Ammonia (NH₃) and hydrogen sulfide (H₂S) must both be stripped from wastewater in a packed tower before the wastewater can be treated for reuse. Individual mass-transfer coefficients for ammonia transfer within a packed tower are k_G = 3.20 × 10^-9 kgmole/m² · s · Pa for the gas film, and k_L = 1.73 × 10^-9 m/s for the liquid film. At the temperature and concentration ranges of the solutes within the process, the equilibrium distribution data for the solutes NH₃ and H₂S are in the linear range. The Henry’s law constants are 1.36 × 10³ m³ · Pa/kgmole for NH₃, and 8.81 × 10⁵ m³ · Pa/kgmole for H₂S. Under the assumption that both k_G and k_L for H₂S transfer is the same as those for NH₃ transfer, estimate and compare the overall mass-transfer coefficients K_G and K_L for H₂S and NH₃, respectively.

A mass-transfer process is used to remove ammonia (NH₃, solute A) from a mixture of NH₃ and air, using water as the absorption solvent. At the present conditions of operation, the partial pressure of ammonia in the bulk gas phase (p_A) is 0.20 atm, and the mole fraction of dissolved NH₃ in the water (x_A) is 0.040. The total system pressure is 2.0 atm, and the temperature is 30°C. At 30°C, the molar solution density is 55.6 kgmole/m³. The film mass-transfer coefficients are k_G = 1.0 kgmole/m² · s · atm, and k_L = 0.045 m/s for the gas and liquid, respectively. The equilibrium distribution data at 30°C for the NH₃-water-air system are given in the table below: