Phosphorus Immobilization And Simutaneous Dewatering For Reiver And Lake Mud By Calcium-based Polymeric Ferric Sulfate

In this paper,the experimental process of the preparation of polyferric sulfate with hydrogen peroxide as oxidant and the modification of polyferric sulfate with calcium salt were studied.The effects of sulfuric acid dosage,amount of hydrogen peroxide,reaction temperature and reaction time on the main components(total iron content,Fe2 + content and basicity)of polyferric sulfate were investigated.At the same time,on the basis of this,the synthesis of ferric sulfate with excellent quality was modified by calcium salt modification,and the response surface optimization design method was used to establish the Box-Behnken mathematical model to investigate the Ca/Fe molar ratio,the reaction temperature,the reaction time on the synthesis of active ingredients(total iron content,Fe2+ content and basicity)the impact of the final quality of calcium-based polymerization of ferric sulfate products.The structure and morphology of the ferric sulfate and modified calcium-based ferric sulfate products were observed by Fourier transform infrared spectroscopy and scanning electron microscopy.The synthesis of polyferric sulfate,calcium-based polymerization Iron sulfate and market sales of ferric sulphate products on the phosphorus-rich mud solid phosphorus dehydration performance.Through the synthesis of polyferric sulfate,calcium-based polymerization of ferric sulfate experimental process research,the following conclusions:1.The optimum reaction conditions were determined by four factors: sulfuric acid,hydrogen peroxide,reaction temperature and reaction time.When n[SO42-]/n [Fe]T=1.3,n[H2O2]/n[Fe]T=0.70,the reaction temperature is 50?,the reaction time is 6h,the total iron content is 12.58%,the Fe2+content is 0.002% and the basicity is 13.84%.2.The optimum reaction conditions were as follows: reaction temperature,time and Ca/Fe molar ratio were 62?,7h,0.05,respectively.The results showed that the optimum reaction conditions were as follows: The average iron content and the average base of the products were 13.82% and 17.95% respectively.The experimental results show that the deviation between the actual value of iron content and salt value is only 0.84% and 0.47%.At the same time,the structure and morphology of calcium-based polymerized ferric sulfate were observed by Fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).The results showed that the calcium-based polymerized ferric sulfate product was an amorphous product containing a small amount of crystals.3.Compared with the commercial PFS found: When the dosage was 4.78 ?g/g,the specific resistance of CaPFS and commercially available PFS were the lowest,and the CaPFS[n(Ca)/n(Fe)=0.05] decreased to 0.40×1012m/kg,the commercially available PFS decreased to 0.96×1012m/kg.The contents of phosphorus in the supernatant and sediment were 0.08mg/L and 0.44mg/L respectively after CaPFS[n(Ca)/n(Fe)= 0.05] treatment Lower than the commercially available PFS(0.23 mg/L,0.59mg/L),corresponding to 94.84% and 87.34% phosphorus being retained in the sediment.The results show that CaPFS is better for improving the performance of sediment and the effect of solid phosphorus than the commercially available PFS.