Study On Controlled Synthesis And Adsorption Performance Of Mesoporous Alumina

This work uses proton-consuming propylene oxide as the gel accelerator of inorganic aluminum salt,in the presence of cationic quaternary ammonium salt surfactants or non-ionic block copolymer templating agents,respectively in alcohol and water systems Three kinds of mesoporous alumina materials were synthesized under a mild condition of 40℃.The structure of the materials was systematically characterized by XRD,N₂adsorption,TG,SEM,and TEM methods,and they were used in simulated dye wastewater.The adsorption performance of Congo Red was comprehensively evaluated using different adsorption models and kinetic equations.The main findings are as follows:（1）A mesoporous alumina material synthesized in a system composed of aluminum nitrate-cationic quaternary ammonium salt surfactant template-alcohol-propylene oxide（PO）,its specific surface area,pore volume and pore size can be passed through the template alkyl The adjustment of the chain length and the change of the PO/Al molar ratio of the system are controlled and synthesized in the range of 318.92～455.54m²/g,0.29～0.64cm³/g and3.7～7.4nm.The results of the study on the adsorption performance of Congo red in the simulated dye wastewater show,The maximum adsorption capacity can reach 751.28mg/g,the adsorption process follows the Langmuir model,the removal rate of Congo red in100mg/L dye solution can reach 80%in 4 minutes,and the removal rate of Congo red solution reaches 100%after 15 minutes,which is better than Most of the mesoporous alumina materials that have been reported publicly conform to the quasi-second-order kinetic equation.The thermodynamic analysis shows that the adsorption of Congo red dye on the mesoporous alumina is an endothermic process,and increasing the temperature is helpful Increase in volume.（2）After replacing the template agent in the above system from cationic quaternary ammonium salt to non-ionic block copolymer,by controlling the gelation of the system,the specific surface area is 176.04～308.19m²/g and the pore volume is 0.29～0.53cm³/g.And the mesoporous alumina material whose pore size is adjusted in the range of 5.3～6.2nm,its adsorption capacity of Congo red in simulated wastewater can reach up to 789.24 mg/g,and the adsorption process also conforms to the Langmuir isotherm model.The removal rate can reach 80%within 6 minutes,and the removal rate of Congo red solution reaches 100%after20 minutes.It has similar adsorption capacity to mesoporousγ-Al2O3 hollow microspheres,but the adsorption performance drops to 56.5%after 6 cycles.（3）the more environmentally friendly aluminum chloride-cationic quaternary ammonium salt surfactant template-H₂O-PO system,the specific surface area is282.79-383.49m²/g,the pore volume is 0.52-1.18cm³/and the pore size is in the range of6.2-9.1nm.The research results of the adjusted mesoporous alumina material on its adsorption performance show that the maximum adsorption capacity of Congo red dye is as high as1012.64mg/g,which is much higher than the adsorption results reported in the traditional literature.It can remove 100mg/L Congo red solution.The rate can reach 86%within 2minutes,and the removal rate of Congo red can still reach 82.3%after 6 cycles of recycling.Compared with the traditional synthesis method,the method used in this work is more environmentally friendly,gentle and efficient,and easier to be synthesized on a large scale.The adsorption performance of the obtained material is also much better than the results reported in most documents,which is expected to be used in industry Play an active role in the treatment of dye wastewater.