فهرست مطالب mir hasan hosseini

In this work, ZnCaO2 (zinc oxide-calcium oxide) nanocomposite were synthesized at different temperatures (500-700°C) by sol-gel method based on polymeric network of polyvinyl alcohol (PVA). The synthesized samples were characterized by SEM/EDAX, FT-IR and XRD techniques. It was found that synthesized nanocomposites have 1.62, 2.05 and 13.91%wt of CaO, respectively. The obtained results show that each particle of nanocomposite has been made of a CaO core which is completely covered by ZnO layers. The smaller average diameter of synthesized nanoparticles (at 600°C) calculated by XRD technique found to be 33 nm for prepared ZnCaO2 nanocomposite. This compound has been used as adsorbing removal for agricultural pesticide. The 2-chloroethyl ethyl sulfide (2-CEES) and dimethyl methyl phosphonate (DMMP) are for the class of compounds containing phosphonate esters and sulfurous with the highly toxic that used such as pesticides, respectively. The adsorption/destruction reactions of 2-CEES and DMMP have been investigated by using ZnCaO2 nanocomposite. Reactions were monitored byGC-FID (gas chromatography) and FT-IR techniques and the reaction products were characterized by GC-MS. The results of GC analysis for the weight ratio of 1:40 (2-CEES/DMMP: ZnCaO2 nanocomposite) at room temperature showed that 2-CEES molecule is destructed about perfectly in the n-pentane solvent by nanocomposite after 12 hours and it changed to less toxic chemical hydrolysis and elimination products and identified via GC-MS (gas chromatographymass spectrometry) instrument, were hydroxyl ethyl ethyl sulfide (HEES) and ethyl vinyl sulfide (EVS), respectively. On the other hand, the 31PNMR analysis emphasized that 100% of DMMP molecule after 14 hours in the n-pentane solvent was adsorbed.

Pure and ZnO-doped Ni0.1Co0.9Fe2O4 catalyst were prepared by co-precipitation method and thermal decomposition in air calcinated at 400-700°C and that treated with different amounts of zinc nitrate (0.46-2.25 w% ZnO). X-ray powder diffractometry, scanning electron microscopy (SEM) and BET analysis of nitrogen adsorption isotherms investigated the crystalline bulk structure and the surface area of pure and doped samples, respectively. The hydrogen peroxide decomposition activity was determined by oxygen gasometry of the reaction kinetics at 20-40°C. The results revealed that the treatment of Ni0.1Co0.9Fe2O4 with ZnO at 400-700°C brought about a significant increase in the specific surface area and catalytic activity of Ni0.1Co0.9Fe2O4 on decomposition of hydrogen peroxide. However, the catalytic activity of H2O2 decomposition on Ni0.1Co0.9Fe2O4 calcined at different temperatures was found to show a considerable increase by doping with ZnO. They were discussed with UV/VIS spectroscopy which the energy band gap of the synthesized Ni0.1Co0.9Fe2O4 nano structure was calculated to be ~5 eV.