Investigation of Removing Mercury from Activated Carbon Using Bioleaching Processes
| Autor: | Min-Yu Shih, 施旻佑 |
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| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 People have been paying attention to the emission of heavy metals (mercury) from stationary sources of air pollution; the traditional air pollution control facilities, however, is so difficult to have a great effect on removing mercury that human health and environment are facing a huge jeopardy. At present, the main prevention method of mercury pollution is adsorbent injection which is the most feasible way today. By such method, an amount of discarded activated carbon would be produced and then be buried or burned. From the environmental point of view, it might cause secondary pollution when the activated carbon was dealt with improperly. Therefore, this study attempted to develop a new bioregeneration technology of presulfurized activated carbon. The bioregeneration technology relied on the oxidization and acidification of Acidithiobacillus thiooxidans to carry out a bioleaching process of activated carbon. That means in the activated carbon, sulfur was oxidized and mercury was leached then. It could advance the desorption efficiency of the mercury and regenerate/recover the presulfurized activated carbon. This study includes the acclimation of soil and the acclimation of activated carbon. According to the results of this study, the more times of acclimation soil had; the better activity of At. thiooxidans performed. The period of soil acclimation decreased to 10-15 days. As to the acclimation of activated carbon, At. thiooxidans was difficult to utilize sulfur-impregnated activated carbon, so medium and soluble nutrition were added in order to increase the efficiency of acclimation. Moreover, in the experiment on activated carbon regeneration it was showed that when the concentration of activated carbon was high, the value of pH decrease rapidly, and the production of sulfate is reduced (the removal efficiency of mercury was 20-40%). The response surface graph showed that the removal efficiency of mercury reached a peak of 40% around when the concentration of activated carbon was 10% and the concentration of culture was 20%. Through the physicochemical analysis, the study found that the sulfide on the surface of activated carbon was oxidized via At. thiooxidans or lowered the value of pH by the production of sulfuric acid. Finally, the washing flow’s direct response and indirect response were verified in this study. After washing flow, the specific area of the activated carbon was from 588.5 m2 g-1 to 757 m2 g-1. The finding is helpful for the recycling research and technology in the future. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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