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Toxic PFAS is harming our water. Now Europe has plans to ban them. This poses major problems for the industrial sector, as these "permanent chemicals" are essential for many products and processes. For more than 70 years, PFAS has been known as a panacea in the industrial field. But in early 2023, the European Chemical Administration (ECHA) announced that their days were numbered. It recommended that the European Commission ban perfluoroalkyl and polyfluoroalkyl compounds and start doing so as quickly and widely as possible. Dr. L ö bbecke, spokesman of the Fraunhofer Chemistry Alliance, said: "Since the European Chemical Administration (ECHA) announced this news, many enterprises and companies have actually been knocking on our door." He reported that in recent months, on alternative chemicals, environmental and human toxicological assessment and recycling of various PFAS materials The number of consultations on filtration and cleaning technologies has grown exponentially. Dr. L ö bbecke seriously added: "I can understand the concerns and difficulties of enterprises, some of which believe that the ban poses a threat to their survival." PFAS exists in daily necessities such as coated pots, pizza boxes and outdoor jackets, as well as in medical equipment, heat pumps and batteries. As a processing chemical, PFAS is used to etch microchip patterns in the semiconductor industry. They can resist water, dirt and oil, withstand high temperatures and corrosive chemicals, and resist bacteria and light. Few other chemicals can compete with them, and their characteristics are so unique, which also explains why they are used so frequently. According to the data of the United States Environmental Protection Agency, PFAS now has many different variants, about 15000 substances. Although these colorless, odorless and tasteless substances can be widely used, they are also found to be toxic in many cases. They can cause cancer and infertility, and weaken the immune system. More importantly, the extremely stable fluorocarbon bonds produced in industry and unique to PFAS cannot be found in nature, nor can they be decomposed. Once they are released into the environment, PFAS will stay there forever, which is why they are often called "permanent chemicals" in public debate. The German Environment Agency (UBA) carried out a study in 2020 to test children aged 3 to 17, and PFAS was found in the blood of each test subject. Despite various risks, it is impossible to stop using PFAS overnight in many applications. Nevertheless, the researchers of Fraunhofer are still carrying out a series of projects aimed at developing alternatives, reducing the pollution of PFAS in the environment over time, and using improved filtration and cleaning technologies to ensure that fewer permanent chemicals eventually enter the watercourses, organisms, soil and other environmental fields resulting in accumulation and diffusion. Not all PFAS are the same. It is important that the risk assessment should distinguish different compounds in order to remove compounds that may pose a particularly high risk to humans and the environment from circulation as soon as possible. For PFOS, PFOA and PFHxS, implementation has started. They are only allowed in a few exceptional cases. Since February 25, 2023, restrictions have also been imposed on perfluorocarbonic acids (the most widely known of which is perfluoroononanoic acid), affecting their marketing, production and use. These substances belong to the PFAS category and are composed of long carbon chains. They accumulate in organisms along the food chain and are difficult to be discharged from the body. Humans are at the top of the food chain. These substances combine with proteins in human blood, kidney and liver, where they can stay for many years and may have harmful effects. During pregnancy, they are transferred to the unborn child through the placenta, and can even be transferred through breast milk. In many cases, the industrial sector has now switched to short chain perfluorocarbons, which consist of up to six perfluorocarbon atoms. Their accumulation in the body is lower, but their mobility is stronger. They are not retained in the soil, but quickly enter groundwater, which is usually used for drinking water supply. Identify that the Fraunhofer Institute of Toxicology and Experimental Medicine ITEM is working with 15 European partners to carry out the zero PM project, which aims to identify the potential risks of different PFAS in drinking water. Dr. Annette Beech, head of the chemical safety department, said: "It is not a trivial matter that one substance is more dangerous than another. It is important to take a comprehensive view of each substance. One of the basic principles of toxicology is that risk is calculated according to the inherent danger and exposure level of the substance, or the frequency of your exposure to it." For this reason, She is analyzing research data and published scientific literature. "In this process, it will soon be clear which substances are key." She added that it is not surprising to first limit the use of PFOS, PFOA, PFHES and