Breakthrough Curves and Column Design Parameters for Sorption of Lead Ions by Natural Zeolite

Abstract

Sorption of lead ions, by natural phillipsite (zeolite) has been studied in a laboratory-scale packed-bed column. Breakthrough curves were obtained under different operating conditions. Bed depth- service time (BDST) model was applied and parameters for column design were determined for lead ions at 5% breakthrough yielding BDST sorption capacity of 24.27-35.73 mg x g(-1), rate constant 2.80 x 10(-4) - 4.16 x 10(-4) dm3 x mg(-1) x min(-1), critical bed depth 4.02-10.37 cm and sorbent exhaustion rate of 12-51.3 g zeolite per dm3 of treated solution over a flow-rate range of 14.15-36.80 cm x min(-1). Breakthrough times at C/Co = 0.05 ranged from 5-100 min depending on flow rate and bed depth. External mass transfer is rate limiting in the initial stages of adsorption as indicated by agreement between Wolborska model and the experimental data in the low C/Co region of the breakthrough curve.