Use of TiO2 in Photocatalysis for Air Purification and Wastewater Treatment: A Review

Mohammed, Seba; Shnain, Zainab Y.; Abid, Mohammad

doi:10.30684/etj.2021.131177.1015

Cited by 5 publications

(5 citation statements)

References 58 publications

(74 reference statements)

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“…Comparing the degradation rate achieved in dry air (RH 5%) and wet air, it was observed that water has a beneficial effect. However, when the humidity level exceeded 55% RH, the adsorption constant significantly decreased, which has been supported by previous studies [28,35,40].…”

Section: H O + E → H * + Oh * + E H O + H → Oh * + Hsupporting

confidence: 88%

“…This analysis is in accordance with the work of Tulebekov and his group [34], who stated that the degradation rate improves with an increasing flow rate and VOC concentration. These results also agree with litterature [27][28][29]. Serhane and his co-workers [35] argued that the increase in the degradation rate is related to the availability of the active species, i.e., if the formation of the first radical species is facilitated; in this case, the degradation of the adsorbed pollutants starts faster, and the residence time could be shorter.…”

Section: Tangential Flow Reactorsupporting

confidence: 81%

“…The Langmuir-Hinshelwood (L-H) model generally represents the degradation kinetics. This model is defined by the following equation [27][28][29]:…”

Section: Methodsmentioning

confidence: 99%

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Kinetic Modeling of the Photocatalytic Degradation of Chlorinated Aromatic Volatile Organic Compounds: Mass Transfer Enhancement

Koné,

Assadi,

Belkessa

et al. 2024

Applied Sciences

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Chlorobenzene (CB) and Chloronaphthalene (CN) emissions from cement plant operations pose significant environmental risks. This study investigates the mass transfer effects of chlorinated aromatic Volatile Organic Compounds (VOCs), specifically CB and CN, in the gas phase of a continuous-tangential-flow annular photocatalytic reactor. The experiments involved introducing CB and CN into the reactor, and the degradation kinetics were analyzed using the Langmuir–Hinshelwood (L-H) model. The L-H model was applied to assess the impact of the flow rate, concentration, and relative humidity (% RH) on the degradation rate (DR). The results indicate that both the experimental and simulated degradation rates improved with increased flow rates (1 to 9 m3·h−¹) and inlet concentrations (30 to 216 mg·m−3). This enhancement of the DR correlates with the availability of active OH* species on the TiO2 surface. The L-H model emphasizes the role of H2O molecules in VOC removal kinetics. The degradation rates increased with a rising water content (5 to 55%), but adverse effects on VOC conversion were observed beyond a 55% RH. This study reveals a mass transfer effect, with internal diffusional limitations in the TiO2 pores under operational conditions. The kinetics were predominantly controlled by chemical kinetics and catalyst pore availability. Furthermore, this study demonstrates a higher CB degradation than CN in the reactor and experimental conditions. For a concentration of 1.328 mM·m−3, the CB DR ranged from 0.70 to 2.84 µM·m2·s−¹, as the flow rate varied from 1 to 9 m3·h−¹. The CN DR varied from 0.60 to 2.20 µM·m2·s−¹ within the same flow rate range.

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Section: H O + E → H * + Oh * + E H O + H → Oh * + Hsupporting

confidence: 88%

Section: Tangential Flow Reactorsupporting

confidence: 81%

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Kinetic Modeling of the Photocatalytic Degradation of Chlorinated Aromatic Volatile Organic Compounds: Mass Transfer Enhancement

Koné,

Assadi,

Belkessa

et al. 2024

Applied Sciences

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“…The generated electrons and holes migrate on the surface of the photocatalyst, where, together with reactive oxygen species produced via redox reactions, they can decompose several organic compounds [55,56]. Titanium dioxide, present in nature in three polymorphs, rutile, anatase and brookite, is one of the most studied photocatalysts because of its easy availability, high reactivity and chemical stability: it has been used in several applications, such as for the purification of environmental pollutants, for the decontamination of water and for its self-cleaning properties in the conservation of cultural heritage [57][58][59][60][61][62][63]. In recent years, numerous photocatalytic materials associated with superhydrophobic surface coatings have been developed for protecting exposed buildings and monuments.…”

