Investigations of Collecting Ability of Metal Ions in Water with Chemically Treated Tea Leaf

This method relates to collecting ability of several metal ions in water with chemically treated tea leaf as an adsorbent. The results are as follows: (1) The tea leaf is treated with formalin and phosphoric acid (0.1M) at 80°C after grinding to powder of a size of 70-100 mesh-pass to prepare an adsorbent. This adsorbent can collect the metal ions in water about 4 times that of nontreated tea leaf. (2) There are no remarkable differences in the collecting abilities among green tea leaf, black tea leaf and oolong tea leaf. The boiled down tea leaf can also be utilized as a material for this adsorbent. (3) By the use of 0.1g of adsorbent in a sample solution at a pH 5, up to 100μg of rare earth, nickel and chromium (III) ions can be collected at more than 90%. (4) The maximum adsorption amounts under the conditions were 7.97 and 5.91 mg /g-1 for nickel and neodymium, respectively.