乳状液膜法处理钢铁冶金烧结烟气脱硫含铊废水

发布时间：2018-02-21 03:24

  本文关键词： 乳状液膜 含铊废水 稳定性 去除率 破乳　出处：《湘潭大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着工业化进程加快,矿产资源不断开发利用,铊污染造成的环境危害严重威胁到人类的健康,引起了社会广泛关注。目前,湖南省环境保护厅颁布了《工业废水铊污染物排放标准》,其排放限值为5μg/L。最近在湖南湘江流域中却发现铊含量超标,经调查后发现部分铊污染物来源于湖南某钢铁公司的烧结烟气脱硫废水。传统方法一般难以对较低浓度含铊废水进行深度处理,而乳状液膜法处理较低浓度的含铊废水具有较好的效果。本文中乳状液膜以航空煤油作为有机溶剂,2-乙基己基膦酸2-乙基己基酯(P507)作为载体,聚异丁烯丁二酰亚胺(T154)作为表面活性剂,聚异丁烯(PIB)作为添加剂,硫酸作为内相溶液制成。由于乳状液膜的稳定性会直接影响到金属离子分离效果,所以首先对乳状液膜的稳定性进行了研究,分别考察了表面活性剂种类与浓度、载体浓度和内相浓度等因素对其稳定性的影响。研究表明,T154较于Span 80能更好的维持体系的稳定;在各影响因素中表面活性剂浓度和水乳比对乳状液膜的稳定性影响较大,破裂率在6%以上,因此要适当增大表面活性剂浓度并减小水乳比使体系达到稳定状态。在乳状液膜稳定性实验的基础之上,进一步研究了该乳状液膜体系对含铊废液的处理效果。在最优条件下,即载体浓度为2%、表面活性剂浓度为5%、内相硫酸浓度为0.5 mol/L、搅拌速度为350 rpm、水乳比为500:40、油内比为3:1,反应15分钟后,经电感耦合等离子体质谱仪检测,处理后废水中的铊浓度低于5μg/L,铊离子的去除率为99.76%,达到了湖南省铊污染物排放的地方标准。随后考察了废水中主要的钙、镁共存离子对乳状液膜体系提取铊离子的影响。结果表明,当外水相由于体系内的离子交换快速转变为酸性环境时,有利于该乳状液膜体系从含有较多钙、镁共存离子的废水中提取铊。反应后的乳液需要破乳进行回收复用,故本文对破乳条件也进行了研究。分别采用超声、离心、加热和破乳剂等方法进行破乳。研究表明单一方法并不能使体系有效破乳,而在加热-破乳剂联合破乳法中:温度为70℃、氧氧化钠作为破乳剂基本可以使体系完全破乳,破乳后的油相经重复利用对铊离子的去除率依然能够达到90%以上。最后本文进行了乳状液膜的膜内研究,解释了铊离子发生迁移的途径。综上所诉,乳状液膜作为一种高效分离的液膜技术,较于传统方法具有传质速率快、传质面积大和选择性好等优点,且乳液破乳后油相能够回收复用,在处理钢铁冶金烧结烟气脱硫含铊废液上有着良好的应用前景。
[Abstract]:With the acceleration of industrialization and the continuous exploitation and utilization of mineral resources, the environmental hazards caused by thallium pollution have seriously threatened the health of human beings and caused widespread social concern. The Environmental Protection Department of Hunan Province promulgated the "Standard for the discharge of Thallium pollutants from Industrial Wastewater", the emission limit of which is 5 渭 g / L. Recently, it was found that the content of thallium exceeded the standard in the Xiangjiang River Basin in Hunan Province. After investigation, it was found that some of the thallium pollutants originated from the flue gas desulphurization wastewater from a certain iron and steel company in Hunan Province, and it was generally difficult to treat the wastewater with lower concentration of thallium by the traditional methods. In this paper, aviation kerosene was used as the organic solvent, 2-ethylhexyl phosphonate 2-ethylhexyl phosphonate (P507) was used as the carrier. Polyisobutene succinimide (T154) as surfactant, polyisobutene (PIBB) as additive and sulfuric acid as internal phase solution. The stability of emulsion liquid membrane will directly affect the separation effect of metal ions. Therefore, the stability of emulsion liquid membrane was studied, and the effects of surfactant type and concentration, carrier concentration and inner phase concentration on the stability of emulsion liquid membrane were investigated. The results showed that T154 could maintain the stability of the system better than Span 80. Among the influencing factors, the concentration of surfactant and the ratio of water to milk have great influence on the stability of emulsion liquid membrane, and the rupture rate is more than 6%. Therefore, it is necessary to increase the concentration of surfactant properly and reduce the water / milk ratio to make the system stable. On the basis of the stability experiment of emulsion liquid membrane, the treatment effect of the emulsion liquid membrane system on thallium waste liquid is further studied. That is, the carrier concentration is 2: 5, the surfactant concentration is 5, the internal phase sulfuric acid concentration is 0.5 mol / L, the stirring speed is 350 rpm, the water / milk ratio is 500: 40, and the oil / oil ratio is 3: 1. After 15 minutes of reaction, the reaction is detected by inductively coupled plasma mass spectrometer. The concentration of thallium in the treated wastewater is less than 5 渭 g / L, and the removal rate of thallium ion is 99.76, which is up to the local standard of thallium pollutant discharge in Hunan Province. The effect of mg coexisting ions on the extraction of thallium ion from emulsion liquid membrane system was studied. The results showed that the external water phase changed rapidly to acidic environment due to ion exchange in the emulsion liquid membrane system, which was favorable for the emulsion liquid membrane system to contain more calcium. Thallium is extracted from waste water containing magnesium ions. The emulsion after reaction needs to be reclaimed and reused by demulsification, so the conditions of demulsification are also studied in this paper. The results of demulsification by heating and demulsifying agent show that the single method can not effectively demulsify the system, but in the combined demulsifying method of heating and demulsifying agent: the temperature is 70 鈩，

本文编号：1520859