在相对真空下以CaSi_(2)为还原剂进行预制球团提镁过程的研究。利用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分别对还原渣的形貌、化学成分和物相进行分析。结果表明,小的氩气流量可以极大地提高氧化镁的还原率,在相对真空...在相对真空下以CaSi_(2)为还原剂进行预制球团提镁过程的研究。利用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分别对还原渣的形貌、化学成分和物相进行分析。结果表明,小的氩气流量可以极大地提高氧化镁的还原率,在相对真空下以CaSi_(2)为还原剂的预制球团提镁过程可以用F_(1)模型解释,CaSi_(2)还原氧化镁为固液反应,此过程为化学反应控制,温度对还原率影响很大,表观活化能为108.99 k J/mol。还原渣的物相分析表明,渣中的MgO含量对Ca_(2)SiO_(4)的晶型转变有影响。展开更多
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
基金supported by the National Natural Science Foundation of China(Nos.U1508217,51504058)the Fundamental Research Funds for the Central Universities of China(No.N162504003)。
文摘在相对真空下以CaSi_(2)为还原剂进行预制球团提镁过程的研究。利用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分别对还原渣的形貌、化学成分和物相进行分析。结果表明,小的氩气流量可以极大地提高氧化镁的还原率,在相对真空下以CaSi_(2)为还原剂的预制球团提镁过程可以用F_(1)模型解释,CaSi_(2)还原氧化镁为固液反应,此过程为化学反应控制,温度对还原率影响很大,表观活化能为108.99 k J/mol。还原渣的物相分析表明,渣中的MgO含量对Ca_(2)SiO_(4)的晶型转变有影响。
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.
