| Geopolymer is a kind of inorganic non-metallic cementite with threedimensional network structure which is composed of silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron.They are usually made from industrial wastes or silicoaluminate minerals such as fly ash,blast furnace slag,metakaolin,etc.,and activated by water glass,strong alkali,strong acid solution and other activators.Geopolymer materials have excellent mechanical,chemical,structural and high temperature resistance properties,and have been well applied in construction and other fields.A large number of literatures have studied the preparation technology,characterization method and property test of geopolymer porous materials in depth,but their practical application still needs to be developed.Alkali activators play an important role in the preparation of geopolymer porous materials,affecting the microstructure,mechanical properties and thermal stability properties of the materials.In this paper,the effects of potassium and sodium water glass activators on the properties of geopolymer porous materials were investigated,the microstructure and thermal stability of porous materials were characterized by fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),X-ray powder diffraction(XRD),specific surface area and pore size distribution teste(BET)and thermal gravimetric analyzer(TG),the true density bottle measures the porosity of the porous material,the universal press tests the mechanical properties of porous materials,water flux measurement characterizes the permeability of porous materials.On this basis,potassium water glass was used as the activator to prepare the ground geopolymer tubular membrane,the effects of water glass modulus on microstructure,mechanical properties and temperature resistance of inorganic membrane were studied in detail.Finally,the prepared tubular inorganic membrane was used to wastewater and fluegas,and the filtration effect of the inorganic membrane on carbon black suspended particulate matters and PM2.5/10 was tested.The main results are as follows:(1)The influence of different alkali activators on the specific surface area and mechanical properties of geopolymer porous materials were investigated.And it turns out experimentally,the specific surface area of potassium based geopolymer porous materials was 81% higher than that of sodium based geopolymer porous materials,the compressive strength was 100% higher,and the breaking strength was 54% higher.(2)The influence of different alkali activators on temperature resistance of porous materials based on geopolymer was investigated.Through testing the mechanical properties of porous materials at different temperatures and TG analysis,it is found that potassium based geopolymer porous materials have better thermal stability and lower mass loss than sodium based geopolymer porous materials.After calcination at 1000 °C,the compressive strength of potassium based porous materials is still above 10 MPa.(3)The potassium based geopolymer porous material was further prepared into address geopolymer tubular inorganic membrane,it was found through experiments that,when the potassium water glass modulus is 1.4 M and the ratio of metakaolin,slag,potassium water glass,water and sodium dodecyl sulfate is1:1:1.2:0.25:0.0024,by adjusting the amount of hydrogen peroxide,the slag/metakaolin based geopolymer tubular inorganic membrane had the best performance.(4)Potassium based geopolymer inorganic membrane has good filtration efficiency in water treatment and flue-gas purification.When the added amount of hydrogen peroxide is within the range of 1.04-1.49 wt%,the inorganic membrane can intercept particles in carbon black suspension with the minimum particle size of 1.67 μm,and the removal rate of PM2.5/10 in flue-gas is above 90%.When the added amount of hydrogen peroxide is 1.21 wt%,after calcination at 600 °C for 2h,the removal rate of inorganic membrane to PM2.5/10 was still above 90%. |
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