离子液体支撑液膜处理含氰废水研究

发布时间：2018-03-11 05:06

  本文选题：离子液体　切入点：支撑液膜　出处：《西安建筑科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：氰化物具有很好的络合能力,因此广泛应用于化工生产中。然而氰化物是剧毒物质,对人体及生态环境有毒害作用,可使细胞失去活性,引起组织窒息,因此氰化废水的处理在环境保护中受到普遍重视。离子液体是一种新型绿色溶剂,具有化学稳定性好、不易挥发、离子迁移率高等特性,可代替传统有机试剂作为膜溶液制备离子液体支撑液膜,用于处理含氰废水。针对某黄金冶炼厂含氰废水治理难题,本论文通过在聚偏氟乙烯基膜(PVDF)中填充室温离子液体(1-丁基-3-甲基咪唑六氟磷酸盐,[Bmim]PF6)制备“填充型”离子液体支撑液膜(SILMs),研究了含氰废水在离子液体支撑液膜中的传输分离过程,考察了膜浸泡时间、原料液中总氰初始浓度、原料液p H、解析相Na OH浓度、反应温度对总氰传输的影响,确定总氰传输过程最优条件。考察不同实验条件下的渗透系数及原料液中总氰浓度变化,研究了萃取条件对传输效率的影响规律。采用电化学阻抗谱法(EIS)实时监测和分析总氰传质过程中膜液流失行为,研究离子液体支撑液膜在应用中的稳定性。(1)以聚偏氟乙烯膜为支撑基膜,煤油为膜溶剂,1-丁基-3-甲基咪唑六氟磷酸盐为离子液体,采用浸渍法制备填充型离子液体支撑液膜,通过计算考察了不同离子液体支撑液膜的膜固容量及膜损失率,通过扫描电子显微镜(SEM)、接触角(CA)等表征方法考察了膜表面及断面形态、膜润湿性等性能,从而制备性能较好的离子液体支撑液膜。(2)考察膜浸泡时间、原料液中总氰初始浓度、原料液p H、解析相Na OH浓度及反应温度对总氰传输的影响。得到了不同实验条件下的总氰去除率。最优的传输分离条件为:膜浸泡时间为1h、原料液浓度为312.24mg/L、原料液p H为4、解析相Na OH溶液浓度为3%及反应温度为25℃。在最优实验条件下,总氰去除率可达95.31%,萃取效率良好。(3)考察了膜浸泡时间、原料液浓度、原料液p H、解析相Na OH浓度及反应温度对总氰传输的影响。得到了不同实验条件下的渗透系数及原料液中总氰浓度变化,从而确定不同反应时间下总氰的传输速率。(4)建立了交流阻抗法研究离子液体支撑液膜稳定性的方法。通过测定体系电阻或电容的变化,可实时连续地监测离子液体支撑液膜中膜液流失情况,进而说明了液膜的稳定性。传质过程中,膜孔中膜液不断流失,其电阻值也不断降低,膜液流失到相邻水相中则溶液电阻不断增加。膜液损失初始阶段,由于支撑液膜表面的离子液体很容易在搅拌条件下脱落,因而流失速度较快;达到中间阶段,膜孔中已有大部分离子液体流失,膜电阻值大幅度降低;当达到穿透阶段,膜孔中的离子液体几乎全部流失,水相溶液浸入膜孔,支撑基体被穿透,即支撑液膜失效。因此,采用交流阻抗谱法可较好地实时监测离子液体支撑液膜的状态,进而表示膜液流失过程。
[Abstract]:Cyanide has good complexation ability, so it is widely used in chemical industry. However, cyanide is a highly toxic substance, which can cause cell inactivation and tissue asphyxia. Therefore, the treatment of cyanide wastewater has been paid more and more attention to in environmental protection. Ionic liquid is a new green solvent with good chemical stability, low volatility and high ionic mobility. It can replace traditional organic reagent as membrane solution to prepare ionic liquid supporting liquid membrane, which can be used to treat cyanide containing wastewater. In this paper, the "filled" ionic liquid supporting liquid membrane SILMsN was prepared by filling room temperature ionic liquid (Bmim) with room temperature ionic liquid (Bmim) in polyvinylidene fluoride (PVDF). The effect of cyanide-containing wastewater on the membrane of ionic liquid supporting liquid was studied. Transport separation process, The effects of membrane soaking time, initial concentration of total cyanide in feedstock solution, pH of raw material solution, concentration of analytical phase NaOH, reaction temperature on total cyanide transport were investigated. The optimum conditions of total cyanide transport were determined. The permeability coefficient and the change of total cyanide concentration in raw liquid under different experimental conditions were investigated. The effect of extraction conditions on transport efficiency was studied. EIS (Electrochemical Impedance Spectroscopy) was used to monitor and analyze the membrane fluid loss in the process of total cyanide mass transfer in real time. The stability of ionic liquid supporting liquid membrane in application was studied. The filled ionic liquid supported liquid membrane was prepared by impregnation method, using polyvinylidene fluoride membrane as the supporting membrane and kerosene as the solvent as the ionic liquid liquid, and the kerosene as the solvent, the 1-#china_person0# -3-methyl imidazolium hexafluorophosphate salt as the ionic liquid liquid liquid. The membrane solid capacity and membrane loss rate of different ionic liquid supported liquid membranes were investigated by calculation. The surface and cross-section morphology and the wettability of the membranes were investigated by means of scanning electron microscopy (SEM) and contact angle (CAA). So as to prepare the better ionic liquid supporting liquid membrane. 2) to investigate the soaking time of the membrane, the initial concentration of total cyanide in the raw liquid, The effect of NaOH concentration and reaction temperature on the total cyanide transport was obtained. The optimum transport conditions were as follows: the time of membrane immersion was 1 h, the concentration of raw material solution was 312.24 mg / L, and the removal rate of total cyanide was obtained under different experimental conditions. The solution pH is 4, the concentration of analytical phase NaOH solution is 3% and the reaction temperature is 25 鈩，

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