| 초록 |
Removing heavy metal ions in water is important in public health because of their harmful effects on nervous and excretory systems of human body. In general, such ions have been removed by chemical precipitation and adsorption. For example, the precipitation method requires toxic chemicals (i.e., metal hydroxide) or generates toxic fumes (i.e., hydrogen sulfide) which may cause secondary pollution, whereas the adsorption method needs special adsorbents such as zeolite and carbon nanotube. Here we propose phase transfer-mediated sorption of aqueous heavy metal ions by using biocompatible oleic acid. Heavy metal ions (i.e., Cu (II), Ni (II), Pb (II), and Zn (II)) spontaneously bind to carboxyl group in an oleic acid, being transferred to the oil phase in the end. We find that adding ligands to the aqueous heavy metal ions can accelerate such phase transfer. Removal time by the oleic acid can also be much shortened from a day to few hours by forming an emulsion. Removal capability of oleic acid layer is systematically investigated by changing the volumetric ratio of the oleic acid to water. Selectivity toward the heavy metal ions over lighter ions (i.e., K+ and Na+) is also addressed. |
