| As an important inorganic chemical, iodine plays a big role in the national economy. Iodine is a worldwide scarce resource at present; it is therefore of great significance to exploit iodine resources.In this work,we used carbon-based sorbents to adsorb iodine from model brine or natural brine, and investigated the influence of granularity and dosage of sorbents, as well as adsorption time and temperature on their performance. It was also our intention to find the relationship between the ash content of an activated carbon sorbent and its adsorptive capacity. The purpose of this thesis is to provide important essential data for the extraction of iodine from brine.The results showed that the granularity of an activated carbon sorbent and the adsorption temperature have great influences on its adsorptive capacity. We found that best adsorption was achieved for stock activated carbon with a mesh number of more than 80 at 40℃.It was also shown that the lower the ash content in the activated carbon, the greater was the adsorptive capacity.In order to find a more efficient and low-cost method for extracting iodine in brine, we also explored the possibility of using modified activated semi-coke to adsorb iodine in model brine. The experimental results showed that better iodine adsorption properties were obtained for semi-coke after activation and modification, with best adsorption for semi-coke hydrothermally modified by KOH solution. In addition, we characterized the physiochemical properties of semi-coke samples, and discussed how the physiochemical nature of semi-coke influences the adsorption properties.Meanwhile, this work compared the adsorption of an activated carbon sorbent and that of a modified semi-coke. We found that the equilibrium adsorption capacity of a modified semi-coke reached nearly two-thirds of that of an activated carbon. This result proposed a great prospective for the application of modified semi-coke as a sorbent in extraction of iodine from brine. |
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