are also large and the drying stress is reduced. (C) 1999 Published by Elsevier Science B.V. All rights reserved