Engineering & Science
Hayduk-Laudie Aqueous Liquid Diffusivity Correlation (EPA VOC Standard)
Calculate the U.S. EPA recommended aqueous diffusivity D_AB = 13.26 / (μ_w^1.14 * V_A^0.589) (× 10^-5 cm^2/s) for VOC air-strippers, carbon adsorbers, and groundwater remediation.
Why U.S. EPA air-stripping models specify Hayduk-Laudie for dissolved VOCs in water!
Designing packed-tower air strippers or granular activated carbon (GAC) contactors for benzene, TCE, or PFAS precursors in groundwater requires accurate aqueous molecular diffusivity D_w across seasonal water temperatures (5–25 °C). Walter Hayduk and Harry Laudie (AIChE Journal, 1974) calibrated a dedicated correlation for dilute non-electrolytes in water across 87 solutes that eliminates explicit T/μ linearity in favor of water viscosity’s true -1.14 power law: D_w = 13.26 × 10^-5 / (μ_w^1.14 * V_A^0.589) cm^2/s (with water viscosity μ_w in centipoise cP and LeBas molar volume V_A in cm^3/mol)!
Evaluate dissolved benzene (LeBas V_A = 96.5 cm^3/mol) in 25 °C water (μ_w = 0.890 cP): Hayduk-Laudie yields D_w = 1.026 × 10^-5 cm^2/s (experimental: 1.02 × 10^-5 cm^2/s), dropping by 35.5% in 10 °C winter groundwater (μ_w = 1.307 cP) to 0.662 × 10^-5 cm^2/s!
| Groundwater Temperature | Water Viscosity μ_w (cP) | Benzene D_w (V_A = 96.5 cm³/mol) | Air-Stripper Impact |
|---|---|---|---|
| 25 °C Summer Water | 0.890 cP | 1.026 × 10^-5 cm²/s | Matches 1.02 Experimental Value |
| 10 °C Winter Groundwater | 1.307 cP | 0.662 × 10^-5 cm²/s | Requires Taller Packing Height HTU |
| Invalid μ_w <= 0 or V_A <= 0 | Undefined | "Invalid Hayduk-Laudie Inputs" | Positivity Guard |
Hayduk-Laudie Aqueous Solute Diffusivity D_w (× 10^-5 cm²/s)
Evaluates 13.26 / (μ_w^1.14 * V_A^0.589) in units of 10^-5 cm^2/s from water viscosity B2 (cP) and solute LeBas molar volume B3 (cm^3/mol).
=IF(OR(B2 <= 0, B3 <= 0), "Invalid Hayduk-Laudie Inputs", ROUND(13.26 / ((B2 ^ 1.14) * (B3 ^ 0.589)), 3))Aqueous Schmidt Number Sc = μ_w / (ρ_w * D_w)
Computes dimensionless liquid Schmidt number (B2 * 0.01) / (B4 * (13.26E-5 / ((B2 ^ 1.14) * (B3 ^ 0.589)))) using water density B4 (g/cm^3) for mass-transfer Sherwood correlations.
=IF(OR(B2 <= 0, B3 <= 0, B4 <= 0), "Invalid Hayduk-Laudie Inputs", ROUND((B2 * 0.01) / (B4 * (0.0001326 / ((B2 ^ 1.14) * (B3 ^ 0.589)))), 0))Try the example
Use the original values or change them to test your understanding.