05.04.2023
AquaVallis filter material and products based on it
The developed filter material based on nanofibers makes it possible to remove viruses and bacteria from aqueous media, the size of which is many times smaller than the average filter pore size.
According to the World Health Organization, 80% of all infectious diseases in the world are associated with unsatisfactory water quality or violation of sanitary and hygienic standards due to its lack. Given the ever-increasing shortage of water supply, these problems will only worsen, and their ubiquity and global nature will ensure a steady and high increase in demand for water purification devices and means. Recently, the solution to the problem of increasing the efficiency of removing microorganisms and other negatively charged particles from water has been associated with the use of filters with a modified charge.
The key operating principle of the AquaVallis filter material developed at the Institute of Physics and Mathematics and Mathematics SB RAS is based on the combination of removing any pathogenic microorganisms (viruses, bacteria) using sorption and filtration, while maintaining the high porosity of the material and, as a consequence, high fluid flow rate (0.2 - 1.0 cm /With). The novelty of the filter material lies in high-speed filtration with complete (similar to microfiltration) removal of pathogenic microorganisms (viruses, bacteria) from water, the size of which is many times smaller than the average pore size of polymer fiber, while maintaining the natural mineralization of water. The use of AquaVallis filter material is promising for the production of individual water purifiers and cartridges for water treatment systems.
Technical and economic advantages
Modern filters made from non-woven fibrous materials usually have a pore size of about 1 micron or more. Membrane filters are used to filter microorganisms and colloids with sizes less than 0.1 microns. Membrane filters, which operate on the principle of matching the pore size to the size of the contaminant, can retain all types of bacteria with a high retention rate (99.99%), but they are not able to retain smaller particles, in particular viruses, measuring around 0.03 microns. The throughput of membrane filters is directly dependent on the pore size, i.e. the smaller the pores, the lower their throughput.
There is another filtration mechanism - electrokinetic adsorption, when the filter material has a charge, and particles with the opposite charge are attracted and adsorbed on the filter material. Most colloidal particles, including microorganisms, in water are negatively charged. The electrical charge of colloids, like a bacterial cell suspended in an aqueous environment, is explained by the appearance of a double electrical layer, the inner part of which is the surface of the particle, and the outer part is the environment in which it is located.
The AquaVallis filter has an electropositive charge, reaching 40 mV in water. Due to this, the filter removes from water all currently tested types of particles: inorganic and organic colloids (heavy metals, humic acid), organic dyes, microorganisms, including viruses, endotoxins, at sufficiently high water flow rates. The range of possible particle sizes is quite wide, from several microns to tens of nanometers.
The sorption capacity of the filter material for E.Coli bacteria is at least 106 CFU/cm2at a flow rate of up to 0.64 cm/s. For bacteriophage MS2, the sorption capacity depends on the water flow rate and is 1.4×103 - 1.4×107 PFU/cm2 at flow rates from 0.45 cm/s to 0.04 cm/s.
Areas of application
- 1. Additional purification of tap water from microbiological contaminants.
- 2. Systems of various capacities for obtaining water of general laboratory, analytical and reagent purity.
- 3. For filtering solutions in medical institutions.
- 4. Ultrafiltration for the microelectronic and chemical industries.