Preparation of new microporous titanium pillared kenyaite materials active for the photodegradation of methyl orange (original) (raw)
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Synthesis and characterisation of novel titania impregnated kaolinite nano-photocatalyst
Microporous and Mesoporous Materials, 2009
Nano-sized titanium dioxide (TiO 2 ) has received a great attention in the field of research and development as a promising photocatalyst to promote the degradation of organic contaminants in water. One of the key technical challenges involved in separation and recovery of the photocatalyst particles from the water treatment system makes this technology unviable as an industrial process. A novel titania impregnated kaolinite (TiO 2 /K) photocatalyst was synthesized by a modified two step sol-gel method: hydrolysis of titanium(IV) butoxide and heterocoagulation with pre-treated kaolinite (K) clay. The TiO 2 /K photocatalysts were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and BET specific surface area measurements (BET). The photocatalytic activity was evaluated by the degradation of Congo red in aqueous solution. The TiO 2 /K photocatalyst had a rigid porous layer structure and promising nano-size properties, and demonstrated an enhanced adsorption and photocatalytic ability for the removal of Congo red. The TiO 2 /K photocatalyst can be easily separated and recovered from the water treatment system. The TiO 2 /K photocatalyst is expected to deliver a true engineering solution for an industrial water/wastewater treatment process.
Catalysis Today, 2015
A purified natural kaolinite was functionalized with titanium(IV) isopropoxide via the hydrolytic sol-gel route and thermally treated at several temperatures, between 100 and 1000 • C, for 24 h. The resulting solids were used for photodegradation (=365 nm, 30 W) of Methylene Blue (MB) and Methyl Orange II (MOII) dyes. All the solids efficiently degraded the dyes and almost total bleaching of the aqueous solutions was observed after 1 h. The best results were found for the solid heated at 400 • C, which degraded 93% of MOII and 99% of MB. Comparative studies with titanium oxide P25 from Degussa were tested and the results reveal lower yields than our systems (45% MB and 15% MOII, 1 h). Kaolinite could promote the dispersion of TiO 2 on the clay surface allowing a fast degradation of dyes. This effect was confirmed by comparison of the results from isolated components (titanium oxide and kaolinite) and titanium oxide-kaolinite nanocomposites.
Journal of Hazardous Materials, 2009
The synthesis and properties of metal oxide pillared cationic clays (PILCs) has been subject to numerous studies in the last decades. In order to obtain TiO 2 -pillared type materials, sodium montmorillonite from Romania-areal of Valea Chioarului, having the following composition (% wt): SiO 2 -72.87; Al 2 O 3 -14.5; MgO-2.15; Fe 2 O 3 -1.13; Na 2 O-0.60; K 2 O-0.60; CaO-0.90; PC-5.70 and cation exchange capacity, determined by ammonium acetate method, of 82 meq/100 g, as matrix, was used. Sodium form of the clay was modified, primarily, by intercalation of cetyl-trimethylammonium cations between negatively charged layers which will lead to the expantion of the interlayer space. For the preparation of the TiO 2 -pillared clay, the alkoxide molecules, as titania precursor, were adsorbed onto/into clay samples (1 mmol Ti/g clay), in hydrochloric acid environment, the resulted species being converted into TiO 2 pillars by calcination. The as-prepared materials have been used as catalysts for Congo Red dye photodegradation, under UV. The photocatalytic activity of the pillared clays is a function of TiO 2 pillars size, their increase leading to the enhancement of the contact areas between dye solution and photoactive species present in the interlayer space.
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/preparation-and-characterization-of-different-tio2-modified-montmorillonite-meso-microporous-materials-with-enhanced-photocatalytic-activity https://www.ijert.org/research/preparation-and-characterization-of-different-tio2-modified-montmorillonite-meso-microporous-materials-with-enhanced-photocatalytic-activity-IJERTV4IS090260.pdf A set of TiO2-modified montmorillonite meso-microporous materials, as photocatalysts, was successfully prepared in different ways and evaluated by the photodegradation of 4-nitrophenol (4-NP) in water, since it is a recalcitrant organic pollutant. The effects of photocatalysts' preparation methods on their textural, structural and catalytic properties were tested. To understand the relationship between the photocatalysts structure and performance, these were characterized by X-Ray Diffraction (XRD), UV-spectroscopy, Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDX), Fourier Transform Infrared Spectroscopy (FTIR), X-ray fluorescence (XRF), specific surface area and porosity measurements. A high specific surface area (up to 231 m 2 /g), a meso-microporous structure and a high stability have been found for the TiCl4-M and TiCl3-M prepared photocatalysts. In addition, to improve the 4-NP degradation, various parameters' effect was studied such as the type of the photocatalyst, its amount loading, the pH of the 4-NP solution and the initial 4-NP concentration. Then, the 4-NP degradation rate has reached 99% only when Anatase Titanium dioxide was supported on montmorillonite, at pH=5, with 0.2 g/100 mL of photocatalyst (TiCl4-M or TiCl3-M) amount and a 4-NP concentration equal to 20 mg.L-1 .
