过硫酸钾氧化去除Cu (CN)32-中的氰污染物

近年来,氰化物污染问题日益严重,冶金工业、电镀工业中含有大量氰化物.采用常规的物化法难以对Cu(CN)_3~(2-)中的CN~-达到很好的去除效果,因此探索高效、环保的氰化物处理方法迫在眉睫.过硫酸钾作为一种绿色清洁氧化剂,目前被广泛应用于有机污染物废水的处理.采用均相过硫酸钾对Cu(CN)_3~(2-)中CN~-进行降解,并分析其降解机制,详细研究过硫酸钾投加量、铜氰络合比对CN~-去除率的影响.CN~-的去除率随着过硫酸钾量的增加而升高,当过硫酸钾量为2 mmol·L~(-1),反应时间为60 min时,CN~-的去除率可达89.6%;铜氰络合比的增加促进CN~-的降解.Cu~+被氧化为Cu~(2+)并且以氧化铜的形式存在于沉淀中.采用电子自旋共振波谱仪和自由基猝灭实验对反应过程中可能的自由基进行研究,结果表明在过硫酸钾氧化去除CN~-的过程中,既存在硫酸根自由基氧化途径,又存在非自由基氧化途径.

Oxidation Destruction of Cu(CN)32- by Persulfate

In recent years, cyanide contamination problem is becoming more and more serious. Cyanides widely occur in the wastewater from metallurgical industry and electroplating industry. The efficiency for cyanides removal of conventional physical and chemical methods is not very satisfactory. Therefore, it is urgent to develop highly efficient and environmental friendly methods for the removal of cyanides. As an environmental-friendly oxidant, potassium persulfate is widely used in the treatment of organic pollutants. The destruction of Cu(CN)₃^2- was investigated by homogeneous K₂S₂O₈ under alkaline conditions, and the reaction mechanism was analyzed. The effects of the amount of K₂S₂O₈ and the ratio of Cu⁺/CN^- on the degradation of CN^- were studied. With the increase of K₂S₂O₈ dose, the rate of CN^-oxidation was accelerated. The removal efficiency of CN^- reached 89.6% after 60 min of reaction in the presence of 2 mmol·L^-1 K₂S₂O₈. Oxidation of CN^- was accelerated with Cu⁺/CN^- increasing from 2.0 to 5.0. Cu⁺ was oxidized to Cu²⁺ and copper oxide was formed during the reaction. The reactive radicals were analyzed using electron spin resonance and radical quenching experiments, and the results indicated that both radicals oxidation pathway and non-radical oxidation pathway were responsible for the removal of Cu(CN)₃^2- by K₂S₂O₈.