ABSTRACT This study investigated the coagulation effect of magnetized polyferric sulfate (PFS) and polyacrylamide (PAM) on papermaking wastewater. Results showed that the co-magnetized PFS-PAM group (Group C) achieved significantly higher removal rates of chemical oxygen demand (COD), color, turbidity, and UV254 than the nonmagnetized PFS-PAM group (Group B) and control group (Group A). Specifically, the effluent COD of Group C decreased to 46.72 mg/L, with color, turbidity, and UV254 removal rates increased by 16.85, 32.38, and 10.78%, respectively, compared with Group A. The enhanced efficiency was attributed to the cutting effect of magnetic induction lines in alternating magnetic fields (AMFs), which promoted coagulation and sedimentation. AMFs converted magnetic energy into internal energy of PFS particles, increasing multinuclear polymers in PFS solutions and strengthening complexation and chelation reactions. Orthogonal experiments identified the optimal parameter combination as A3B1C1D3E3 (PFS dosage: 1,000 mg/L, PAM dosage: 1.5 mg/L, magnetization intensity: 6 mT, magnetization time: 5 min, magnetization frequency: 130 Hz), under which the removal rates of COD, color, turbidity, and UV254 reached 94.2, 93.08, 90.07, and 89.35%, respectively. Importantly, PAM did not alter the magnetization effect, supporting the wide application of AMFs in wastewater treatment.
Gu et al. (Sat,) studied this question.