Pentachlorophenol association with fulvic acids from recycled wastes

The apparent water solubility of pentachlorophenol was measured at pH = 6 and at 25 °C in pure water, aqueous solutions of three salts (NaCl, KNO3 and CaCl2 at 0.010, 0.10 and 1.0 M) and in aqueous solutions of three fulvic acids samples extracted from a natural soil (sFA), composted sewage sludge (csFA) and composted livestock's material (lsFA). A solubility enhancement method was developed for the measurement of partition coefficients (Koc, L/kg organic carbon). Pentachlorophenol associates strongly with the fulvic acid samples and the calculated Koc were the following (averages and standard deviations): (sFA) (211 ± 22) × 102, (csFA) (253 ± 26) × 102, (lsFA) (235 ± 10) × 102. For comparison purposes the Koc for pyrene were also calculated for the three FA samples and were the following: (sFA) (119 ± 10) × 102, (csFA) (239 ± 21) × 102, (lsFA) (92 ± 10) × 102. The analysis of variance (one-way ANOVA) of the effect of the type of FA sample on the solubilization of pentachlorophenol and pyrene shows that this factor causes significant differences on the aqueous solubilization of these two organic substances.