Building charge-MOSAIC nanofiltration membranes for removing micro-pollutants from surface and drinking water

Introduction

Our surface and drinking water sources are increasingly threatened by the presence of organic micropollutants (OMPs). OMPs are small molecules (100-1000 Da) that originate from industrial, agricultural, and pharmaceutical residues, and can cause long-term harm to humans and ecosystems.

Limitations of Existing Technologies

While OMPs can be removed from water with existing membrane technologies (e.g., reverse osmosis), these methods have significant limitations:

• They are energy-intensive.
• They lead to problematic brine waste streams due to their low water and salt permeability.

Project Objectives

In this project, I aim to solve these limitations by building charge-mosaic membranes. These membranes feature small (nm²) oppositely charged patches that allow coupled passage of negative and positive ions.

Historical Context

This design, aimed at reducing salt retention, was conceived over 90 years ago but was never realized in a scalable manner due to its challenging design.

Proposed Solution

Here, I propose a simple and fully scalable approach to achieve such membranes, using polyelectrolyte multilayers (PEMs) of oppositely charged polymers. I will build these charge-mosaic membranes using ultrathin, ultradense layers in an asymmetric PEM approach to achieve a very high (> 99%) retention of OMPs and a high water permeability.

Expected Outcomes

Combined with state-of-the-art modelling, this project will also provide new fundamental insights into membrane mass transport. Moreover, the project will directly lead to membranes with unique separation properties, allowing the design of completely new processes to effectively remove OMPs from wastewater and drinking water.