Industrial Membranes: Expanding into the International Market

By Wang Jiwen, China Membrane Industry Association

The 5 major technologies

1. Forward osmosis (FO)  
FO membrane technology shows promise for industrial waste water treatment, trash percolate treatment, seawater desalination, high-quality regenerated water treatment, municipal sewage treatment, and aviation/spaceflight water treatment. Although the technology and membrane products have not yet fully matured in China, some well-known companies have already introduced FO membrane technology and membrane products from abroad through investment and equity participation, beginning to disseminate the technology and apply it commercially.
2. Reverse osmosis (RO)
Sales of RO membrane products in China account for 30-35% of global RO membrane trade. Imported RO membrane products dominate the domestic market, but their share has fallen somewhat in recent years.
3. Ultrafiltration/microfiltration (UF/MF)
UF/MF technology is the most rapidly developing membrane technology in China, with the greatest product variety and the most extensive applications. Materials for UF/MF include polysulfone, polyethersulfone, polyvinylidene fluoride, polyethylene, polypropylene, polyvinyl alcohol, polyacrylonitrile, cellulose acetate and their modified materials.
UF/MF membranes can effectively remove granular substances including microorganisms. They are widely applicable and can be used to treat water with different qualities.
There are several hundred producers of UF/MF membranes in China today. Various enterprises have proposed a number of new technologies and new products in recent years. Examples include a polyvinylidene fluoride membrane coating on the outside of braiding bobbins, a “concrete membrane” for adding several chemical fibers directly into hollow walls and “medium lining membranes”. Domestic UF and MBR membranes are used successfully in many super large projects in China. Some well-known companies with considerable production scale own intellectual property rights to their unique recipes for materials used in membrane production, as well as complete production equipment.
4. Nanofiltration (NF)
NF membrane technology is a new molecular-grade membrane separation technology. Globally, it is one of the main focuses of membrane separation research. NF membrane technology is suitable for removing salts from water from various sources. The utilization rate of water is usually 75-85%, being 30-50% in case of seawater desalination. No acidic or alkali waste water is produced.
Most cities’ water sources are more or less polluted today. The rate of removing organisms in the treatment processes conventionally employed for tap water plants, however, is quite low. When chlorine is used for sterilization, the chlorine will generate halogenated byproducts with organisms contained in water. NF membrane technology can remove most ions such as calcium and magnesium. The desalination sector is the biggest user of NF membrane technology. NF membrane technology can be directly used in softening underground water, surface water and waste water and also in pretreating water in tandem with reverse osmosis and solar photovoltaic desalination units.
5. Electrically driven filtration
Electrodialysis membrane separation employs ion exchange methods. In its first years of development and application, electrodialysis was extensively used in desalination of seawater and brackish water. Its high consumption of electricity was seen as a shortcoming however, so with the extensive application of RO membranes electrodialysis seawater desalination technology lost some development impetus. Nevertheless, as electrodialysis can produce good quality water from water with high salt content, it can play a greater role in the re-concentration of concentrated water and the separation and purification of sea salt.
Bipolar membranes are usually composed of an anion/cation exchange resin layer and an interfacial hydrophilic layer. Such membranes are used mainly in producing acids and alkalis from salt solutions.
Bipolar membrane is a new type of membrane with unique advantages. It has prompted many new ideas and solutions to some longstanding technical bottlenecks in environmental projects.

Prospect

The total output value of the membrane industry in China in 2005 was only RMB10.0 billion. By 2016, it reached approximately RMB100.0 billion. The overall level of membrane technologies has been improved remarkably, but the needs in the domestic market still can hardly be satisfied. The technology development opportunities are huge.
According to incomplete statistics, there are already 994 membrane producers, membrane contractors and related enterprises in China. Eighty percent of these enterprises are situated in Beijing, Jiangsu, Shanghai, Zhejiang, Shandong and Guangdong. The total proportion held by these regions reaches 80%. Membrane enterprises in China have started to do business outside of the country in recent years, expanding international sales considerably.
Improved standards for water drainage and water supply will directly promote large-scale adoption of membrane technologies in upgrading and renovating treatment facilities. The market is expected to grow to more than RMB500.0 billion during the Thirteenth Five-Year Plan period (2016-2020).
The “One Belt One Road” map includes mostly emerging economies and developing countries that face environmental pollution from industrialization and global industrial transition. Implementation of “One Belt One Road” will surely bring the membrane industry bright prospects in environmental protection for Mid Asian industrial plants, and in applications such as gas separation and water treatment in Mid Asian oil/gas fields.