Beijing scientists improve industrial applicability of immiscible phases

Beijing scientists have moved away from the industry-standard liquid-liquid extraction to improve the functionality of an extraction system involving three immiscible phases.

In the world of liquid extractions, liquid-liquid extraction is the most commonly used technique, where one of the phases is used to extract the target substances from the other. But there has been an increased interest in an extraction system involving three immiscible phases, which has recently been improved by a team of scientists in Beijing, who have tailored the properties of each phase for the particular needs of the application.

Huizhou Liu and colleagues from the Key Laboratory of Green Process and Engineering at the Institute of Process Engineering, the National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, and the Graduate University of the Chinese
Academy of Sciences, have already developed a three-liquid-phase extraction system (TLPS) which offered fast phase separation and could be tuned for different types of compounds.

However, its use for metals was quite limited because of the poor affinity of the polymer phase for metals ions. To resolve this, the team have set out to try to find a better complexing agent which would provide improved partition of the three metals over the three phases.

The agent they chose was 1,10-phenanthroline (phen), finding from initial trials that the agent brought about good separation in iron, titanium and magnesium. In their results, published in the Journal of Chemical Technology and Biotechnology, they noted that some adjustments had to be made to the solution conditions, but once these were made they found the adapted TLPS system using phen to form complexes with iron allowed the almost quantitative separation of titanium, iron and magnesium into the top, middle and bottom layers.

The success of the project suggests that it could be useful in industry for the separation of iron and other target metals, although some tuning of the conditions might be required to get the best separations for different metals.

Posted by Ben Evans