Efficient & Selective Ion Pumps based on Ratchet Mechanisms

Introduction

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.

Importance of Ion Selective Separation

Ion selective separation with membrane-based processes may advance dramatically technologies for:

• Water treatment
• Resource extraction from seawater
• Ion-specific sensors
• Many other applications

Moreover, since about 10-15% of the global energy consumption is used for chemical separations, high-efficiency, membrane-based ion separation processes can reduce greenhouse gas emissions significantly.

Challenges in Current Technologies

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 have shown limited success in ion-specific separations.

Furthermore, the need for 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.

Proposed Solution: Ratchet-Based Ion Pump

Our proposed device, the ratchet-based ion pump, is driven by 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. This approach aims to design highly selective, fit-to-purpose, and real-time controlled ion separation systems, thereby bypassing the limitations faced by current technologies.

Research Approach

In this research, we will combine theory, simulation, and experiment to:

1. Improve our understanding of the ratchet mechanism
2. Design and optimize ratchet-based ion pumps
3. Demonstrate ion selective ratchet-based separation systems
4. Set their thermodynamic performance limits