A Deeper Understanding of Filter Paper
Filter papers are essential to supply for the scientists working in the lab. Hawach has quantitative and qualitative filter papers to meet almost all the customer’s requirements.
Quantitative filter paper(Quantitative Medium Flow Filter Paper Grade: BIO-40, Quantitative Laboratory Filter Paper Grade: BIO-42 ) is widely used for filtration after filtration, which refers to the weight method analysis test and the corresponding analysis test in quantitative chemical analysis. We offer ash-free filter papers for quantitative analysis, which are top quality, ash-free (ash content <0.01%), and with pure cotton fiber linter filters. And our ash-free filters are sorted by a variety of thicknesses, with characteristics and flow rates from wide pore and fast to narrow pore, and slow rates too.
Used to identify the properties of substances in qualitative analysis, the wet strength qualitative filter paper (Wet Strengthened 10 Micron Filter Paper Grade: BIO-91, Wet Strengthened Chemistry Filter Paper Grade: BIO-113) contains a small amount of chemically stabilized resin to enhance the wet strength and avoid introducing obvious impurities into the filtrate. Our qualitative filter papers(Qualitative Chromatography Filter Paper Grade: BIO-5) which have low ash content (0,06 – 0,15 %) are available for different needs and applications in multiple diameters, thicknesses, and filtration rates.
Introduction of filter paper technical indicators
Filter paper technical indicators are essential characteristics used to assess its suitability for specific filtration tasks. These include basis weight (g/m²), pore size (µm), porosity (%), ash content (%), wetting time (s), filtration speed (mL/min), retention efficiency (%), flow rate (mL/s), wet strength (g/cm), chemical compatibility, pH compatibility, binder type, and certifications. Understanding these indicators helps in choosing the right filter paper for precise and efficient filtration processes in laboratories.
On the other hand, the technical specifications of the filter paper can be mainly divided into two aspects, filtration characteristics, and physical characteristics. Filtration characteristics include air permeability, maximum pore size, and average pore size. Physical characteristics include quantitation, thickness, stiffness, burst strength, resin content, and the like.
1. Air permeability refers to the amount of air passing through the filter paper under a certain area and a certain degree of vacuum, unit: l/m2·s.
2. Maximum pore size is the diameter of the largest sphere that can pass through the filter paper, unit: μm
3. The average pore size is the pore size derived from the “burst” bubbling pressure, unit: μm.
1. Quantitation refers to the quantity of filter paper per square meter, unit: g / m2.
2. Thickness refers to the thickness of the filter paper, excluding the corrugation depth, unit: mm.
3. Stiffness is the ability of the filter paper to deform, unit: mg.
4. Burst strength refers to the maximum pressure that can be applied to the unit area of the filter paper, unit: Kpa.
5. Resin content refers to the percentage of resin in the weight of the filter paper.
Relationship between physical characteristics of filter paper and filter performance
Quantitation in the filter is mainly reflected in the weight and price of the filter. Under a certain filtration area, the larger the amount, the heavier the filter paper and the heavier the filter. Since the cost of filter paper accounts for a large proportion of the cost of the filter, the cost is higher.
For corrugated cylindrical filters, the thickness of the filter paper limits the maximum filtration area of the filter.
3. Stiffness and bursting resistance
Stiffness and bursting resistance indicate the resistance to deformation, high-pressure resistance, high stiffness, and high bursting resistance of the filter paper. It can show that the filter has good durability, but if the stiffness is too high and it is easy to become brittle, and the filter is easily damaged.
4. Resin content
The resin is added to the filter paper in order to increase the stiffness of the filter paper and the shaping in the filter paper processing and is generally between 10% and 30% depending on the usage. If the resin content is too high, the resin will easily block the pore structure of the filter paper.