High salt rejection RO membrane:widelyed in various fields requiring high-quality water.

High salt rejection RO membrane:widelyed in various fields requiring high-quality water

 High salt rejection RO membrane is a semi-permeable separation material designed specifically to remove dissolved salts, ions and other impurities from water.

1. Product Introduction

A high salt rejection RO membrane is a semi-permeable separation material designed specifically to remove dissolved salts, ions and other impurities from water. Unlike conventional RO membranes, it features a denser and more precisely structured active layer, typically made of advanced thin-film composite materials with a polyamide selective layer supported by a porous substrate. This special structure enables it to achieve ultra-high salt rejection rates while maintaining stable water production efficiency. It is the core component of reverse osmosis water treatment systems, playing a decisive role in improving water quality and ensuring the reliability of water treatment processes. Whether dealing with high-salinity seawater, brackish water or industrial high-salt wastewater, this membrane can effectively separate salts from water, providinghigh-purity water resources for various applications.

The high salt rejection RO membrane has a wide range of applications, covering water treatment fields that require strict salt removal. 

Firstly, in seawater desalination, it is the core component of coastal and offshore desalination projects, converting high-salinity seawater  into drinkable water or industrial water, solving the problem of freshwater scarcity in coastal areas and islands. 

Secondly, in brackish water treatment, it is used to treat groundwater and surface water with moderate salt content , providing qualified drinking water for inland areas with insufficient freshwater resources. 

Thirdly, in industrial wastewater treatment, it is widely applied in chemical, pharmaceutical, food processing and other industries to treat high-salt wastewater, realizing water recycling and reducing environmental pollution.

 In addition, it is also used in the production of high-purity water for electronics, semiconductor and pharmaceutical industries, where even trace salts can affect product quality, and in municipal water supply to improve drinking water quality by reducing salt content and harmful ions.

3. Technical Parameters

The technical parameters of high salt rejection RO membranes directly determine their performance and application scope. The key parameters are as follows: Salt rejection rate: stabilized at 99.7%-99.85%, minimum 99.7%, which can effectively reject monovalent ions  and divalent ions; Boron rejection rate: up to 93%, meeting the requirements of drinking water and industrial water for boron content; Active membrane area: 41-45 m² (440-480 ft²)

4. Product Advantages

Compared with conventional RO membranes, the high salt rejection RO membrane has obvious core advantages. Firstly, ultra-high salt rejection performance: its salt rejection rate is as high as 99.7% or more, which is 1-2 percentage points higher than that of standard membranes, ensuring that the treated water meets strict quality standards, especially suitable for scenarios requiring high-purity water. 

Secondly, stable operation and long service life: the advanced TFC material and optimized membrane structure enhance its resistance to pollution, scaling and chemical corrosion, and the service life can reach 2-5 years under proper maintenance, which is longer than that of conventional membranes.

 Thirdly, high energy efficiency: although it requires a slightly higher operating pressure, the optimized membrane structure reduces the pressure loss during operation, and matching with energy recovery devices can reduce energy consumption by 30%-50%, reducing the overall operation cost.

 Fourthly, wide adaptability: it can operate stably in a wide range of water salinity, temperature and pH, and is suitable for various complex water quality conditions, with strong practicality. 

Finally, environmental protection and energy saving: it does not require chemical agents (except necessary antiscalants) during operation, avoids secondary pollution, and realizes water recycling, conforming to the concept of green development.

The correct application procedure of high salt rejection RO membrane is crucial to ensure its performance and service life. The specific steps are as follows: First, pre-treatment of feed water: remove suspended solids, colloids, organic matter and free chlorine from the feed water through sand filtration, ultrafiltration and activated carbon adsorption, control turbidity ≤1.0 NTU, SDI ≤5.0, and chlorine concentration <0.1 ppm to prevent membrane fouling and oxidation damage. Second, membrane installation: install the membrane element in the RO pressure vessel correctly, ensure that the connection is tight, avoid water leakage and uneven pressure, and pay attention to protecting the membrane surface during installation. Third, system start-up: flush the membrane with clean water for 30-60 minutes before starting, remove impurities in the system, then gradually increase the pressure to the operating pressure, and monitor the permeate flow rate and salt rejection rate in real time. Fourth, daily operation: maintain stable operating parameters (pressure, temperature, flow rate), regularly monitor the water quality of feed water and permeate, and record operation data. Fifth, regular maintenance: clean the membrane with acid-base cleaning agents every 3-6 months to remove scale and organic pollution; check the membrane element regularly, and replace it in time if the salt rejection rate drops by more than 5% or the flow rate decreases significantly. Sixth, shutdown and preservation: if the system is shut down for a long time, flush the membrane with preservative solution to prevent membrane aging and microbial pollution.

