7.6 Prediction of the Break-Point Time in Fixed-Bed Adsorption

At low concentrations, the equilibrium for the antibiotic novobiocin and Dowex 21K anion exchange resin is linear, q_i = 125c_i* for q_i and c_i* in units of milligrams per milliliter. For the range of concentrations where this isotherm is valid, the mass transfer coefficient K_a averages 82 h^-1. Assuming a linear isotherm, estimate the break-point time (where c_i/c_io = 0.05) in a fixed-bed adsorber with a bed length of 20 cm and superficial velocity of 40 cm/h.