Pb²⁺ SEPARATION FROM CONCENTRATED ELECTROLYTE SOLUTION BY A CRYPTOMELANE-TYPE MANGANIC ACID AND TITANIUM ANTIMONIC ACID

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.