The aim of this work was to apply the many various oxidation agents namely H2O2, K2S2O8 and Fe2+ on the aqueous solution of vitamin B12 with the presence of ZnO. The results indicated that the use of the mixture of H2O2 and K2S2O8 in suspension of vitamin B12 and ZnO gave a maximum efficiency percentage about 95.85% in 12 min; it was higher than that without the addition of oxidation reagent 79.33% in the same time. The obtained results demonstrated that the activation energy for this photoreaction without the addition of oxidation agent was more than that the apparent activation energy value with the used mixture of H2O2 and K2S2O8. The thermodynamic study showed that both reactions were endothermic, less-random and non-spontaneous. The ΔH# with the oxidant agents (31.43 kJ mol-1) is less than that without using oxidant agents (35.81 kJ mol-1). Moreover, the addition of series of oxidant agent solution to vitamin B12 solution led to change the photocatalytic activity for decolorization of vitamin B12 in suspension solution of ZnO, and was found the activity sequence as follows: (H2O2 + K2S2O8) > (H2O2 + Fe(II)) (Fenton reaction) > (H2O2) > (K2S2O8) > (without the oxidation agents) > (K2S2O8 + Fe(II)) > Fe(II).

T hIs research compares the addition of some oxidant agents such as Fe 2+ , h 2 O 2 and mixture from both to aqueous solution of dispersive yellow 42 dye, which regarded as an organic contaminant. This work performed during the dark reaction and photo reaction under artificial UV-A light (hPML-125 watt). In reality, the addition of the oxidant agents leaded to raise the light resistance of this dye to decolorize, this results can be used to increase the life time for textile materials which painted by this dye. The removal percentage without addition oxidant agent at 20 o C was decreased from 32.710 % to 21.445, 11.439 and 8.785% for addition Fe 2+ , h 2 O 2 and mixing of both respectively. Moreover, the decolorization percentage for mention materials was depressed from 94.444 to 60.869, 4.163 and 16.044 respectively. The effect of temperature determined with chose Fe 2+ as oxidant agent and compared with reaction without any addition, because the change is less compared with the other studied cases. The kinetic study of the photo-decolorization process of this dye demonstrated that the generated response is pseudo-first order. The Fenton and photo-Fenton improve the resistance of dye to decolorize during illuminated by light.The dye removal rates depress with the temperature increases from 288 K to 303 K; that due to the dark reaction is exothermic, nonspontaneous and obeys the physical adsorption depending on the values of enthalpy and free energy. In the contrast, the responsed of photodecolorization for this dye is found to be endothermic m non spontaneous and less random.

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Thin films of nanometer sized cadmium sulfide were directly prepared by aerosol-assisted chemical vapor deposition (AA-CVD) method, cadmium ethyl xanthate complex was used as precursor material at 225 o C, 250 o C and 275 o C. The thermal decomposition of complex was characterized by thermal analysis, (thermogravimetric analysis (TGA) and a differential scanning calorimetry (DSC)). The prepared CdS thin films have been characterized by XRD and SEM-EDX analysis. TGA curves ensured that the rapid decomposition of [Cd(S2COEt)2] gives a CdS in single step between 150 o C and 200 o C. XRD patterns confirmed that the CdS particles crystalized as a hexagonal crystallographic phase at low temperatures. The grain size of particles increased with increasing the preparation temperatures from 225 o C to 275 o C,. The spherical CdS nanoparticals were observed in SEM analysis.