Question

Water flows at 20 cm3/sec through a long straight tube that has an inner diameter of 1 cm. As the water flows, a toxin leaches from the tube into the water. At the inner surface of the tube, the toxin attains its saturation concentration, Csat = 2 mM. Fortunately, upon entering the water the toxin also irreversibly degrades into a non-toxic compound; this degradation follows first-order kinetics. Toxin Diffusivity D = 10-5 cm2/sec Toxin mass transfer coefficient k = 1.38 X 10-3 cm/sec Toxin degradation rate constant k1 = 5.5 X 10-3 /sec In order to evaluate whether the water is still safe to drink, we need to know the limiting concentration of the toxin? (In other words, what concentration does the toxin approach as the length of the tube approaches infinity)

Answer 1