Highly hydrophobic TiO2 pillared clay for photocatalytic degradation of organic compounds in water

Ooka, Chihiro; Yoshida, Hisao; Suzuki, Kenzi; Hattori, Tadashi

doi:10.1016/j.micromeso.2003.10.011

Cited by 143 publications

(63 citation statements)

References 34 publications

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“…This band is assigned to charge transfer band for the structural iron present in the octahedral layer of the clay mineral [15]. MMT was almost transparent in the wavelength range longer than 350 nm [16]. In case of Ti-PILM, the broad absorption feature extending towards higher wavelength is because of the presence of TiO 2 pillars.…”

Section: Surface Aciditiesmentioning

confidence: 95%

Facile Synthesis of Dodecatungstophosphoric Acid @ TiO2 Pillared Montmorillonite and Its Effectual Exploitation Towards Solvent Free Esterification of Acetic Acid with n-Butanol

Varadwaj

Parida

2011

Catal Lett

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An acid activated montmorillonite, treated with organic cationic surfactant, i.e. cetyltrimethylammonium bromide (CTAB), was used as a template to prepare TiO 2 pillared montmorillonite taking titanium ethoxide as titania precursor in hydrochloric acid environment. The pillared montmorillonite was further promoted by dodecatungstophosphoric acid impregnation. The as prepared materials were characterized by various spectroscopic and analytical characterization techniques. The catalyst was employed towards a solvent free esterification of acetic acid with n-butanol. The catalyst showed excellent results with 88% conversion and 100% butyl acetate selectivity. It can be recovered and reused readily, making product isolation and catalyst reuse simple.

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Section: Surface Aciditiesmentioning

confidence: 95%

Facile Synthesis of Dodecatungstophosphoric Acid @ TiO2 Pillared Montmorillonite and Its Effectual Exploitation Towards Solvent Free Esterification of Acetic Acid with n-Butanol

Varadwaj

Parida

2011

Catal Lett

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“…This effect is due to the interlayer space expansion originated from the pillaring process [14]. Nevertheless, this swelling effect (related to the starting TiO 2 pillared clay) is not observed when the surfactant is introduced after the pillaring process, in this situation, the BET surface and the TPV decrease.…”

Section: Table1: Cation Exchange Capacity (Cec) and Surfactant Adsorbedmentioning

confidence: 96%

“…The surface and textural properties of clays pillared with inorganic cations depends on the nature of alcoxide used as precursor, the acid of hydrolysis, the relative ratio between the alcoxide and the acid, the pH, the drying process, the calcination temperature, and other parameters [11][12]. The clays pillared with inorganic cations are generally hydrophobic; the hydrophobicity degree depends on the raw clay [13][14][15]. This characteristic would enhance the chances of separation of pollutants from aqueous systems by adsorption because of the facility to remove the adsorbent from the dispersion [16].…”

Section: Introductionmentioning

confidence: 99%

Surface and textural characterization of TiO2 pillared organoclays

Vercelone¹,

Sham²,

Torres³

2015

Matéria (Rio J.)

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TiO 2 organoclays are potential adsorbents for aqueous pollutants and subsequently they could favour the photocatalysis of them. For this reason, the study of their surface and textural characteristics is important for the improvement of those processes. In this work TiO 2 pillared organoclays were studied. The surfactant (hexadecyltrimethilammonium bromide) was introduced post-pillaring or during the pillaring process. The effect of the use of different acids of hydrolysis and different surfactants ratios was investigated. The clays were characterized by thermogravimetric analysis, infrared spectroscopy and nitrogen sorptometry. It was found that the highest adsorption capacity post-pillaring of the surfactant is near to 0.5 times the CEC of the original pillared clay, independently of the amount of surfactant offered. An increment in the amount of the surfactant introduced only increased the ratio adsorbed as ionic pair. In these samples the CEC measured after the adsorption was between 0.26 and 0.47 times the original CEC. It was observed a decrease in the total pore volume and the BET surface for every sample. The surface hydrophobicity of the samples with post-pillaring adsorption was higher than in those with co-adsorption. In conclusion, it was demonstrated that the incorporation of surfactant modifies the surface and textural properties of the material in different extent in accordance with the incorporation stage and the amount of surfactant used.

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“…Water adsorption isotherms of the TNTs were obtained at 15°C in the range of relative pressure to 0.82 (Cahn D-200 microbalance). Surface hydrophobicity of the TNTs was evaluated numerically by using the surface hydrophobicity index (SHI) defined as follows (Ooka et al 2004):…”

Section: Preparation and Characterization Of Tntsmentioning

confidence: 99%

Effects of pore structure and surface chemical characteristics on the adsorption of organic vapors on titanate nanotubes

et al. 2012

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Effects of pore structure and surface chemical characteristics of titanate nanotubes (TNTs) on their adsorptive removal of organic vapors were investigated. TNTs were prepared via a hydrothermal treatment of TiO 2 powders in a 10 M NaOH solution at 150°C for 24 h, and subsequently washed with HCl aqueous solution of different concentrations. Effects of acid washing process (or the sodium content) on the microstructures and surface chemical characteristics of TNTs were characterized with nitrogen adsorption-desorption isotherms, FTIR, and water vapor adsorption isotherms. For the adsorption experiments, gravimetric techniques were employed to determine the adsorption capacities of TNTs for four organic vapors with similar heats of vaporization (i.e., comparable heats of adsorption) but varying dipole moments and structures, including n-hexane, cyclohexane, toluene, and methyl ethyl ketone (MEK), at isothermal conditions of 20 and 25°C. The experimental data were correlated by well-known vapor phase models including BET and GAB models. Isosteric heats of adsorption were calculated and heat curves were established. Equilibrium isotherms of organic vapors on TNTs were type II, characterizing vapor condensation to form multilayers. The specific surface area (and pore volume) and hydrophilicity of TNTs were the dominating factors for the determination of their organic vapors adsorption capacity. The GAB isotherm equation fitted the experimental data more closely than the BET equation. The heats of adsorption showed that the adsorption of organic vapors on TNTs was primarily due to physical forces and adsorbates with larger polarity might induce a stronger interaction with TNTs.

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Highly hydrophobic TiO2 pillared clay for photocatalytic degradation of organic compounds in water

Cited by 143 publications

References 34 publications

Facile Synthesis of Dodecatungstophosphoric Acid @ TiO2 Pillared Montmorillonite and Its Effectual Exploitation Towards Solvent Free Esterification of Acetic Acid with n-Butanol

Facile Synthesis of Dodecatungstophosphoric Acid @ TiO2 Pillared Montmorillonite and Its Effectual Exploitation Towards Solvent Free Esterification of Acetic Acid with n-Butanol

Surface and textural characterization of TiO2 pillared organoclays

Effects of pore structure and surface chemical characteristics on the adsorption of organic vapors on titanate nanotubes

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