title: Oxidation of pentachlorophenol in manganese oxide suspensions under controlled Eh and pH environments.
abstract: Abiotic oxidation of pentachlorophenol (PCP) by manganese(IV) oxide (MnO2) was examined in orderto understand the physiochemical environment(s) where PCP oxidation occurs. An Eh-pH potentiostat was used to simulate natural groundwater environments where MnO2 (0.025 g L(-1)) and PCP (0.020 g L(-1)) suspensions were incubated from Eh -300 to 300 mV and pH 4.5 to 7.0. The pH-Eh region where maximum PCP sorption occurred corresponded to the same region where the greatest concentrations of soluble Mn(II) where measured (Eh > -100 mV and pH <5.0). Reduced Mn species [Mn(II,III)] released by reductive dissolution were readsorbed and restricted further abiotic oxidation of PCP by the MnO2 surface. A greater transformation of PCP to primarily tetrachloro-1,4-benzoquinone (p-chloranil) and smaller amounts of lesser chlorinated phenols occurred under increasing pH and Eh conditions.
mesh_terms: D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D017895:Manganese Compounds / Q000737:chemistry*; D008962:Models, Theoretical; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010416:Pentachlorophenol / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D013535:Suspensions
chemical_list: D017895:Manganese Compounds; D010087:Oxides; D012989:Soil Pollutants; D013535:Suspensions; C027424:manganese oxide; D010416:Pentachlorophenol