title: To postpone the precipitation of manganese oxides in the degradation of tetrachloroethylene by controlling the permanganate concentration.
abstract: Controlled-release permanganate (CRP) is a relatively new technology used to treat contaminated groundwater. This study tested the encapsulation of permanganate using stearic acid to realize controlled-release properties. Batch experiments were conducted to investigate the performance of manganese oxides (MnO2) in the reaction between CRP and the contaminant of interest: tetrachloroethylene (PCE). The results showed that higher ionic strengths (I = 0.1 mol/L) cause earlier precipitation of MnO2colloids. Using CRP to degrade PCE could decrease the amount of MnO2colloids produced and postpone precipitation compared to raw potassium permanganate (KMnO4) under high ionic strength conditions by controlling the KMnO4concentration in the solution. The amount of MnO2colloids produced and the time of precipitation depended more on the CRP grain size than on the CRP mass ratio. Controlling the KMnO4concentration used in the reaction could control the formation of MnO2precipitates in the premise of guarantee the removal rate of PCE.
authors.affiliation: a State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process , East China University of Science and Technology , Shanghai , China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Yang
authors.affiliation: a State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process , East China University of Science and Technology , Shanghai , China.
authors.forename: Zhaofu
authors.initials: Z
authors.lastname: Qiu
authors.affiliation: a State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process , East China University of Science and Technology , Shanghai , China.
authors.forename: Zhexuan
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: a State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process , East China University of Science and Technology , Shanghai , China.
authors.forename: Shuguang
authors.initials: S
authors.lastname: Lu
authors.affiliation: a State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process , East China University of Science and Technology , Shanghai , China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Sui
authors.affiliation: a State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process , East China University of Science and Technology , Shanghai , China.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Gu
mesh_terms: D011232:Chemical Precipitation; D017895:Manganese Compounds / Q000737:chemistry*; D009994:Osmolar Concentration; D010087:Oxides / Q000737:chemistry*; D011196:Potassium Permanganate / Q000737:chemistry*; D013750:Tetrachloroethylene / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification
chemical_list: D017895:Manganese Compounds; D010087:Oxides; D014874:Water Pollutants, Chemical; D011196:Potassium Permanganate; C027424:manganese oxide; D013750:Tetrachloroethylene
keywords: Controlled-release permanganate; grain size; ionic strength; manganese oxides; mass ratio; tetrachloroethylene