Everything In The World Is Contaminated With PFAS
When you read the news these days then probably you have heard about PFAS. PFAS contamination seems to be everywhere in the environment, especially the two well-known types PFOA and PFOS. PFAS chemicals have been found in deer, fish, drinking water, buildings, ground and probably NASA will soon find PFAS in rocks that they took from the moon. From the positive site, production is getting more restraint and globally more and regulations are put into force on certain types of PFAS chemicals. In this blog we will go into 3 questions on PFAS and describe three potential purification technologies for the removal of PFAS (or removal of PFOA and removal of PFOS).
What is a PFAS Chemical?
A PFAS chemical is a synthetic chemical which is also called a fluorinated surfactant, per- and polyfluoroalkyl substance. There are about 6000 types of PFAS chemicals and the most “famous” are PFOA (Perfluorooctanoic acid) and PFOS (Perfluorooctanesulfonic acid).
What can you do with a PFAS chemical?
PFAS Chemicals can lower the surface tension of water and is used in the emulsion polymerization to produce fluoropolymers. The main markets for the PFAS are 1. stain repellents, 2. use in polishes, paints, and coatings.
Can PFAS chemicals have health effects?
PFAS chemicals can have potential health effects like;
- Affect growth, learning, and behavior of infants and older children
- lower a woman’s chance of getting pregnant
- interfere with the body’s natural hormones
- increase cholesterol levels
- affect the immune system
- increase the risk of cancer
Source: https://www.atsdr.cdc.gov/pfas/health-effects.html
Removal of PFAS
The website of the EPA, The United States environmental protection agency mentions 3 potential technologies for the removal of Per- and Polyfluorinated substances (PFAS) from water. The three technologies that are mentioned are; activated carbon, ion exchange and membranes.
source: https://www.epa.gov/sciencematters/reducing-pfas-drinking-water-treatment-technologies
Below is a short description about the three removal technologies for PFAS removal.
1. Activated carbon
Activated carbon or activated charcoal is a special type of carbon that can adsorb various molecules and these molecules are adsorbed in the large surface area by van der Waals forces. A gram of activated carbon has a surface area that can be as large as a football field, this means a surface area of 500 to 2000 m2/g and sometimes even more. The surface area of activated carbon is divided into micro, meso and marco pores.
2. Ion exchange
Ion exchangers (IEX) are spheres of sulphonated synthetic resin that can take ions from for example water, process water, condensate water and swimming pool water, by changing them out against other ions. The liquid will flow over a with beads filled ion exchanger resin column. The beads are solid, and this is often referred to as adsorption resin
3. Membranes
In reversed osmosis , an applied pressure is used to overcome the osmotic pressure and in this way you can remove various unwanted molecules, larger particles or ions from for example water. This process works like other common membrane technology applications and the pore size of the membranes is .0001 micron which is extremely small. Another membrane technology that can be used are nano filtration membranes.
