Showing papers by "Elimame Elaloui published in 2019"

Effect of dysprosium ion (Dy3+) doping on morphological, crystal growth and optical properties of TiO2 particles and thin films

Abstract: Dy3+ doped (0.5, 2.5, 5 and 7.5 wt %) TiO2 particles and thin films were obtained by modified alcoholysis-sol-gel route using tetrabutyl orthotitanate as a precurspor. By controlling the hydrolysis of this precursor through alcoholysis reaction, monodisperse and spherical TiO2 particles were obtained. X-ray diffraction and Raman results confirmed that the Dy3+ doped TiO2 particles are composed of only anatase phase. The Dy3+ doping inhibited any phase transformation and slowed down the particle growth of anatase TiO2. Scanning electron microscopy of bare TiO2 showed monodisperse, spherical and non-aggregated particles. In contrast, the Dy3+doped TiO2 samples exhibited poor dispersity. The luminescence spectra show three characteristic bands at 481, 577 and 683 nm, which are due to 4F9/2 → 6H15/2 (blue), 4F9/2 → 6H13/2 (yellow), and 4F9/2 → 6H11/2 (red) transitions of trivalent Dy3+ ions. The photoluminescence study revealed the dependence of the luminescent intensity on dopant concentration in TiO2 particles.

The Effect of Surfactant Chain Length and Type on the Photocatalytic Activity of Mesoporous TiO2 Nanoparticles Obtained via Modified Sol-Gel Process

Abstract: Mesoporous amorphous and nanocrystalline titanium dioxide were prepared by simple and environmental friendly modified Sol-Gel method using cationic (C14TAB, C16TAB, C18TAB) and nonionic (Plantacare UP K55) surfactant as pore forming agent. The obtained particles were characterized by BET, TEM, FT-IR and XRD techniques. The effect of cationic surfactant chain length and type of template on the photocatalytic activity of as prepared TiO2 nanoparticles were investigated by the degradation of rhodamine B in water solution under UV irradiation. The results indicated that this process was well described by pseudo-first order kinetic model. All the prepared titanium dioxide particles with cationic and nonionic surfactant exhibited higher performance for rhodamine B photo-degradation. The sample with large pore size and small particle size which obtained by using C18TAB surfactant showed high photocatalytic activity compared with the others samples and commercial P25. The mechanism of photocatalytic degradation of rhodamine B was proposed based on the degradation products determined by GC/MS and LC/MS. The performance of the recycled TiO2 as photocatalyst was investigated.

Optimized Activation of Bentonite for Adsorption of Magnesium and Cadmium from Phosphoric Acid

Abstract: The adsorption of magnesium (II) and cadmium (II) from industrial phosphoric acid onto 4 samples of clays: crude (a), purified (b), activated (c) and purified-activated (d) bentonite have been studied using a batch adsorber. The parameters that affect the magnesium (II) and cadmium (II) adsorption, such as bentonite amount, temperature, contact time and solution pH have been investigated and optimized conditions determined (bentonite amount 12g/ 100mL of industrial phosphoric acid; temperature 293.15 K; contact time 15 min; pH 1.78±0.1). The loading capacity values were found respectively to be 51.21%and 56.25% for magnesium and cadmium using the purified-activated bentonite.