Preparation And Properties Of Porous Mullite-corundum Ceramics Via Organic Foam Impregnation

With the development and growth of industry,chromium pollution is becoming more and more serious,which seriously endangers human health.At present,porous materials have a wide range of applications in the field of wastewater treatment.Porous ceramics,as one of many porous materials,have the advantages of specific surface area,high hardness,many active sites,good thermal stability and reusability,and porous ceramics are also good carriers,which can achieve loading on the surface as well as inside to achieve the purpose of improving the ability of treating wastewater.Therefore,porous ceramics have a broad application prospect in the field of wastewater treatment.In this paper,porous mullite-corundum ceramics were prepared by organic foam impregnation method with Al₂O₃ and Si O₂as the main raw materials,and lanthanum oxide was loaded on the surface of porous mullite-corundum ceramics to prepare lanthanum oxide-loaded porous mullite-corundum ceramics,and to investigate the adsorption performance of Cr（Ⅵ）wastewater,and to explore the adsorption mechanism of lanthanum oxide-loaded porous mullite-corundum ceramics on Cr（Ⅵ）.adsorption mechanism.The main research elements of this paper are as follows.（1）Polyurethane foam was selected as the organic foam.The effects of alkali treatment and surface modification treatment on the performance of polyurethane foam were investigated.It was shown that the hydrophilicity of the foam polyurethane was significantly improved after the foam polyurethane was treated with 25 wt%Na OH solution in a water bath at 75℃for 2hours,and then treated with 3 wt%SDS solution at 75℃for 2 hours,at which time the foam polyurethane had the largest hanging amount.（2）Aluminum oxide and silicon oxide was selected as the main raw materials,then,porous mullite-corundum ceramics were prepared by organic foam impregnation method.The effects of sintering temperature,holding time and raw material composition on the properties of porous mullite-corundum ceramics were investigated.The results showed that the best performance of the porous mullite-corundum ceramics was prepared,which m（Al₂O₃/Si O₂）was 2.5 sintered at1600°C for 3 hours.At this time,the apparent porosity and compressive strength of porous mullite-corundum was 80.71%and 6.23 MPa,respectively.As well as the pore size distribution porous mullite-corundum of average pore size was 0.4 mm.（3）The porous mullite-corundum ceramics were prepared successfully by 25 wt%La（NO₃）₃ soaking,drying and sintering treatment with a series of characterization of composition and surface morphology was characterized by XRD,SEM,EDS and XPS.（4）The adsorption performance of lanthanum oxide-loaded porous mullite-corundum ceramics on Cr（Ⅵ）was investigated by simulating Cr（Ⅵ）wastewater with potassium dichromate as the Cr（Ⅵ）source.It was shown that the lanthanum oxide loaded porous mullite-corundum has good adsorption performance and reusability for Cr（Ⅵ）.Kinetic and thermodynamic studies showed that the adsorption of Cr（Ⅵ）by lanthanum oxide-loaded porous mullite-corundum ceramics is a chemisorption-based multi-molecular layer adsorption.