Solubility of Polycyclic Aromatic Hydrocarbons in Subcritical Water from 298 K to 498 K

TLDR

The study measured PAH solubilities in subcritical water at 298–498 K and 30–60 bar and estimated temperature dependence using empirical correlations that require only ambient solubility data. Solubilities rose by up to five orders of magnitude with temperature, with chrysene’s mole‑fraction solubility increasing from 0.63 × 10⁻⁹ to 75 800 × 10⁻⁹, while pressure had minimal effect and the empirical estimates matched experiments within a factor of four.

Abstract

The solubility of anthracene, pyrene, chrysene, perylene, and carbazole were determined at temperatures ranging from 298 K to 498 K and pressures from 30 bar to 60 bar in subcritical (superheated) water. Increasing temperature up to 498 K increased solubilities by 5 orders of magnitude. For example, increasing the temperature from 298 K to 498 K increased the mole fraction solubility of chrysene from (0.63 ± 0.08) × 10-9 to (75 800 ± 4000) × 10-9. While large increases in pressure result in lower solubilities, over the narrow range of pressures studied, pressure had a minimal effect. Solubilities as a function of temperature were estimated on the basis of simplifying assumptions and empirical correlations based on data presented in this and previously reported work. The method only requires knowledge of ambient temperature solubility. Estimated values generally agree with experimental results within a factor of 4, even over 5 orders of magnitude in solubility changes.