Hydrophobic thin film composite nanofiltration membranes derived solely from sustainable sources†
Membrane separations are considered to be sustainable technologies because of their relatively low energy consumption. However, the fabrication of membranes is yet to turn green. Thin film composite (TFC) membranes are fabricated from petroleum-based monomers and solvent systems, which can undermine the energy-saving benefits of their application in separation processes. Here, we report high-performance TFC membranes fabricated solely from sustainable resources such as plant-based monomers (priamine, tannic acid), green solvents (p-Cymene, water) and recycled polymer waste (PET). We found that the ultrathin selective layer (30 nm) of the hydrophobic membrane exhibited excellent performance, and an acetone permeance as high as 13.7 L m−2 h−1 bar−1 with a 90% rejection of styrene dimer (235 g mol−1). Stability in six solvents and long-term continuous nanofiltration over one week demonstrated the robustness of the membranes. Control over the selectivity of the membrane (cut-off between 236 and 795 g mol−1) was successfully achieved by changing the conditions of the interfacial polymerization.