Preparation,Mechanical Properties And Adsorption Properties Of Porous ZnO

Porous zinc oxide not only has the advantages of high porosity,large specific surface area,etc.,but also has the characteristics of nanomaterials because its pore wall thickness is nanometer.Therefore,it has a wide range of applications in environmental materials,piezoelectric materials,sensing materials,and ion adsorption.In this paper,the Al-Zn alloy is firstly smelted,and then the porous ZnO sample with pore wall size in the range of 80-206nm is prepared by solid solution,corrosion and oxidation by dealloying combined with metal oxidation.The microstructure,microstructure and specific surface area of the microstructure were studied by means of metallographic microscope,X-ray diffraction and scanning electron microscopy.At the same time,the bending strength of porous ZnO samples and their adsorption properties for heavy metal copper ions were measured by electronic universal testing machine and atomic absorption spectrophotometer.The main conclusions were as follows:(1)When the Zn content in the alloy is 35%-65%;the concentration of NaOH etching solution is lmol/L-3mol/L;the oxidation temperature is 400℃-500℃;when the molar ratio of NaOH to Al is 1-2,the porous ZnO sample obtained by laminating ZnO sheets and sheets was obtained.When the temperature of the NaOH etching solution is raised from 25℃ to 40℃,the pore morphology of the porous ZnO sample changes,and the porous structure formed by the overlap of the sheet and the sheet becomes a rod-like array structure.(2)The bending strength test of the sample shows that when the Zn content in the alloy is between 35%and 65%,the porosity of the porous ZnO sample is gradually reduced and the bending strength is gradually increased with the increase of Zn content.The flexural strength of porous ZnO prepared by alloy with Zn content of 65%is 25MPa;when the concentration of NaOH corrosive solution is 1 mol/L to 2mol/L,the porosity of porous ZnO sample increases with the concentration of corrosive solution Increase,the bending strength decreases.When the concentration of corrosive solution is 3mol/L,the bending strength of the sample will increase to some extent due to agglomeration.When the oxidation temperature is between 400℃ and 500℃,the pores of porous ZnO ceramics increase with the increase of oxidation temperature.The rate is reduced,the wall thickness is thickened,and the bending strength of the sample is gradually increased.The bending strength of the sample is 32MPa when oxidized at 500℃.The porosity of the porous ZnO sample increases with the increase of the amount of NaOH in the etching solution.The intensity gradually decreases.In the corrosion temperature range of 25℃ to 55℃,as the corrosion temperature increases,the porosity of the sample increases,and the bending strength of the sample gradually decreases.(3)The adsorption performance of heavy metal copper ions by porous ZnO was found.When the adsorption time was within 0-120 min,the concentration of copper ions in the solution gradually decreased with the increase of adsorption time.When the adsorption time was 120 min,the porous ZnO was heavy metal.The adsorption of copper ions is saturated.With the decrease of Zn content in the alloy,the porosity of the porous ZnO obtained under the corresponding conditions increases and the specific surface area increases,which makes the adsorption capacity of heavy metal copper ions gradually increase.The Zn content is The adsorption capacity of porous ZnO for heavy metal copper ions was 19.48mg/g in 35%alloy;the porosity and ratio of porous ZnO ceramics obtained under corresponding conditions increased with the concentration of NaOH in corrosion solution increased from lmol/L to 3mol/L.The surface area increased,which made the adsorption performance of porous ZnO samples to heavy metal copper ions increase.The adsorption capacity of heavy metal copper ions in porous ZnO ceramic samples with NaOH concentration of 2mol/L was 18.62mg/g.The molar ratio of NaOH to Al increased from 1:1 to 2:1,and the pore wall of the porous ZnO sample was thinned and the specific surface area was increased,so that the adsorption performance of heavy metal copper ions was enhanced.When the molar ratio of NaOH to Al was 2:1,A sample of porous ZnO adsorption amount of Cu ions 18.3 8mg/g.