【作者】 张梅；

【导师】 赵云斌；

【作者基本信息】 华中科技大学 ， 分析化学， 2015， 硕士

【摘要】 重金属在工农业生产、国防安全中的应用非常广泛。同时,人类活动导致环境中的重金属污染也日益严重,环境质量下降,直接危害人体健康,治理环境中重金属污染迫在眉睫。目前对于重金属污染的处理技术一般有沉淀法、电化学方法、吸附法、萃取法等。溶剂萃取作为一种操作简便、技术相对成熟的传统处理方法,适用于水中重金属离子的分离与富集。其中,萃取剂的选择是萃取技术的关键。本课题组利用自行合成的一种有机磷化合物,即三(2-丁基亚甲基胺)氧化磷(NSC)作为萃取剂,以重金属离子铅、镉、铜为研究对象,对NSC萃取这三种重金属离子进行了系统性研究。实验结果表明,NSC在较低的相比条件下(o/w),对镉、铅的萃取可达95%以上的萃取效率,相比于其他有机磷类萃取剂,NSC的使用减少了有机相的用量,从而降低了萃取剂成本,减小了有机溶剂污染。在重金属离子的分离富集、重金属工业废水处理及重金属土壤污染治理等方面具有良好的应用前景。本论文的主要工作开展如下:以NSC为萃取剂,在不同相比、酸度、萃取剂浓度、萃取时间、温度等条件下分别对铅、镉、铜三种离子的萃取行为进行了研究,在镉的萃取研究中,选用了三种常用的有机磷萃取剂与之进行了比较,显示出NSC具有明显的优势。同时,为了有效回收重金属离子进行了反萃取实验,研究结果表明:1、在1:5相比条件下,20%萃取剂对Cd2+的一次萃取率可达到95%以上,萃取剂的饱和容量大于900 mg/L,并初步推导了NSC对Cd2+的萃取机理。反萃实验表明,NH4Cl对Cd2+具有良好的反萃效果。NSC与三种常用的有机磷萃取剂D2EHPA、TOPO、TBP对比试验显示,NSC萃取效果明显优于另外三种有机磷物质。对于低浓度Cd2+,经萃取、反萃取步骤,该萃取剂对0.1 mg/L和1.0 mg/L Cd2+的水溶液,可实现15倍左右的富集,对5 mg/L Cd2+的水溶液,富集倍数也可达8倍左右。这对于低浓度镉离子分离富集和回收利用具有重要意义。2、NSC对Pb2+萃取效果很好,在1:10相比条件下,5%萃取剂对50 mg/L Pb2+的一次萃取率达到95%以上。萃取剂的饱和容量大于2000 mg/L。反萃实验表明,所用反萃试剂对Pb2+的反萃效果均不理想。3、NSC对Cu2+萃取效果较Pb2+、Cd2+差,在1:1相比条件下,20%萃取剂对50 mg/L Cu2+的一次萃取率为85%左右。反萃实验表明,0.1 mol/L HNO3一次反萃效率约为80%。更多还原

【Abstract】 The heavy metals are applied more and more widely in the industrial and agricultural production, national defense and security.While, the heavy metal pollution in the environment is increasingly serious by human activities,environmental quality decline, and endanger human health directly, the heavy metal has become the major pollution in the environment, and focus in environmental governance. In general, the processing technology of heavy metal pollution include precipitation method, electrochemical method, adsorption, extraction and so on. As a kind of traditional separation technology,solvent extraction is simple of operation, mature technology for separation and enrichmen for heavy metal ions from water sample. The extracting agent selection is the key technology of the extraction. In this paper, tri-(2- butyl amine methylene) phosphine oxide(NSC) was selected as extractant agent, and the heavy metals lead, cadmium, copper as the object of study, the extraction behavior of the material on the three kinds of heavy metal ions were systematically studied. Especially for cadmium, lead, NSC had the advantage of high extraction efficiency, simple operation. The use of NSC reduced the amount of organic phase, the extraction cost is cut down,and organic solvent pollution was less.Three(2-butyl amine methylene) phosphine oxide had good application prospect in separation and enrichment of heavy metals, industrial wastewater and heavy soil pollution.The main contents as follows.The extraction behavior of NSC was investigated on Cd2+、Pb2+、Cu2+. These conditions such as phase ratio, acidity, concentration of extractant, extraction time, temperature, metal ion concentration were studied and the optimal extraction conditions had been achieved. In the cadmium experiment,three commercial organic phosphorus compounds were selected were selected and compared with NSC.The results indicsted that NSC had obvious advantages in the extraction field.At the same time, the reverse extraction experiment was carried out for the effective recovery of heavy metal ions. These findings suggest:1、The extraction rate of cadium reached above 95% in a single-stage under the condition of 20% for extractant concentration, 1:1 for phase ratio. The load capacity of the extractant was above 900 mg/L. The stripping experiment showed that NH4 Cl had a good stripping effect on the Cd2+.The contrast test indicated NSC had the advantages of high extraction efficiency, simple operation, low cost of extraction. For the low concentration of Cd2+, After extraction, reverse extraction steps, the enrichment factor of the low concentration of Cd2+(0.1mg/L and 1.0 mg/L) was more than 15 times,the aqueous solution of 5 mg/L Cd2+, up to 8 times. It playd an important role in separation and recycling for the low concentration of cadmium ions.2、The extraction experiment of lead displayed that the extraction rate of lead reached above 95% in a single-stage under the condition of 5% for extractant concentration, 1:1 for phase ratio.However, the stripping effect was less than ideal.3、The extraction experiment of copper showd that, the organic phosphorus on the Cu2+ extraction effect was poor, approximately,the extraction efficiency was 85% at phase ratio 1. The stripping experiment showed that the stripping efficiency of 0.1 mol/L HNO3 was about 80%.更多还原