双子型两亲性离子液体构建的自组装体系从HCI介质中萃取Au

发布时间：2018-05-30 08:58

本文选题：双子型两亲性离子液体 + 自组装　；参考：《山东大学》2017年硕士论文

【摘要】：针对贵金属Au分离困难、选择性差、后处理不充分等问题,本课题将双子型表面活性剂与离子液体相结8合,利用双子型两亲性离子液体构建了 W/O型微乳液、反相囊泡、囊泡等分子自组装体系萃取HC1介质中的Au(Ⅲ)。通过电导率、TEM、DLS等手段对构建出的自组装体系进行了表征,采用UV-vis、FT-IR、1H NMR、zeta电位等多种方法分析了三种自组装体系的萃取机理。对影响萃取的因素,如平衡时间、萃取剂浓度、Au(Ⅲ)液中HC1浓度、Au(Ⅲ)液中盐浓度等进行了优化,采用草酸、NaBH4、水合肼、萃取剂自还原等多种手段反萃得到了单质Au。本课题的研究丰富了贵金属Au的分离方法,为其工业化萃取中的工艺设计、设备选型、条件优化等提供了理论依据。首先,我们构建了[C_(14)-4-C_(14)im]Br_2/正庚烷/正戊醇/HC1微乳液自组装体系用于萃取HC1介质中的Au。在该自组装体系中,[C_(14)-4-C_(14)im]Br_2平铺在油水界面处,正戊醇穿插其中,两者合作形成液膜。相比于[C_(14)mim]Br/正庚烷/正戊醇/HC1体系,[C_(14)-4-C_(14)im]Br_2/正庚烷/正戊醇/HC1微乳液体系持水量大、电荷数量多,稳定时间长。UV-vis、FT-IR、1HNMR、斜率法确定了阴离子交换的萃取机理。本研究还对影响萃取的因素(平衡时间、水乳比、醇的体积比、Au(Ⅲ)液中HC1浓度等)进行了优化。此外,[C_(14)-4-C_(14)im]Br_2/正庚烷/正戊醇/HC1体系表现出了较高的选择性:Au的萃取率能达到99.55%,分配比可达3000以上,而其他杂质离子Co(Ⅱ)、Cu(Ⅱ)、Fe(Ⅲ)、Ni(Ⅱ)、Sn(Ⅳ)、Al(Ⅲ)萃取率均在7%以下,分配比在1以下。H2C2O4、水合肼、NaBH4用于Au(Ⅲ)的反萃,反萃率接近100%。[C_(14)-4-C_(14)im]Br_2/正庚烷/正戊醇/HC1微乳液体系在萃取Au的方面展现了较好的优势,是一种萃取率高、选择性好的方法。其次,双子型两亲性离子液体12-2-12分别与4种阴离子表面活性剂复配构建反相囊泡自组装体系萃取HCl介质中的Au((Ⅲ)。通过调节阴阳离子表面活性剂的摩尔比确定了 12-2-12/SDBS为n12-2-12:nSDBS=1:1时最佳萃取体系。在此比例下,12-2-12/SDBS对Au的萃取率最高,并且通过TEM表征发现形成了反相囊泡。通过改进的等摩尔变换法,确定了 12-2-12/SDBS体系萃取AuCl4-依据离子交换萃取机理。我们还对Au(Ⅲ)液中HC1浓度、反相囊泡浓度等影响萃取的因素进行了考察。该体系的选择性相对其他体系来说较高,在相同的萃取实验条件下Au的萃取率能高达99.26%,而其他杂质离子Co(Ⅱ)、Cu(Ⅱ)、Fe(Ⅲ)、Ni(Ⅱ)、Sn(Ⅳ)、Al(Ⅲ)萃取率均在6%以下。利用萃取剂自身可还原的性质优点,在该体系中得到了球形Au纳米颗粒,反萃率可接近100%。该自组装体系协同效果好,反萃方法简单,适用于Au的回收。最后,双子型两亲性离子液体12-3-12与脱氧胆酸钠(SDC)复配得到了双分子层的囊泡自组装体系。通过调节12-3-12与SDC的摩尔比,可调控囊泡表面的带电性质。通过动态光散射与zeta电位可确定,12-3-12与SDC摩尔比为1:2时,囊泡表面带正电且较为稳定,尺寸在240 nm左右,适于HC1介质中Au的萃取。与囊泡萃取前相比,萃取后的zeta电位降低了约15 mV左右,TEM照片显示的微观结构没有明显变化,从而确定了正负电荷相互吸引的萃取机理。本部分还对萃取达到平衡的过程条件进行了优化,在最优条件下,Au的萃取率可高达99.67%。通过分步萃取与金属配体离子改进的相互结合,完成了 Au(Ⅲ)、Cu(Ⅱ)、Fe(Ⅲ)三种金属的分离。利用NaCl-NH3·H20将Au(Ⅲ)从囊泡上洗脱下来,并通过还原剂还原,得到了树枝状Au纳米颗粒。
[Abstract]:In view of the difficulties in separating Au from precious metals, poor selectivity and inadequate post-processing, this topic combines the double sub type surfactants with ionic liquids 8, and constructs a W/O microemulsion, reverse phase vesicles, vesicles and other molecular self-assembly systems to extract Au (III) in the HC1 medium by using a dual type two Pro ionic liquid. By means of conductivity, TEM, DLS and other means UV-vis, FT-IR, 1H NMR, zeta potential were used to analyze the extraction mechanism of the three self-assembly systems. The factors affecting the extraction, such as equilibrium time, concentration of extractant, HC1 concentration in Au (III) solution and the concentration of salt in Au (III) liquid, were optimized, using oxalic acid, NaBH4, hydrazine and extraction. A variety of methods, such as agent self reduction, have been used to reverse the extraction of Au., which has enriched the separation method of precious metal Au. It provides a theoretical basis for the process design, equipment selection and conditions optimization in the industrial extraction. First, we constructed the [C_ (14) -4-C_ (14) im] Br_2/ n-Heptane / pentyl alcohol /HC1 microemulsion self assembly system for the extraction of the Au. In the HC1 medium, Au. in the self-assembly system, [C_ (14) -4-C_ (14) im]Br_2 is spread at the oil and water interface, and n-pentyl alcohol is interspersed and the two forms a liquid film. Compared to [C_ (14) mim]Br/ n-Heptane / n-pentyl alcohol /HC1 system, [C_ (14) -4-C_ (14) im]Br_2/ n-Heptane / n-pentyl alcohol microemulsion system has large water holding capacity, more charge and stable time. The extraction mechanism of anion exchange is determined by long.UV-vis, FT-IR, 1HNMR and slope