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Photoabatement of water pollutants in turbid suspensions by means of photoactive fluorinated transparent coatings
No full textPhotoactive Perfluorinated Ionomeric Transparent Coatings in the Oxidative Abatement of Hydrosoluble Pollutants in Turbid Suspensions
No full textPhotoactive perfluorinated ionomeric transparent coatings in the
oxidative abatement of hydrosoluble pollutants in turbid suspensions
Walter Navarrini*(1,2), Federico Persico(1,2), Maurizio Sansotera(1,2)
(1) Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di
Milano, Via Mancinelli 7, 20131, Milano, Italy.
(2) Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali, Via G. Giusti
9, 50121 Firenze, Italy.
*Walter Navarrini: Tel: +39.02.2399.3035; email address: [email protected];
The abatement of organic pollutants in water phase promoted by photoactive titanium dioxide has
been widely studied in the last decade [1]. Despite the high photodegradative rates guaranteed by
slurry TiO2, its industrial use is strongly limited by the catalyst recovery cost. To overcome this
obstacle powder TiO2 was immobilized into a multilayer ionomeric-perfluorinated matrix and the
activity of this Photoactive Coating (PAC) was studied.
In order to obtain the correct interaction between the activated TiO2 and the polluted aqueous
solutions the polymeric matrix must be characterized by high chemical resistance, high
transparency towards UV light, good wettability and good permeability to oxygen and water vapor
[2,3].
The multilayer coating photocatalytic activity towards hydrosoluble organic pollutants was
evaluated in clear as well as in highly turbid conditions obtained by dispersing barium sulphate
microparticles in the polluted solution.
The perfluorinated multilayer photoactive coating was applied directly on the UV source and
employed as substrate for immobilization of the photocatalyst. A TFE/perfluorodioxole copolymer
double-layer acted as primer; a dispersion of TiO2 in the perfluorinated ionomeric solution of a
copolymer between TFE/perfluorosulphonylvinylether acted as photoactive layer. The strong
acidity of the ionomeric side chains conferred hydrophilicity to the coating , allowing a good
interaction with the polluted aqueous solutions. Rhodamine B-base (RhB) and Crystal Violet (CV)
were used as organic hydrosoluble pollutants and their
concentration in solution was monitored by UV-Vis
spectroscopy and HPLC-MS technique.
In both clear and turbid conditions, TiO2-embedded
transparent fluorinated coating revealed higher
photocatalytic activity than merely dispersed TiO2
(Image1). This behavior was particularly evident at low
pollutant concentrations. In addition, catalyst
immobilization prevented TiO2 separation and catalyst
losses, allowing the development of a simple and
efficient continuous apparatus.
I Image 1. Degradative efficiency of PAC compared
to the performances obtained with slurry TiO2
References
[1] M. Sansotera, et al., Appl. Catal., B, 148 (2014) 29.
[2], F. Persico, et al., Thin Solid Films, 545 (2013) 210.
[3] W. Navarrini, et al., Prog. Org. Coat., 74 (2012) 794
Abatement of Hydrosoluble Pollutants in Turbid Suspensions by Photoactive Transparent Coatings
No full textPhotocatalytic Activity Of TiO2-Embedded Fluorinated Transparent Coating For Oxidation Of Hydrosoluble Pollutants In Turbid Suspensions
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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