研究对比了热,碱和Fe3O43种方法激活过硫酸钠对二恶烷的降解情况.结果表明,加碱且反应液pH值不超过12h,过硫酸钠对二恶烷的降解受到了抑制.加热可以有效激活过硫酸钠降解二恶烷,在40℃、过硫酸钠与二恶烷的物质的量比为20∶1的条件下,反应48h时二恶烷的降解率达98％,降解反应的准一级反应速率常数为68.1×10 6h-1.非均相体系中,Fe3O4也可显著激活过硫酸钠降解二恶烷,过硫酸钠与二恶烷的物质的量比为80∶1,Fe3O4与混合溶液固液比仅为1∶100时,二恶烷降解的准一级反应速率常数为61.1×10-6h-1,接近上述加热激活的水平.Fe3O4激活过硫酸根降解二恶烷时,由于过硫酸根优先与二恶烷反应而不是Fe3O4发生反应,因此在二恶烷降解完成之前溶解态Fe产生量低、Fe3O4消耗少.该研究结果反映出应用Fe3O4激活过硫酸盐的方法修复有机污染地下水的较大潜力.%In this study activation ofpersulfate by heat,base,and magnetic oxide (Fe3O4) for degradation of 1.4-dioxane was investigated and compared.The results showed that degradation of 1,4-dioxane was inhibited in the base-activation system with pH low than 12.Heat was effective for persulfate activation to degrade 1,4-dioxane.When the temperature was 40℃ and the molar ratio ofpersulfate and 1,4-dioxane was 20∶1,the percentage of 1,4-dioxane removal reached 98％in 48h and the pseudo-first-order reaction rate constant was 68.1 × 10-6h-1.Degradation of 1,4-dioxane was also significant in the heterogeneous system with Fe3O4 as the activator.When the molar ratio ofpersulfate and 1,4-dioxane was 80∶1 and the solid-liquid ratio between Fe3O4 and solution was 1∶100,the pseudo-first-order reaction rate constant for 1,4-dioxane removal was 61.1×10 6h-1,which was close to that obtained with heating (40℃) as the activation method.In this Fe3O4-based heterogeneous activation system,production of soluble Fe and consumption of Fe3O4 were minimal before depletion of 1,4-dioxane,which is due to preference of the reaction between persulfate and 1.4-dioxane to the reaction between persulfate and Fe3O4.The results of this study indicated the potential of application of the Fe3O4-based method for persulfate activation for remediation of groundwater contaminated by organic compounds.
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