Gotowa bibliografia na temat „Oxy-hydroxide nanoparticles”

ZnO nanoparticles synthesized by precipitation method using zinc nitrate tetrahydrate and sodium hydroxide as starting materials. ZnO nanoparticles synthesized exhibited a crystalline structure with hexagonal structure. The average primary size of ZnO synthesized around 22.71 nm and the specific surface area around 28.17 m2/g. EPDM foam used oxy-bis benzene sulfonylhydrazide (OBSH) as blowing agent and ZnO nanoparticles synthesized as activator of sulphur vulcanization. The effect of ZnO nanoparticles synthesized compared with conventional ZnO on cure characteristics and morphology of EPDM foam were investigated. The result showed that the maximum torque (MH) increased, optimum cure time (t90) and scorch time (T5) decreased with increasing ZnO nanoparticles synthesized loading. The cell structure of EPDM foam was spherulite and smaller when increased ZnO nanoparticles synthesized loading. The compressive load value increased with increasing ZnO nanoparticles synthesized loading which may be attributed to thickness of the cell wall and hardness increased. ZnO nanoparticles synthesized could be reduced successfully from 5 to 3 phr (40%) for EPDM foam.

A parent Mg-Al-LDH was upgraded in its adsorption properties due to the incorporation of tri-metal species oxy(hydroxide) nanoparticles obtaining Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite for the phosphate recovery from simulated urban treated wastewater. The physicochemical properties of the synthesized Mn2+/Zn2+/Fe3+/Mg-Al-LDH make promising for real application without being environmentally harmful. The performance of Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite was evaluated through batch adsorption assays. The support of iron, manganese, and zinc (oxy)hydroxide nanoparticles onto the parent Mg-Al-LDH structure was performed by precipitation, isomorphic substitution, and complexation reactions. The main improvement of the Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite was the highest phosphate adsorption capacity (82.3 mg∙g−1) in comparison to the parent Mg-Al-LDH (65.3 mg∙g−1), in a broad range of concentrations and the effective phosphate adsorption at neutral pH (7.5) near to the real wastewater effluents conditions in comparison to the conventional limitations of other adsorbents. The effectiveness of Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite was higher than the conventional metal LDHs materials synthesized in a single co-precipitation step. The phosphate adsorption onto Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite was described to be governed by both physical and chemical interactions. The support of Mn2+/Zn2+/Fe3+ oxy(hydroxide) nanoparticles over the parent Mg-Al-LDH was a determinant for the improvement of the phosphate adsorption that was governed by complexation, hydrogen bonding, precipitation, and anion exchange. The intra-particular diffusion also described well the phosphate adsorption onto the Mn2+/Zn2+/Fe3+/Mg-Al-LDH composite. Three specific stages of adsorption were determined during the phosphate immobilization with an initial fast rate, followed by the diffusion through the internal pores and the final equilibrium stage, reaching 80% of removal and the equilibrium within 1 h. The Mn2+/Zn2+/Fe3+/Mg-Al-LDH was strongly selective towards phosphate adsorption in presence of competing ions reducing the adsorption capacity at 20%. The Mn2+/Zn2+/Fe3+/Mg-Al-LDH has limited reusability, only 51% of the adsorbed phosphate could be recovered in the second cycle of the adsorption-desorption process. Around 14% of phosphate was loosely-bond to Mn2+/Zn2+/Fe3+/Mg-Al-LDH which brings the opportunity to be a new source of phosphorus. The use of eluted concentrates and the final disposal of the exhausted adsorbent for soil amendment applications can be an integral nutrient system (P, Mn, Zn, Fe) for agriculture purposes.

The Ir/AlO(OH) catalyst was prepared by sol-gel method and used for selective hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroniamine (p-CAN). The mechanism of p-CNB hydrogenation over the catalyst was discussed. The hydrogen bond between the surface hydroxyl groups of the catalyst and the nitrogen present in p-CNB facilitated the hydrogenation of nitro group. On the other hand, the formation of hydrogen bond between the hydrogenation product and water promotes the rapid desorption of the hydrogenation product on the surface of the catalyst. Thus the activity and selectivity were greatly promoted.