REMOVAL OF TOXIC IONS FROM AQUEOUS SOLUTIONS USING LIGNITE-COAL-BASED ACTIVATED CARBONS MODIFIED BY OXIDATION

The possibilities for removal of toxic ions from aqueous solutions by novel porous material obtained from Bulgarian lignite and its oxidized modifications were studied. Adsorption of Hg(II), Cd(II), Pb(II), As(III), and As(V) ions was investigated using aqueous solutions with different concentrations and acidity. Equilibrium modeling data were fitted to linear Langmuir, Freundlich, and Dubinin-Radushkevich models and maximum adsorption capacities of the investigated ions were calculated. The activated carbon treated with hydrogen peroxide proved to be the best one concerning toxic ion adsorption. Both oxidized modifications indicated a significant potential for mercury removal from aqueous solutions.