Spherical flower-like Mg(OH)_(2) was fabricated from MgSO_(4) effluent and its adsorption performance for heavy metal ions was evaluated.The appropriate fabrication conditions are as follows:Mg^(2+)/NH4OH molar ratio ...Spherical flower-like Mg(OH)_(2) was fabricated from MgSO_(4) effluent and its adsorption performance for heavy metal ions was evaluated.The appropriate fabrication conditions are as follows:Mg^(2+)/NH4OH molar ratio of 1:0.5,temperature of 120°C and time of 1 h at Mg^(2+)concentration of 2 mol/L.Spherical flower-like Mg(OH)_(2) composed of ultra-thin sheets exhibits an excellent adsorption ability for Ni^(2+),Cu^(2+),Zn^(2+),Pb^(2+),Fe^(3+)and Co^(2+),and the adsorption reaches the equilibrium in 6 min.The maximum adsorption capacities of the studied heavy metal ions onto Mg(OH)_(2) at 20°C are 58.55,85.84,44.94,485.44,625.00 and 27.86 mg/g,respectively.The adsorption is well fitted by the Langmuir model,indicating that the adsorption is monolayer.The adsorption kinetics follows the pseudo-second-order model.Chemisorption is the operative mechanism.Spherical flower-like Mg(OH)_(2) is a qualified candidate for heavy metal ions removal.展开更多
In this paper,a new electrolysis device was presented with corundum crucible as an electrolytic cell in place of a graphite crucible,and in the corundum crucible a sleeve with a cathode pellet with a fluted base place...In this paper,a new electrolysis device was presented with corundum crucible as an electrolytic cell in place of a graphite crucible,and in the corundum crucible a sleeve with a cathode pellet with a fluted base placed flat in it was adopted to separate the cathode and anode.The process of electrochemical reduction of solid TiO_(2) to Ti in situ was studied and characterized by the time-current curves and X-ray diffraction(XRD) patterns of the electrochemical reduction products.The influence of CaCl_(2)doping in the cathode and the electrolysis device structures on electrochemical reduction mechanisms and the process strengthening was systematically studied.The results show that the oxygen content in the obtained Ti is reduced to0.51% with a cathode pellet sintering temperature of1000 ℃,sample preparation pressure of 20 MPa and CaCl_(2) doping amount of 30%.Tiny holes are formed in the cathode pellet by CaCl_(2) doping in the electrochemical reduction process,which could increase the contact area between the electrolyte and cathode and improve the electrode reaction efficiency.The new electrolysis device could reduce the carbon content in the molten salt,cathode polarization and the electrode reaction overvoltage,inhibit the chances of secondary reactions,increase the contact area between the produced Ca and cathode and strengthen the thermal reduction of TiO_(2) by Ca.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 51774070 and 52004165)the Science and Technology Project of Yunnan Province, China (No. 202101AS070029)
文摘Spherical flower-like Mg(OH)_(2) was fabricated from MgSO_(4) effluent and its adsorption performance for heavy metal ions was evaluated.The appropriate fabrication conditions are as follows:Mg^(2+)/NH4OH molar ratio of 1:0.5,temperature of 120°C and time of 1 h at Mg^(2+)concentration of 2 mol/L.Spherical flower-like Mg(OH)_(2) composed of ultra-thin sheets exhibits an excellent adsorption ability for Ni^(2+),Cu^(2+),Zn^(2+),Pb^(2+),Fe^(3+)and Co^(2+),and the adsorption reaches the equilibrium in 6 min.The maximum adsorption capacities of the studied heavy metal ions onto Mg(OH)_(2) at 20°C are 58.55,85.84,44.94,485.44,625.00 and 27.86 mg/g,respectively.The adsorption is well fitted by the Langmuir model,indicating that the adsorption is monolayer.The adsorption kinetics follows the pseudo-second-order model.Chemisorption is the operative mechanism.Spherical flower-like Mg(OH)_(2) is a qualified candidate for heavy metal ions removal.
基金financially supported by the National Key Basic Research Program of China (No.2013CB6326062)the Fundamental Research Funds for the Central Universities (Nos.N110202003 and N130102002)the National Natural Science Foundation of China (Nos.51274064 and 51422403)。
文摘In this paper,a new electrolysis device was presented with corundum crucible as an electrolytic cell in place of a graphite crucible,and in the corundum crucible a sleeve with a cathode pellet with a fluted base placed flat in it was adopted to separate the cathode and anode.The process of electrochemical reduction of solid TiO_(2) to Ti in situ was studied and characterized by the time-current curves and X-ray diffraction(XRD) patterns of the electrochemical reduction products.The influence of CaCl_(2)doping in the cathode and the electrolysis device structures on electrochemical reduction mechanisms and the process strengthening was systematically studied.The results show that the oxygen content in the obtained Ti is reduced to0.51% with a cathode pellet sintering temperature of1000 ℃,sample preparation pressure of 20 MPa and CaCl_(2) doping amount of 30%.Tiny holes are formed in the cathode pellet by CaCl_(2) doping in the electrochemical reduction process,which could increase the contact area between the electrolyte and cathode and improve the electrode reaction efficiency.The new electrolysis device could reduce the carbon content in the molten salt,cathode polarization and the electrode reaction overvoltage,inhibit the chances of secondary reactions,increase the contact area between the produced Ca and cathode and strengthen the thermal reduction of TiO_(2) by Ca.
