Study On Preparation And Water Treatment Of Composite Flocculation Materials Based On Polymeric Ferric Sulfate

Composite flocculants can fully exploit the synergistic promotion between components in the wastewater treatment process,thereby compensating for the limitations of single flocculants and holding promising development and application prospects.In this paper,based on the inorganic polymeric ferric sulfate(PFS)prepared in our laboratory,the inorganic-inorganic composite flocculant PFSS was prepared by combining PFS with polysilicic acid(PSi),and the inorganic-organic polymer flocculant PFS·PAM was prepared by combining PFS with polyacrylamide(PAM),and their application in wastewater treatment was studied.Specific research content is as follows:1.Preparation of polyferric silicate sulfate and its catalytic oxidation for decolorization of dye wastewater.(1)Inorganic-inorganic flocculant PFSS was prepared by composite polymerization of PFS and polysilic acid(PSi).The morphology,structure,surface charge and particle size of the flocculant were characterized and analyzed by scanning electron microscope,energy spectrum test,X-ray diffraction analysis,infrared analysis,thermogravimetric analysis,Zeta potential test and particle size test.It can be confirmed that a chemical reaction occurred between PFS and PSi during the polymerization process.(2)The influence of Fe/Si molar ratio and reaction temperature on PFSS performance was studied.The results showed that the PFSS prepared which the Fe/Si molar ratio was 5:1and the synthesis temperature was 60 ℃,namely PFSS-5:1-60,had the best decolorization effect on the simulated printing and dyeing wastewater prepared with indigo disulfonate(IC)and rhodamine B(Rh B)dyes,respectively.(3)Decolorization conditions were optimized,and the decolorization effects of PFSS-5:1-60,PFS,commercial PFS(c PFS)and c PFSS-5:1-60 on dyes were compared under different conditions.Experimental results showed that PFSS-5:1-60 had better decolorization ability for dyes,and the decolorization rates of IC and Rh B could reach 99.6%and 100%,respectively.2.Preparation of polymeric ferric sulfate and polyacrylamide composite flocculant and its application in papermaking wastewater treatment.(1)The inorganic-organic composite flocculant PFS·PAM was prepared with PFS and PAM as raw materials by solid phase grinding.The morphology and structure of the flocculant,as well as the surface charge and particle size,were characterized and analyzed by scanning electron microscope,X-ray diffraction analysis,infrared analysis,thermogravimetric analysis,Zeta potential test and particle size test,indicating that there is intermolecular interaction between PFS and PAM during the grinding process,not only physical mechanical mixing.(2)The influence of PFS·PAM prepared under different conditions on the treatment effect of papermaking wastewater was investigated.The treatment effect was measured by testing and comparing turbidity,chemical oxygen demand(COD)and total phosphorus removal rate of papermaking wastewater.The results reflected that the composite flocculant prepared which the mass ratio of PFS and PAM was 1:1,namely PFS·PAM-1:1,had better treatment capacity for papermaking wastewater.When the flocculant dosage is 0.03%,the flocculation effect is quite good,in which the turbidity removal rate is 92.45%,the COD removal rate is 78.32%,and the total phosphorus removal rate is 98.26%.(3)The treatment effects of PFS·PAM-1:1 and PFS,c PFS,PAM,c PFS·PAM-1:1,as well as the non-abrasive mixture of PFS,c PFS and PAM(PFS+PAM,c PFS+PAM)on papermaking wastewater were compared,further indicating that PFS·PAM-1:1 can effectively improve the treatment capacity of papermaking wastewater,and the composite formula has a certain impact on the flocculation capacity of flocculants.(4)By testing the p H,Zeta potential and particle size of the water after flocculation,and comparing their changes under the conditions of different flocculants and different flocculant dosage,the relationship between flocculation effect and flocculant dosage is analyzed from the principle of electric neutralization.It can be concluded that the potential Zeta changes from negative to positive as the dose of flocculant increases.When the Zeta potential is close to 0,the corresponding amount of flocculant can make the negatively charged colloidal particles in the wastewater completely neutralized by electricity.