Process for removal, separation and recovery of heavy metal ions from solutions using activated alumina including acid treated activated alumina

An improved process is disclosed for the purification of an impure aqueous solution containing heavy metal ions which comprises passing the impure solution through a bed of activated alumina adsorbent. The heavy metal ions are removed from the impure aqueous solution by adsorption onto the activated alumina adsorbent. The adsorbent may be regenerated for reuse and the adsorbed metals recovered by subsequently stripping the metal ions from the adsorbent and recycling the metal ions back to the process of origin. The pH of the effluent may be monitored to determine when the capacity of the adsorbent has been reached and regeneration of the adsorbent should be commenced. In a preferred embodiment, a portion of the activated alumina is pretreated with acid before passing the impure solution through the adsorbent to enhance the chromium ion adsorption of the acid-treated activated alumina and a portion of the regenerated activated alumina is again treated with acid after each regeneration cycle.