Removal of graffiti paint from construction materials coated with TiO-based photocatalysts.

Graffiti on construction materials has significant social and economic impacts, especially on artistic and historical artefacts. Anti-graffiti protective coatings are used to generate low surface energies that limit graffiti adhesion to the surface, thereby reducing surface damage and facilitating removal. The anti-graffiti properties of three commercial TiO-based coatings were tested under outdoor exposure conditions using four colours of graffiti paint (red, blue, black, and white).

Face Mask Wastes as Cementitious Materials: A Possible Solution to a Big Concern.

After more than two years wearing surgical masks due to the COVID-19 pandemic, used masks have become a significant risk for ecosystems, as they are producing wastes in huge amounts. They are a potential source of disturbance by themselves and as microplastic contamination in the water system. As 5500 tons of face masks are estimated to be used each year, there is an urgent need to manage them according to the circular economy principles and avoid their inadequate disposal.

Synergetic adsorption-photocatalysis process for water treatment using TiO supported on waste stainless steel slag.

This study presents an economical and efficient method to decolourise dye wastewater using industrial waste stainless steel slag (SSS). Titanium dioxide was immobilised on SSS by a precipitation-calcination method. Samples with different TiO loadings (prepared using either titanium isopropoxide precursor or commercial TiO nanoparticles) were used to decolourise an organic contaminant (methylene blue) under dark and UV conditions in aqueous solution, and their adsorption and photocatalytic performances were compared.

Primary and Secondary Emissions of VOCs and PAHs in Indoor Air from a Waterproof Coal-Tar Membrane: Diagnosis and Remediation.

Primary and secondary emissions of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) from a waterproof coal tar membrane and their effect on the indoor air quality were investigated through a case study in a residential building situated in Madrid, Spain. The air contaminants were analyzed in situ using photoionization method and several samples of contaminants were taken using three sorbents: activated carbon, XAD2 and Tenax GR. It was found that various VOCs such as toluene, p- and m-Xylene, PAHs such as naphthalene, methyl-naphthalenes, acenaphthene, acenaphthylene, phenanthrene and fluorine, volatile organic halogens including chloroform and trichlorofluoromethane, and alkylbenzene (1,2,4-trimethylbenzene) were found at concentrations, which exceeded the limits established by international and national agencies (WHO, EPA, OSHA).

Unusual photodegradation reactions of Asteraceae and Poaceae grass pollen enzymatic extracts on P25 photocatalyst.

In previous studies, it was demonstrated that photocatalysis by TiO nanoparticles can be effective for decomposition of pollen grains and pollen allergen extracts (PAEs) for Cupressus arizonica and Platanus hybrida species. In this work, the chemical and photochemical processes of five types of PAEs belonging to family Asteraceae, tribe Astereae, and family Poaceae, tribes Poeae and Triticea, were studied. It was confirmed that the PAEs suffered almost complete decomposition, which likely led to gaseous final products.

High-capacity adsorbents from stainless steel slag for the control of dye pollutants in water.

Adsorbent materials for the control of dye pollutants in water were synthetized from stainless steel slag (SSS) using different acid-base treatments. Using HCl (SS-Cl) and HNO (SS-NO) produced high-capacity adsorbents, with BET areas of 232 m/g and 110 m/g respectively. Specifically, the SS-Cl had a structure of amorphous silica sponge.

New Holistic Conceptual Framework for the Assessment of the Performance of Photocatalytic Pavement.

Despite serious health and environmental burdens associated with air pollution by NO, the emission ceilings have been systematically exceeded in big European cities for several years. Photocatalytic technology can be an efficient solution for the removal of chemical air pollutants. Because diesel engine exhaust is the main source of NO emissions, the application of a photocatalyst onto road pavement appears to be an effective NO abatement method due to the large surface area, proximity to the emission source, and relatively good solar irradiance.

Photocatalytic Activity of Zn Mn O Oxides and ZnO Prepared From Spent Alkaline Batteries.

Oxides with Zn MnO stoichiometries and ZnO were synthesized from the "black mass" material recovered from spent alkaline batteries. The oxides were characterized by XRF, XRD with Rietveld refinement, SEM, and TEM methods. Optical characterization included diffuse reflectance (DRS) and photoluminescence (PL) measurements.

Assessment of urban air pollution related to potential nanoparticle emission from photocatalytic pavements.

The main objective was to evaluate whether wearing and weathering of nanofunctionalized photocatalytic pavement in real urban environment can lead to undesirable emission of potentially toxic nanoparticle aerosols in urban air. The photocatalytic material was thoroughly tested before its application for conformity criteria in terms of photocatalytic effectiveness, intrinsic performance and undesired secondary effects, and then applied on a pilot scale in downtown Madrid. The aerosol monitoring on the pilot street before the coating applications as well as on the neighbouring streets during 10 months was used as a benchmark for evaluation of spatial and temporal variations.

Environmental impact of nano-functionalized construction materials: leaching of titanium and nitrates from photocatalytic pavements under outdoor conditions.

There is a growing use of nano-functionalized construction materials, which contain nanoparticles embedded in their bulk or deposited on their surfaces. In the case of photocatalytic materials, nano-TiO is usually added to provide it's functionality. One concern about these materials, in addition to release of nanoparticles as airborne, is that they can be leached into the aquatic environment.

In situ evaluation of the NO removal efficiency of photocatalytic pavements: statistical analysis of the relevance of exposure time and environmental variables.

In the recent past, the NO removal efficiency of photocatalytic materials has been subject of many studies with promising results. However, many of these studies involve laboratory tests carried out under standardized climatic exposure conditions, often not representative of the real-world environment. With the aim to bridge this gap, selected photocatalytic materials have been applied to different substrates in outdoor demonstrator platforms at pilot scale as part of the project LIFE-PHOTOSCALING.