PFNAA. The European Food Safety Agency (EFSA) also identified these four compounds in its latest report in 2020, and defined the threshold of the maximum weekly intake, which is considered harmless to health. This is 4.4 ng per kg. "This is equivalent to about 0.00003 mg per person per day," Beech explained. These substances are most commonly found in drinking water, fish, fruits, eggs and egg products. When talking about the European Chemical Administration (ECHA)'s plan to impose restrictions on all PFAS in the near future, Bitsch expressed her understanding: "This is a huge category of substances, with many subcategories. It will take decades to conduct a thorough toxicological assessment of them. We can't wait that long." She added that there may still be exceptions, such as certain medical applications need certain substances. If the assessment of their benefits and risks shows that continued use is desirable, Or if science proves that a substance is harmless. However, proof experiments are a burden for the industrial sector, she said. The latest research results published by the Fraunhofer Institute of Molecular Biology and Applied Ecology (IME) in January 2023 also confirmed the urgency of EU regulation. In the SumPFAS study conducted on behalf of the German Environment Agency (UBA), researchers concluded that PFAS is much broader than previously known. Dr. Bernd G ö ckener, head of the trace analysis and environmental monitoring department of Fraunhofer IME, said: "Even in smaller rivers, we have found a large number of PFAS, including the less well-known PFAS. The problem is often not local, but universal. PFAS is almost everywhere." He and his team examined about 200 suspended solids and sediment samples from 170 rivers and lakes in Germany and compared them with archived samples from the German environmental specimen bank. The German environmental specimen bank has been recording the chemical pollution of the environment and human beings since the 1980s. The good news is that PFAS has reduced the pollution of waterways; The EU ban is working. The bad news is that when G ö ckener and his team used improved analytical tests, including precursors, they found that the overall concentration of PFAS was 346 times higher than that of traditional tests. Once they are released into the environment, the precursors will be oxidized to form traditional PFAS. G ö ckener: "From the perspective of analysis, we can never fully understand these thousands of substances. We assume that the pollution level is far higher than the level we can measure." G ö ckener and his team found that the PFAS content is particularly high downstream of large sewage treatment plants and industrial facilities that produce or process PFAS. These permanent chemicals enter rivers mainly through waste water and finally flow into the North Sea or the Baltic Sea. "The ocean is a huge repository for all PFAS around the world. This is where they will continue to accumulate," G ö ckener said. Substitution Unless a substitute for PFAS is successfully developed, the continuous inflow of PFAS can be reduced. Dr. Jakob Barz of the Fraunhofer Institute of Interface Engineering and Biotechnology (IGB) is developing this task. He is using plasma technology to functionalize the surfaces of different materials to make them chemically stable or resistant to dirt, water and ice. Dr. Barz said: "Strictly speaking, PFAS coatings are not required in many application fields. The only thing that we haven't done well is really effective oil prevention function. " He adds different chemicals to the plasma according to the required characteristics. "Molecules are decomposed. Individual fragments react on the material surface to form a polymer layer. The type of polymer always depends on the material we add to the plasma and the process conditions." One advantage of the plasma coating is that it can be applied to a very thin layer, just like the film on the surface. The texture and pores are retained without being blocked, making this method very suitable for coating solder templates for computer circuit boards or membranes for wastewater filtration. These are the application fields where PFAS is currently used. For the waterproof coating of outdoor fabrics, the researchers of Fraunhofer IGB used a bio based, sustainable alternative: chitosan. This forms a strong shell around the fiber, which improves wear resistance. It can be obtained from various sources, including crustaceans. The EU handles about 250000 tons of crustacean waste every year, and accumulates more than 6 million tons every year worldwide, which is a rich natural resource. Insect cuticle and exoskeleton are common residues in animal food production, which contain chitin, and chitosan is composed of chitin. "Chitosan is much more reactive than chitin. We take advantage of this. We apply it to fabrics at the same time as waterproof vegetable oil." Dr. Thomas Hahn, deputy leader of the IGB Biological Process Engineering Working Group in Fraunhofer explained: "Under the effect of heating and pressure, these substances combine to form a uniform and solid protective layer." His colleague Dr. Achim Weber added: "The