Preparation Of Cu-based Complex Metal Oxide Drived From Hydrotalcites Precursor And Its Catalytic Properties

CuNiAl-LDHs were synthesized by coprecipitation method using Cu （NO3）2·3H₂O,NiNO3·6H₂O, Al （NO3）3·9H₂O, NaOH and Na2CO3as raw materials. And then thesynthesized hydrotalcite-like were calcined to obtain the highly dispersed Cu basedcomplex metal oxide as catalyst. The crystal structure, surface chemical structure andthermal stability of hydrotalcite-like compounds and complex metal oxides werecharacterized by FT-IR, XRD, SEM and DTA-TG. Futhermore, the catalytic performancesof composite metal oxide for ClO2catalyatic oxidation of phenol were studied, using CODremoval rate as characterization parameters. The influences of reaction conditions oncatalytic oxidation were investigated. The concrete content is as follows:1) CuNiAl-LDHs were synthesized by coprecipitation method，and the influences ofmaterial component ratio, reaction pH and crystallization time on the structure ofCuNiAl-LDHs were investigated. XRD results show that the optimal synthesis parameterswere1:3:2molar ratios of Cu, Ni and Al,8-10of pH and6h of crystallizing time. FT-IRanalysis shows that the alkaline co-precipitation method could generate a hydrotalcite-likecompounds containing OH-、CO₃^2-、H₂O. SEM shows that CuNiAl-LDHs had layeredstructure, single crystal phase and oderly structure.2) Cu-based composite metal oxides were prepared by calcinations of CuNiAl-LDHsprecursor, and calcinations temperature and calcinations time on the structer of compositemetal oxides were studied. XRD results indicate that calcination temperature influnced thescatter of active component and the surface area. DTA-TG analysis show that the weightloss of CuNiAl-LDHs below200℃indicated the evaporation of interlayer water andcombined water, and the weight loss in the200-400℃indicated the loss of interlayeranions (the CO₃^2-) and hydroxyl water.3) The catalytic performances of composite metal oxide for ClO2catalyatic oxidationof phenol were investigated. The effects of preparation conditions on phenol CODremoval ratio were studied. The maximum COD removal ratio for catalytic oxidation ofcomposite metal oxide was65.7%, when composite metal oxide catalyst was synthesizedunder the contions of1:3:2molar ratio of Cu, Ni and Al,8-10of pH value, the6h ofcrystallization time,600℃of calcination temperature.4) The effect of reaction conditions of chlorine dioxide catalytic oxidation of phenolwastewater on COD removal rate. The results indicate the optimal reaction conditions were catalyst dosage of3g/L, reaction temperature of room temperature （20℃）, reactiontime of60min, the reaction pH of7.5) The stability of LDHs-600was investigated. The results show that COD removalratio was more than60%when the catalyst was reused for eight times.6) The chlorine dioxide catalytic oxidation of phenol in wastewater using compositmetal oxides as catalyst was a first order reaction.