Grinding (solvent-free) method was used as a superior technique to prepare mesoporous photocatalysts of ZnO, ZnS, ZnO / ZnS, CdO, CdS and CdO / CdS-SBA-15. In this technique, the nitrate, acetate and chloride salts of zinc and/or cadmium were grinded with as-synthesized SBA-15 as a mesoporous material. The controllable sulfurationis was used to prepare ZnS, ZnO/ZnS, CdS and CdO/CdS-SBA-15 at temperature of 80oC. The advantages of grinding technique were: i) the elimination of solvent and thus decrease of expense and ii) the complete incorporation of metal salts in the nanochannel of mesoporous material in a short time. X-ray powder diffraction, N2 adsorption-desorption and FT-IR spectroscopy were used to characterize the prepared materials. The highly dispersed semiconductors in SBA-15 demonstrate an active photodegradation of Congo red in aqueous solution. The nanocomposites of ZnO/ZnS and CdO/CdS in channels of SBA-15 showed the highest photocatalytic activity. The photocatalytic activity of ZnO-, ZnS- and ZnO/ZnS-SBA-15 were also dependent on the salt precursor of zinc. The prepared composite photocatalysts of zinc/SBA-15, by using ZnCl2 as salt precursor, indicated the higher activity.

Cadmium oxide (CdO) thin films were deposited on the glass substrate by the modified SILAR method, using cadmium acetate dihydrate and ammonium hydroxide aqueous solution as precursors. The structural, surface morphological, elemental composition and optical properties of the deposited films were investigated via X-Ray Diffraction (XRD), scanning electron microscopy, EDAX, optical absorption, photo luminescence and FT-IR spectroscopy. The XRD analysis reveals that the films were polycrystalline with cubic structure. Both crystallinity and grain size were found to increase with increasing solution concentration. The energy-dispersive spectroscopic analysis confirmed the presence of Cd and O elements. The films exhibited a maximum transmittance (50%-70%) in the infra-red region. Transmittance was found to increase with increasing precursor concentration and estimated band gap energy (Eg) was in the range of 2. 17 – 2. 21 eV.

Cadmium oxide rhombus-shaped nanostructure was synthesized using hydrothermal process followed by heating treatment. Clearly, X-ray diffraction pattern demonstrated the formation of CdO crystalline phase. Scanning electron microscopy (SEM) showed that the obtained rhombus-like structure is composed of nanoparticles with the average size of 29 nm. In addition, we evaluated adsorption of organic dye i.e. Congo red from water using the prepared CdO rhombus like microstructure. UV-visible absorption spectroscopy was used to record the adsorption behavior. It was found that the removal process is performed via electrostatic absorption mechanism. The maximum adsorption capacity of CdO rhombus structures (0.01 g) for Congo Red (CR) in the concentration range (5-50 mg L-1) studied, as calculated from the Langmuir isotherm model at 250C and neutral pH, was found to be 41.20 mg g-1.

Template synthesis is a powerful method for the preparation of nanoscale materials with specific size and shape. Cadmium oxide (CdO) nanoparticles were prepared by using sodium dodecyl sulfate (SDS), Cd(OAc)2.2H2O and sodium hydroxide as starting materials. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The XRD pattern proves that the final product has cubic phase and the particle size diameter of the nanoparticles are 36.4 nm. The SEM was used for direct visualization of the size and shape of the nanoparticles. The morphology of the CdO was found nanospherical. Antibiotics are a major class of drugs included in the designation of emerging contaminants, representing a high risk to natural ecosystems. We studied the degradation of Sulfathiazole antibiotic by nanosized CdO under ultraviolet irradiation. Various experimental parameters such as initial Sulfathiazole (STZ) concentrations, initial CdO concentration and initial pH were investigated. According to the results this method can be good performance in removal of Sulfathiazole.

In the present research, CdO nanoparticles were synthesized using the chemical reduction method at six different temperatures. Due to have different calcination temperature, the nanoparticles were synthesized in different sizes. Structural and optical properties of nanoparticles were characterized using XRD and UV-Vis spectroscopy. Based on the results, the CdO nanoparticles have cubic structure with the particles size of 27 – 60 nanometer. To investigate the photocatalytic properties of CdO nanoparticles, dye degradation effect in the presence of CdO nanoparticles and UV beam was studied in a batch reactor as a function of time at three different pH values. Studies showed that the optical absorption was decreased as a function of time. The photocatalytic reaction revealed that the dye degradation in methylene blue was speeded up with increasing the pH value.