SORPTION OF ALPHA-NAPHTHOL ONTO ORGANIC SORBENTS VARYING IN POLARITY AND AROMATICITY

Relation of alpha-naphthol uptake with polarity and aromaticity of sel ected organic matter surrogates was investigated using batch equilibra tion. The organic sorbents used were: lignin (organosolv), lignin (alk ali), collagen, chitin, cellulose, and a collagen-tannic acid mixture (CTM). These materials represent model input sources for soil organic matter. Aromaticity of the sorbents was calculated from CPMAS C-13 NMR spectrum data. Concentration of alpha-naphthol in solution was measur ed using liquid scintillation counting and elemental composition of th e sorbents was determined with an elemental analyzer. Hysteresis betwe en adsorption and desorption was not observed. We infer that uptake of alpha-naphthol is through partitioning as indicated by linear isother ms. K(d) values for lignins were 12 to 24 fold higher than that for ch itin and 130 to 260 fold higher than that for cellulose. The carbon re ferenced sorption coefficient (K(OC)) decreased from approximately 436 to approximately 3 mLg with increasing polarity index [(O+N)/C] and d ecreasing aromaticity of organic sorbents. We concluded that the quali ty of organic sorbents significantly influences partitioning of hydrop hobic organic chemicals in aqueous systems. If this conclusion holds f or all hydrophobic organic pollutants, then K(OC) of such xenobiotics cannot be accurately predicted from its K(OW) or solubility without so me description of organic sorbent quality such as polarity and degree of aromaticity.