The rates of electron exchange between oxidized and reduced forms of sev- eral derivatives of ferrocene(1-3)have been measured in acetonitrile by the NMR line h(?)oadening method at 25℃。It was found that the r(?)tes...The rates of electron exchange between oxidized and reduced forms of sev- eral derivatives of ferrocene(1-3)have been measured in acetonitrile by the NMR line h(?)oadening method at 25℃。It was found that the r(?)tes vary with the lengtn of the substitutent chain and the potential of E_(Fe(Ⅲ)/Fe(Ⅱ))in the ferrocene derivatives.展开更多
The release and accumulation dynamics of trace metals in soils and aquatic sediments were exemplarily investigated in the catchment area of the Reservoir Klingenberg(Germany).Catchment soils were examined for mobiliza...The release and accumulation dynamics of trace metals in soils and aquatic sediments were exemplarily investigated in the catchment area of the Reservoir Klingenberg(Germany).Catchment soils were examined for mobilizable and total concentrations of arsenic(As),cadmium(Cd),chrome(Cr),iron(Fe),manganese(Mn),nickel(Ni),lead(Pb),and zinc(Zn)and compared with trace metal quantities accumulated in riverbed and reservoir sediments.The comparison of all samples showed relatively small variations of Cr(7.96–46.0 mg/kg),Fe(7.79–40.4 g/kg),and Ni(6.06–56.5 mg/kg),while stronger differences were found for As(11.2–164 mg/kg),Cd(0.14–30.5 mg/kg),Mn(0.08–1.84 g/kg),Pb(20.7–183 mg/kg),and Zn(69.1–916 mg/kg).The catchment soils were slightly enriched by Cd,Pb,and Zn.Especially Cd and Zn were characterized by large mobilizable proportions.The mean trace metal concentrations in riverbed sediments were higher than in catchment soils,while reservoir sediments accumulated the highest amounts of the analyzed elements.The enrichment of trace metals in reservoir sediments was generally determined by the sedimentation of fine particles,while the distribution of As,Fe,and Mn was additionally impacted by redox conditions.For Cd and Zn,which in comparison were most enriched in riverbed and reservoir sediments,a significant release from soils by leaching processes was observed.The accumulation of As and Pb in reservoir sediments was influenced to a greater extent by soil erosion and by anthropogenic or chalcogen sources in the catchment.展开更多
文摘The rates of electron exchange between oxidized and reduced forms of sev- eral derivatives of ferrocene(1-3)have been measured in acetonitrile by the NMR line h(?)oadening method at 25℃。It was found that the r(?)tes vary with the lengtn of the substitutent chain and the potential of E_(Fe(Ⅲ)/Fe(Ⅱ))in the ferrocene derivatives.
文摘The release and accumulation dynamics of trace metals in soils and aquatic sediments were exemplarily investigated in the catchment area of the Reservoir Klingenberg(Germany).Catchment soils were examined for mobilizable and total concentrations of arsenic(As),cadmium(Cd),chrome(Cr),iron(Fe),manganese(Mn),nickel(Ni),lead(Pb),and zinc(Zn)and compared with trace metal quantities accumulated in riverbed and reservoir sediments.The comparison of all samples showed relatively small variations of Cr(7.96–46.0 mg/kg),Fe(7.79–40.4 g/kg),and Ni(6.06–56.5 mg/kg),while stronger differences were found for As(11.2–164 mg/kg),Cd(0.14–30.5 mg/kg),Mn(0.08–1.84 g/kg),Pb(20.7–183 mg/kg),and Zn(69.1–916 mg/kg).The catchment soils were slightly enriched by Cd,Pb,and Zn.Especially Cd and Zn were characterized by large mobilizable proportions.The mean trace metal concentrations in riverbed sediments were higher than in catchment soils,while reservoir sediments accumulated the highest amounts of the analyzed elements.The enrichment of trace metals in reservoir sediments was generally determined by the sedimentation of fine particles,while the distribution of As,Fe,and Mn was additionally impacted by redox conditions.For Cd and Zn,which in comparison were most enriched in riverbed and reservoir sediments,a significant release from soils by leaching processes was observed.The accumulation of As and Pb in reservoir sediments was influenced to a greater extent by soil erosion and by anthropogenic or chalcogen sources in the catchment.
