Due to its high efficiency,Fe(Ⅱ)-based catalytic oxidation has been one of the most popular types of technology for treating growing organic pollutants.A lot of chemical Fe sludge alongwith various refractory polluta...Due to its high efficiency,Fe(Ⅱ)-based catalytic oxidation has been one of the most popular types of technology for treating growing organic pollutants.A lot of chemical Fe sludge alongwith various refractory pollutantswas concomitantly produced,whichmay cause secondary environmental problemswithout proper disposal.We here innovatively proposed an effective method of achieving zero Fe sludge,reusing Fe resources(Fe recovery=100%)and advancing organics removal(final TOC removal>70%)simultaneously,based on the in situ formation of magnetic Ca-Fe layered double hydroxide(Fe_(3)O_(4)@CaFe-LDH)nano-material.Cations(Ca^(2+)and Fe^(3+))concentration(≥30 mmol/L)and their molar ratio(Ca:Fe≥1.75)were crucial to the success of the method.Extrinsic nano Fe_(3)O_(4)was designed to be involved in the Fe(Ⅱ)-catalytic wastewater treatment process,and was modified by oxidation intermediates/products(especially those with COO-structure),which promoted the co-precipitation of Ca^(2+)(originated from Ca(OH)_(2)added after oxidation process)and byproduced Fe^(3+)cations on its surface to in situ generate core-shell Fe_(3)O_(4)@CaFe-LDH.The oxidation products were further removed during Fe_(3)O_(4)@CaFe-LDH material formation via intercalation and adsorption.Thismethodwas applicable to many kinds of organicwastewater,such as bisphenol A,methyl orange,humics,and biogas slurry.The prepared magnetic and hierarchical CaFe-LDH nanocomposite material showed comparable application performance to the recently reported CaFe-LDHs.This work provides a new strategy for efficiently enhancing the efficiency and economy of Fe(Ⅱ)-catalyzed oxidative wastewater treatment by producing high value-added LDHs materials.展开更多
采用CAFE模型(Cellular automata finite element method)模拟第二代镍基高温合金CMSX4凝固过程中的晶粒生长,并探讨浇注温度和冷却速度对凝固组织的影响。结果表明:凝固开始时,首先在铸锭底部会形成一层取向随机的细小等轴晶,由于晶粒...采用CAFE模型(Cellular automata finite element method)模拟第二代镍基高温合金CMSX4凝固过程中的晶粒生长,并探讨浇注温度和冷却速度对凝固组织的影响。结果表明:凝固开始时,首先在铸锭底部会形成一层取向随机的细小等轴晶,由于晶粒间的竞争生长,晶粒数目减小,晶粒尺寸增大,?001?晶向与热流方向偏离角较大的晶粒逐渐被偏离角较小的晶粒淘汰。浇注温度的提高会使晶粒尺寸变大、晶粒数目变小,而冷却速度的升高却会使晶粒尺寸变小,与理论分析一致。展开更多
基金supported by the Chinese Agriculture Research System(No.CARS-35-06B)111 Project(No.B17030)the Sichuan Science and Technology Program(No.2021ZDZX0012).
文摘Due to its high efficiency,Fe(Ⅱ)-based catalytic oxidation has been one of the most popular types of technology for treating growing organic pollutants.A lot of chemical Fe sludge alongwith various refractory pollutantswas concomitantly produced,whichmay cause secondary environmental problemswithout proper disposal.We here innovatively proposed an effective method of achieving zero Fe sludge,reusing Fe resources(Fe recovery=100%)and advancing organics removal(final TOC removal>70%)simultaneously,based on the in situ formation of magnetic Ca-Fe layered double hydroxide(Fe_(3)O_(4)@CaFe-LDH)nano-material.Cations(Ca^(2+)and Fe^(3+))concentration(≥30 mmol/L)and their molar ratio(Ca:Fe≥1.75)were crucial to the success of the method.Extrinsic nano Fe_(3)O_(4)was designed to be involved in the Fe(Ⅱ)-catalytic wastewater treatment process,and was modified by oxidation intermediates/products(especially those with COO-structure),which promoted the co-precipitation of Ca^(2+)(originated from Ca(OH)_(2)added after oxidation process)and byproduced Fe^(3+)cations on its surface to in situ generate core-shell Fe_(3)O_(4)@CaFe-LDH.The oxidation products were further removed during Fe_(3)O_(4)@CaFe-LDH material formation via intercalation and adsorption.Thismethodwas applicable to many kinds of organicwastewater,such as bisphenol A,methyl orange,humics,and biogas slurry.The prepared magnetic and hierarchical CaFe-LDH nanocomposite material showed comparable application performance to the recently reported CaFe-LDHs.This work provides a new strategy for efficiently enhancing the efficiency and economy of Fe(Ⅱ)-catalyzed oxidative wastewater treatment by producing high value-added LDHs materials.
文摘采用CAFE模型(Cellular automata finite element method)模拟第二代镍基高温合金CMSX4凝固过程中的晶粒生长,并探讨浇注温度和冷却速度对凝固组织的影响。结果表明:凝固开始时,首先在铸锭底部会形成一层取向随机的细小等轴晶,由于晶粒间的竞争生长,晶粒数目减小,晶粒尺寸增大,?001?晶向与热流方向偏离角较大的晶粒逐渐被偏离角较小的晶粒淘汰。浇注温度的提高会使晶粒尺寸变大、晶粒数目变小,而冷却速度的升高却会使晶粒尺寸变小,与理论分析一致。
