Heavy metal removal by olive pomace:: biosorbent characterisation and equilibrium modelling

This paper concerns with metal biosorption onto an agricultural waste, olive pomace. Experimental tests of adsorbent characterisation (potentiometric titration, IR analyses, selective extractions) and titration modelling (accounting for adsorbent heterogeneity by the introduction of a two-peak proton affinity distribution function) evidence that carboxylic and phenolic groups are the main active sites involved in metal removal. Potentiometric titration and single metal system biosorption tests (Pb, Cu, Cd) onto native and treated olive pomace samples are represented by an equilibrium model describing the competition among heavy metals and hydrogen ions in solution. (C) 2003 Elsevier Ltd. All rights reserved.