To understand the mechanism of fluoride removal from the simulated zinc sulfate solution by the La(III)-modified zeolite,the adsorbent was characterized by XRD,SEM and EDS.The effects of absorbent dose and contact tim...To understand the mechanism of fluoride removal from the simulated zinc sulfate solution by the La(III)-modified zeolite,the adsorbent was characterized by XRD,SEM and EDS.The effects of absorbent dose and contact time,the adsorption isotherms and the sorption kinetics were investigated.The experimental results were compatible with the Langmuir isotherm model.The theoretical maximum adsorption capacities are 20.83 and 23.04 mg/g at 303 and 313 K,respectively.And the physisorption is revealed using the Temkin isotherm model and the D-R isotherm model.The sorption process is more suitable by the pseudo-second-order kinetic models.Thermodynamic parameters such as standard free energy change(ΔGΘ<0 kJ/mol),standard enthalpy change(ΔHΘ=8.28 kJ/mol)and standard entropy change(ΔSΘ=0.030 kJ/(mol?K))indicate the spontaneity of adsorption and endothermic physical sorption.Furthermore,the fluoride concentration in the industrial zinc sulfate solution decreases from 98.05 to 44.09 mg/L with the adsorbent dosage of 15 g/L.展开更多
Solvent extraction experiments of La(III) with di-(2-ethylhexyl)phosphoric acid (P204) from chloride solution in the presence of a complexing agent (lactic acid) have been performed. The effective separation factors c...Solvent extraction experiments of La(III) with di-(2-ethylhexyl)phosphoric acid (P204) from chloride solution in the presence of a complexing agent (lactic acid) have been performed. The effective separation factors can be achieved when the complexing agent is added to the aqueous phase of the extraction system. The complexing agent lactic acid can be effectively recycled using tributyl phosphate (TBP) as extractant, by the use of a countercurrent extraction process, and the chemical oxygen demand (COD) value in the raffinate is 57.7 mg/L, which meets the emission standards of pollutants from rare earths industry. Thus, the simple and environment-friendly complexing method has been proved to be an effective strategy for separating light rare earths, and provides a positive influence on the purification of La(III).展开更多
A new ligand N,N′-bis(2-methelene-1,10-phenanthroline)-3,6-dioxa-1,8-octaneethylenediamine(L) and the corresponding complexes LaL, LaL(Phe), and LaL( Try) were synthesized. The interaction of the complexes with calf ...A new ligand N,N′-bis(2-methelene-1,10-phenanthroline)-3,6-dioxa-1,8-octaneethylenediamine(L) and the corresponding complexes LaL, LaL(Phe), and LaL( Try) were synthesized. The interaction of the complexes with calf thymus DNA was studied by means of electronic absorbance spectra, flurescence spectra, circula r dichroic spectra and viscosity experiments. All the results indicate that the complexes may interact mainly with calf thymus DNA by intercalation and coordina tion binding.展开更多
[ Objective] The aim was to provide strategies for development of rare earth and control of environmental pollution. [ Method] Responses of membrane lipid peroxidation and endogenous hormones of soybean seedlings to U...[ Objective] The aim was to provide strategies for development of rare earth and control of environmental pollution. [ Method] Responses of membrane lipid peroxidation and endogenous hormones of soybean seedlings to UV-B radiation and rare earth were studied through hydroponics in laboratory. [ Result] The results showed that under irradiation of UV-B（ T1-0.15 W/m^2 and T2-0.45 W/m^2）, chlorophyll and indole-3-acetic acid（IAA） contents firstly decreased during the stress phase （1 -5 d） and then increased during the restoration phase （6 -9 d） while contents of malonadialdehyde（MDA） and abscisic acid（ABA） gradually increased during the imposition of UV-B radiation （1 -5 d） and subsequently decreased during recovery from UV-B stress （6 -9 d） . With adding of La （III） with the concentration of 20 mg · L^-1 , the decline/dse trend of chlorophyll, IAA, MDA and ABA contents was slowed down during the stress period while the rise/decline speed was accelerated during the recovery period. [ Conclusion] It suggests that the regulation of La （ III ） on membrane lipid peroxidation and endogenous hormones could increase chlorophyll and IAA contents, improve the metabolism of reactive oxygen species （ ROS）, inhibit membrane lipid peroxidation, decrease the accumulation amount of ABA and alleviate injury of UV-B radiation to soybean seedlings. Further, the protective potential of La （ III ） was better under low UV-B radiation than under high one.展开更多
