The paper adopts the chemical speciation method of direct oxidation to prepare polyferric sulfate (PFS), taking the ferrous sulfate(FeSO4•7H2O) as the raw material, and then compounds PFS with a certain quantity of polyacrylamide (PAM) to produce a stable homogeneous phase composite flocculent, polyferric sulfate - Polyacrylamide (PFS-PAM). In addition, the paper employs Kaolin clay suspension as the simulated sample to explore the optimum flocculation conditions of the mixtures, and compares flocculating effects of PFS-PAM with that using PFS, PAM, and PFSS alone. Among them, the parameters such as PFS/PAM mass ratio, amounts of composite flocculants, acidity, reaction temperature, settling time for turbidity elimination rate were evaluated. The results show that under conditions of PFS/PAM mass ratio for 44, pH value for 6.0～8.0, amounts of PFS-PAM 2.5mg/L, reaction temperature for 40°C, and settling time for 40 min, the turbidity elimination rate of PFS-PAM on Kaolin clay suspension could reach around 75%, while the turbidity elimination rate on oily wastewater even could reach up to 96%, which is much better than that achieved by using the single coagulant.
展开▼
