Researchers built two crystalline membranes whose molecular rings stack with controlled offsets. The resulting channels impose different restrictions on molecules of similar size, allowing staged separation when the membranes are combined. One peer-reviewed laboratory study tested the structures and enriched a pharmaceutical compound from a mixture. Its energy and cost comparisons apply to selected separation designs rather than industry as a whole.
Two thin crystalline membranes separated similarly sized molecules by making their passage through stacked molecular rings more restrictive. The single peer-reviewed laboratory study built the rings from metal atoms and organic linkers. Their controlled offsets created constrictions along the channels, adding a way to tune selectivity beyond a simple fixed pore size.[1]
Precursors with different bonding angles assembled at a liquid boundary into membranes called CCM-1 and CCM-2. Microscopy indicated a thickness of about 90 nanometres. Their principal measured pore diameters were 1.63 and 1.44 nanometres respectively. Spectroscopic tests examined the chemical structure and coordination around the metal atoms.[1]
Simulations linked the separation to restrictions on molecular movement within those misaligned channels. Molecules of close size could lose different amounts of freedom as they passed through. Structural measurements and free-energy calculations therefore examined both the available space and the molecular motion within it.[1]
Using the two membranes in succession fractionated mixtures in stages. One experiment enriched tacrolimus, a pharmaceutical compound, from a mixture containing glucan and leucine. Energy, cost and emissions comparisons concerned selected separation processes and their design assumptions. The work tested purification rather than medical efficacy, and did not demonstrate the same savings across all industrial separations.[1]
