Chemical and Electrochemical Studies of Interactions between Iron(III) Ions and an Activated Carbon Surface

Abstract

Activated carbon (CWZ) produced from hardwood (HPSDD, Hajnówka, Poland) was powdered (to 0.060−0.075-mm grain size) and then deashed (concentrated HF and HCl). A part of the deashed carbon was oxidized with concentrated 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 structures of carbon samples were estimated from a benzene adsorption−desorption isotherm. Spectroscopic studies (XPS and FTIR) of carbon samples without 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 solutions was investigated as the reference system. The influence of the surface chemistry of the powdered carbon material in terms of its electrochemical properties was discussed, also.