Efficient & Selective Ion Pumps based on Ratchet Mechanisms

ongoing

I propose a novel membrane-like device that utilizes a ratchet mechanism to drive ions selectively up a concentration gradient. This device can serve as a building block for an efficient, ion selective separations technology. Ion selective separation with membrane-based processes may advance dramatically technologies for water treatment, resource extraction from sea water, ion specific sensors and many other applications. Moreover, since about 10-15% of the global energy consumption is used for chemical separations, a high efficiency, membrane-based ion separation processes can reduce greenhouse gas emissions significantly. However, membrane-based ion selective separation is a longstanding unmet challenge in science and engineering. Although conventional membrane-based separation is extremely efficient in unselective separation processes such as reverse osmosis water desalination, membrane-based processes showed limited success in ion specific separations. Furthermore, the need for a molecular level control of the membrane properties, limits the scalability of most of the membrane-based ion selective separation techniques that are currently being studied. Our proposed device, the ratchet-based ion pump, is driven with a ratchet mechanism which utilizes modulations of a spatially asymmetric electric field to induce a non-zero net ion flux up a concentration gradient. We will utilize a fundamental ratchet process in which the ratchet input signal drives particles with the same charge but different transport properties in opposite directions, to design highly selective, fit-to-purpose, and real-time controlled ion separation systems thereby bypassing the limitations faced by current technologies. In this research we will combine theory, simulation and experiment to improve our understanding of the ratchet mechanism, design and optimize ratchet based ion pumps, demonstrate ion selective ratchet-based separation systems, and set their thermodynamic performance limits