Section: Of 18mentioning

confidence: 99%

Hydrophobic and Photocatalytic Treatment for the Conservation of Painted Lecce stone in Outdoor Conditions: A New Cleaning Approach

Bergamonti,

Potenza,

Scigliuzzo

et al. 2024

Applied Sciences

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Self-cleaning and hydrophobic treatments based on TiO2 and SiO2 nanoparticles are widely applied for the preservation of cultural heritage materials, to improve their resilience in polluted environments. Excellent results have been obtained on stone materials, but experiments on painted stone surfaces, such as wall paintings and polychrome plasters used in historic buildings, are still limited. In this work, we present a study on the use of water dispersions of TiO2 nanoparticles obtained via sol-gel and organically modified silica (OrMoSil) for cleaning and protective purposes on Lecce stone, a carbonate stone, widely used for its excellent workability but easily attacked by atmospheric agents and pollutants. First, we evaluated the harmlessness of the treatment on Lecce stone through colorimetric tests, water absorption by capillarity and permeability to water vapor. The photocatalytic activity of the TiO2 nanoparticles was assessed by photo-degradation of methyl orange and methylene blue dyes. The dispersion was then applied on painted samples prepared according to ancient recipes to confirm the effectiveness of the cleaning. The proposed TiO2/OrMoSil-based coating can act as a self-cleaning and protective treatment on lithic surfaces to prevent degradation phenomena and preserve the original appearance of the monument.

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“…Although, direct using of photocatalyst nanoparticles for degradation of dyes is more effective but their separation from purified water and also their agglomeration in wastewater are two challenging issues 20 . To solve the first problem, many researches have been performed to immobilize these nanoparticles on different surfaces such as concretes 21 , 22 , asphalts 23 , rubbers 24 , plastics 25 , 26 , carbon cloth 27 and metals 28 . To eliminate agglomeration of hydrophilic nanoparticles in aqueous condition, coupling agents (e.g.…”

Section: Introductionmentioning

confidence: 99%

Silane modification of TiO2 nanoparticles and usage in acrylic film for effective photocatalytic degradation of methylene blue under visible light

Ataabadi

Jamshidi

2023

Sci Rep

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To fabricate a photocatalytic acrylic paint, TiO2 nanoparticles were surface modified by a bi-functional amino silane (i.e. bis-3-(aminopropyltriethoxysilane)) at different concentrations and applied at 1, 3 and 5 wt% to an acrylic latex. It was found that the surface modification of nano TiO2 enhanced its specific surface area about 42%. The tensile properties of the pristine and nanocomposite acrylic films were assessed. The photocatalytic degradation of aqueous solution and stain of methylene blue (MB) were evaluated (under solar, visible, and UV illuminations) by nanoparticles and nanocomposites, respectively. Results showed that incorporating 3 wt% of the pure and modified nano TiO2 to arylic film caused 62 and 144% increment in the tensile strength. The modified nanoparticles showed higher MB degradation contents under UV, visible and solar irradiation (82, 70, 48%, respectively). The addition of pure and modified nanoparticles to the acrylic film caused decrement in the water contact angle from 84 to 70 and 46°, respectively. It also caused considerable enhancement in the glass transition temperature (Tg) of acrylic film compared to the pristine and pure nanocomposite films (i.e. about 17 and 9 °C, respectively). Furthermore, it was found that the modified nanocomposite caused more color change of MB stain (65%).

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Use of TiO2 in Photocatalysis for Air Purification and Wastewater Treatment: A Review

Cited by 5 publications

References 58 publications

Kinetic Modeling of the Photocatalytic Degradation of Chlorinated Aromatic Volatile Organic Compounds: Mass Transfer Enhancement

Kinetic Modeling of the Photocatalytic Degradation of Chlorinated Aromatic Volatile Organic Compounds: Mass Transfer Enhancement

Hydrophobic and Photocatalytic Treatment for the Conservation of Painted Lecce stone in Outdoor Conditions: A New Cleaning Approach

Silane modification of TiO2 nanoparticles and usage in acrylic film for effective photocatalytic degradation of methylene blue under visible light

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