In this study a series of trivalent lanthanum complexes with 4-（R）-cinnamate （4-Rcinn, R=H（1）, MeO（2）, Cl（3）） and 4-methoxyphenylacetate ligands （4） were prepared and their antifungal activity against Cand...In this study a series of trivalent lanthanum complexes with 4-（R）-cinnamate （4-Rcinn, R=H（1）, MeO（2）, Cl（3）） and 4-methoxyphenylacetate ligands （4） were prepared and their antifungal activity against Candida albicans, Aspergillus niger and Trichophyton mentagrophytes were examined. Compounds 1-4 were synthesized by a metathesis reaction and fully characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, fluorescence spectra, thermogravimetry （TG）, derivative thermogravimetry （DTG）, differential scanning calorimetry （DSC） and X-ray diffraction powder patterns. In emission studies, it was observed that lu-minescence intensity was enhanced in the presence of lanthanide ion. The results of X-ray diffraction patterns indicated that all com-plexes studied exhibited crystalline structure. Thermal behavior by TG, DTG, and DSC studies permitted to estimating the hydration degree of the compounds and showed the formation of decomposition products like lanthanum oxide. Determined by antifungal stud-ies, lanthanum complexes 1-4 demonstrated antifungal activity toward all pathogenic fungal strains tested. Compounds 2 and 4 showed significant growth inhibition for A. niger and C. albicans, respectively.展开更多
Developing low-cost and effective materials for excess fluoride removal is important for providing safe water. A novel ad- sorbent, La（IlI）-loaded bentonite/chitosan beads （La-BCB） was prepared for defluoridation ...Developing low-cost and effective materials for excess fluoride removal is important for providing safe water. A novel ad- sorbent, La（IlI）-loaded bentonite/chitosan beads （La-BCB） was prepared for defluoridation from aqueous solution. The effects of various parameters such as dosage of La（III）, pH, temperature, contact time, initial fluoride concentration and presence of co-existing anions were investigated to examine the defluoridation behavior. The maximum defluoridation capacity of La-BCB was 2.87 mg/g at pH 5, 30 ℃. Scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDX） and Fourier transform infrared spectros- copy （FTIR） were employed to analyze the characteristics of La-BCB. The equilibrium fluoride adsorption data fitted well with both Langmuir and Freundlich isotherm models. The RL value revealed that the defluoridation process using La-BCB was favorable. The adsorption kinetics followed pseudo-second order kinetic as well as particle and intraparticle diffusion models. The presence of car- bonate and bicarbonate reduced defluoridation capacity of La-BCB while sulphate, nitrate and chloride showed slight effect. The ex- hausted La-BCB was regenerated using sodium hydroxide with only 17% loss. The reasonable defluoridation mechanism could be interpreted as adsorption and ion exchange.展开更多
This paper described the fluoride removal from water using a new adsorbent namely mixed rare earths modified chitosan （CR）. Mixed rare earths mainly contained La followed by Ce which was analyzed by inductively coup...This paper described the fluoride removal from water using a new adsorbent namely mixed rare earths modified chitosan （CR）. Mixed rare earths mainly contained La followed by Ce which was analyzed by inductively coupled plasma mass spectrometry （ICP-MS）. La（III）-modifled chitosan （CL） was also prepared as control. For the batch technique, the effects of various parameters such as contact time, pH, adsorbent dose, initial fluoride concentration and co-ions on fluoride adsorption were studied. Fourier trans- form infrared spectroscopy （FTIR） and X-ray diffraction （XRD） were used to characterize adsorbents. It was observed that the fluo- ride adsorption capacity of CR （3.72 mgF-/g） was higher than CL （3.16 mgF-/g） at 2 h. The presence of co-ions such as bicarbonate and carbonate greatly affected the fluoride adsorption from water. Characterization experiments indicated the successful chelation between mixed rare earths and chitosan. The possible fluoride adsorption mechanism of CR was explained by a chemical reaction.展开更多
