title: Enhanced coagulation with in situ manganese dioxide on removal of humic acid in micro-polluted water.
abstract: The morphology and surface characteristics of manganese dioxide (MnO₂) formed in situ, which was prepared through the oxidation of MnSO₄using KMnO₄, were studied. The effects of factors including the form of MnO₂, dosage, pH, dosing sequence of in situ MnO₂on the enhanced coagulation were systematically evaluated. The results of analysis by the UV254 and permanganate index CODMn methods indicated that humic acid removal increased from 9.2 and 2.5% to 55.0 and 38.9%, when 10 mg/L of the in situ MnO₂ was added in the presence of 2 mg/L of polyaluminum sulfate. The studies of orthogonal experiment revealed that coagulation was most affected by the pH, whereas the dosage of in situ MnO₂and slow stirring duration exhibited a weaker effect. At a pH value of 4.0, in situ MnO₂dosage of 10 mg/L, slow stir over 40 min, and the total solids content was 20 mg/L, the humic acid removal by UV254 and CODMn methods reached 71.2 and 61.2%. These results indicated that the presence of in situ MnO₂enhanced the coagulation and removal of humic acid from water.
authors.affiliation: Department of Water Quality Engineering, School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China E-mail: zengyubin@whu.edu.cn.
authors.forename: Yubin
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto M5S 3E5, Canada.
authors.forename: Ziyang
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Department of Water Quality Engineering, School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China E-mail: zengyubin@whu.edu.cn.
authors.forename: Junlin
authors.initials: J
authors.lastname: Wang
mesh_terms: D011232:Chemical Precipitation; D006812:Humic Substances / Q000032:analysis*; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014876:Water Pollution; D018508:Water Purification / Q000379:methods*
chemical_list: D006812:Humic Substances; D017895:Manganese Compounds; D010087:Oxides; D014874:Water Pollutants, Chemical; C016552:manganese dioxide