【作者】 李元岗；

【导师】 杨胜科；

【作者基本信息】 长安大学 ， 环境工程， 2010， 硕士

【摘要】 镉是列入我国“水中优先控制污染物黑名单”的重点控制与监测污染物,在水体中不仅会以离子态存在,还能与多种配体形成可溶解的络合物,镉氨络合物是其中一种。镉氨络合物废水处理难度大,用普通化学沉淀法处理效果不佳,需要建立一种处理效率高、对环境无二次污染的处理方法。通过实验研究,本文在废水中镉的测定方法和镉氨络合物废水处理方面,取得了以下研究成果：(1)建立了铁氰化钾一钙黄绿素后化学发光体系测定水中镉的方法,优化了测定条件。在最佳的测定条件下,Cd(Ⅱ)在1.0×10-5～1×10-3mol/L浓度范围内与化学发光强度呈良好的线性关系。回归方程为：I=7.461C-5.96(C为Cd(Ⅱ)浓度,10-5mol/L),相关系数为0.9980。方法的检出限为3.6×10-6mol/L,相对标准偏差为2.84%(n=11)。此方法用于催化剂废水中Cd(Ⅱ)的测定,结果令人满意。(2)探讨了Cd(Ⅱ)在铁氰化钾-钙黄绿素体系中后化学发光反应可能的机理：钙黄绿素与铁氰化钾在碱性条件下发生化学反应,生成激发态的钙黄绿素和亚铁氰化钾,当激发态的钙黄绿素回到基态时,产生第一次化学发光现象。当Cd(Ⅱ)加入到已完成反应的混合溶液中,Cd(Ⅱ)将会催化亚铁氰化钾和钙黄绿素发生反应,生成激发态的钙黄绿素,同时Cd(Ⅱ)又可以与钙黄绿素发生反应生成能产生荧光的反应产物,当激发态的钙黄绿素回到基态时,产生化学发光并释放出能量。(3)比较了普通化学沉淀法和TMT螯合沉淀法处理含镉离子废水的效果。结果显示,与NaOH、Na2S和Na2CO3相比,TMT螯合沉淀处理含镉离子废水的效果最好。2×10-3mol/L的含镉离子废水经TMT螯合沉淀处理以后,滤液中剩余镉的含量仅为0.103mg/L,经絮凝沉淀处理以后,废水可达标排放。(4)TMT螯合沉淀处理镉氨络合物废水实验研究表明：在pH=7,TMT投加量为0.855倍镉的物质的量剂量,絮凝剂投加量为聚合氯化铝100mg/L或聚合氯化铝铁60mg/L时,处理效果最好。2×10-3mol/L的镉氨络合物废水经处理后镉的含量分别降至0.09mg/L和0.06mg/L,低于国家工业废水排放标准要求的0.1mg/L。TMT与镉氨络合物反应在30min内即可达到平衡,生成的沉淀物稳定,对环境不会造成二次污染。更多还原

【Abstract】 Cadmium is one of priority controlled pollutants in water blacklist. The existence form of Cadmium in water not only stated in ionic condition, but also formed complex with many kinds of ligands. Those complex compounds could dissolubled in water; the cadmium ammonia complex is the typical one. The cadmium ammonia complex wastewater was intractable. The treated effect was ineffective through ordinary chemical precipitation. So, a high efficiency and no secondary pollutants treatment should be eatablished to treate the cadmium ammonia complex wastewater.In this paper, the Cd(Ⅱ) determination and cadmium ammonia complex wastewater treated were studied through experiments, the following findings can be drawn:(1) A post-chemiluminescence method for determination of cadmium with potassium ferricyanide-calcein system was established, the experimental conditions of the CL reactions were optimized. The linear response ranger of this method was from 1.0×10-5 to 1×10-3mol/L with a linear correlation of 0.9980. The detection limit was 3.6×10-6mol/L and the relative standard deviztion was 2.84%(n=11). The method was applied to the determination of Cd(Ⅱ) in catalyst wastewater with satisfactory results.(2) The possible PCL mechanism of Cd(Ⅱ) in calcein-potassium ferricyanide reaction system was discussed:Calcein reacted with potassium ferricyanide in the alkaline solution, generated the excitated calcein and potassium ferrocyanide. When the excitated calcein came to original state, a chemiluminescence reaction was observed. When Cd(Ⅱ) added in to the complete reacted mixture solution, Cd (Ⅱ) may catalysis potassium ferrocyanide reacted with calcein generated the excitated calcein again. A chemiluminescence reaction was observed when the excitated calcein came to original state. At the same time, Cd(Ⅱ) could reacted with calcein generated the reaction which could produced fluorescence.(3) Comparing the effects of treating wastewater containing cadmium by common chemical precipitation process and TMT chelation precipitation process. The results showed that, comparison of removing cadmium among NaOH, Na2S, Na2CO3 and chelating agent TMT, TMT treating the wastewater containing cadmium was the best.2×10-3mol/L cadmium ions wastewater treated by TMT, cadmium remaining in the filtrate was only 0.103mg/L. After TMT chelation precipitation process, adding flocculant could make the wastewater meet the discharge standards.(4) Through the TMT chelation precipitation treated cadmium ammonia complex wastewater experiments, the results show:when the wastewater pH value was 7, the TMT/Cd ratio was 0.855:1 and the flocculants dosage were PAC 100mg/L or PAFC 60mg/L, the treatment effect was good.2×10-3mol/L cadmium ammonia complex wastewater after treated, cadmium were reducted to 0.09mg/L and 0.06mg/L respectively, lower than the industrial wastewater discharge standard of 0.1mg/L. TMT chelated cadmium ammonia complex and formed precipition finished in 30 minuts. The precipitation has more stabilization and it will not cause secondary pollution on the environment.更多还原