[Introduction] Separation membranes, as materials with special selective permeability, enable precise separation, purification, and concentration of substances at a molecular or microscopic particle level. They are widely used in numerous core sectors such as water treatment, food & beverage, pharmaceuticals, chemicals & petrochemicals, and energy. The stability of their performance directly determines the production efficiency and product quality in these related industries. Gas barrier property, being a core indicator for evaluating separation membrane performance, is crucial for ensuring separation purity and efficiency. The following sections provide a systematic analysis covering classification, test methods, core instruments, and actual test results.

▍1. Classification of Separation Membranes

The separation capability of membranes stems from their "selective permeability." Different types of separation membranes achieve substance separation through different principles, and the gas barrier property directly affects the purity and efficiency of the separation process:

Microfiltration / Ultrafiltration Membranes:

Rely on membrane pore size screening for solid-liquid or macromolecule separation (e.g., intercepting suspended solids in wastewater treatment, separating proteins in biopharmaceuticals). Insufficient gas barrier properties can lead to permeation of impurity gases, affecting product purity.

Reverse Osmosis / Nanofiltration Membranes:

Rely on selective permeation under pressure driving force for desalination or small molecule separation (e.g., seawater desalination, drinking water softening). Poor gas barrier properties can reduce water flux and desalination rate.

Pervaporation Membranes (e.g., PVA membrane):

Used for separating close-boiling mixtures like alcohol-water or organic-water mixtures. The gas barrier property directly determines separation selectivity – if the target gas permeates easily, separation efficiency can be significantly compromised.

Inorganic Ceramic Membranes (e.g., Alumina membrane):

Suitable for separation under high-temperature and highly corrosive conditions (e.g., high-temperature fluid filtration in chemical industry). Their barrier property, along with mechanical strength, determines separation stability in harsh environments.

▍2. Test Method

The performance indicators of separation membranes include separation efficiency, flux, barrier property, stability, and service life. Among these, barrier property testing is a key link in evaluating the comprehensive performance of separation membranes, directly determining their suitability and reliability in complex application scenarios. Referencing GB/T 1038.1-2022 "Plastics - Film and Sheeting - Determination of Gas Transmission Rate - Part 1: Differential-Pressure Method", the differential pressure method is adopted as the core testing method. This method quantifies the rate at which gas permeates through the membrane by establishing a pressure difference across it, and is suitable for evaluating the gas barrier performance of various membrane/sheet materials, including gas separation membranes and packaging materials.

▍3. Test Instrument

Our company has long focused on the technological innovation and product development of separation membranes. To accurately evaluate the gas transmission characteristics of separation membranes made from different materials, we utilized our self-developed N530 2.0 Gas Transmission Rate Tester to test the gas barrier properties of PVA-based pervaporation membranes and alumina-based ceramic membranes during in-depth research.

The instrument strictly complies with GB/T 1038.1-2022 (a core standard for separation membrane testing), the Chinese Pharmacopoeia (25th Edition), and other international and domestic specifications, ensuring test data highly corresponds to the actual separation performance of the membranes, thereby providing authoritative support for R&D and quality inspection.

 Differential Pressure Method Gas Transmission Rate Tester 530 20

▲ N530 2.0 Gas Transmission Rate Tester

▍4. Test Results

1. Test Conditions:

Testing Center Ambient Temperature: 23°C, Humidity: 50% RH.

Test Temperature: 23°C.

Test Samples: Single-coated PVA membrane, Triple-coated PVA membrane, Alumina ceramic membrane (3 parallel samples per group).

2. Actual Results:

After the test concluded, the results were displayed in the testing software. The results of this test are as follows:

This would typically be a table or chart showing the specific Gas Transmission Rate (GTR) results for each sample type, likely indicating very low GTR for the ceramic membrane and varying GTR for the PVA membranes, with the triple-coated PVA expected to have a lower GTR than the single-coated one.

▍5. Conclusion

The innovation and application upgrading of separation membrane technology rely heavily on a precise and reliable performance evaluation system. Gas barrier property testing, as a core part of this system, directly provides scientific basis for material development, process optimization, and scenario-specific selection. The N530 2.0 Gas Transmission Rate Tester, with its core advantages of wide adaptability, high-standard compliance, and high testing precision, has become the preferred testing equipment in the separation membrane industry. It effectively addresses the challenges of evaluating the barrier properties of separation membranes made from different materials and based on different separation principles.