零价铁去除水中Cu(Ⅱ)的研究

A study on the removal of Cu(Ⅱ) by zero-valent iron

重金属污染是我国河道中普遍关注的环境问题。本文以石井河为对象,采用批实验和柱实验模拟铁屑和铁粉两种零价铁去除水中Cu(Ⅱ)。XRD和XPS表征结果表明:铁屑和铁粉具有核壳结构,核为Fe(110)型Fe^0,反应前壳为以Fe(Ⅱ)为主的铁氧化物。反应过程中,Cu(Ⅱ)主要被还原并固定在零价铁颗粒表面,Fe^0不断氧化生成Fe_3O_4。批实验表明,两种零价铁都能较快速地去除水中的Cu(Ⅱ)。零价铁去除Cu(Ⅱ)符合准一级动力学方程,去除率和反应速率k_(obs)随着铁屑或铁粉投加量的增加而上升,随着Cu(Ⅱ)初始浓度的增加而降低。当Cu(Ⅱ)初始浓度为45mg/L、零价铁投加量为10g/L时,3h之后铁粉对Cu(Ⅱ)去除率几乎达到100%,而铁屑的去除率为75%,其表观反应速率k_(obs)分别为1.07h^(-1)和0.59h^(-1)。柱实验结果表明,铁屑和铁粉对Cu(Ⅱ)具有较高的去除容量,分别为75.67mg/g和78.60mg/g,铁粉对Cu(Ⅱ)的处理效果略优于铁屑。

Heavy metal pollution in water environment is one of the common concerns in China.Since zero-valent iron has great advantages on heavy metal removal,iron filing and iron powder were applied to Cu（Ⅱ） in Cu（Ⅱ） spiked Shijing River water.XRD and XPS results indicate that both iron filing and iron powder have a core-shell structure with Fe（110） as the core and Fe（Ⅱ） oxides as the shell.During the reaction process,the iron particles were oxidized progressively and formed Fe3O4 at the surface.Batch experimental results showed that both iron filling and iron powder can quickly remove Cu（Ⅱ）from water and the reactions follow pseudo-first-order reaction kinetics.The removal rate and the reaction rate constant kobs increased with the increase of iron dosage,and decreased with the increase of initial concentration of Cu（Ⅱ）.At Cu（Ⅱ） initial concentration of 45mg/L and zero-valent iron dosage of 10g/L,Cu（Ⅱ） was completely removed by iron powder after 3h,while the removal rate was only75%for iron filling.kobs are 1.07h-1 and 0.59h-1,respectively.Column tests showed that iron filing and iron powder have high removal capacity for Cu（Ⅱ）,which were 75.67mg/g and 78.60mg/g,respectively.Overall,iron powder shows higher removal capacity and efficiency than that of iron filling.