Abstract
The Pb2+ separation from concentrated electrolyte solution was studied on a cryptomelane-type manganic acid (CMA) and titanium antimonic acid (TAA). The Pb2+/H+ exchange reaction was reversible on these cation exchangers and the ion-exchange data were evaluated for separation of Pb2+ by different three expressions: (1) the plot of the corrected selectivity coefficient, K H M, vs. the charge fraction, (2) Langmuir plot, and (3) the power-exchange function. The K H M value as a function of the charge fraction allowed the estimation of the distribution coefficient K d (cm3/g) at a zero charge fraction in exchanger: 1.9 × 108 on the CMA and 9.1 × 104 on the TAA in 0.1 M HNO3. The anomalously large Pb2+ selectivity of the CMA will find successful utilization for Pb2+ separation/fixation from Pb2+-contaminated liquid effluents discharged from industries and ground waters, while Pb2+ selectivity of the TAA may be not sufficient to lower Pb2+ concentration below the discharge standard in highly alkaline electrolyte solution.
ACKNOWLEDGMENT
A part of this research was supported by the Salt Science Foundation Grant No. 9939.