离子交换—还原沉淀耦合工艺处理Cr(Ⅵ)废水试验研究

摘要

为了高效、低成本地处理含Cr(Ⅵ)废水,提出采用离子交换—还原沉淀耦合工艺处理该废水.结果表明,将质量浓度为100 mg/L的含Cr(Ⅵ)废水以20 mL/min连续10.5 h流经离子交换柱,Cr(Ⅵ)的吸附率高达99.9％；用5％ NaOH溶液洗脱饱和的离子交换树脂,洗脱液含Cr(Ⅵ)高达6918.7 mg/L.FeS04·7H20还原处理浓缩后的高浓度含Cr(Ⅵ)废水的最佳反应条件为pH≥7,反应时间30 min,搅拌速度100 r/min,FeSO4·7H20投加量为理论投加量的1.2倍,此条件下Cr(Ⅵ)去除率高达99.7％.%The coupling process of ion-exchange-reduction precipitation, has been carried out for treating the wastewater containing Cr(Ⅳ) with high efficiency and low cost. The results show that when the Cr(Ⅳ)-containing wastewater, whose mass concentration is 100 mg/L,is used for flowing through the ion exchange column continuously for 10.5 h,with 20 mL/min,the adsorbing rate of Cr (Ⅳ) is as high as 99.9%. 5% NaOH solution is used for eluting the saturated ion exchange resin. The Cr( Ⅳ) contained in eluting liquid is as high as 6 918.7 mg/L. After the Cr(Ⅳ )-containing wastewater with high concentration is treated by FeSO4·7H2O reduction process. Under the following optimum reaction conditions:pH ≥ 7,reaction time 30 min,stirring speed 100 r/min,and dosage of FeSO4·7H2O 1.2 times of the theoretical amount,its Cr( Ⅳ ) removing rate can be up to 99.7%.