Applied Clay Science, 2019
The incorporation of titanium oxide and other transition metals on the surface of different materials has been shown to be a promising strategy to improve the of photocatalytic processes efficiency aiming at the decontamination of aqueous systems caused by persistent organic contaminants such as dyes. The objective of this work was to evaluate the catalytic properties of nanocomposites based on the kaolinite (Kaol) with TiO 2 incorporated, obtained from the sol-gel method, used in discoloration of the coomasie brilliant blue dye (CBB) in aqueous solution. The nanocomposites were prepared from the reaction of titanium tetraisopropoxide with purified natural kaolinite and calcined at different temperatures. The samples were characterized by the XRD, FTIR, SEM-XED, BET-BJH and diffuse reflectance spectroscopy techniques, which demonstrated the structure, crystalline pattern, as well as the incorporation of titanium in the clay structure, changes caused by modification in morphology, texture and energy gap. The photocatalytic tests were performed using 5 × 10 −5 mol L −1 , 1.0 and 1.5 g L −1 concentration, respectively, to the CBB dye solution and to the synthesized materials. Among the nanocomposites, the sample calcined at 300°C, KaolBT-300, presented the best photocatalytic performance. The addition of the H 2 O 2 oxidant to the solution containing KaolBT-300 at the concentration of 1.5 g L −1 increased the discoloration percentage to 97.31% of the CBB solution dye after 120 min of irradiation. The discoloration kinetics of the CBB dye obeys the pseudo-first-order velocity law. Finally, the reuse of the KaolBT-300 sample in three consecutive cycles of photocatalysis demonstrated a significant adhesion stability of the TiO 2 particles on the clay surface, indicating that it can be used in advanced oxidative processes for the degradation of organic pollutants. reducing the amount of material used and the cost of treatment (Fatimah et al., 2011; Li et al., 2015). The kaolinite, [Si 2 Al 2 O 5 (OH) 4 ], belongs to the clay mineral group and is structured by layer stacking (1:1). Each layer consists of two sheets: a sheet formed by Si 2 O 5 2− tetrahedrons and another formed by alumina [Al 2 (OH) 4 ] 2+ octahedrons, both bonded by common oxygen atoms and the lamellar structure kept by hydrogen bonds (Leonel et al., 2014; Štengl et al., 2014). The hydroxyls (OH) groups present in kaolinite are the most reactive groups and can take part in many chemical reactions (Ming, 2004). In this sense, the incorporation of catalysts in its structure is an effective method for application in catalytic processes.
Jordanian Kaolinite with TiO2 for Improving Solar Light Harvesting Used in Dye Removal
Molecules
TiO2–Kaolinite nanocomposite photocatalysts were synthesized using the sol–gel method, with titanium isopropoxide/HCl as reactants and Jordanian kaolinite clay as a support material. The samples’ TiO2 content ranged from 10% to 70% (m/m). TiO2–Kaolinite composites were characterized using FTIR, SEM, XRF, and XRD. According to XRD measurements of the nano-composite samples, the intensity of the anatase peaks increased as the TiO2 percentage of the composition increased. As the percentage of TiO2 increased, so did the peaks of Ti–O–Si in FTIR. The extent of photocatalytic degradation of Congo-red dye was used to evaluate the photocatalytic activity of the prepared nanocomposites. After four hours under the sun, the percentage of Congo-red degradation ranged from 27 to 99 percent depending on the TiO2 content of the used nanocomposite. Meanwhile, the concentration drop in the dark did not exceed 10%. Photodegradation outperforms traditional treatment methods in terms of target degradat...
