Combination of Green Technique with Ionic Liquid Extraction for Removal Synthetic Dyes and Hexavalent Chromium from Aqueous Solution
| Autor: | Kuen-ying Lee, 李坤穎 |
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| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 Liquid-liquid extraction technique is able to separate or concentrate pollutants. In the past decay, the traditional toxic organic solvents such as benzene, toluene, n-hexane, dichloromethane, chloroform and tri-chloroethene were often used. However, these volatile organic compounds (VOCs) are extremely hazardous to earth environment and the human beings. Therefore, numerous countries have legislated to ban the usage of these organic solvents. In the recent years, room temperature ionic liquids as green solvent has been developed to replace the toxic organic solvents. The superior characteristics of ionic liquid include low vapor pressure, not flammable, less toxicity and environment friendly. One of the applications by using ionic liquid is used to remove the organic matters from the aqueous solution. This study is aimed to use ionic liquid as novel extracting agent to extract synthetic dyes and metal ions from water solution. First, two types of synthetic dyes were selected in this study. One is hydrophilic Rhodamine-B dye which is easily to dissolve in water, and the other is hydrophobic Para-red dye which have limit solubility dissolve only in alkalinity solution and heated up to 75℃. Two kinds of dyes were rapidly extracted by ionic liquid and the extraction efficiency could be up to 99%. Our studies have shown the feasibility and as a green technology to use ionic liquids to extract the dyes from aqueous solution at ambient conditions. Secondly, [BMPy][Tf2N] was also used to extract Cr(VI) from water. Chelating agents were needed to complex the metals before the extraction. Acetylacetone were used as chelating agent for Cr(VI). Graphite furnance atomic absorption spectrophotometer was used for evaluation the extraction efficiency. Experimental conditions such as the dosages addition of chelating agent, pH of aqueous, and volume ratio of water to IL were carefully discussed. Pipet 5mL of 10 mg/L of Cr(VI), the volume ratio for aqueous to IL extraction is 10:1. With two aliquots extraction the removal of Cr(VI) for aqueous was about 95% when acetylactone as[BMPy][Tf2N] were used. Our studies have proven that the ionic liquid as green solvent has shown its superior characteristics for remove toxic organic and inorganic pollutants from water solution. Key words：Ionic liquid, Dye, Cr(VI), extraction, green technique |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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