Removal of nickel and cobalt ions from aqueous solutions using electron-beam treatment

Radiation removal of Co²⁺ and Ni²⁺ ions from aqueous solutions containing Me²⁺ and various scavengers for OH radicals has been studied. In nondeaerated solutions containing HCOOK as OH radical scavenger, two mechanisms of removal were found: reduction leading to the insoluble colloidal metals and precipitation causing predominant formation of carbonate. The processes taking place are mainly affected by the concentration of formate scavenger and depend on the type of metal ions in solution. In the presence of aliphatic alcohols as OH radical scavengers at pH in the interval 6-8, the radiation treatment leads to the metallic product. The efficiency of reduction depends on the rate constant for the reaction of Me⁺ intermediate with corresponding alcohol radical