UV-resistant amorphous fluorinated coating for anodized titanium surfaces

The effect of oxygen in the photocatalytic oxidation pathways of perfluorooctanoic acid

“…These hypotheses were confirmed by detecting carbonyl difluoride, COF 2 , specifically produced in the β-scission pathway. An appropriate kinetic test was set for COF 2 …”

“…Carbonyl difluoride is an important intermediate for the industrial synthesis of key fluorinated monomers and it is essential in the preparation of fluoroplastics and perfluororubbers [43][44][45]. In this work, we firstly report that the intermediate COF 2 can be isolated in pure form and in good selectivity by performing the photocatalytic oxidation of PFOA in a suitable perfluorinated aprotic solvent, instead of water. Moreover, in these conditions the catalyst deactivation due to fluoride ions is mostly inhibited [27].…”

“…The intent of this work is to give our contribution to the understanding of this intriguing reaction. In particular, we focused on the influence of oxygen in the photocatalytic oxidation of PFOA induced by UV-activated TiO 2 and we obtained that, differently from static conditions, a continuous oxygen feeding enhanced the decomposition of PFOA till its mineralization. On the contrary, PFOA photooxidation was hindered in a nitrogensaturated reaction environment.…”

Photocatalytic activity of TiO2-embedded fluorinated transparent coating for oxidation of hydrosoluble pollutants in turbid suspensions

“…The SO 3 H groups are placed as terminals of the lateral chains, conferring hydrophilicity and consequently good wettability to the photoactive coating, while the backbone of the polymer is hydrophobic due to the presence of C F bonds. AD is a random copolymer of TFE and 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (TTD), characterized by outstanding chemical stability [24], low refractive index (equal to 1.327) and T g of 130 • C [24]. AD was employed in solution during the experimental tests, using GALDEN ® HT110 (Solvay Specialty Polymers) as solvent.…”

“…It is well known that soiling on TiO 2 thin layers (e.g., TiO 2 nanotubes by titanium anodizing) can easily deactivate the catalyst [21]. Perfluoropolymeric materials, due to the massive presence of highly stable C F bonds, as high as 544 kJ/mol [22], are characterized by thermal and chemical stability [22,23], in particular toward UV radiation and UV-activated TiO 2 [24], low surface energy and, if amorphous, also high transparency [14,25]. The interaction between the embedded TiO 2 catalyst and the aqueous polluted solution can be optimized by the use of ionomeric materials.…”