Study on the Effect of Manganese(II) Removal with Oxidation and Coagulation Aid of Potassium Manganate

In order to obtain a more efficient method of manganese( II) removal, jar test was used to study the effect of potassium manganese(K₂MnO₄) pre-oxidation on aluminum chloride (AlCl₃) coagulation to remove manganese(II). It was investigated that the effect of the dosage ofK₂MnO₄, dosing time, sedimentation time and common ions on manganese(II) removal. The results showed that, when K₂MnO₄ was added before AICI₃ and its dosage ranged from 2.87 mg/L to 4.31 mg/L, with the sedimentation time longer than 5 minutes (min) , the manganese(II) removal rate can achieve 82% even 100%. Acid and neutral condition was adverse for manganese( II) removal, while alkaline condition can achieve better results. The optimal pH was 9.20. The effect on manganese(II) removal of calcium ion(Ca²⁺) and magnesium ion(Mg²⁺)was unconspicuous, whereas phosphate ions(PO₄ ^3-) had some negative effect. The effect of AICI₃ to remove manganese (II) in the way of coagulation can be enhanced by using K₂MnO₄ oxidation and coagulation aid, which was a kind of fairly effective technology for manganese( II) removal.