method. This study also optimizes the factors affecting extraction (equilibrium time, water emulsion ratio, volume ratio of alcohol, HC1 concentration in Au (III)). In addition, [C_ (14) -4-C_ (14) im]Br_2/ n-Heptane / n-pentyl alcohol /HC1 system shows higher selectivity: Au extraction rate energy Up to 99.55%, the distribution ratio can be over 3000, while other impurity ions Co (II), Cu (II), Fe (III), Ni (II), Sn (IV), Al (III) are all under 7%, the distribution ratio is below 1.H2C2O4, hydrazine hydrate, NaBH4 is used in the reverse extraction of Au (III), and the stripping rate is close to 100%.[C_ (14) -4-C_ (14) im]Br_2/ n-Heptane / pentyl alcohol micro emulsion system in extraction It shows a good advantage, which is a high extraction rate and good selectivity. Secondly, double sub type two Pro ionic liquid 12-2-12 is combined with 4 kinds of anionic surfactants to construct the Au ((III) in the HCl medium for the reverse phase vesicle self assembly system. The 12-2-12/SDBS is n12- by adjusting the mole ratio of the cation and cation surfactants. The best extraction system at 2-12:nSDBS=1:1. Under this proportion, the extraction rate of 12-2-12/SDBS to Au is the highest, and the reverse phase vesicles are formed by TEM characterization. Through the improved equimolar transformation method, the mechanism of the extraction of AuCl4- based on the ion exchange extraction is determined by the 12-2-12/SDBS system. We also have the concentration of HC1 in the Au (III) liquid and the concentration of the reverse phase vesicle in the Au (III) liquid. The factors affecting extraction are investigated. The selectivity of this system is higher than that of other systems. The extraction rate of Au can be as high as 99.26% under the same extraction conditions, while other impurity ions Co (II), Cu (II), Fe (III), Ni (II), Sn (IV), and Al (III) are both less than 6%. The properties of the extractant's self reducible property are in this body. Spherical Au nanoparticles were obtained in the system, and the stripping rate was close to 100%.. The synergistic effect of the self-assembled system was good, and the stripping method was simple and suitable for the recovery of Au. Finally, the double molecular two Pro ionic liquid 12-3-12 and sodium deoxycholate (SDC) were mixed with the double molecular layer vesicle self-assembly system. By adjusting the molar ratio of 12-3-12 to SDC, it could be regulated. By dynamic light scattering and zeta potential, it is determined by dynamic light scattering and zeta potential that when the molar ratio of 12-3-12 to SDC is 1:2, the surface of the vesicle is positive and stable, the size is about 240 nm, suitable for the extraction of Au in the HC1 medium. Compared with the vesicle extraction, the zeta potential decreases about 15 mV after the extraction, and the microstructure of the TEM photo shows no microstructure. The extraction mechanism of the mutual attraction between positive and negative charges is determined. This part also optimizes the process conditions for the extraction equilibrium. Under the optimal conditions, the extraction rate of Au can be as high as 99.67%. by the combination of step extraction and metal ligand improvement, and the separation of three metals (III), Cu (II), Fe (III) is completed. NaCl-NH3 (H20) was used to remove Au (III) from the vesicles and the dendritic Au nanoparticles were obtained by reducing agent.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ028.32

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