基金Projects(51474238,51674301)supported by the National Natural Science Foundation of China
文摘To understand the mechanism of fluoride removal from the simulated zinc sulfate solution by the La(III)-modified zeolite,the adsorbent was characterized by XRD,SEM and EDS.The effects of absorbent dose and contact time,the adsorption isotherms and the sorption kinetics were investigated.The experimental results were compatible with the Langmuir isotherm model.The theoretical maximum adsorption capacities are 20.83 and 23.04 mg/g at 303 and 313 K,respectively.And the physisorption is revealed using the Temkin isotherm model and the D-R isotherm model.The sorption process is more suitable by the pseudo-second-order kinetic models.Thermodynamic parameters such as standard free energy change(ΔGΘ<0 kJ/mol),standard enthalpy change(ΔHΘ=8.28 kJ/mol)and standard entropy change(ΔSΘ=0.030 kJ/(mol?K))indicate the spontaneity of adsorption and endothermic physical sorption.Furthermore,the fluoride concentration in the industrial zinc sulfate solution decreases from 98.05 to 44.09 mg/L with the adsorbent dosage of 15 g/L.
文摘Solvent extraction experiments of La(III) with di-(2-ethylhexyl)phosphoric acid (P204) from chloride solution in the presence of a complexing agent (lactic acid) have been performed. The effective separation factors can be achieved when the complexing agent is added to the aqueous phase of the extraction system. The complexing agent lactic acid can be effectively recycled using tributyl phosphate (TBP) as extractant, by the use of a countercurrent extraction process, and the chemical oxygen demand (COD) value in the raffinate is 57.7 mg/L, which meets the emission standards of pollutants from rare earths industry. Thus, the simple and environment-friendly complexing method has been proved to be an effective strategy for separating light rare earths, and provides a positive influence on the purification of La(III).
文摘A new ligand N,N′-bis(2-methelene-1,10-phenanthroline)-3,6-dioxa-1,8-octaneethylenediamine(L) and the corresponding complexes LaL, LaL(Phe), and LaL( Try) were synthesized. The interaction of the complexes with calf thymus DNA was studied by means of electronic absorbance spectra, flurescence spectra, circula r dichroic spectra and viscosity experiments. All the results indicate that the complexes may interact mainly with calf thymus DNA by intercalation and coordina tion binding.
基金Supported by the Foundation of State Developing and ReformingCommittee(No.IFZ20051210)the National Natural Science Foundationof China(No.30570323,No.20471030)the Programsin Science and Technology of Nantong(No.DE2009006,No.S2009019)~~
文摘[ Objective] The aim was to provide strategies for development of rare earth and control of environmental pollution. [ Method] Responses of membrane lipid peroxidation and endogenous hormones of soybean seedlings to UV-B radiation and rare earth were studied through hydroponics in laboratory. [ Result] The results showed that under irradiation of UV-B（ T1-0.15 W/m^2 and T2-0.45 W/m^2）, chlorophyll and indole-3-acetic acid（IAA） contents firstly decreased during the stress phase （1 -5 d） and then increased during the restoration phase （6 -9 d） while contents of malonadialdehyde（MDA） and abscisic acid（ABA） gradually increased during the imposition of UV-B radiation （1 -5 d） and subsequently decreased during recovery from UV-B stress （6 -9 d） . With adding of La （III） with the concentration of 20 mg · L^-1 , the decline/dse trend of chlorophyll, IAA, MDA and ABA contents was slowed down during the stress period while the rise/decline speed was accelerated during the recovery period. [ Conclusion] It suggests that the regulation of La （ III ） on membrane lipid peroxidation and endogenous hormones could increase chlorophyll and IAA contents, improve the metabolism of reactive oxygen species （ ROS）, inhibit membrane lipid peroxidation, decrease the accumulation amount of ABA and alleviate injury of UV-B radiation to soybean seedlings. Further, the protective potential of La （ III ） was better under low UV-B radiation than under high one.