ingenuity lies in that our impregnant - based on natural products - can be easily reactivated after washing in the washing machine by ironing the fabric or putting it into the dryer." Another advantage is that the formula using the existing machinery and production technology in the textile industry is simple. Weber said: "For example, chitosan is also an effective solution for food packaging or coating boxes, which can prevent washing powder from being damp and caking." He said that in this case, PFAS can also be safely exempted from use. However, so far, these permanent chemicals are indispensable in the energy transition. Whether it is used for electrolyzer to obtain hydrogen, or for fuel cell and battery, membranes containing PFAS can be seen everywhere. They need to provide properties such as high chemical stability and special levels of conductivity and permeability. "The requirements for materials are extreme," said Dr. Taybet Bilkay Troni, head of IAP, Polymer and Electronics Department, Fraunhofer Institute for Applied Polymers. Nevertheless, she and her team are looking for alternatives - they have succeeded. Together with the fuel cell technology center ZBT, they developed a new polymer and used it in the production of membranes for the anion exchange membrane water electrolyzer (AEM-WE). As Bilkay Troni explained, "The membrane is the core part of any electrolytic cell. This is critical to the reliability and effectiveness of the electrolytic process, in other words, the process of using electricity to decompose water into hydrogen and oxygen." In addition to the membrane, electrolysis also requires two electrodes (anode and cathode), a DC power supply and a conductive fluid called electrolyte. The positively charged hydrogen gathers on the cathode, and the negatively charged oxygen gathers on the anode. The membrane ensures that negatively charged ions (or anions) are transported and separates the anode and cathode chambers. Electrolyte is in a weak alkaline state. Electrolysis occurs at a temperature of about 60 to 80 degrees Celsius, which is the operating condition for continuous membrane exposure. However, it should not become brittle and should maintain its flexibility and ionic conductivity. The preliminary results of the electrolytic test cell are promising, and the membrane without PFAS remains stable. New polymers used to make membranes can also be processed very efficiently. Another advantage is that the electrode made of expensive rare earth metals is not needed, such as the electrode required for proton exchange membrane electrolysis, which is often used at present. In the future, this kind of membrane can also be used in fuel cells. Bilkay Troni added: "But before we achieve this goal, we need to carry out more development steps." "Our research has just begun. Next, we hope to cooperate with our partner ZBT GmbH to conduct longer tests in the real environment, so that we can continue to improve stability and conductivity." She believes that this kind of film can be put on the market within three to five years. "The demand is huge. But enterprises always prefer finished products. We cannot provide them yet. The only way we can develop a good solution to meet their needs is to cooperate with the industrial sector." As long as we cannot completely replace PFAS, it is more important to capture them as effectively as possible and prevent their proliferation in the environment. To this end, Dr. Stefano Bruzzano from the Fraunhofer Institute of Environment, Security and Energy Technology UMSICHT developed a clean purification technology several years ago in cooperation with CornelsenUmwelttechnology GmbH, while constantly improving and perfecting it. This method is particularly effective in places with high emission levels and local restrictions, such as using special foam to extinguish fires, or in landfills where consumer goods containing PFAS slowly "seep out" and release chemicals into groundwater. The PerfluorAd ® cleaning system can be used in on-site mobile containers to clean contaminated water. To do this, pump water into the system container, where PerfluorAd is added ®; This is a biodegradable liquid agent. PFAS combines with it to make them precipitate at the bottom. The remaining water passes through the activated carbon filter, and a few PFAS not captured in the first cleaning step are retained. The heavily contaminated sediments are then properly disposed of in an incinerator at temperatures well above 1000 degrees Celsius. Bruzano: "The advantage of our process is that it combines different methods." The activated carbon filters that have been used in many water treatment plants are not enough to provide a powerful and environmentally friendly cleaning process. When the pollution per liter of PFAS exceeds 10 micrograms, they will soon become blocked. Bruzano stressed that "it is very important to analyze the polluted water in advance, so that our process can adapt to the PFAS and related substances in the water and the degree of pollution." This determines how much PerfluorAd needs to be added ®， And whether any other process additives, such as flocculants, are needed to separate PFAS.