REMOVAL AND RECOVERY OF GALLIUM ION FROM SOLUTION BY INSOLUBLE AMPHOTERIC STARCHES

The removal and recovery of gallium ion (Ga+3) from a solution with the high cross-linked amphoteric starches containing the phosphate anionic group and the quaternary ammonium or tertiary amine cationic group was investigated. The adsorption capacity of tertiary amine phosphate starch (TAP) and quaternary ammonium phosphate starch (QAP) is 0.54 and 0.48 meq/g, respectively. The adsorption process has been found to be concentration dependent and endothermic, and follows the Langmuir isothermal adsorption. The heat of adsorption (DELTAH) is equal to 7.65 kcal/mol for the QAP and equal to 7.84 kcal / mol for the TAP. The percentage of adsorbed Ga+3 ion decreases when HCl, H2SO4, NaCl, or Na2SO4 is added to the solution. The Ga+3 ion adsorbed on the adsorbents can be recovered by treating with an NaOH or HCl solution (1M and 3M); the maximum percentage of recovery is about 70% when 1M NaOH solution is used. (C) 1993 John Wiley & Sons, Inc.