Journal of Photochemistry and Photobiology A: Chemistry, 2003
Titanium(IV) oxide (TiO 2 ) nano-particles with various physical properties, which had been prepared by hydrothermal crystallization in organic media (HyCOM) and post-calcination, were used for photocatalytic decomposition of malachite green (MG) in an aqueous suspension under aerated conditions. The amount of MG adsorbed on TiO 2 ([MG] ad ) increased as the surface area of HyCOM TiO 2 increased. The apparent initial rate constant of pseudo zero-order kinetics, k 0 , for decolorization of MG in an early stage (∼15 min) coincided well with [MG] ad , indicating that adsorptivity is a decisive factor for the initial bleaching of MG. However, in a 1 h irradiation experiment, a HyCOM sample with a smaller [MG] ad but improved crystallinity exhibited higher decolorization activity than did HyCOM TiO 2 with the largest [MG] ad , suggesting that this reaction process includes deactivation of the photocatalyst due to deposition of intermediate(s) that had been formed by degradation of MG. Longer irradiation was required for mineralization of MG. Total organic carbon (TOC) in the suspension of HyCOM TiO 2 with improved crystallinity continuously decreased whereas TOC in Degussa P-25 TiO 2 did not decrease any more after 5 h of irradiation, although one-third of the initial TOC still remained in the suspension.
International journal of engineering research and technology, 2015
A set of TiO2-modified montmorillonite mesomicroporous materials, as photocatalysts, was successfully prepared in different ways and evaluated by the photodegradation of 4-nitrophenol (4-NP) in water, since it is a recalcitrant organic pollutant. The effects of photocatalysts' preparation methods on their textural, structural and catalytic properties were tested. To understand the relationship between the photocatalysts structure and performance, these were characterized by X-Ray Diffraction (XRD), UV-spectroscopy, Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDX), Fourier Transform Infrared Spectroscopy (FTIR), X-ray fluorescence (XRF), specific surface area and porosity measurements. A high specific surface area (up to 231 m 2 /g), a mesomicroporous structure and a high stability have been found for the TiCl4-M and TiCl3-M prepared photocatalysts. In addition, to improve the 4-NP degradation, various parameters' effect was studied such as the type of the photocatalyst, its amount loading, the pH of the 4-NP solution and the initial 4-NP concentration. Then, the 4-NP degradation rate has reached 99% only when Anatase Titanium dioxide was supported on montmorillonite, at pH=5, with 0.2 g/100 mL of photocatalyst (TiCl4-M or TiCl3-M) amount and a 4-NP concentration equal to 20 mg.L-1 .
Mediterranean Journal of Chemistry, 2019
In this paper, Clay-TiO2 nanomaterials were synthesized via hydrothermal sol-gel method using Ivorian clays and titanium tetra-isopropoxide as precursors. The synthesized composite was characterized through XRD, SEM/EDX, FTIR and BET surface measurements. The photocatalytic activity of composite towards the degradation of methyl orange (MO), a model pollutant, has been investigated under UV and simulated solar radiation. Comparative experiments done in a solution with and without H2O2 indicate an increase in efficiency for methyl orange removal from the polluted water in the presence of H2O2. The optimized parameters (contact time, amount of nanocomposite and amount of Fe2+/H2O2) allowed to reach removal efficiency up to 60 % of MO. Immobilization of TiO2 on clay facilitate repeated using of nanomaterials, two time.
Preparation of TiO2-activated kaolinite composite for photocatalytic degradation of rhodamine B dye
Bulletin of the Chemical Society of Ethiopia
ABSTRACT. Rhodamine B (RhB) is one of the prominent dyes discovered to be carcinogenic and mutagenic substance present in the ecosystem. Alteration of the characteristics of TiO2 through modification with clay influences the behavior of some organic molecules at its surface, and thus its photocatalytic properties. This study investigates the photocatalytic degradation of RhB using TiO2-activated kaolinite composite (TiO2-AKC). TiO2-AKC was prepared in absolute ethanol and characterized using SEM, EDX, TEM, BET and FTIR. The photodegradation of RhB using TiO2-AKC at room temperature under visible-light was studied at various time intervals and the concentration of RhB was monitored using Ultraviolet-Visible spectrophotometer. Characterisation of TiO2-AKC revealed an adequate distribution of TiO2 over the AKC surface, with an enhanced surface area (TiO2-AKC 808 m2g-1, TiO2 50.0 m2g-1, AKC 20.6 m2g-1) necessary for effective degradation. The degradation was efficient in TiO2-AKC than i...