In the production processes of industries such as fine chemicals, new energy lithium batteries, pharmaceutical acid washing, and electroplating wastewater treatment, enterprises often need to deal with strong acids, strong bases, strong oxidants, and various organic solvents. Many factories commonly face a common problem: ordinary PP filter cartridge tend to have problems such as membrane layer swelling, cracking, shedding, and filtration failure after a short period of use. Frequent replacement of folding filter cartridge not only increases material costs but also delays production progress. When facing corrosive liquid conditions, what kind of filter element should be selected? Currently, the industry's consensus optimal solution is the PVDF polyvinylidene fluoride folded filter element.
To facilitate everyone's understanding, we first compare the common filtering filter elements on the market. The PP polypropylene filter element is cost-effective, but has poor solvent resistance. When exposed to ketones, high-concentration acids and bases, it is prone to aging and damage, which is a common defect of polypropylene pleated filter cartridge; the PES polyethersulfone filter element has good sterilization effect and is suitable for pharmaceutical pure water scenarios, but is not resistant to strong oxidants and strong bases, and cannot be adapted to electrolyte solutions, acid-washing waste liquids, etc.; the PTFE polytetrafluoroethylene filter element has top-notch corrosion resistance, but is expensive, has poor hydrophilicity, and has a low water flow rate. Considering comprehensive performance and cost, the PVDF filter element is the compromise preferred choice to replace defective pp pleated filter cartridge for corrosive liquid filtration.
The reason why the PVDF folded filter element can handle various high-corrosion and complex working conditions smoothly lies in its outstanding material physical and chemical properties. The chemical structure of PVDF is stable and it has excellent corrosion resistance. It can be in long-term stable contact with strong acids and alkalis such as hydrochloric acid, nitric acid, caustic soda, hydrogen peroxide, and sodium hypochlorite, as well as oxidizing media. It is also compatible with various polar organic solvents such as carbonate and NMP. During the filtration process, the membrane sheet is unlikely to experience swelling, layering, damage, leakage, etc., completely eliminating the problem of secondary pollution caused by material detachment, a fatal issue that often occurs in pleated membrane filter cartridge under corrosive environments. In addition, the filter element can withstand 121℃ high-temperature steam sterilization, has a wide temperature tolerance range, and can easily adapt to various industrial production scenarios such as high-temperature filtration and alternating hot and cold operations, with adaptability far exceeding that of conventional filter materials and ordinary folding filter cartridge.
According to different filtration requirements, the PVDF filter element is divided into two versions: hydrophilic and hydrophobic. They are specifically designed to solve various filtration problems. The hydrophilic product has its surface modified, with a fast water absorption speed, high flow rate, and extremely low protein adsorption rate, suitable for acid-base solutions, electroplating wastewater, purified water, etc., and focuses on particle removal and bacterial purification; the hydrophobic product does not require hydrophilic additives and is specifically designed for various organic solvents, high-viscosity liquid solutions, and can also be used for process gas sterilization, achieving liquid-gas dual use, with extremely strong practicality, outperforming traditional PP filter cartridge and polypropylene pleated filter cartridge in harsh medium filtration.
Structurally, the PVDF folded filter element adopts a folded deep filtration process, which increases the effective filtration area by 2-3 times compared to melt-blown filter elements, has a higher filtration capacity, and the pressure difference rises slowly, effectively extending the service life. Combined with an internal and external porous support layer structure, it has stronger anti-pressure ability, can maintain membrane stability under high-pressure conditions, and perfectly adapts to industrial security filters, precision filters, and other conventional filtration equipment. Enterprises do not need to modify the equipment and can directly replace aging pp pleated filter cartridge and pleated membrane filter cartridge with PVDF folded filter elements.
In conclusion, for complex and highly corrosive working conditions, one should not blindly purchase ordinary filter elements such as PP filter cartridge or PES just to save costs. Although the initial purchase cost may be lower, these folding filter cartridge are prone to wear and frequent replacement, which will increase the burden of subsequent operation and maintenance, resulting in a loss of benefits. PVDF folded filter elements balance the three core factors of corrosion resistance, filtration accuracy, and usage cost. They can handle various corrosive liquids and can withstand high-temperature repeated sterilization. They are the most cost-effective precision filtration solution for harsh working conditions in the chemical, lithium battery, pharmaceutical, and electroplating industries, superior to all conventional polypropylene pleated filter cartridge and pleated membrane filter cartridge.