Chromium(VI) removal in a semi-continuous process of hollow fiber membrane with organic extractants

Chromium(VI) extraction from aqueous metal solution was experimentally studied by using a hollow fiber supported liquid membrane module. Organic extractants of D2EHPA, TBP, Lix79 and TOA were used to investigate the extraction performance. The extraction efficiencies of single and multiple component systems were examined with single or multiple extractants, and the role of multiple extraction operations and the difference between batch and continuous processes were inspected to find the optimum extraction condition. The experimental outcome indicates that the extraction process is controlled by aqueous phase mass transfer and multiple extraction operations do not reduce the extraction efficiency. The coexisting elements give no significant effect on chromium removal, while the mixed extractants of D2EHPA and TBP enhance the extraction efficiency by 84%. The efficiencies of batch and continuous extraction processes are nearly identical. This paper was presented at the 2004 Korea/Japan/Taiwan Chemical Engineering Conference held at Busan, Korea between November 3 and 4, 2004.