6. Quality Standards

The production and detection of high salt rejection RO membrane must comply with strict quality standards to ensure its performance and reliability. Internationally, it mainly complies with ASTM D4516 (standard test method for reverse osmosis membranes) and ISO 14001 (environmental management system standard). Domestically, it complies with GB/T 30307-2013 (reverse osmosis membrane elements for water treatment). The key quality inspection indicators include: salt rejection rate (stabilized ≥99.7%), permeate flow rate (within ±15% of the standard value), membrane integrity (no leakage), chemical stability (tolerance to acid-base and oxidants), and mechanical strength (ability to withstand high operating pressure). In the production process, strict quality control is carried out from raw material selection, membrane casting to element assembly, and each membrane element must pass strict water test before leaving the factory to ensure that its performance meets the standard requirements.

The working principle of high salt rejection RO membrane is based on the reverse osmosis phenomenon, which is the reverse process of natural osmosis. Natural osmosis refers to the spontaneous migration of pure water from the low-concentration solution side to the high-concentration solution side through a semi-permeable membrane until the concentrations on both sides are balanced. The high salt rejection RO membrane uses external pressure greater than the osmotic pressure of the feed water to force water molecules to move in the opposite direction—from the high-salinity feed water side  through the semi-permeable membrane to the low-salinity permeate side . The membrane’s dense active layer has a pore size of about 0.0001 μm, which is only 2-5 times the size of water molecules, so it can selectively allow water molecules to pass through, while rejecting most dissolved salts, ions, organic matter and microorganisms. The separation mechanism also includes charge repulsion effect: the charged membrane surface enhances the rejection of multivalent ions through electrostatic repulsion, further improving the salt rejection effect.

With the increasing global water scarcity and the continuous improvement of environmental protection requirements, the market demand for high salt rejection RO membrane will continue to grow, and its future development prospects are broad. Firstly, in terms of material innovation, the research and development of new membrane materials (such as ceramic composite membranes, graphene modified membranes) will further improve the salt rejection rate, pollution resistance and service life of the membrane, and reduce energy consumption. Secondly, in terms of application expansion, it will be more widely used in ultra-high salt wastewater treatment, space water recycling and other emerging fields, and combined with other water treatment technologies (such as forward osmosis, evaporation crystallization) to form a more efficient water treatment system. Thirdly, in terms of intelligence, the integration of Internet of Things technology will realize real-time monitoring and intelligent adjustment of membrane operation status, improve operation efficiency and reduce maintenance costs. In addition, with the continuous advancement of industrialization and urbanization, the demand for high-purity water in various industries will continue to increase, which will further promote the technological upgrading and industrial development of high salt rejection RO membrane.

The high salt rejection RO membrane is a key material in the field of water treatment, with ultra-high salt rejection performance, stable operation, wide adaptability and other core advantages. It plays an irreplaceable role in seawater desalination, brackish water treatment, industrial wastewater recycling and high-purity water production, effectively solving the problem of freshwater scarcity and water pollution. Its working principle is based on reverse osmosis, relying on the semi-permeable membrane’s selective separation effect to achieve efficient salt-water separation. With the continuous advancement of technology and the expansion of application scenarios, the high salt rejection RO membrane will be further optimized in terms of performance and cost, making greater contributions to global water resource utilization and environmental protection. To ensure its long-term stable operation, it is necessary to strictly follow the application procedures and quality standards, and do a good job in daily maintenance and management.

Q1: What is the main difference between high salt rejection RO membrane and standard RO membrane? A1: The main difference lies in the salt rejection rate and membrane structure. The high salt rejection RO membrane has a denser active layer, with a salt rejection rate of 99.7% or more, which is 1-2 percentage points higher than that of standard RO membranes (98%-99.5%). It is more suitable for scenarios requiring high-purity water, while standard RO membranes are more suitable for general water treatment with lower salt removal requirements.

Q2: How to extend the service life of high salt rejection RO membrane? A2: To extend the service life, it is necessary to do a good job in pre-treatment of feed water to avoid membrane fouling and oxidation; maintain stable operating parameters, avoid excessive pressure and temperature fluctuations; clean the membrane regularly to remove scale and organic pollution; and use preservative solution for preservation when the system is shut down for a long time.

Q3: Can the high salt rejection RO membrane treat ultra-high salt wastewater (TDS >100,000 ppm)? A3: It can be used, but it is not suitable for direct desalination. For ultra-high salt wastewater, the high salt rejection RO membrane is usually used as a concentration tool, combined with evaporation crystallization and other technologies to reduce the wastewater volume and recover salts, so as to achieve efficient treatment and resource utilization.

Q4: What factors will affect the salt rejection rate of the membrane? A4: The main influencing factors include membrane material and structure, feed water composition (salt concentration, ion type), operating conditions (pressure, temperature, pH), and membrane pollution degree. For example, high feed water temperature will slightly reduce the salt rejection rate, while sufficient operating pressure can ensure the stability of the salt rejection rate.

Q5: How often should the high salt rejection RO membrane be replaced? A5: Under normal operation and proper maintenance, the service life of the membrane is 2-5 years. When the salt rejection rate drops by more than 5% or the permeate flow rate decreases significantly, and it cannot be recovered after cleaning, the membrane should be replaced in time.