Search Results

You are looking at 11 - 20 of 381 items for :

  • Chemistry and Chemical Engineering x
  • Refine by Access: All Content x
Clear All

Abstract  

A spherical polyacrylonitrile–TiO2 composite adsorbent was prepared and its strontium removal potential was investigated. The Langmuir equation fixed well the equilibrium data. The value of ∆H° = 8.943 kJ/mol and ∆G° = 6.291 kJ/mol at 298 K indicate that the adsorption of strontium onto TiO2/PAN composite adsorbent is an endothermic and non-spontaneous reaction. The kinetic process was described by a pseudo-second-order rate model very well.

Restricted access

Abstract  

DSC was used for heat capacity measurements of pure RuO2 in the temperature range from 300 to 1170 K of solid solutions corresponding to the compositions of (Ti1−x Rux )O2 (x ≤0.15 and x ≥0.85) and in the temperature range from 300 to 1550 K of pure TiO2. The analysis of experimental data obtained within 2% of accuracy has shown that the characteristic temperatures representing the harmonic lattice vibrations do not strongly depend on the chemical composition x . It was demonstrated that non-harmonic heat capacity is strongly correlated to x. The existence of additional excess heat capacity was observed with the mixed oxide solid solution samples of low Ru content and explained by the defect formation model.

Restricted access

carrier, which satisfies the environmental and energy requirements. Since Fujishima and Honda [ 1 ] first reported the photocatalytic activity of TiO 2 to generate hydrogen by photocatalytic water splitting in 1972, numerous studies scrutinized the

Restricted access

Abstract  

A new method for the possible incorporation of nuclear wastes has been attempted here by using ceramic matrix of TiO2 as a host precursor for confinement. Hafnium is used as a simulant for actinide high-level waste. After incorporating 181Hf tracer into TiO2 matrix, the leaching property of the resulting matrix was studied in water, sodium chloride and humic acid solutions. The leaching was measured in each of the case by following the radioactivity of 181Hf. TiO2 matrix has also been exposed to γ-radiation in order to simulate the radiation field for nuclear waste. It has been investigated with a nuclear technique called time differential perturbed Angular Correlation (TDPAC) that the lattice structure of titania remains undisturbed even under a strong radiation field. The leaching of 181Hf has also been studied after irradiating the TiO2 matrix with γ-radiation and the leaching behavior was observed not to change from that before irradiation.

Restricted access

conditions and the fact that it can be powered by sunlight, thus significantly reducing the electric power required and therefore the operating costs. Owing to the strong oxidation ability, nontoxicity and long-term photostability, nano-TiO 2 exhibits many

Restricted access
Reaction Kinetics, Mechanisms and Catalysis
Authors:
Mohammad Saleh Ghodrati
,
Mohammad Haghighi
,
Jafar Sadegh Soltan Mohamdzadeh
,
Behzad Pourabas
, and
Ehsan Pipelzadeh

light, which is free and inexhaustible [ 6 ]. Several semiconductors with photocatalytic properties have been developed. The most commonly used semiconductors for waste degradation are TiO 2 [ 9 ], ZnO [ 10 ] and CdSe [ 6 ]. Most studies on

Restricted access
Reaction Kinetics, Mechanisms and Catalysis
Authors:
Ekkachai Kanchanatip
,
Nurak Grisdanurak
,
Raumporn Thongruang
, and
Arthit Neramittagapong

removed in a short time and the broken down products are much less toxic than their parents. Cantavenera et al. [ 7 ] revealed that TiO 2 completely degraded paraquat (20 ppm) under UV light within approximately 3 h. Products from the degradation

Restricted access

influenced by changing either the support or promoter for the synthesis of ethanol from syngas [ 13 – 17 ]. Most previous reports have studied the SiO 2 support with relatively less literature on carbon or Al 2 O 3 supports, and several on TiO 2 support

Restricted access

gas and in liquid phase [ 8 ]. In the last few years, there have been a number of studies and reviews about this process [ 9 – 11 ]. Various researchers compared the efficiency of different semiconductor photocatalysts such as ZnO, TiO 2 , SnO 2 , ZrO

Restricted access

intervening in the effectiveness of photodegradation is adsorption of pollutants on the photocatalyst surface. Many studies measured the adsorption and the kinetics of photodegradation of different compounds on TiO 2 photocatalyst, such as potassium

Restricted access