Oxygen distribution within oxidised active carbon granules

The differences in chemical structure within activated carbon granules were estimated for oxidised and unmodified carbon substrates. Samples from vari ous parts of the carbon granules were obtained using the spouted-bed attrit ion method. A commercial granulated active carbon (Norit R3ex) demineralise d with concentrated HF and HCl acids was used. Suitable powdered and core s amples were obtained by stripping off successive layers of granules from ca rbon oxidised with concentrated HNO3 and from unmodified carbon for compari son. The following techniques were employed to characterise the surface pro perties of these samples: selective neutralisation and pa-metric titration of functional groups, and transmission FTIR spectroscopy. The distribution of oxygen chemically bound to the internal surface of the granules is discu ssed on the basis of the results. (C) 1999 Elsevier Science Ltd. All rights reserved.