Iron-based Polymer Modified Flocculant And Its Performance Analysis

FeSO4 7H2 O is a type of byproduct which is used as raw material to prepare flocculant.This creats a new way for reuseing pollutants.The best properties flocculant of poly-ferric sulfate(PFS) is prepared in this paper.Cl- ,PO4 3- and Mg2+are added to the PFS respectively,so three newtype of flocculants of poly-ferric sulfate chloride(PFSC),poly-phosphoric ferric sulfate(PPFS) and poly-ferric magnesian sulfate(PFMS) are prepared.On the basis of production method PFS,the technological conditions of PFSC is optimized by using orthogonal method and the optimum conditions of preparation of PFSC,PPFS and PFMS are gotten.The results are:the reaction temperature is 65C,70C~80C and 60C~70 C,the molar ratio is Cr/Fe=0.24,P/Fe=0.3~0.4 and Mg/Fe=0.2~0.4 for PFSC,PPFS and PFMS respectively.The dosage of oxidant is about 6% of the dosage of ferrous sulfate septihydrate for all the flocculants. PFSC,PPFS and PFMS are applied to treat wastewater and compared with PFS and PAC.The performance of flocculant of PFSC,PPFS and PFMS are the best in pH of 6~9,6~10 and 6~9.In the treatment of municipal wastewater, the best dosage of PFSC,PPFS and PFMS are 4.8mg/L and the best dosage of PFS and PAC are 6.4mg/L,the removal rates of CODCr of PFSC,PPFS and PFMS are all above 91.4% ,thehighest removal rates of CODCr of PFS and PAC are only 88.4%.Whenthese flocculants are applied to treat printing and dyeing wastewater orvinetage wastewater,experimental results show that PFSC,PPFS and PFMS have higher the removal rates of COD Cr,the photic rates,theremoval rates of turbidity,the rates of decolorization and the removal rates of SS than those of PFS and PAC.The results show that PFSC,PPFS and PFMS which are applied to treat wastewater have better flocculating efficiency than PFS and PAC .