Polysilicate-ferric Coagulation for Removal of Humic Acid

The removal efficiency of humic acid(HA) by polysilicate-ferric(PSF) and the influencing factors were investigated and compared with those by polyferric sulfate(PFS) and Fe2(SO4)3.The results show that when the pH is 5 to 9,the removal rate of HA by PSF is the best and increases with increasing PSF dosage,which can reach above 85%.Compared with the traditional coagulants PFS and Fe2(SO4)3,PSF can improve the HA removal efficiency and the settleability of flocs.