In industries such as fine chemicals, hydrometallurgy, and surface treatment, the precise filtration of strong acids, strong bases, and strong oxidizing liquid media is a common pain point. Traditional pleated membrane filter cartridge often encounter problems such as membrane swelling, framework corrosion, fiber detachment, and pore size deformation in high-corrosive media environments. This not only leads to the failure of filtration accuracy but also causes material contamination, frequent equipment shutdown for core replacement, and an increase in production and operation costs. To address this industry challenge, PVDF folding filter cartridge, with their outstanding chemical corrosion resistance, have become the optimal solution for chemical acid and alkali conditions.
The folding filter cartridge in chemical processing conditions frequently fail. The core problem lies in the chemical stability deficiency of the filtering material, which cannot withstand the long-term erosion by strong corrosive media. The main common filter elements have their own drawbacks: The PP filter cartridge, although having a low procurement cost, has weak resistance to strong alkalis and solvents, and is prone to brittleness, cracking, and structural disintegration when exposed to high-concentration acid and alkali solutions for a long time; The PES (polyether sulfone) filter element is suitable for pure water aseptic filtration scenarios, but is not resistant to high-temperature strong alkalis and high-concentration hypochlorous acid; In oxidative conditions, it is prone to material degradation and membrane layer damage; The PTFE (polytetrafluoroethylene) filter element has excellent corrosion resistance, but has poor hydrophilicity, low water flux, and high procurement costs, resulting in a relatively low overall cost performance in large-scale chemical production. These inherent defects make traditional polypropylene pleated filter cartridge unable to handle the demanding strong acid and strong alkali filtration scenarios.
However, PVDF (polyvinylidene fluoride) has solved the core pain points of chemical acid and alkali filtration at its fundamental level. Its molecular arrangement is dense and regular, with extremely strong chemical inertness, which can withstand the erosion of strong corrosive and highly oxidizing media such as hydrochloric acid, nitric acid, caustic soda, hydrogen peroxide, and hypochlorous acid for a long time. During operation, it will not experience membrane swelling, interlayer separation, or fiber detachment, completely avoiding the risk of secondary contamination caused by material precipitation. In addition, PVDF has outstanding high-temperature performance, capable of withstanding repeated sterilization at 121°C high-temperature steam, suitable for complex conditions such as high-temperature acid and alkali liquid filtration and online SIP disinfection of equipment, and has comprehensive operational stability that is superior to conventional filter materials such as pp pleated filter cartridge, PES, and PTFE.
To meet the diversified filtration needs of the chemical industry, PVDF folding filter cartridge are divided into two versions: hydrophilic and hydrophobic. The hydrophilic type is surface-modified, with fast water absorption speed, high filtration capacity, and low adsorption rate, suitable for acid and alkali water solutions, electroplating etching solutions, and chemical process water for particle removal, clarification, and sterilization. The hydrophobic type is specifically designed for organic solvents, high-viscosity corrosive liquid media, and is suitable for both sterile breathing inside tanks and filtration of corrosive process gases, achieving integrated liquid-gas filtration, covering most industrial conditions in the chemical industry.
At the structural level, the folded design of the pleated membrane filter cartridge significantly increases the effective filtration area, has a higher filtration capacity, a more gradual increase in operating pressure difference, and stronger anti-clogging ability. Combined with a high-strength internal and external supporting framework, the filter element has excellent pressure-bearing performance, is not prone to deformation under high-pressure pipeline conditions, and is not easily damaged. It can directly be adapted to conventional security filters and precision filters, without the need to modify existing equipment, and is easy to replace and install, with a very low implementation threshold.
For chemical enterprises, choosing PVDF folding filter cartridge breaks the vicious cycle of "frequent replacement of low-cost PP filter cartridge". Their core advantages of long service life, high stability, and strong corrosion resistance effectively reduce downtime, lower material and labor costs. Nowadays, PVDF polypropylene pleated filter cartridge have become the standard consumable for precise acid and alkali filtration in the chemical industry, efficiently solving the problem of corrosion filtration, and enabling enterprises to improve quality and reduce costs.