ADSORPTIVE SEPARATION OF HEAVY METALS BY TANNIN ADSORBENT AND REGENERATING METHOD FOR THIS ADSORBENT

摘要

PURPOSE:To efficiently adsorb all heavy metal elements with good efficiency from a soln. contg. many kinds of the heavy metal elements by utilizing the dependency of the adsorptivity and elution rate of the tannin adsorbent on pH and to elute the adsorbed heavy metal elements successively at high elution rates. CONSTITUTION:The adsorption of the heavy metal elements is executed by bringing the soln., which is prepd. by adjusting the soln. contg. the heavy metal elements to prescribed pH, and the tannin adsorbent into contact with each other and adjusting the soln. brought into contact with this adsorbent to the pH different from this pH, then bringing the fresh tannin adsorbent and the above-mentioned soln. adjusted to the different pH into contact with each other. The regeneration of the adsorbent eluting the adsorbed heavy metal elements is executed by washing the adsorbent brought into contact with the heavy metal element-contg. soln. adjusted in the pH in the adsorption stage with pure water and bringing an aq. mineral acid soln. of the pH different from the adjusted pH or an aq. alkaline soln. into contact with the washed adsorbent to elute the heavy metal elements, then washing this adsorbent further with the pure water.