Imagine turning seawater into fresh water without booster pumps or massive power consumption — and even generating electricity in the process. This is not science fiction, but a reality enabled by forward osmosis membrane technology.

What Is Forward Osmosis?Forward osmosis is a common natural phenomenon. If you place a radish in salt water, it will wilt as moisture flows out of the radish into the saline solution. This is osmosis: water moves spontaneously across a semi‑permeable membrane from a low‑concentration side to a high‑concentration side.

Forward osmosis (FO) technology operates on this exact principle. Unlike reverse osmosis, which requires high external pressure, it relies on the natural osmotic pressure difference between solutions to drive water through the membrane spontaneously. This drastically cuts energy consumption and delivers superior environmental performance.

Applications of Forward Osmosis

Wastewater Treatment

Forward osmosis features exceptional antifouling performance. In membrane bioreactors, FO membranes are far less prone to clogging than traditional membranes. Even when fouled, they can be fully restored with simple cleaning. The technology performs remarkably well in treating refractory wastewater such as landfill leachate and textile dyeing effluent.

Green Energy

The concept of generating power through the osmotic pressure difference between seawater and fresh water was proposed decades ago. Statkraft of Europe has built the world’s first osmotic power plant. When fresh water permeates through the membrane into seawater, the resulting volume expansion creates sufficient pressure to drive turbines, achieving zero carbon emissions throughout the entire process.

Seawater Desalination

A special ammonium salt solution is used as the draw solution, acting like a powerful sponge to extract fresh water from seawater. The ammonium salt is then decomposed and recycled via mild heating (around 60℃), leaving pure fresh water. Compared with conventional technologies, this system saves over 70% of energy.

Emergency Drinking Water 

HTI, an American enterprise, has developed a portable water pouch adopting forward osmosis. It consists of an inner FO membrane layer and two separate chambers: the outer layer holds raw contaminated water, and the inner layer contains edible sugar solution. Pure water from the contaminated source automatically permeates the membrane to dilute the sugar solution, providing safe drinking water in extreme environments.All FO products of HTI are exclusively supplied to the U.S. military and not available on the civilian market. By contrast, the self‑developed VitaH₂O emergency survival water pouch developed by Chenhao Technology also adopts forward osmosis technology. Its membrane material delivers superior rejection efficiency, higher water flux, and stronger resistance to organic solvents.

Promising Prospects 

Still in the early stage of development, forward osmosis boasts enormous potential. China included forward osmosis research in the National Basic Research Program (973 Program) as early as 2009. With continuous breakthroughs in membrane materials and draw solution optimization, this nature-inspired cutting-edge technology is offering innovative solutions to global water scarcity and energy challenges.

From deep oceans to outer space, from industrial factories to household use, forward osmosis will soon become an indispensable part of daily life.