A carbon dioxide (CO2) gas in air diffuse through a packed bed of sand at 310 K and a total pressure of 1.2 atm. The column length is 1.8 m and the void fraction is 0.42. The partial pressure of CO2 at the top and bottom of the column is measured to be 68 mmHg and 15 mmHg respectively. Having a tortuosity factor of 1.87, calculate the diffusion rate of CO2 inside the packed bed column in kg mol/m2.s. The diffusivity of CO2 at 276 K and atmospheric pressure is 0.142 x 10-4 m2/s.