Green recovery of low concentration of lithium from geothermal water by a novel FPO/KNiFC ion pump technique

As a unique and indispensable element in modern battery and energy industries, the recovery of lithium has attracted wide attention worldwide. In this work, the recovery of low concentration of Li + in geothermal water was carried out by a green and novel FePO 4 /K 2 NiFe(CN) 6 [FPO/KNiFC] electrochemical ion pump technique. Different K 2 MFe(CN) 6 (M = Cu, Co, or Ni) was synthesized and used to construct an electrochemical ion pump with FePO 4 . It was found that K 2 NiFe(CN) 6 has excellent electrochemical properties, and the recovery of Li + is mainly restricted by the insertion capacity and rate of the FePO 4 electrode. This problem was successfully solved by the modification of electrode using multiwalled carbon nanotube . Even though the optimized ion pump system has a low single insertion capacity for low concentrations of Li + , a cycle extraction method was developed and successfully realized high-effective recovery of Li + from geothermal water. Subsequently, a multi-stage extraction device was designed and proposed for the continuous recovery of low concentrations of Li + .