The filter process begins by purifying the water, passing it through layers of porous materials, each specially selected for its ability to remove specific forms of contamination. All porous materials can filter particles by size, many have additional capabilities thanks to their chemical properties. For example, charcoal, or activated carbon, is a porous component of household and industrial water filters that can also bind large or electron-rich molecules and catalyze the breakdown of other chemicals such as molecular chlorine. While there are many different types of filters, we can classify and compare them using their measurable physical and chemical properties.
The key physical properties are:
Pore size: Average or maximum pore size of the material.
Porosity: Volume of the filter not occupied by solid material
Tortuosity: Length of paths through the filter, compared to a straight line.
Adhesion: The strength of hydrogen bonding interactions between the fluid and the filter.
Kinetic rate constants: Parameters that define how the filter material affects chemical reactions in the fluid.
Bacterial Cellulose Membrane Filter
Bacterial cellulose membranes completely eliminate inlet water turbidity and suspended particles, resulting in clean, drinkable water.
This mechanism shows that cellulose itself is capable of removing contaminants from water. Filtration is a common way of obtaining pure drinking water by removing particles and microorganisms based on size exclusion. Cellulose-based filters are an affordable, bio-based option for particulate removal, but the bacteria are often too small to remove by size exclusion alone. Cellulose fiber surfaces in two types of commercial paper filters have been given a net positive charge to trap bacteria through electrostatic interactions without releasing any biocide.
The results show the potential to create cellulose membrane water purification filters from bio-based products, with a simple modification process, is a good option for the future, which could save lives without using bactericides.
