Adsorption Of Cu(Ⅱ) On Amorphous Magnesium-aluminum Oxide Catalyst

Hydrotalcite-like compounds (LDH) is a sort of anionic clays with double-layer structure. It is layered mixed hydroxides containing exchangeable anions. This material has memory effect and adjustable aperture. The anionic clays were found application in agriculture, industry, medicine and other field. Because of surface basicity and memory effect, calcined Mg3Al-CO32"-LDH(LDO) can be used in treatment of wastewater as adsorbent of heavy metal cations on the interface. It can be used as catalytic materials precursor because of its unique structure and properties so that it has high specific surface area and good water thermal stability. It would have higher catalytic efficiency if LDHs load precious metal.Mg3A1-CO32+-LDHs were synthysized by the constant co-precipitation method, and a series of modified products of LDH were obtained by ion exchange and calcinations. The LDHs and synthesized compounds were characterized by XRD, SEM, TEM, FT-IR and BET. Calcined Mg/Al-layered double hydroxides were tested for removal of copper from simulated wastewater. Adsorption experiments were carried out as a function of pH before and after reaction, and contact time. Adsorption mechanism and regeneration of absorbent were investigated. MgsAl-NCV—LDH was modified by sodium citrate. Then modified sample is used to react with chloride gold acid. The classical method that citric acid reduction chloroauric acid and the property of LDH were used to get small particle size of nanometer gold particles for CO low temperature oxidation.The study indicated:LDO can effectively adsorb Cu solution and the adsorption equilibrium time was2h. Changes of pH had few effect on the adsorption reaction. Equilibrium experimental data were well represented by Langmuir isotherm using linear methods, and the adsorption process was spontaneous and endothermic according to the thermodynamic study Adsorption kinetics results showed that the adsorption followed pseudo-second-order model. From the adsorption mechanism study, it was the interface adsorption between Cu (Ⅱ) and LDO in the process of recovery, which accounted for the most After recovery it changed to micropore adsorption and the sorption amount of Cu (Ⅱ) arising from this mechanism may be evaluated to be very low according to the mean pore volumes of LDH and CLDH.Citric acid were introduced into the structure layer of LDH, which enlarged the interlayer spacing And it would be favorable to bind with other compounds to get catalytic materials precursor Then the modified Mg-AI hydrotalcite was reacted with chloroauric acid The classical method that citric acid reduction chloride gold acid and the property of LDH were used to get small particle size of nanometer gold particles for CO low temperature oxidation.