EQUILIBRIA FOR THE ADSORPTION OF ANTIBIOTICS ONTO NEUTRAL POLYMERIC SORBENTS - EXPERIMENTAL AND MODELING STUDIES

The objective of this work was to study the equilibria for adsorption of three antibiotics (penicillin V, tetracycline, and cephalosporin C) from water onto commercially available neutral polymeric sorbents. Th e pH was observed to be an important factor in adsorption as our resul ts suggest that the neutral forms of penicillin V and cephalosporin C are preferentially adsorbed onto the neutral sorbents. Also, sorbent s urface chemistry was observed to be important for adsorption, as the a ntibiotics adsorbed more favorably (both in terms of affinities and en thalpies) onto the aromatic sorbent as compared to the aliphatic ester sorbent. In addition to these thermodynamic measurements, molecular m odeling studies and Monte Carlo simulations suggest that adsorption on to aromatic sorbents may involve specific interactions between the pla nar regions of the antibiotic molecules and the phenyl rings of the ar omatic sorbent. The interaction energies predicted from Monte Carte si mulations were observed to provide qualitative agreement with experime ntally determined adsorption affinities. (C) 1995 John Wiley and Sons, Inc.