Effect of environmental conditions on degradation of NOx gases by photocatalytic nanotitania-based cement mortars after long-term hydration

Casagrande, Cézar Augusto; Repette, Wellington Longuini; Hotza, Dachamir

doi:10.1016/j.jclepro.2020.123067

Cited by 34 publications

(10 citation statements)

References 48 publications

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“…A two-fold increase in gas flow rate caused a remarkable decrease in NO2 conversion. This may be related to the short contact time between pollutant and photocatalyst surface during the passage of higher gas flow rate [47]. A similar effect was observed by Li et al [48] in photocatalytic depolymerization of the oxidized β-O-4 molecule in the continuousflow reactor.…”

Section: Effect Of Process Parameterssupporting

confidence: 69%

Pilot-Scale Studies of WO3/S-Doped g-C3N4 Heterojunction toward Photocatalytic NOx Removal

et al. 2022

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Due to the rising concentration of toxic nitrogen oxides (NOx) in the air, effective methods of NOx removal have been extensively studied recently. In the present study, the first developed WO3/S-doped g-C3N4 nanocomposite was synthesized using a facile method to remove NOx in air efficiently. The photocatalytic tests performed in a newly designed continuous-flow photoreactor with an LED array and online monitored NO2 and NO system allowed the investigation of photocatalyst layers at the pilot scale. The WO3/S-doped-g-C3N4 nanocomposite, as well as single components, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller surface area analysis (BET), X-ray fluorescence spectroscopy (XRF), X-ray photoemission spectroscopy method (XPS), UV–vis diffuse reflectance spectroscopy (DR/UV–vis), and photoluminescence spectroscopy with charge carriers’ lifetime measurements. All materials exhibited high efficiency in photocatalytic NO2 conversion, and 100% was reached in less than 5 min of illumination under simulated solar light. The effect of process parameters in the experimental setup together with WO3/S-doped g-C3N4 photocatalysts was studied in detail. Finally, the stability of the composite was tested in five subsequent cycles of photocatalytic degradation. The WO3/S-doped g-C3N4 was stable in time and did not undergo deactivation due to the blocking of active sites on the photocatalyst’s surface.

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Section: Effect Of Process Parameterssupporting

confidence: 69%

Pilot-Scale Studies of WO3/S-Doped g-C3N4 Heterojunction toward Photocatalytic NOx Removal

et al. 2022

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“…Nanoparticles have been used in cement-based materials mainly to provide new properties (e.g., photocatalytic properties) [ 10 , 11 , 12 ] or improve the existing ones (e.g., increasing mechanical strength and durability) [ 13 , 14 ]. However, due to the very high specific surface area of nanoparticles, they can also be used to control the rheology of paste, mortar, and concrete.…”

Section: Introductionmentioning

confidence: 99%

“…TiO 2 nanoparticles are often used in cement-based materials for photocatalytic purposes, as mentioned above [ 10 , 11 , 12 ]. In turn, the fresh-state performance of cementitious materials containing nano-TiO 2 is much less addressed than materials containing other nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Effect of TiO2 Nanoparticles on the Fresh Performance of 3D-Printed Cementitious Materials

et al. 2022

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3D printing (3DP) of cementitious materials shows several advantages compared to conventional construction methods, but it requires specific fresh-state properties. Nanomaterials have been used in cement-based materials to achieve specific fresh and hardened properties, being potential candidates for 3DP applications. However, there are no reports on using TiO2 nanoparticles (nano-TiO2) in 3DP cementitious composites. Thus, the current work aims to assess the effect of nano-TiO2 on the fresh performance of 3DP cementitious materials. For this purpose, nano-TiO2 was incorporated in pastes and mortars from 0 to 1.5 wt.%. Time-resolved hydration (in situ XRD) and rheological and printing-related properties (buildability and printability) were evaluated. Results showed that nano-TiO2 particles enhanced the cement hydration kinetics, leading to further ettringite formation up to 140 min compared to plain cement paste. Rheological measurements showed that the nano-TiO2 incorporation progressively increased the static and dynamic stress, viscosity, and structuration rate of pastes. Furthermore, nano-TiO2 improved the buildability of the composites, progressively increasing the maximum number of successive layers printed before failure from 11 (0 wt.% TiO2) to 64 (1.5 wt.% TiO2). By contrast, the nano-TiO2 addition reduced the printability (i.e., the printable period during which the sample was able to be molded by the 3D-printing process) from 140 min (0% TiO2) to 90 min (1.5% TiO2). Thus, incorporating “high” nano-TiO2 contents (e.g., >1 wt.%) was beneficial for buildability but would require a quicker 3DP process. The adoption of nano-TiO2 contents of around 0.75–1.00% may be an interesting choice since it reduced the printability of paste by 30 min compared with the control mix but allowed for printing 24 layers (118% higher than plain mortar).

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“…When we take or inhale radon gas or and its daughters along with normal air, most of radon is exhaled, and its decay products got logged to the inner walls and membranes of our respiratory organ and continue constant change due their alpha ionization power. Different cancers and kidney diseases are so influenced by the intake of solid radon daughter products [5,[16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Radioactivity and health risk assessments in cement samples commonly used as construction materials in the case of South Gondar Zone, Ethiopia

Abate¹

2022

EPJ Nuclear Sci. Technol.

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This work deals with the measurement of the radioactivity concentrations from different cement samples collected from the South Gondar Zone, Ethiopia. The measurement of naturally occurring radioisotopes and radiation health impact indices caused by these nuclides in cement samples are indisputable in the dwellings. Specifically, the average concentrations for 226Ra, 232Th and 40K were estimated as 76.53, 81.67, and 407 Bq kg−1, respectively. It was seen that all the measured mean values were greater than the world’s limited levels. External and internal hazard indices are calculated as defined by the European Commission from the corresponding concentrations of 226Ra, 232Th and 40K nuclides. Moreover, the natural radionuclides have variety of concentrations which must be caused by the types of raw materials used in the industries for the production of cement.

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Effect of environmental conditions on degradation of NOx gases by photocatalytic nanotitania-based cement mortars after long-term hydration

Cited by 34 publications

References 48 publications

Pilot-Scale Studies of WO3/S-Doped g-C3N4 Heterojunction toward Photocatalytic NOx Removal

Pilot-Scale Studies of WO3/S-Doped g-C3N4 Heterojunction toward Photocatalytic NOx Removal

Effect of TiO2 Nanoparticles on the Fresh Performance of 3D-Printed Cementitious Materials

Radioactivity and health risk assessments in cement samples commonly used as construction materials in the case of South Gondar Zone, Ethiopia

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