Composite and Popular Science of Filter Paper
Composite filter paper disc
Generally speaking, the quantity of composite filter paper disc is larger, less than 300g/m2, less than 300g/m2 (1.0mm). Filter paper can be processed into various shapes of filter elements and used with filters. The number of special filter paper boards exceeds 300 g/m2, and the thickness is also large (5 mm). Filter paper can be processed into the required size and size and can be used with a plate and frame filter.
In the filter paper manufacturers, the manufacturing process of special filter paper (cardboard), two contradictory issues must be resolved between paper strength (tensile strength, burst resistance) and filtration performance (pore size, filtration time).
Depends on the object of separation. There are generally two types of filtered gas and filtered liquid.
The filtered gas includes (1) Dust gas, that is, exhaust gas and tail gas burned by the factory; (2) Toxic aerosol, that is, aerosol containing bacteria, toxic gas, and lead smoke; (3) Radioactive gas, that is natural or artificial Radioactive dust gas; (4) Radioactive air, that is, the gas containing radium. Iodine, radon, and xenon.
The liquid in the filtrate is (1) oil, that is, fuel, lubricating oil, hydraulic oil, etc.; (2) water, which is an aqueous solution, water emulsion, etc.; (3) organic solvent, that is, benzene, xylene, and other solutions.
The raw and auxiliary materials required for the production of composite filter paper include: glass fiber, synthetic fiber, plant fiber, activated carbon fiber, etc., and fillers include titanium dioxide, diatomaceous earth, perlite, wet strength agent, molecular sieve, ion exchange resin, etc.
The technical indicators of filter paper can be divided into two aspects, one is the filter characteristics of the filter paper, and the other is the physical characteristics. Filtration characteristics include air permeability, air resistance, pore size, and average pore size. Physical properties include quantitative, thickness, stiffness, corrugation depth, burst resistance, resin content, etc.
Quantity: refers to the quality of composite filter paper per square meter. Thickness: refers to the thickness of the composite filter paper, excluding the corrugated depth. Air resistance: The resistance of composite filter paper to air flow. Use 2500px2 composite filter paper to pass 85 liters of air in one minute to express the pressure drop value. Corrugated depth: the depth of the groove pressed to strengthen the longitudinal stiffness of the composite filter paper, in mm. Under normal circumstances, its value is 0.2mm.
Air permeability: The amount of air passing through the composite filter paper per unit time under a certain area and pressure (20 mm water column). Nominal filtration accuracy: refers to the ability of composite filter paper to retain particles of a certain size, and the particle size of 50% of the tiny spheres that can be retained or filtered out shall prevail. Pore size: the void size calculated by the pressure when a bubble emerges on the composite filter paper sample during the test. Average pore diameter: The pore diameter calculated by the pressure during “dense” bubbling is called the average pore diameter. Resin content: the percentage of resin in the weight of the composite filter paper. Generally 10%~30%. Stiffness: the ability of composite filter paper to resist deformation. Bursting resistance: the larger pressure that the composite filter paper can withstand per unit area.
Popular science about filter paper disc
Recently, the research team led by Zhu Yingjie, a researcher at the Shanghai Institute of Ceramics, Chinese Academy of Sciences, has made new progress in the study of a new type of filter paper that can be used to efficiently remove airborne PM2.5 fine particles.
Based on the previous research work of hydroxyapatite ultra-long nanowire refractory paper, the team successfully developed a new type of hydroxyapatite ultra-long nanowire-based filter paper that can effectively remove PM2.5 fine particles in the air, and This material is used as a filter mask for the filter element. The new nano filter paper has good biocompatibility, environmentally friendly, non-toxic and harmless, high flexibility, self-assembly between nanowires to form a three-dimensional network nano porous structure, strong surface adsorption capacity, and can effectively intercept, adsorb and filter air PM2 .5 Fine particles, high filtration efficiency.
In addition, in order to significantly improve the air permeability of the new filter paper, the team used hydroxyapatite ultra-long nanowires as the main construction material and then composited with plant fibers to form a multi-level composite pore structure, which achieved the ability to maintain PM2.5 in the air. The high filtration efficiency of fine particles can also greatly improve the air permeability of the filter paper. The new nano filter paper has a filtration efficiency of more than 95% for air PM2.5 and PM10 particles and has good air permeability, and the filtration efficiency is better than that of many commercial masks.
More importantly, the new filter paper has a filtering efficiency of more than 95% for PM2.5 fine particles in moderate, severe, and severely polluted air pollution environments, and can be used as a core filter material to be embedded in daily filtration In the mask, the effective protection of individuals in various haze weather environments is realized. In addition, the new filter paper can be used repeatedly and for a long time.
The new filter paper is also expected to be used as a high-efficiency filter element material in air purifiers, air conditioners, and other products. The team also developed a new type of hydroxyapatite ultra-long nanowire-based filter paper with antibacterial function, which has high antibacterial activity against common bacteria such as Escherichia coli and Staphylococcus aureus and is expected to be used in high-efficiency antibacterial filter masks.
