Please provide proper working as past posted answer didnt add up properly

6.4 In a dialysis treatment, urea is removed from blood at a temperature of 40 C using a membrane. The tortuosity and porosity of the membrane are 0.043 and 1.1, respectively. it also has pores that are 12 nm in diameter and 0.03 mm in thickness. Dialyzed blood has a urea content of 0 g L^-1, whereas there is urea present at a concentration of 1.8 g L^-1 in blood. The urea's diffusivity, Di, is 13.56 x 10^-6 cm2 s^-1 and molecular weight of urea is dm = 0.528 nm.

i)figure out the theoretical flux of urea carried over the membrane, and the overall surface area required If the intended rate of urea removal is 10 g h^-1 .

ii) Explain the mass transfer methods of Knudsen diffusion and Poisseuille flow over porous membranes.