The electrochemical behavior of Mn (Ⅲ)/Mn(Ⅱ)ion-pair on platinum electrode in acid media were studied by cyclic voltammetry.It was demonstrated that the redox process of Mn(Ⅲ)/Mn(Ⅱ) pair was a simple pseudo-revers...The electrochemical behavior of Mn (Ⅲ)/Mn(Ⅱ)ion-pair on platinum electrode in acid media were studied by cyclic voltammetry.It was demonstrated that the redox process of Mn(Ⅲ)/Mn(Ⅱ) pair was a simple pseudo-reversible one-electron reaction between Mn(Ⅲ) and Mn(Ⅱ).The electrochemical kinetics of the redox reaction on static Pt electrode was a mass transfer controlled one.The calculated diffusion coefficient of Mn(Ⅱ) was 1.48×10 -6cm 2/s.展开更多
In this study,greatly enhanced Mn(Ⅱ) adsorption was achieved by as-synthesized diethylenetriaminepentaacetate acid intercalated Mg/Al layered double hydroxides (LDHs-DTPA).The adsorption capacity of LDHs-DTPA was 83....In this study,greatly enhanced Mn(Ⅱ) adsorption was achieved by as-synthesized diethylenetriaminepentaacetate acid intercalated Mg/Al layered double hydroxides (LDHs-DTPA).The adsorption capacity of LDHs-DTPA was 83.5 mg/g,which is much higher than that of LDHs-EDTA (44.4 mg/g),LDHs-Oxalate (21.6 mg/g) and LDHs (28.8 mg/g).The adsorption data of aqueous Mn(Ⅱ) using LDHs-DTPA could be well described by the pseudosecond order kinetics and Langrnuir isotherm model.Thermodynamics study results also showed that the adsorption process of Mn(Ⅱ) by LDHs-DTPA was exothermic as indicated by the negative △H value.Furthermore,based on the structural,morphological and thermostable features,as well as FT-IR and XPS characterizations of LDHs-DTPA and the pristine LDHs,the adsorption mechanism of Mn(Ⅱ) was proposed.The carboxyl groups of DTPA were proposed to be the main binding sites for Mn(Ⅱ),and the hydroxyl groups of LDHs also played a minor role in the adsorption process.Among the three common regeneration reagents,0.1 mol/L Na2CO3 was the best for reusing LDHs-DTPA in Mn(Ⅱ) adsorption.Besides,the Mn(Ⅱ) adsorption performance could be hindered in the presence of typical inorganic ions,especially cations.Further specific modifications of LDHs-DTPA are suggested to get more selective adsorption of Mn(ll) in practical applications.展开更多
文摘The electrochemical behavior of Mn (Ⅲ)/Mn(Ⅱ)ion-pair on platinum electrode in acid media were studied by cyclic voltammetry.It was demonstrated that the redox process of Mn(Ⅲ)/Mn(Ⅱ) pair was a simple pseudo-reversible one-electron reaction between Mn(Ⅲ) and Mn(Ⅱ).The electrochemical kinetics of the redox reaction on static Pt electrode was a mass transfer controlled one.The calculated diffusion coefficient of Mn(Ⅱ) was 1.48×10 -6cm 2/s.
基金Supported by the Natural Science Foundation of China(U1504209,21403053)Young Backbone Teacher Project of Henan Colleges and Universities(2016GGJS-023)Foundation of Henan University(0000A40478)
基金supported by the National Natural Science Foundation of China(Nos.21677055 and 21407052)the Key Project in the National Science&Technology Pillar Program during the Twelfth Five-year Plan Period(No.2015BAB01B04)the Fundamental Research Funds for the Central Universities,HUST(Nos.2017KFXKJC004 and 2016YXMS287)
文摘In this study,greatly enhanced Mn(Ⅱ) adsorption was achieved by as-synthesized diethylenetriaminepentaacetate acid intercalated Mg/Al layered double hydroxides (LDHs-DTPA).The adsorption capacity of LDHs-DTPA was 83.5 mg/g,which is much higher than that of LDHs-EDTA (44.4 mg/g),LDHs-Oxalate (21.6 mg/g) and LDHs (28.8 mg/g).The adsorption data of aqueous Mn(Ⅱ) using LDHs-DTPA could be well described by the pseudosecond order kinetics and Langrnuir isotherm model.Thermodynamics study results also showed that the adsorption process of Mn(Ⅱ) by LDHs-DTPA was exothermic as indicated by the negative △H value.Furthermore,based on the structural,morphological and thermostable features,as well as FT-IR and XPS characterizations of LDHs-DTPA and the pristine LDHs,the adsorption mechanism of Mn(Ⅱ) was proposed.The carboxyl groups of DTPA were proposed to be the main binding sites for Mn(Ⅱ),and the hydroxyl groups of LDHs also played a minor role in the adsorption process.Among the three common regeneration reagents,0.1 mol/L Na2CO3 was the best for reusing LDHs-DTPA in Mn(Ⅱ) adsorption.Besides,the Mn(Ⅱ) adsorption performance could be hindered in the presence of typical inorganic ions,especially cations.Further specific modifications of LDHs-DTPA are suggested to get more selective adsorption of Mn(ll) in practical applications.
