Emulsion liquid membranes stripping agents

The information provided by the equilibrium isotherms depicted in Figure 29.5 confirms the commercial selective carrier bis(2,4,4-trimethylpenthyl) phosphinic acid (Cyanex 272) as a suitable reagent to formulate the liquid membrane due to its capacity to selectively separate iron and zinc from chromium under the typical pH conditions of the passivation baths. Therefore, the typical composition of the pseudo emulsion employed in the EPT regeneration process contains Cyanex 272 and sulfuric acid as stripping agent, and the extraction and BEX of zinc and iron are described, respectively, by the following reversible chemical reactions ... 

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