1. Natural material filter media
1). Quartz sand
- The main component is silicon dioxide (SiO₂), with high hardness (Mohs hardness 7) and strong chemical stability. It is widely used in water treatment filter layers.
- Common specifications: 0.5-1.2mm (coarse filtration), 0.3-0.5mm (fine filtration), refer to the "Standard for Quartz Sand Filter Media for Water Treatment" (CJ/T 43-2005).
- Disadvantages: high density (2.65g/cm³), high backwashing energy consumption.
2). Anthracite
- Porosity is as high as 50%-60%, with strong adsorption capacity, and it is often used with quartz sand to form a double-layer filter tank.
- Particle size range: 0.8-1.8mm, density 1.4-1.6g/cm³ (lighter than quartz sand, which can reduce backwashing pressure).
3). Zeolite
- Natural ion exchange material, with significant adsorption effect on ammonia nitrogen and heavy metals, suitable for aquaculture wastewater treatment.
2. Synthetic polymer material filter media
1). Polypropylene (PP) fiber
- Acid and alkali resistant (pH 1-14), anti-microbial corrosion, made into filter bags or filter elements, used in the chemical and food industries.
- Filtration accuracy: 1-100μm (adjusted according to weaving density).
2). Polyester (PET) non-woven fabric
- High strength and good air permeability, commonly used in air filtration (such as HEPA filter).
3). Polyethylene (PE) sintered filter element
- Microporous structure formed by high-temperature sintering, with an accuracy of up to 0.1μm, used for ultrapure water preparation.
3. Metal and ceramic filter media
1). Stainless steel wire mesh
- Model 304/316L, high temperature resistant (≤800℃), pore size range 20-200 mesh, used in the petroleum and pharmaceutical industries.
2). Porous ceramics
- Made of alumina or silicon carbide, with a compressive strength of >10MPa, suitable for high-temperature flue gas dust removal (such as waste incineration plants).
4. Special functional materials
1). Activated carbon
- Specific surface area 500-1500m²/g (refer to "Coal Granular Activated Carbon Standard" GB/T 7701.1-2008), can adsorb organic matter and residual chlorine.
2). Magnetic filter media
- The surface is loaded with Fe₃O₄, and the metal particles in oily wastewater are quickly separated by magnetic field, with a recovery rate of >90%.
Extended suggestions:
- Composite filter media (such as "quartz sand + activated carbon") can take into account both physical filtration and chemical adsorption;
- Emerging materials such as graphene filter membranes (filtration accuracy 0.001μm) are still in the laboratory stage and are relatively expensive.