| Title |
Mg/Al, Co/Mg/Al ir Ni/Mg/Al sluoksniuotų dvigubų hidroksidų sintezė, modifikavimas ir apibūdinimas / |
| Translation of Title |
Synthesis, Modification and Characterization of Mg/Al, Co/Mg/Al and Ni/Mg/Al Layered Double Hydroxides. |
| Authors |
Klemkaitė-Ramanauskė, Kristina |
| Full Text |
|
| Pages |
27 |
| Keywords [eng] |
layered double hydroxide ; hydrotalcite ; reformation ; reconstitution ; morphology |
| Abstract [eng] |
Three layered double hydroxides Mg/Al, Co/Mg/Al and Ni/Mg/Al were successfully synthesized by the low supersaturation method, thermally decomposed and derived mixed metal oxides reformed to layered structures in water and for first time to our knowledge in magnesium nitrate media. XRD measurements provided direct evidence for phase transformation processes during calcination and reformation of layered structure at different temperatures. From XRF and TG analyses data the formulas of synthesized LDH were proposed. Incomplete regeneration of Co and Ni containing LDH samples at room temperature in aqueous media has been observed. However, with increasing temperature up to 80 °C the reconstitution process of LDH proceeds fully. Changes of cations composition after reformation could be explained by the increase of magnesium content when the reconstitution in magnesium nitrate solution followed. The hydration causes the formation of LDH with higher crystallite size in comparison with the LDH samples reformed in magnesium nitrate media. In most of the cases, with increasing the temperature of reconstitution media to 80ºC the crystallite size also increased. Reformation media had a considerable influence to the morphology of mixed metal oxides. Moreover, the effects for nickel or cobalt containing samples were found to be different. Catalysts prepared from LDH containing cobalt were tested in the removal of NOx and nickel containing LDH were tested in gasification gas cleaning. |
| Type |
Summaries of doctoral thesis |
| Language |
Lithuanian |
| Publication date |
2012 |
