摘要
本文从亚铁离子和负二价硫离子还原Cr(Ⅵ)的试验开始,逐步探讨了FeS处理含Cr(Ⅵ)废水的反应机理。实验发现,亚铁离子除Cr(Ⅵ)速度随pH变化关系较为复杂。酸性条件下除Cr(Ⅵ)速度很大。当溶液酸度减小时除Cr(Ⅵ)速度逐渐减小,但当溶液接近中性或碱性时,除Cr(Ⅵ)速度重新增大。若用FeS处理含Cr(Ⅵ)废水,除Cr(Ⅵ)速度随水样酸度的增加而增大。除Cr(Ⅵ)过程的速度控制步骤是FeS的溶解。实验还表明,FeS除Cr(Ⅵ)的主要作用是亚铁和负二价硫对Cr(Ⅵ)的还原。
In this paper the mechanism about the treatment of wastewater containing hexavalent chromium by FeS is studied, It is found that the velocity of removing the Cr(Ⅵ) by Fe(Ⅱ) varies with pH in a complex relation. In acidic solution Fe^(2+) reacts with Cr(Ⅵ) quickly and the velocity decreases with the decreasing of its acidity.But when the solution gets near neutral or alkaline the velocity increases and they can fastly react again. It is also discovored that in the process of removing Cr(Ⅵ) by FeS the main action is that the Cr(Ⅵ) is reduced by the solved Fe^(2+) and H_2S in acidic condition but in neutral or alkaline solution it is reduced only by Fe(Ⅱ) as a main reductor. The slowest step Of the process is the solving of FeS.
关键词
硫化铁
机理
铬
废水
处理
treatment,mechanism,reduction ferrous sulfide,chromium wastewater
