| Industrial fluorinated wastewater has attracted widespread attention due to its complex composition,high concentration and high acidity.However,common aluminum-based materials are unstable and easy to dissolve in acidic solution,which cannot effectively meet the needs of industrial fluorinated wastewater treatment.In this paper,the factors affecting the stability and adsorption performance of polypyrrole were explored based on the chemical oxidative polymerization method.A class of polypyrrole（PPy）materials with high stability was synthesized,which realized the efficient adsorption and separation of fluoride ions in an acidic solution environment.Through in-situ loading of cerium,the effect of cerium doping strengthening of polypyrrole material on the defluorination of solution was studied,and its application in the actual acid lead-zinc smelting wastewater was investigated,which provided a feasible technical method for the disposal of industrial fluorinated wastewater.The main research contents and results are as follows:（1）Polypyrrole materials with good acid stability and defluorination performance were synthesized.Based on the chemical oxidative polymerization method,the influence of factors such as the type of oxidant,the amount of oxidant,and the ratio of nitrile to water on the structure and defluorination performance of the synthesized polypyrrole was studied.The phase,morphology and structure of polypyrrole were analyzed by characterization of XRD,SEM and FTIR.The optimal process conditions are that the ratio of oxidant to pyrrole monomer is 1.5:1,the ratio of nitrile to water is 1:9,the synthesis temperature is 0℃,and the polymerization time is 5 h,and the obtained polypyrrole materials has the highest stability.Compared with most related materials reported in the literature and commonly used commercially available fluoride-removing resins,the synthesized product exhibits excellent fluoride-removing performance.When the solution p H≤3,the adsorption capacity is around 5-15 mg/g,which is significantly better than the industrialized Purolite PFS951 and other resin adsorption performance（around 1-5 mg/g）.（2）The fluoride removal behavior and performance of polypyrrole composites by cerium doping were investigated,that has demonstrated the feasibility of practical application in lead-zinc smelting wastewater treatment.Through in-situ loading high F-affinity cerium element,a class of HCe O2@PPy composites was prepared,which significantly enhanced the fluoride removal performance in solution.It is suitable for a wide p H range（p H=1-11）with good selectivity.Fluoride adsorption capacity of the HCe O2@PPy composite was significantly improved（about 4 times that of PPy）,and its maximum theoretical adsorption capacity was 80.93 mg/g.In the actual treatment of lead-zinc smelting wastewater,it shows a good selective adsorption capacity for fluoride ions,and the removal rate can reach 71.7%,showing a practical application prospect.（3）The adsorption mechanism of fluoride ions on HCe O2@PPy was explored.The study found that Ce-OH is an efficient and active structure for adsorbing F-.Fluoride ions take ion exchange reaction with Ce-OH on the material to form a chemical bond（M-F）,which was adsorbed and removed.The mechanism of defluorination includes:（i）electrostatic interaction,in which HCe O2@PPy adsorbs F-to the surface through electrostatic interaction,（ii）ion exchange,in which OH-on HCe O2@PPy take ion exchange with F-.This thesis contains 47 figures,17 tables and 120 references... |
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