ABSTRACT
Stepwise recovery of silver(I), palladium(II) and platinum(IV) with suitable calix[4]arene extractants was carried out by investigating the extraction and stripping process using a droplet-based microreactor system. The highest percentages of silver, palladium (100%) and platinum ion (37.2%) were extracted from a real waste only within 4.00s using a microreactor system compared with 24 and 72 h to reach extraction equilibrium in a batch method. Fourier transform infrared spectroscopy studies revealed a very good relation in peak shifts on the metal complexation with calix[4]arene derivatives after extraction and stripping. The droplet-based microreactor system emerges as an effective tool to be applied in metal recovery.
Acknowledgements
We thank Ms Kazuma Matsuura, AIST Kyushu Center, for her assistance in the microreactor fabrication. This work was partially supported by “The Environment Research and Technology Development Fund, (No. 3K-123022) from the Ministry of Environment, Government of Japan” and partially by “Collaborative research expense of partner graduate school between Graduate School of Science and Engineering, Saga University and AIST Kyushu”.