CHEMICAL AND ELECTROCHEMICAL STUDIES OF INTERACTIONS BETWEEN IRON(III) IONS AND AN ACTIVATED CARBON SURFACE

Activated carbon (CWZ) produced from hardwood(HPSDD, Hajnowka, Poland) was powdered (to 0.060-0.075-mm grain size) and then deashed (concent rated HF and HCl). A part of the deashed carbon was oxidized with conc entrated HNO3. The surface chemical properties of both the nonoxidized and oxidized samples were studied by various methods: neutralization of surface acidic groups with bases of different strength, estimation of total oxygen contents, and determination of water vapor adsorption isotherms and sorption capacity toward Fe3+ ions. The porous structure s of carbon samples were estimated from a benzene adsorption-desorptio n isotherm. Spectroscopic studies (XPS and FTIR) of carbon samples wit hout and with adsorbed iron ions were also performed. A correlation of different determinations was discussed. Using cyclic voltametry, the electrochemical behavior of the powdered activated electrodes (PACEs) was compared with that of solid graphite and glassy carbon electrodes. The Fe(III)Fe(II) couple in acidic (0.01-0.1 M HNO3) aqueous solution s was investigated as the reference system. The influence of the surfa ce chemistry of the powdered carbon material in terms of its electroch emical properties was discussed, also.