A reverse-osmosis membrane containing artificial water channels retained more of the small contaminant NDMA while allowing water to pass. In one peer-reviewed laboratory study, NDMA rejection reached 93.9 per cent under the tested conditions. Simulations linked rapid water transport to a changing hydrogen-bond network inside the channels. The measurements describe a membrane material rather than the safety or operation of an entire treatment plant.
A reverse-osmosis membrane containing artificial water channels retained 93.9 percent of N-nitrosodimethylamine, or NDMA, under laboratory conditions. This small, uncharged contaminant can be difficult for conventional membranes to reject. The result comes from one peer-reviewed study combining material experiments and molecular simulations, with water reuse as its separation context.[1]
Researchers incorporated hydroxyl-bearing channels into the selective polyamide layer. Simulations suggested that hydrogen bonds between water and hydroxyl groups continually rearranged, allowing short residence times and frequent molecular jumps. Salt and NDMA faced higher energy barriers through the same channels. The calculations offer a molecular explanation for the measured separation.[1]
Sodium chloride rejection reached 99.2 percent. For each bar of pressure, pure-water flow across one square metre of membrane reached 4.5 litres an hour. Comparisons included membranes with different artificial channels. These measurements assess the material under the reported conditions, rather than the output of an entire treatment plant.[1]
The study did not establish equal removal of every contaminant. Pure-water permeance also cannot specify performance with all the constituents of real wastewater. Plant-scale continuity, maintenance and changing feedwater conditions require further evaluation; high NDMA rejection alone does not determine every aspect of treated-water safety.[1]
