Nanocomposite Photocatalyst Based on Layered Double Hydroxides (LDHs) Associated with TiO2

2014 ◽  
Vol 92 ◽  
pp. 100-109 ◽  
Author(s):  
Jonjaua Ranogajec ◽  
Andrijana Sever-Skapin ◽  
Ognjen Rudic ◽  
Snezana Vucetic
Keyword(s):  
Photocatalytic Activity ◽  
Layered Double Hydroxides ◽  
Direct Contact ◽  
Building Materials ◽  
Specific Problem ◽  
The Self ◽  
Different Types ◽  
Double Hydroxides ◽  
Positive Effect ◽  
Material Porosity

The surfaces of building materials are constantly exposed to the actions of environmental factors, pollutants of inorganic and organic origin as well as to microorganisms, which significantly contribute to corrosion phenomena.The application of coatings decreases the negative action of the pollutants minimizing their direct contact with the substrate. Different types of coatings with additional functions have been developed. A specific problem of these applications is the lack of compatibility of the photocatalysts with the surface of the building materials and the detachment of potentially toxic TiO2nanoparticles. In the present study, this problem was solved by the proper immobilization of TiO2nanoparticles onto the photocatalyst support, layered double hydroxides (LDHs). The newly formed coating possesses acceptable porosity for a porous building material (porosity within the range of 30-46 %) and satisfied photocatalytic activity, as well as mineralogical compatibility with the substrates (mortars, renders, bricks). Additionally, a positive effect considering the self-cleaning phenomenon was attained.

scholarly journals Novel photocatalytic coating on façade paints: Functional properties and durability

2018 ◽  
pp. 181-191
Author(s):  
Tatjana Vulic ◽  
Snezana Vucetic ◽  
Bojan Miljevic ◽  
Jonjaua Ranogajec
Keyword(s):  
Photocatalytic Activity ◽  
Functional Properties ◽  
Building Materials ◽  
Environmental Pollutants ◽  
Weather Conditions ◽  
Negative Influence ◽  
The Self ◽  
Before And After ◽  
Materials Used ◽  
Double Hydroxides

The negative influence of the environmental pollutants on building materials used for fa?ades could be minimized by applying protective photocatalytic coatings with selfcleaning properties. Novel inorganic-inorganic nanocomposite photocatalytic coating based on TiO2/Zn-Al layered double hydroxides (LDHs) was applied on commercial fa?ade paint and the functional properties (photocatalytic activity and surface properties) were studied before and after durability tests towards the adhesion of the coating. The results showed that the TiO2/ZnAl LDH based coating did not influence esthetic appearance, surface roughness and microhardness of the fa?ade paints. The coating demonstrated a significant photocatalytic activity and the photo-induced hydrophilicity, enabling the self-cleaning effect. The study of the influence of temperature and relative humidity on photocatalytic activity indicated that optimal weather conditions for the application of coating precursors onto the fa?ade paints are in the spring and in autumn seasons.

Nanostructured Zn-Ti layered double hydroxides with reduced photocatalytic activity for sunscreen application

2019 ◽  
Vol 21 (3) ◽  
Author(s):  
Orielia Pria Egambaram ◽  
Sreejarani Kesavan Pillai ◽  
Marlize Lategan ◽  
Suprakas Sinha Ray
Keyword(s):  
Photocatalytic Activity ◽  
Layered Double Hydroxides ◽  
Double Hydroxides

scholarly journals Recent advances on the utilization of layered double hydroxides (LDHs) and related heterogeneous catalysts in a lignocellulosic-feedstock biorefinery scheme

2017 ◽  
Vol 19 (22) ◽  
pp. 5269-5302 ◽  
Author(s):  
Willinton Y. Hernández ◽  
Jeroen Lauwaert ◽  
Pascal Van Der Voort ◽  
An Verberckmoes
Keyword(s):  
Liquid Phase ◽  
Layered Double Hydroxides ◽  
Heterogeneous Catalysts ◽  
Recent Advances ◽  
Lignocellulosic Feedstock ◽  
Different Types ◽  
Double Hydroxides

Layered double hydroxides (LDHs) and derived materials have been widely used as heterogeneous catalysts for different types of reactions either in gas or in liquid phase.

scholarly journals High efficient photocatalytic activity of Zn-Al-Ti layered double hydroxides nanocomposite

2018 ◽  
Vol 149 ◽  
pp. 01087 ◽  
Author(s):  
F. Amor ◽  
A. Diouri ◽  
I. Ellouzi ◽  
F. Ouanji ◽  
M. Kacimi
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Uv Irradiation ◽  
Layered Double Hydroxides ◽  
Removal Rate ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
High Efficient ◽  
Double Hydroxides

