Study On Preparation And Adsorption Performance Of Red Mud-based Geopolymer Porous Materials

Red mud is industrial solid waste generated during the process of refining alumina,and has strong alkaline and high pollution.How to deal with the large amount of red mud discharged in the alumina production process,reduce the environmental pollution and utilize it comprehensively,is a serious challenge we have to face.In recent years,with the development of industry and urbanization process accelerated,the emissions of waste water has heavy metal is increasing,which is not only destroyed the ecosystem,but also posed a threat to human survival.To solve these problems,The paper,referred to the reaction mechanism and conditions of phosphoric acid-based geopolymer,synthesized the red mud-based geopolymer,which is used red mud as the raw material,phosphoric acid as the as the acid-activate agent.With compressive strength as the pHysical performance indicators,the paper studied the effect of different curing system,amounts of H₃PO₄ and H₂O on performance of red mud-based geopolymer.It can be studied that different mass ratio of H₃PO₄/Red mud and H₂O/Red mud on the ability of red mud-based geopolymer to adsorb Cu²⁺ after a certain processing.Static adsorption experiment of Cu²⁺ is studied by Red mud-based geopolymer prepared by the best conditions.With performance on Cu²⁺adsorption as indicators,the red mud-based geopolymer porous materials were prepared by used H₂O₂ and K12 as foam agent at the process of preparing red mud-based geopolymer.Static adsorption experiment of Cu²⁺ be studied by red mud-based geopolymer porous materials prepared by the best conditions.The principal conclusions are as follows:（1）when the mass ratio of H3PO₄/Red mud is 1,H₂O/Red mud is 0.5,the sample demould after a day in the drying oven of 60 ℃,then 3 days for seal curing and 2 days for opening curing,the compressive strength of red mud-based geopolymer we prepared is 3.81 MPa.（2）At the static adsorption experiment about red mud-based geopolymer and red mud-based geopolymer porous materials,we found that the adsorption effect of these two materials is almost the same about The adsorption time and pH and the Removal rate is almost unchanged after 24 h later.The bigger the pH,the better adsorption effect,In order to prevent the pH is too large to produce precipitation of heavy metals,this thesis chooses pH=5.When the initial concentration is 120 mg/L,pH=5,the Red mud-based geopolymer adsorbent need 1 g to reach adsorption equilibrium,while the Red mud-based geopolymer porous materials adsorbent need 0.6 g to reach adsorption equilibrium,and the removal rate of two materials on Cu²⁺ is above 90%.The equilibrium adsorption quantity of Red mud-based geopolymer is 12.25 mg/g.The equilibrium adsorption quantity of Red mud-based geopolymer porous materials is 21.34 mg/g.（3）Analyzed the red mud-based geopolymer and red mud-based geopolymer porous materials by characterization analysis of XRD、FTIR etc.The phase of the red mud-based geopolymer and red mud-based geopolymer porous materials is almost same,there is a diffuse peak in 20-40°,which Shows that their main product is amorpHous and is similar to pHase of metakaolin-based geopolymer.The analysis of FT-IR shows infrared spectrum of the red mud-based geopolymer and Red mud-based geopolymer porous materials is basically the same and the red mud-based geopolymer do not have other key.This suggests that adding hydrogen peroxide and sodium dodecyl sulfate was not involved in geopolymer reaction,but just have the effect on the foam.