Aquaporin-Based Biomimetic Reverse Osmosis Membranes: Stability and Long Term Performance

This study investigated the stability of the aquaporin-based biomimetic (ABM) membrane and its long-term reverse osmosis (RO) performance. A series of experiments showed that the ABM membranes exhibited good chemical stability after soaking in three commonly used chemical cleaning agents, namely ethylenediamine tetraacetic acid (EDTA), sodium hydroxide (NaOH) and citric acid, respectively. In addition, it was found that both water permeability (flux per unit applied pressure) and solute rejection of ABM membranes are sensitive to the temperature and applied pressure. In the long-term RO performance evaluation, a real RO feed water from water reclamation process was used as feed; this is the first reported application of real RO feed water to ABM membranes. The membranes were periodically cleaned and the recovery of water permeability of the ABM membranes was found to be greater than 90%. The quality of the water permeate exceeded the World Health Organisation standard for drinking water. Compared with a commercial RO membrane, the ABM membrane only needed half of the applied pressure to achieve the same water flux, suggesting the advantage and potential of ABM membranes to reduce energy consumption in practical applications.