No abstract

The present study investigates the efficiency of adsorption and photodegradation catalyzed by TiO2, ZnO, CdS and Co3O4 on the removal of methylene blue dye, in different pH values (4, 6, 9 and 11). The photocatalytic degradation of methylene blue dye in aqueous catalysts TiO2, ZnO, CdS and Co3O4 suspension follows apparent after 0.5 h of photodegradation a first-order kinetics. The photodegradation efficiency of methylene blue was fast in the present condition (pH 11, pH 6, pH 6 and pH 4) and slower in (pH 4, pH 11, pH 11 and pH 11) of ZnO, TiO2, CdS and Co3O4, respectively. The highest adsorption capacity as follow: TiO2 > ZnO ≈ CdS ≈ Co3O4, while the photocatalytic activity: ZnO > TiO2 > CdS > Co3O4.

No abstract

No abstract

Multiwall carbon nanotubes (MWCNTs) have been hydrothermally prepared using polyethylene glycol as the carbon source. Herein, new MWCNTs composites with high adsorption capacity were prepared and applied as efficient adsorbents for adsorption of maxilon blue dye (GRL) from aqueous solution. The morphologies of the MWCNTs were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform-infrared (FT-IR) spectroscopy. The adsorption property of maxilon blue (GRL) from aqueous solution onto MWCNTs was studied as a function of mass dosage, pH of solution, initial dye concentration and temperature. The adsorption of GRL depends on the initial pH of the solution with maximum uptake occurring at about pH 10. The maximum adsorption capacity of prepared MWCNTs was 260.7 mg/g. Langmuir, Freundlich and Temkin isotherms were applied to fit the experimental data. The Freundlich equilibrium isotherm fitted well the experimental data indicating the homogeneity of the adsorbent surface sites. Thermodynamics parameters were studied the changes in free energy (ΔG 0 ), enthalpy (ΔH 0 ) and entropy (ΔS 0 ) during adsorption. It is noticeable that the adsorption of GRL dye onto MWCNTs was a spontaneous and endothermic process and indicates that the adsorption is favored at high temperature.