Selective system scan for multizone radiotelephone subscriber units.

摘要

The invention relates to a process for recovering caffeine from caffeine-loaded activated carbon and which is characterized in that the caffeine destroying activity of the activated carbon is reduced before or after loading with caffeine. The activated carbon can to that end be treated with acids, buffers, complexing agents, redox substances, caffeine and other xanthine derivatives. The caffeine recovery yield can be considerably increased by this means.