Investigations on the Recovery of Different Structure Types of Polyoxometalates from Aqueous Solution Using Nanofiltration Membranes

Polyoxometalates (POMs) are promising compounds for green and sustainable chemistry, particularly for the valorization of biomass. When used in aqueous solutions for various bioprocesses, the main challenge lies in the efficient and cost-effective recovery and separation of the POM from the heterogeneous reaction mixture. A solution could be the use of nanofiltration membranes, which were applied for different POM structure types in this work. Herein, the use of different commercial polymer membranes for the recovery of various POM structure types from an aqueous solution was investigated. Using the optimal TS-80 membrane, various parameters like concentration, flow rate, and pressure, as well as membrane stability, were analyzed to gain a fundamental understanding of POM recovery via nanofiltration. Additionally, the POM structures before and after the membrane separation process were analyzed to confirm their integrity. Through the use of nanofiltration, an efficient purification method for processing POM-based aqueous solutions could be implemented.