MS Positively Charged Nylon Membrane

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Positively Charged Nylon Membrane Datasheet

Features

Membrane Solutions positively charged Nylon membrane are modified in a Class Million cleanroom to give the nylon positively charged membranes a high amount of positively charged energy and an excellent service life.

• Good hydrophilicity
• High flux, low extractables
• High positive charge density, large adsorption capacity Removal of endotoxin and fine particles
• Bacterial retention of 0.22um : >7LRV (Brevundimonas diminuta)

Applications

• Water filtration for electronics, microelectronics, and semiconductor industries.
• Terminal filtration and point of use filtration of high purity water, deionized water and distilled water.
• Sterilizing filtration and clarification filtration of APIs,pharmaceutical solvents, water for injection, injections, medicinal liquids.
• Sterilizing filtration and clarifying filtration of liquor, wine and beverage.
• Pharmaceutical water de-heat source; high endotoxin content liquid filtration.

Technical Parameters

FAQ

1. Basic Concepts

Q1.1: What is a positively charged nylon membrane? How does it differ from ordinary nylon membranes?

A: Ordinary nylon membranes (such as natural nylon 66) typically carry a negative charge or a weak positive charge on their surface (depending on the pH). In contrast, positively charged nylon membranes are chemically modified to permanently carry a high-density positive charge on their surface.

Key Difference: Cationic membranes can efficiently trap negatively charged microparticles, endotoxins, viruses, and negatively charged proteins through electrostatic adsorption, whereas standard nylon membranes primarily rely on mechanical interception.

Q1.2: Is the material of nylon cationic membranes naturally hydrophilic? Does it require pre-wetting?

A: Yes, the nylon substrate itself is hydrophilic. However, after positive charge modification, the contact angle of some products may increase slightly.

Usage Recommendations: The vast majority of positively charged nylon membranes do not require pre-wetting (e.g., with ethanol or surfactants) and can be used directly for filtering aqueous solutions. However, when filtering high-viscosity liquids, it is recommended to first rinse the membrane with pure water to activate the pore structure.

Q1.3: Which solvents are cationic membranes compatible with? Which ones are they not compatible with?

A: Compatible with: Alcohols (ethanol, isopropanol), acetonitrile, ketones (at certain concentrations), DMSO, DMF (for short periods).

Not compatible: Strong acids (pH < 2), strong bases (pH > 12), concentrated sulfuric acid, formic acid, phenol, hypochlorous acid, and other strong oxidizing agents. Note: The positively charged coating may peel off if immersed in extreme pH conditions or organic solvents for extended periods.

2. Performance and Filtration Efficiency

Q2.1: What is the primary application of positively charged nylon membranes?

A: Specialized in the removal or capture of “negatively charged” targets:

Endotoxin (LPS) removal: Removal of pyrogens from pharmaceutical water and biopharmaceuticals.

Bacterial removal: Removal of bacteria from pharmaceutical water and biopharmaceuticals.

Nanoparticle/pigment removal: Removal of negatively charged colloids or pigments in the beverage and syrup industries.

Q2.2: Does it have high protein binding capacity (non-specific adsorption)?

A: Very high. This is a double-edged sword.

Advantages: Highly efficient capture of target proteins (e.g., negatively charged BSA, IgG subtypes).

Disadvantages: Not recommended if the goal is to filter out particles while retaining proteins (e.g., sterilization of protein solutions), as the positively charged membrane will adsorb large amounts of protein, resulting in extremely low yield. In such cases, please select membranes with low protein adsorption (e.g., PES, RC).

Q2.3: What are the advantages of a positively charged nylon membrane compared to positively charged PES or PVDF membranes?

A:

In short: Nylon positively charged membranes strike an optimal balance between high flow rates, mechanical strength, and solvent compatibility, making them suitable for industrial-scale high-flux filtration.

3. Usage and Operation

Q3.1: What pretreatment is required before use?

A: Recommended steps (especially for endotoxin removal):

Rinsing: Rinse the membrane with at least three times the filtration volume of pyrogen-free pure water or buffer to remove wetting agents or trace impurities left over from the manufacturing process.

Equilibration: Soak the membrane in the buffer system of the target filtrate (e.g., PBS, pH 7) for 10 minutes to stabilize the surface charge.

Avoid air bubbles: If using a needle filter, ensure all air is removed from the filter; otherwise, air bubbles may block the pores and reduce the effective surface area for charge interaction.

Q3.2: Why does the filtration rate gradually decrease?

A: There are typically two reasons:

Pore blockage: Particles or colloids are mechanically trapped, forming a filter cake layer.

Charge saturation (specific cause): Negatively charged target molecules (e.g., endotoxins) are adsorbed onto the inner walls of the membrane pores. Once all positively charged binding sites are occupied, subsequent negatively charged particles form an “electrostatic shielding layer,” reducing the effective pore size and decreasing flow rate.

Countermeasures: If high loading capacity is required, increase the membrane area; if the goal is solely to remove particles, switch to a non-charged membrane.

Q3.3: Can positively charged nylon membranes be used for nucleic acid blotting?

A: We are currently developing positively charged nylon membranes for nucleic acid blotting and can provide free A4 sample sheets.

4. Storage and Stability

Q4.1: How should unopened positively charged nylon membranes be stored? What is their shelf life?

A: Storage conditions: Protect from light, keep sealed and dry (relative humidity < 60%), at a temperature of 25±5°C. Freezing is strictly prohibited (ice crystals will damage the pore structure).

Shelf Life: Typically 3 years when stored under sealed conditions. However, the stability of the positive charge will slowly decline over time (charge density decreases by approximately 5–10% per year).

Q4.2: How can you determine if a positively charged membrane has failed?

A: Simple test method: Prepare a 100 ppm Congo red dye solution (strongly negatively charged). Filter this solution through the membrane. Failure indication: The filtrate immediately turns red (no adsorption); Normal indication: The initial portion of the filtrate is colorless or pale red (the dye is adsorbed), and only turns red once saturation is reached.

5. Product Selection

Q5.1 What widths are available for nylon positively charged membranes?

A: Currently, the main widths for nylon positively charged membranes are 270 mm and 300 mm; however, certain pore sizes can be produced in widths of 500–550 mm.

Q5.2 Can you provide samples of nylon positively charged membranes?

A: We can currently provide free A4-sized samples of nylon positively charged membranes.