Resumo

CESPEDES, Nubia E.; VALENCIA, Jesús S.  e  DIAZ, José de J.. REMOVAL OF CROMIUM (VI) FROM AQUEOUS SOLUTIONS OVER MODIFIED ACTIVATED CARBONS. Rev.Colomb.Quim. [online]. 2007, vol.36, n.3, pp.305-322. ISSN 0120-2804.

In this work, the influence of the degree of surface modification of activated carbons in the adsorption of Cr6+ from aqueous solution was determined modifying two commercial activated carbons by thermal oxidative and reductive treatments (oxygen or nitric acid and hydrogen, respectively). The surface chemistry of the original and modified activated carbons was examined by Böehm’s titrationand thermal programmed decomposition (TPD). The adsorption capacities were tested with model solutions of chromate ion, and under different initial concentrations, contact times, pH, temperature and adsorbent mass. The surface chemistry modifications showed that they have an important influence in the adsorption capacity of the activated carbons, being the hydrogen modified carbons the best for the chromate ion adsorption. The conditions that presented the maximum adsorption capacity were: initial concentration of 100 ppm, initial pH of 2.0, temperature of 25°C and adsorbent mass of 100 mg.

Palavras-chave : Activated carbon; surface chemistry; thermal treatments; Cr VI removal.

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