This work establishes a simple method for synthesising layered double hydroxides (LDHs) powders with coprecipitation. The characteristics of the samples were investigated y X-ray diffraction (XRD), scanning electron microscopy (SEM) and spectrophotometer UV–Vis (DRS). Non-uniform distribution was shown for LDHs samples by SEM. Photocatalytic efficiencies were tested using methylene blue (MB) dye as a model contaminant under UV irradiation. In particular, Zn–Al-Ti LDH exhibited an excellent performance towards MB degradation compared with commercial TiO2 nanoparticles. Methylene blue removal percentage was reached at almost 100%, whereas commercial TiO2 reached a removal rate of only 66% under the same conditions within 20 min. The aim of the current work is to prepare Zn-Al-Ti layered double hydroxides nanocomposite and to evaluate their photocatalytic activity in the removal of methylene blue under UV irradiation.

Photocatalytic decolourization of methylene blue using [Zn-Al] layered double hydroxides synthesized at different molar cationic ratios

Clay Minerals ◽  
2017 ◽  
Vol 52 (2) ◽  
pp. 203-215 ◽  
Author(s):  
Kaouther Abderrazek ◽  
Najoua Frini Srasra ◽  
Ezzeddine Srasra
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Layered Double Hydroxides ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Molar Ratios ◽  
Constant Ph ◽  
Double Hydroxides

Abstract[Zn-Al] layered double hydroxides (LDH) with cationic molar ratios of R = Zn/Al 1–5 were synthesized by the coprecipitation method at constant pH = 10. The samples synthesized and their derived forms obtained after calcination at 500°C and at 900°C (denoted Zn-Al-R, Zn-Al-R-500 and Zn-Al-R-900, respectively), were characterized by X-ray diffraction (XRD), inductively coupled plasmamass spectrometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, diffuse reflectance spectroscopy and nitrogen physisorption at −196°C. The XRD study showed: (1) the presence of accessory ZnO with the LDH in samples synthesized with R ≥ 3; and (2) the lamellar structure was destroyed at 500°C which made room for a poorly ordered ZnO phase, while calcination at 900°C yielded well crystallized ZnO and ZnAl2O4. The photocatalytic activity of the calcined and the unheated samples was evaluated for the decolourization of methylene blue. The photocatalytic activity was dependent on the cationic ratio R and on the calcination temperature. The sample Zn-Al-3 displayed maximum photocatalytic activity. Calcination at 500 and 900°C improved the photocatalytic activity of LDH synthesized at R = 1 and 2.

Properties of self-compacting mortar made with various mineralogical sources different types of sands and fillers

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Brahim Nécira ◽  
Yacine Abadou
Keyword(s):  
Design Methodology ◽  
The Self ◽  
River Sand ◽  
Content Type ◽  
Different Types ◽  
Negative Effect ◽  
Great Availability ◽  
Mechanical Strengths ◽  
Positive Effect ◽  
Saturation Dose

Purpose By its high fluidity, great deformability and rheological stability, the self-compacting mortar (SCM) is capable of ensuring the ability to be easily implemented without vibration. However, its formulation requires a large volume of fine materials with a high dosage of cement, which is necessary to ensure adequate workability and mechanical strengths, which is necessary to allow its flow. Current environmental considerations encourage reducing the production of cement, it is essential to use additions to replace the cement, because of their great availability and their moderate price. On another side, their use contributes to an economic sort to solve the problems related to the environment. Design/methodology/approach The formulations and characteristics of SCM made with two types of mineralogical sources (silica and limestone) were investigated. Different materials were used separately and in binary combinations; silica river sand (SRS), limestone quarry sand (LQS), silica fillers (SF) and limestone fillers (LF). The formulation starts with the self-compacting pastes (SCPs) then the SCMs at the SRS and the LQS whose the cement is partially replaced by volume contents of SF and LF with 15%, 30% and 45%. Findings The results obtained prove that the incorporation of LQS instead of SRS has a negative effect on the fluidity and deformability and a positive effect on the mechanical strengths of SCM. In addition, the incorporation of the SF and LF reduces the need for water and the saturation dose of superplasticizer in the pastes. Thus, the addition of the SF and LF in specific voluminal contents (15% SF and 30% LF) in the binder can have a beneficial effect on the parameters of the workability and the mechanical strengths of SCM. These results are very interesting to aspects such as technological, economic and environmental. Originality/value Influence of the different type of sands and fillers in improvements the properties of SCM made from various mineralogical sources.

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