Nanofibers for water
Adequate safe drinking water may be the most critical natural resource issue facing our world. Nanofibers offer several solutions for water filtration and purification.
Nanofibers can be used in the following applications:
- Waste water cleaning
- Contaminants removal - heavy metals, organics
- Industrial water treatment and recycling
The primary benefits of nanofibers in these applications are:
- High efficiency
- Fast function
- Selectivity
Affinity (adsorptive) membranes selectively capture specific molecules by immobilizing a specific capturing agent onto the membrane surface. In the environmental industry, affinity membranes have applications in decontamination and recuperation of waste streams - recycling of industrial water, removal of heavy metal ions, recuperation of metals, ammonia removal, removal of radioactive substances and isotope separation, enabling the removal of some classes of environmental contaminants which cannot be completely eliminated by conventional purification methods. Inorganic pollutants, such as cadmium, mercury and lead and organic compounds can be removed from waste water by affinity membranes.
Nanofibers can be utilized in photocatalysis by capturing the catalyst, between two or more nanofiber membranes. The highly permeable nanofiber membranes will hold the catalyst in place and allow the whole surface of the catalyst to be available for reaction. If nanoparticles are used as the catalyst, a multilayer nanofiber membranes is effective in preventing the escape of harmful nanoparticles.
Water preparation processes can exploit the value added by nanofibers for different purposes, such as, preparation of pure and ultrapure deionized water, water softening, potable water preparation, desalination and many others.
Nanofibers can become a better alternative to widely used coagulation/flocculation and chlorination technology, which are unable to completely remove the contaminants. In addition, these methods, generate extra volumes of sludge, which requires further treatment and disposal. Nanofibers can outperform the most commonly used porous gel resin ion exchangers and even microfiber ion exchangers due to:
- Faster kinetics - rapid ion exchange velocity, high connectivity in the interstitial space
- High selectivity – wide range of functional groups can be applied
- Low volume, low weight – low basis weight of nanofibrous membrane
- High degree of purification – total removal
