How can chemical engineering help produce fresh water through seawater desalination?

Chemical engineering plays a critical role in seawater desalination by developing and optimizing large-scale processes to remove dissolved salts, rendering water suitable for consumption and industrial use. These processes generally fall into two categories: thermal and membrane-based.1

Thermal Processes

Thermal methods involve heat transfer and phase changes. Multistage flash distillation is a primary example, where seawater is heated and then flashed into vapor across a series of tanks set at progressively lower pressures. The resulting vapor is condensed into fresh water. Chemical engineers also utilize cogeneration, where high-pressure steam from power generation is recycled to heat the brine, significantly improving energy efficiency.12

Membrane Processes

Membrane technologies use semipermeable materials to separate water from solutes.1
* Reverse Osmosis: This is the most widely used method. Engineers design systems that apply high pressure to force seawater against a membrane, allowing fresh water to pass through while retaining concentrated salts.13
* Electrodialysis: This process uses electrical potential to drive salt ions through selective membranes, leaving fresh water behind.13

Through the development of more durable membranes and the integration of hybrid systems, chemical engineering continues to drive efforts to make these processes more cost-effective and energy-efficient.423