scholarly journals Moving toward Smart Cities: Evaluation of the Self-Cleaning Properties of Si-Based Consolidants Containing Nanocrystalline TiO2 Activated by Either UV-A or UV-B Radiation

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2577
Author(s):  
José Santiago Pozo-Antonio ◽  
Daniel Noya-Pintos ◽  
Patricia Sanmartín

This study evaluated the self-cleaning ability and durability of Si-based consolidants (an ethyl silicate consolidant and a consolidant based on nanosized silica) spiked with nanocrystalline TiO2 activated by either UV-A radiation (spectral region between 340 and 400 nm, and main peak at 365 nm) or UV-B radiation (spectral region between 270 and 420 nm, and main peak at 310 nm). Granite samples were coated with consolidant, to which nanocrystalline TiO2 was added at different concentrations (0.5, 1, and 3%, by wt.). Diesel soot was then applied to the coated surfaces, and the samples were exposed to UV-A or UV-B radiation for 1650 h. The surface color changes, relative to the color of untreated granite, were determined every 330 h by color spectrophotometry. Slight color changes indicated a recovery of the reference color due to the degradation of the soot. The final surfaces of both the untreated and treated surfaces were compared by stereomicroscopy and scanning electron microscopy. The main findings were that: (1) In general, the consolidant containing nanosized silica induced the most intense photocatalytic activity. In the more compact xerogel coating formed by the nanosized silica, more TiO2 nanoparticles were available to interact with the radiation. (2) For all consolidant mixtures, soot degradation remained constant or decreased over time, except with ethyl silicate with 0.5 wt % TiO2 (no self-cleaning capacity). (3) Soot degradation increased with the concentration of TiO2. (4) The UV-B radiation was the most effective in terms of soot degradation, except for the surface coated with the ethyl silicate and 3% wt. TiO2.

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 215 ◽  
Author(s):  
J. Santiago Pozo-Antonio ◽  
Daniel Noya ◽  
Cristina Montojo

Considering that consolidant products are commonly used in the cultural heritage field and the titanium oxide nanoparticles (TiO2) have been used to develop photocatalyst films to induce self-cleaning property, the scientific research on consolidants doped with TiO2 is justified. However, the addition of TiO2 can affect to the physical properties of the cultural heritage object, questioning the adequacy of the procedure. In this paper, we evaluated the influence of nanoparticle TiO2 addition to two different commercial consolidant products (ethyl silicate or nano-sized silica) on the appearance and the color of a granite and the penetration through its fissure system. The stone was previously subjected to high temperature simulating the effect of a fire and the subsequent tap water jet to cool down. Therefore, different concentrations of nanocrystalline TiO2 (0.5, 1, and 3 wt %) were considered. The different compositions were also studied considering the compactness, the extent and the thickness of the superficial xerogel coating, and as well the penetration of the consolidant. The minimal TiO2 concentration tested (0.5 wt %) implied a low-medium risk of incompatibility as an intervention in cultural heritage field, because its low-medium potential as inducer of visible color changes of the granite surface. Regardless of the TiO2 content, the nano-sized silica induced surface xerogel coatings more compact and continue than those formed in the ethyl silicate coated surfaces. Higher penetration rates were identified in the granite treated with nano-sized silica colloidal solution, while ethyl silicate was only found in the first few µm. It was found that penetration could depend on the application procedure, the solvent of the consolidant and the silica particle size. The TiO2 addition reduced the penetration of the nano-sized silica consolidant.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Subhrangsu Sarkar ◽  
Indrani Mukherjee ◽  
Sriparna Chatterjee ◽  
Smita Gohil ◽  
Bimal P. Singh ◽  
...  

We report a simple, solution-based technique for coating arbitrary surfaces with thin layers of self-assembled copper tetradecanoate (CTD) nanostrips, resulting in an optically transparent, superhydrophobic coating. The nanostrip-coated surfaces show water contact angles close to 150° and roll-off angles as small as 2°-3°. Importantly, CTD retains its hydrophobic nature even after annealing the self-assembled nanostrips at 200°C, which does not alter the crystal structure but “melts” the surface microstructure. This clearly indicates that the hydrophobicity in CTD is likely to be intrinsic in nature and not induced by the surface microstructure (as has been suggested earlier). Strong hydrophobicity in CTD over a relatively wide temperature range presumably results from the presence of the long aliphatic (tetradecanoate) chains in its structure. Importantly, the self-assembled copper tetradecanoate nanostrips can be dip-coated on glass to render it hydrophobic and at the same time retain a significant level of transparency over the entire visible region. Such nanostructured thin films may be expected to find applications not only as a self-cleaning glass, but also as a corrosion resistant coating, in gas storage (due to the layered structure), and as an active catalyst because of the visible absorbance.


1987 ◽  
Vol 52 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Vesselin C. Noninski ◽  
Emanuel B. Sobowale

Nine pyrazolone derivatives have been studied by anodic voltammetry using gold self-cleaning rotating electrode (SRE). Voltamograms of good reproducibility are presented. On the basis of voltammetric data a mechanism is proposed for the electrochemical oxidation of sodium 1-phenyl-2,3-dimethyl-4-(N-methylamino)pyrazol-5-one-N-methansulphonate and 1-phenyl-2,3-dimethyl-4-(dimethylamino)pyrazol-5-one in protic medium.


2021 ◽  
Author(s):  
Maulida Rahayu ◽  
Sujito ◽  
Edy Wibowo ◽  
S. Sutisna
Keyword(s):  
The Self ◽  

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 387
Author(s):  
Euigyung Jeong ◽  
Heeju Woo ◽  
Yejin Moon ◽  
Dong Yun Lee ◽  
Minjung Jung ◽  
...  

In this study, self-cleaning polyester (PET) fabrics were prepared using TiOF2 and hexadecyltrimethoxysilane(HDS) treatment. TiOF2 was synthesized via direct fluorination of a precursor TiO2 at various reaction temperatures. The prepared PET fabrics had superior photocatalytic self-cleaning properties compared with anatase TiO2/HDS-treated PET fabrics under UV and sunlight with 98% decomposition of methylene blue. TiOF2/HDS-treated PET fabrics also had superior superhydrophobic self-cleaning properties compared with anatase TiO2/HDS-treated PET fabrics with a 161° water contact angle and 6° roll-off angle. After the self-cleaning tests of the non-dyed TiOF2/HDS-treated PET fabrics, we prepared dyed TiOF2/HDS-treated PET fabrics to test practical aspects of the treatment method. These PET fabrics were barely stained by tomato ketchup; even when stained, they could be self-cleaned within 4 h. These results suggest that practical self-cleaning PET fabrics with superhydrophobicity and photocatalytic degradation could be prepared using TiOF2/HDS-treatment.


2009 ◽  
Vol 17 (2) ◽  
pp. 383-391 ◽  
Author(s):  
Huda Mahmoud ◽  
Redha Al-Hasan ◽  
Majida Khanafer ◽  
Samir Radwan

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