Basic Theory of Membrane Filter

Hawach Scientific always specializes in the production of round disc membrane filters and roll membrane filters. With decades of accumulated experience in working with the most difficult problems in filtration and sterilization of liquids, gas, and other samples, advanced production equipment, and scientific management, Hawach membrane filter can meet the diverse needs of customers with excellent quality, reasonable price, and the great variety of goods. A variety of pore sizes are available to meet different microbial detection requirements. Besides, all membrane filters are aseptically and independently packaged, which avoids potential contamination in the production and packing process.

Membrane filter plays an important role in the filtration industry. It removes almost all microorganisms and particles and has no influence on the ingredients while doing filtration, which is very crucial in the lab or other significant experiments. No matter why you filter, for analytical, sterilization, or any other purpose, there are many kinds of membranes specifically produced to meet your needs.

Hawach membrane filter is a poly-nuclear membrane composed of tens of thousands of micropores. Through a membrane filter, particles larger than the aperture are filtered onto the surface. It is used to filter various solutions and remove bacteria and impurities. Also, the membrane filter is a critical part of the syringe filter and has different parameters and types.

Materials and types of Membrane Filters

Membranes are made of different materials, such as PTFE, PVDF, Nylon, MCE, CA, PES, GF, PP, and so on. But which material you should choose depends on what kind of material you want to filter. Two common types of membrane filters are round-disc membrane filters and roll-type membrane filters. Because they all can be applied infiltration and sterilization of many samples.

Basically, according to the shape of the membrane filter, membrane filter can fall into 2 major types: flat membrane and curly membrane. The flat membrane filter is mainly domestic membrane, including MCE, Nylon, PTFE, MCE,  PES, CA, PVDF, GF,  and PP. For curly membrane filters, we can see there are imported and homemade ones in the market. The imported mainly includes Nylon, PTFE, PTFE-L, MCE, PES, CA, PVDF, and GF; Nylon, PTFE, PTFE-L, MCE, PES, CA, PVDF, and PP.brands are produced locally, such as PTFE Membrane Filter, MCE Membrane Filter, Cellulose Acetate Membrane Filter, and PP Membrane Filter, and Microporous Glass Fiber Membrane Filter.

Classification of filter membranes

Filter membranes are classified according to the size of retained raw water particles, and the pores of the membranes are divided into microfiltration membrane (MF), ultrafiltration membrane (UF), nanofiltration membrane (NF), and reverse osmosis membrane (RO). MF membrane has a pore diameter of 0.05um or more or a molecular weight of 1,000 or more. It is intended to remove colloids and polymer organic matter.

The NF membrane has a pore size of 100 to 1,000 molecular weights. It removes substances between UF and RO to remove trihalomethane, odor, color, pesticides, soluble organics, Ca, Mg, etc. The RO separation particle size is tens of molecular weights, and the object is to remove common salts and inorganic salts.

RO osmotic pressure is 1-2 times more than its osmotic pressure. In addition to the above four, there are ion-exchange membranes and gas permeable membranes. The ion-exchange membrane is driven by electricity to separate the salt molecules and promote desalination. The gas-permeable membrane is a new type of membrane that has been researched to pass through gas, which can make ethanol concentration and seawater desalination.

Ultrafiltration membrane, microporous membrane, nanofiltration membrane, microfiltration membrane, hollow fiber ultrafiltration membrane, Xaar filtration membrane, etc. Ultrafiltration membranes are the most widely used. According to the form of the membrane, they are mainly divided into roll type, plate and frame type, tube type, and hollow fiber type.

Important technical parameters of membrane filter

Aperture: 0.1um, 0.22um, 0.45um, 0.8um, 1.0um, 3.0um, 5.0um, 10.0um. But it’s important to note that not all the membranes, some only have a limited aperture.

Size: 1). The membrane is round, it will be expressed in diameter. Diameter: 13; 2; 47; 90; 142 and 293mm.
2). Roll membrane is a rectangular roll together, expressed by the width. Width: 25; 260; 270; 280; 310mm. filling：22mm.

Bubble point: to test if the aperture conforms to the standard.

Velocity: The aperture is proportional to the velocity, the larger the aperture, the faster the velocity.

Membrane abbreviations

SFCA: Surfactant-free cellulose acetate
APES: Asymmetrical polyethersulfone
PTFE: Polytetrafluoroethylene
NYL: Nylon
CN: Cellulose nitrate
CA: Cellulose acetate
GF: Glass fiber

Attractive Aspects of Membrane Filter

Hawach membrane filter is specially designed to support different filtration needs. It is of lower extractability and high flow rates, a smooth surface, and proper structure will be most fitting for analytical usage. Diverse filter materials are used based on the properties of the fluid or gas type to improve peak filtration performance. Membranes with high binding of proteins may clog prematurely and remove desired materials from the filtrate that you discover in the retentate.

The function of the PP Membrane Filter

PP Membrane Filter supplied by Hawach Scientific is best suited for industrial processes such as gas filtration, chemical processes, and photo-resist production, and also can be used for pre-filter for samples with a high filtration speed. Hawach chooses a pure hydrocarbon material, which directly avoids disposal problems concerned with halogen content with the PP membrane filter in contrast with other membrane filters such as PVDF or PES types. Perfect chemical compatibility, a high particular content, high performance, and a high flow rate make it suitable for pharmaceutical, environmental, and biotechnological.

Structure of Micro-porous Glass Membrane Filter

Hawach micro-porous Glass Membrane Filter is the best choice for contaminated samples and can work with the most difficult samples with less hand pressure. Hawach constantly puts forward the designing and improving principles of the materials and structure of the micro-porous glass membrane filter.

Directed by these principles, the designing of technological conditions for preparing membrane filters has been done to effectively improve membrane filter performance. Meanwhile, the blend spinning and cold stretching process make most membrane filters can withstand strong acids, aggressive solvents, alcohol, and so on.