零价铁处理冷轧含铬废水的研究

研究了Fe0处理冷轧含铬废水的适宜条件,并对Fe0去除废水中Cr(Ⅵ)的反应机制及动力学规律进行了探讨。结果表明,在30℃,Fe0和酸液的投加量分别为2.2 g/L和1.2%(体积分数),振荡转速为200r/min,反应时间20 min,沉淀pH值为8～9,沉淀1 h时,总Cr和Cr(Ⅵ)去除率高达99.99%和100%。Cr(Ⅵ)去除的反应机制主要是Fe0对Cr(Ⅵ)的还原作用及金属氢氧化物在Fe0表面的沉积和共沉积作用,其中Cr(Ⅵ)的还原反应符合拟一级反应动力学规律,表观速率常数随反应温度的升高而增大。

Chromium Removal From Cold Rolling Wastewater by Zero- valent Iron

This paper studies the optimum conditions of treatment for cold rolling wastewater containing chromium by zero-valent iron,and discusses the reaction mechanism and kinetics rules for Cr(Ⅵ) removal in the wastewater.When the reaction temperature,dosage of Fe0 and acid solution,oscillator speed,reaction time,pH value range of precipitation and precipitation time shows 30 ℃,2.2 g/L,1.2%,200 r/min,20 min,8～9 and 1h respectively,the removal efficiencies of total Cr and Cr(Ⅵ) could achieve 99.99% and 100%.The Cr(Ⅵ)removal is mainly attributed to reduction effect of Fe0,moreover the precipitation and co-precipitation effect of metal hydroxides on the Fe0 surface.The reduction process of Cr(Ⅵ)follows to pseudo first order reaction law and the apparent rate constant increases with the increase of reaction temperature.