Synthesis and Characterization of ZnCaO2 Nanocomposite Catalyst and the Evaluation of its Adsorption/Destruction Reactions with 2-CEES and DMMP

Abstract

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 by GC-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.