炉渣去除废水中六价铬

Removal of Chromium(Ⅵ)from Wastewater by Slag

采用炉渣处理模拟含Cr(Ⅵ)废水,确定了炉渣去除Cr(Ⅵ)的适宜条件,并对去除机理及动力学规律进行了探讨。实验结果表明,对于初始质量浓度为10mg/L的含Cr(Ⅵ)废水,在室温、废水初始pH=1.00、炉渣加入量为8g/L、反应时间为240min的条件下,Cr(Ⅵ)去除率达99.2%。对于初始质量浓度低于50mg/L的含Cr(Ⅵ)废水,投加适量的炉渣,可使处理后出水中的Cr(Ⅵ)质量浓度降至排放标准以下。炉渣对Cr(Ⅵ)的去除机理主要是炉渣中溶出的Fe2+对Cr(Ⅵ)的还原作用,炉渣对Cr(Ⅵ)的吸附作用很小。炉渣对Cr(Ⅵ)的还原反应符合一级反应动力学规律,在pH分别为0.55,1.00,2.00的条件下,反应速率常数分别为6.0×10-3,3.3×10-3,4.0×10-4min-1。

Simulated chromium （ Ⅵ） wastewater was treated by slag. The optimum conditions for chromium （ Ⅵ ） removal were determined. The mechanism and kinetics for removal of chromium （ Ⅵ ） were discussed. The results show that： The removal rate of chromium（ Ⅵ ） can reach 99.2% under the conditions of chromium （ Ⅵ ） ＇ s initial concentration 10 mg/L, ambient temperature, initial pH l, slag dosage 8g/L and reaction time 4 h; Cr（Ⅵ） wastewater with initial concentration of less than 50 mg/L can be treated effectively by adding appropriate amount of slag, and the Cr（Ⅵ） concentration in the effluent can meet the national discharge standard. The mechanism for Cr （Ⅵ） removal is due to the reduction by FeE＋ dissolved out of slag. The adsorption of Cr （Ⅵ） on to slag is insignificant. The reduction of Cr（Ⅵ） by slag conforms to the first order reaction law. As pH is 0.55, 1.00 and 2.00, the reaction rate constants are 6.0 × 10 ^-3 , 3.3 × 10^ -3 , 4.0 × 10 ^-4min ^-1 respectively.