【作者】 陈华进；

【导师】 李方实；

【作者基本信息】 南京工业大学 ， 应用化学， 2005， 硕士

【摘要】 含氰废水主要来源于选矿、有色金属冶炼、金属加工、炼焦、电镀、电子、化工、制革、仪表等工业生产。氰化物属于剧毒物,从环境工程和生物安全角度考虑应非常重视含氰废水除毒处理问题。本文对近年来含氰废水处理方法的进展进行了阐述。含氰废水处理与回收方法很多,不能简单判断那种方法的优劣。在选用处理含氰废水的方法时,一定要综合考虑废水的来源和性质。硫酸亚铁法处理含氰废水有许多优点,但不能使废水达到排放标准。从化学平衡的角度分析,该法难以使处理后废水达到排放标准。但是其控制一定反应条件能使处理后废水中几乎不含亚铁氰化物和铁氰化物,只要一步氧化其中的简单氰化物即可使其达到排放标准。实验研究表明,硫酸亚铁络合处理含氰废水最佳工艺条件为:调节废水pH 为6,硫酸亚铁加入量为理论化学计量比1.05 倍,曝气反应20min,处理后总氰浓度为1.982mg/L。二氧化氯是一种新型的水处理剂。与氯气相比,它具有氧化性更强、操作安全简便、受pH 值的影响较小并且不生成产生致癌的氯代有机副产物等优点。实验研究表明,用稳定性二氧化氯处理硫酸亚铁处理后的二级出水时,活化后浓度为1.313%的稳定性二氧化氯加入量为15mL/L 废水,反应pH 为6,反应时间为30 分钟时,处理后废水达到排放标准。对于自制以过氧水合碳酸钠为稳定剂的自制稳定性二氧化氯和市售不同稳定剂稳定的稳定性二氧化氯在处理含氰废水时,两者反应条件基本一致。经过硫酸亚铁法和二氧化氯两步处理,可使废水达到排放标准以下,但是反应分两个单元进行。实验研究表明,铁蓝在pH 为6 的水中即使搅拌4 小时,静置,过滤后其滤液中几乎没有氰化物。二氧化氯在处理硫酸亚铁处理后二级废水时,可以在硫酸亚铁处理废水相同pH 下使废水达到排放标准。这为直接在硫酸亚铁处理后废水不先分离沉淀,直接加入二氧化氯氧化达到排放标准提供了可能性。实验研究表明,硫酸亚铁-二氧化氯一次处理能使废水达到排放标准。硫酸亚铁-二氧化氯处理含氰废水的最佳反应条件为:用硫酸调节pH 为6,加入理论更多还原

【Abstract】 The cyanide-containing wastewater mainly derives from different process industries, such as those waters from the processing of precious metals resource, coal conversion or coking effluents, electroplating waste, chemical engineering and meter industries. It is very important to treat this kind of wastewater because of the redundant toxic contaminants it contains. The recent advance in the treatment methods for cyanide-contained wastewater was reviewed in the paper. The cyanide-containing wastewater has varied characteristics, therefore, different processing and treatment strategies should depend on the source and character of the waters. Complexing precipitation method for cyanide-containing wastewater has many advantages, however, the contents of cyanide of treated water is higher than the highest permission discharging contents of cyanide. We analyzed the ferrous ferrocyanide’s and ferric ferrocyanide’s balance concentration in different pH. It showed that it is difficult to make the concentration of total cyanide under permission discharging contents. But, it is possible to make the treated water by complexing precipitation have little ferrous ferrocyanide and ferric ferrocyanide. Then we easily use oxidation method making the water under permission discharging. The results of the experiments showed that the optimal conditions of complexing precipitation were: FeSO4 dosage 1.05 times of the theoretical value, aeration ror 20min and pH=6. Chlorine dioxide is a very activated oxidant. The results of the experiments showed that the optimal conditions of ClO₂ oxidation process for complexing precipitation treated water were: stable chlorine dioxide is activated 10min, 1.313% activated stable chlorine dioxide dosage is 15mL/L wastewater, mix for 30min and pH=6. The concentration of total cyanide was under permission discharging contents after ClO₂ extensive oxidation. We used stable chlorine dioxide stabled by different stable reagent for treatment. It showed the reagent for stable had little effect for the cyanide-containing wastewater treatment. Complexing precipitation and chlorine dioxide are reacted by two steps. It is expensive in treatment process. We can make the process by one step. Two steps are reacted in the same pH. The ferrous ferrocyanide and ferric ferrocyanide are very stabled in water on pH equal to 6. The results of the experiments showed the concentration of total cyanide could be under permission discharging contents by affiliate ClO2 to wastewater followed Complexing precipitation. The optimal conditions of Complexing precipitation -ClO2 oxidation process was: FeSO4 dosage 1.05 times of the theoretical value, aeration for 20min and pH=6; followed, affiliate ClO2 to wastewater, chlorine dioxide dosage is 18mL/L wastewater, mix for 30min. The concentration of total cyanide was under permission discharging contents after treatment. This process is cheaper because it omitted the step of filtration before the treatment by ClO2.更多还原