An Ag-MnFe2O4-bentonite composite was synthesized by a chemical co-precipitation method and used for adsorption removal of Pb（II）, Cd（II） and disinfection. The result of X-ray diffraction indicate that the diffrac...An Ag-MnFe2O4-bentonite composite was synthesized by a chemical co-precipitation method and used for adsorption removal of Pb（II）, Cd（II） and disinfection. The result of X-ray diffraction indicate that the diffraction peaks of MnFe2O4 and Ag can be perfectly indexed to the cubic spinel MnFe2O4（JCPDS No.88-1965） and metallic Ag（JCPDS No.41-1402）, respectively. The results of scanning electron microscopy and energy dispersive X-ray spectroscopy manifest the deposition of MnFe2O4 and Ag on the bentonite surface and the presence ofMn, Fe and Ag. The result of X-ray photoelectron spectroscopy displayed that the composition of Ag-MnFe2O4-bentonite was Mn（II）, Fe（III） and metallic Ag. The analysis of Brunauer-Emmett-Teller showed that the specific surface area of Ag-MnFe2O4-bentonite was the largest compared with that of bentonite, MnFe2O4 and MnFe2O4-bentonite. Thermo- dynamic studies revealed that the adsorption of Pb（II） and Cd（II） ions was spontaneous and endothermic. Langmuir model showed an adsorption capacity of 129.87 mg/g for Pb（II） and 48.31 mg/g for Cd（II） ions. The adsorption ki- netics of Pb（II） and Cd（II） ions onto Ag-MnFe2O4-bentonite can be best described by a pseudo-second-order model. The adsorption rate constant of the pseudo-second-order model was 0.0019 g·mg^-1·min^-1 for Pb（II） and 0.0065 g·mg^-1·min^-1 for Cd（II） ions. In addition to the adsorption experiment, the antibacterial properties of Ag-MnFe2O4-bentonite were studied through plate count method. Gram-negative（G-） bacteria Escherichia coli and Gram-positive（G＋） bacteria Lactobacillus plantarum were used to test the antibacterial properties. The results showed that the composite demonstrated excellent antibacterial activity. Thus, Ag-MnFe2O4-bentonite can be em- ployed as an adsorbent as well as an antimicrobial agent.展开更多
基金Supported by the Graduate Innovation Fund of Jilin University, China（No.2017146） and the Key Project of National Natural Science Foundation of China（No.41530636）.
文摘An Ag-MnFe2O4-bentonite composite was synthesized by a chemical co-precipitation method and used for adsorption removal of Pb（II）, Cd（II） and disinfection. The result of X-ray diffraction indicate that the diffraction peaks of MnFe2O4 and Ag can be perfectly indexed to the cubic spinel MnFe2O4（JCPDS No.88-1965） and metallic Ag（JCPDS No.41-1402）, respectively. The results of scanning electron microscopy and energy dispersive X-ray spectroscopy manifest the deposition of MnFe2O4 and Ag on the bentonite surface and the presence ofMn, Fe and Ag. The result of X-ray photoelectron spectroscopy displayed that the composition of Ag-MnFe2O4-bentonite was Mn（II）, Fe（III） and metallic Ag. The analysis of Brunauer-Emmett-Teller showed that the specific surface area of Ag-MnFe2O4-bentonite was the largest compared with that of bentonite, MnFe2O4 and MnFe2O4-bentonite. Thermo- dynamic studies revealed that the adsorption of Pb（II） and Cd（II） ions was spontaneous and endothermic. Langmuir model showed an adsorption capacity of 129.87 mg/g for Pb（II） and 48.31 mg/g for Cd（II） ions. The adsorption ki- netics of Pb（II） and Cd（II） ions onto Ag-MnFe2O4-bentonite can be best described by a pseudo-second-order model. The adsorption rate constant of the pseudo-second-order model was 0.0019 g·mg^-1·min^-1 for Pb（II） and 0.0065 g·mg^-1·min^-1 for Cd（II） ions. In addition to the adsorption experiment, the antibacterial properties of Ag-MnFe2O4-bentonite were studied through plate count method. Gram-negative（G-） bacteria Escherichia coli and Gram-positive（G＋） bacteria Lactobacillus plantarum were used to test the antibacterial properties. The results showed that the composite demonstrated excellent antibacterial activity. Thus, Ag-MnFe2O4-bentonite can be em- ployed as an adsorbent as well as an antimicrobial agent.