文摘In this study a series of trivalent lanthanum complexes with 4-（R）-cinnamate （4-Rcinn, R=H（1）, MeO（2）, Cl（3）） and 4-methoxyphenylacetate ligands （4） were prepared and their antifungal activity against Candida albicans, Aspergillus niger and Trichophyton mentagrophytes were examined. Compounds 1-4 were synthesized by a metathesis reaction and fully characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, fluorescence spectra, thermogravimetry （TG）, derivative thermogravimetry （DTG）, differential scanning calorimetry （DSC） and X-ray diffraction powder patterns. In emission studies, it was observed that lu-minescence intensity was enhanced in the presence of lanthanide ion. The results of X-ray diffraction patterns indicated that all com-plexes studied exhibited crystalline structure. Thermal behavior by TG, DTG, and DSC studies permitted to estimating the hydration degree of the compounds and showed the formation of decomposition products like lanthanum oxide. Determined by antifungal stud-ies, lanthanum complexes 1-4 demonstrated antifungal activity toward all pathogenic fungal strains tested. Compounds 2 and 4 showed significant growth inhibition for A. niger and C. albicans, respectively.
基金Project supported by National Special Fund for Scientific Research on Public Causes(201005020)China Postdoctoral Science Foundation(2013M531652)National Natural Science Foundation of China(31302162)
文摘Developing low-cost and effective materials for excess fluoride removal is important for providing safe water. A novel ad- sorbent, La（IlI）-loaded bentonite/chitosan beads （La-BCB） was prepared for defluoridation from aqueous solution. The effects of various parameters such as dosage of La（III）, pH, temperature, contact time, initial fluoride concentration and presence of co-existing anions were investigated to examine the defluoridation behavior. The maximum defluoridation capacity of La-BCB was 2.87 mg/g at pH 5, 30 ℃. Scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDX） and Fourier transform infrared spectros- copy （FTIR） were employed to analyze the characteristics of La-BCB. The equilibrium fluoride adsorption data fitted well with both Langmuir and Freundlich isotherm models. The RL value revealed that the defluoridation process using La-BCB was favorable. The adsorption kinetics followed pseudo-second order kinetic as well as particle and intraparticle diffusion models. The presence of car- bonate and bicarbonate reduced defluoridation capacity of La-BCB while sulphate, nitrate and chloride showed slight effect. The ex- hausted La-BCB was regenerated using sodium hydroxide with only 17% loss. The reasonable defluoridation mechanism could be interpreted as adsorption and ion exchange.
基金supported by National Natural Science Foundation of China (31101330)International Joint Research Program(2010DFA31330)Public Science and Technology Research Funds Projects of Ocean (201005020-6)
文摘This paper described the fluoride removal from water using a new adsorbent namely mixed rare earths modified chitosan （CR）. Mixed rare earths mainly contained La followed by Ce which was analyzed by inductively coupled plasma mass spectrometry （ICP-MS）. La（III）-modifled chitosan （CL） was also prepared as control. For the batch technique, the effects of various parameters such as contact time, pH, adsorbent dose, initial fluoride concentration and co-ions on fluoride adsorption were studied. Fourier trans- form infrared spectroscopy （FTIR） and X-ray diffraction （XRD） were used to characterize adsorbents. It was observed that the fluo- ride adsorption capacity of CR （3.72 mgF-/g） was higher than CL （3.16 mgF-/g） at 2 h. The presence of co-ions such as bicarbonate and carbonate greatly affected the fluoride adsorption from water. Characterization experiments indicated the successful chelation between mixed rare earths and chitosan. The possible fluoride adsorption mechanism of CR was explained by a chemical reaction.
