Study On Catalytic Performance Of M/Al Composite Oxides

With the continuous development of economy and the expansion of industrialization,the problem of environmental pollution is becoming more and more serious.M/Al composite oxide materials contain both MO_x,Al₂O₃and MAl₂O₄,among which both MO_xand MAl₂O₄have certain photocatalytic performance.The two components are uniformly dispersed on the surface of Al₂O₃with high stability and large specific surface area,which can increase their response ability to visible light,and have strong adsorption and catalytic performance under visible light,which makes their practical significance in the research on the treatment of industrial wastewater more important.Based on the solid-phase method and coprecipitation method,M/Al composite oxide materials was synthesized under different calcination atmosphere.The composition,structure,morphology,pore structure,specific surface area of the composite material to influence on adsorption catalytic activity were researched through testing its adsorption catalytic properties by simulated dye wastewater,and XRD,TEM,BET,DRS,XPS method for material characterization.Firstly,M/Al composite oxides were prepared by solid phase method with different metal oxides as the corresponding M source and Al₂O₃as the aluminum source.In the presence of reducing template,the composite oxides were uniformly ground in a certain proportion,then calcined in air and nitrogen atmosphere.The adsorption catalytic activity of M/Al composite oxide synthesized was investigated by using M/Al composite oxide as adsorption catalyst and the aqueous solution of azo dye methyl orange as simulated wastewater.The results showed that the Cu/Al composite oxide prepared by calcination at450℃under nitrogen atmosphere with Cu:CTAB:Al molar ratio of 1:0.1:4 and CuO as the source of Cu,Al₂O₃as the source of Al and CTAB as the reducing template displayed the best adsorption catalytic performance for the removal of methyl orange.Secondly,using different metal salts as the corresponding M salts and aluminum nitrate as the aluminum source,the composite precursors were prepared by co-precipitation method,and then the M/Al composite oxide materials with different properties were achieved under different calcination atmosphere.The synthesis conditions of M/Al composite oxide with good selectivity and high adsorption catalytic activity were studied through the removal reaction of azo dye wastewater solution over M/Al composite oxide.The results showed that the Cu/Al composite oxide synthesized by the co-precipitation method with copper nitrate as the source of Cu,aluminum nitrate as the source of Al,ammonium carbonate as the precipitator,the molar ratio of Cuto Al is 1:4,and calcined at 450℃under nitrogen atmosphere displayed the best adsorption catalytic performance for the removal of methyl orange.Thirdly,M/Al composite oxide composite material was prepared by using aluminum extracted from industrial waste fly ash instead of commercial aluminum nitrate as aluminum source combining co-precipitation method,which not only improved the utilization value of fly ash,but also solved the problem of aluminum source tension.The results showed that the Cu/Al composite oxide extracted by acid leaching method and prepared by co-precipitation method had a good removal effect on methyl orange,and almost the same performance can be achieved after recycling.Finally,the influence of the composition,structure and specific surface area of the composites on the adsorption catalytic activity were investigated through the adsorption catalytic performance test and the characterization analysis of the materials.Cu₂O and spinel CuAl₂O₄in the Cu/Al composite oxides had catalytic effect on the removal of methyl orange.The increase of Al₂O₃content increased the specific surface area of the composite oxides,which was conducive to the dispersion of the active components.However,the presence of Copper and CuO had no adsorption and catalytic effect on the removal of methyl orange.