Membrane technology contributes to the realization of low-carbon seawater desalination.

The problem of water resource shortage is becoming increasingly prominent, and seawater desalination technology has become one of the important methods to solve the problem .

Seawater desalination is the process of removing excess salt and minerals from seawater to obtain usable fresh water. Currently, there are over twenty seawater desalination technologies worldwide. These technologies can mainly be classified into two categories: one is thermal desalination technologies represented by multi-effect distillation and multi-stage flash distillation; the other is membrane technologies represented by reverse osmosis.

Reverse osmosis membranes are an efficient separation technology. In both daily life and industrial production, we can always find the traces of membranes in various fields such as new energy, biomedicine, and water treatment.

Currently, reverse osmosis membrane method has become the most widely used desalination technology globally, accounting for approximately 69% of the installed capacity. Reverse osmosis, also known as membrane filtration, is a physical process with the core technology being the desalination membrane. High-power water pumps are used to force seawater towards the desalination membrane, which can retain substances larger than 0.0001 microns while allowing water molecules to pass through. During the desalination process, bacteria and trace elements in the water are also largely filtered out. However, this method requires that the water be pre-treated to remove residual chlorine and large particles before entering the membrane to prevent it from damaging.

In recent years, a new type of desalination technology has emerged, namely the heat-membrane coupling desalination technology, such as pervaporation. The principle of desalination by pervaporation is that under the driving force of the vapor pressure difference on both sides of the membrane, water molecules in seawater pass through the membrane in the form of liquid flow, undergo phase change, and finally pass through the membrane in gaseous form, and then are condensed and collected.

Permeation evaporation has the advantage of low energy consumption compared with other membrane desalination technologies. Its energy consumption is estimated to be about 5 to 7 kWh/m³, which is lower than that of reverse osmosis technology. Therefore, the production cost of water is expected to be ￥4.5-12.9(CNY) per cubic meter, making it one of the most economical desalination technologies.