Heavy Metal Adsorption of Untreated Barks by Treatment Conditions of Aqueous Solution

This study was designed to investigate the adsorption of heavy metal ions by untreated bark according to the treatment conditions of aqueous solution. The effect of temperature and pH of aqueous solution, particle size of bark, addition of light metal ions on the adsorption was examined, and the competition in adsorption among heavy metal ions was also evaluated. te The adsorption ratio of and increased with increasing themperature of solution from to however, it was relatively constant at temperatures between and . The adsorption ratio of increased continuously with increasing the temperature of solution. The maximum adsorption ratio of , , and was noted at pHs ranged 6 to 7; however, the adsorption ratio declined sharply on either sides of the optimum. The adsorption ratio of decreased continuously with increasing the pH of solution. The adsorption ratio increased as decreasing the particle size of bark, and there was little differences in adsorption tendency between pine and oak bark. By the addition of or (10~25 ppm), the adsorption ratio of and increased. An increase of the adsorption ratio was higher in oak bark than in pine bark. However, the adsorption ratio of and was not affected by the addition of light metal ions. As the mixed solution of 2 or 3 kinds of heavy metal ions(, , ) was treated with the untreated bark, the adsorption of decreased considerably because of the competitive adsorption among heavy metal ions. Also the adsorption of was more and less reduced. However the adsorption of was not affected by the presence of other heavy metal ions.