Micro Analysis of Efficacy and Mechanism of Aid-Coagulation with Hydrated MnO_2

摘要

The coagulation experiment, with Kaolin and humic acids (nature organics) as objects, aluminum chloride (PAC) as coagulant and hydrated MnO_2 as coagulant aid, were accomplished under different conditions. In the experiment, the particle size distribution, turbidity and streaming current (SCD) in water were detected by on-line detector. Then the variation rules of particle size distribution and SCD for the microscopic efficacy and mechanism of aid- coagulation with hydrated MnO_2 was analyzed. The results shows that a low dosage of hydrated MnO_2 (0.01～0.02 mmol/L) can lead to a good aid-coagulation efficacy after precipitation, reducing total particle counts, <5 μm particle counts and turbidity effectually, adding stability of flocculating constituents and decreasing the counts of small particles releasing again. Hydrated MnO_2 could strengthen adsorption bridging action. In coagulation process, hydrated MnO_2 particle could adsorb small particles to its surface, then aggregate into bigger one.