Industry Trends | Can Ceramic Membrane Replace PVDF Membrane?Issuing time:2024-07-15 16:00 Introduction: It has been a year since the European Union released its proposal to restrict perfluorinated and polyfluoroalkyl compounds (PFAS). At that time, people were concerned that the industry's preferred membrane material, polyvinylidene fluoride (PVDF), might conflict with the proposal. Dr. Graeme Pearce discussed whether PVDF membranes still have long-term prospects, and if not, would ceramic membranes benefit from limitations? Difluoroethylene (VDF) belongs to the PFAS family The most commonly used material in the membrane industry is PVDF (polyvinylidene fluoride). However, PVDF is considered a type of PFAS, so it may not meet certain exemption conditions and cannot obtain corresponding exemptions.
Figure 1 Perfluoroalkyl Chemicals (PFAS) (from website)
Figure 2 PVDF membrane (from website) Recent statements indicate that there has not been much change in both support and opposition for the continued use of PVDF. However, the prospects for the right to produce and use PFAS in water treatment products are not optimistic. How to balance the different perspectives of businesses and users, as well as environmental and health issues in all 27 EU member states, will continue to be a headache. However, based on the current situation, PVDF membranes are likely to face restrictions from the European Union. The market is developing towards ceramic membranes PVDF has become a key material for water treatment membranes and is clearly leading the market in certain application areas. Is there any indication that ceramic membranes will benefit from the uncertain future of PVDF? The answer seems ambiguous!
Figure 3 PVDF membrane structure diagram (from webpage) Before discussing PFAS, some markets had already shifted their focus from polymer materials. For example, about half of the UK municipal markets now specify the use of ceramic membranes, and the world's largest ceramic membrane drinking water plant will be put into use near Birmingham within a year.
Figure 4 (a) Schematic diagram of the cross-section of the ceramic film and product image; (b) Product photos of single/multi-channel sheet-like ceramic films with different geometric shapes developed by IKTS company in Fraunhofer, Germany (source paper)“Ceramic membrane technology for water and wastewater treatment: A critical review of performance, full-scale applications, membrane fouling and prospects”） As early adopters of polymers, some users in the UK had several negative experiences, causing decision-makers in these companies to now say, 'We will never use PVDF again.'. Although the development issues of those early generation products have actually become a thing of the past, these emotional traumas have transformed into an unchangeable perspective. Comparison of Ceramic Membrane and PVDF Membrane in the Market When evaluating the selection of polymer and ceramic materials, most markets require fair competition. In the early days of reverse osmosis technology, engineers were able to make comprehensive comparisons of the flow rate, removal rate, and price of new standardized products. When ultrafiltration technology emerged, it became easier because particle removal had become a matter of course, and the only parameters to consider were flow rate and price. It can be said that considering only traffic and price due to the existence of different modes may have taken this step too far, but the desire to make simple comparisons has led to the promotion of this method. The emergence of ceramic membranes has raised doubts about this comparative method that focuses on flux and price. Ceramics have higher flux, but they are also more expensive. Of course, when considering a project, there are other applicability issues or cascading effects of systems and operations that need to be taken into account.
Figure 5: Zhejiang Tianxingjian Water Service Co., Ltd. Tubular Ceramic Membrane This is precisely why ceramic membranes are difficult to achieve significant breakthroughs in markets that are still open to both options. Attempting to make extensive comparisons in situations where performance and price differences are so disparate may be misleading. Maintaining the status quo obviously carries less risk. The fair competition environment hinders the popularization of ceramic membranes Ceramic membranes perform best in the industrial market, where end-users are not concerned about the flow and price between different membrane suppliers, but only focus on the value and return provided by the membrane system for its application. Industrial applications usually have certain difficulties, such as membrane fouling, corrosive liquids, etc., which are all areas where ceramic membranes are very suitable. What measures can be taken to enhance the attractiveness of ceramic membranes in a wider market? Can we push the discussion to focus on the problems that polymer membranes are difficult to solve with ceramic membranes? Due to the diverse demands of water treatment applications, a fair competition environment is most unfavorable for ceramic membranes. In which aspects are ceramic membranes superior to PVDF membranes Ceramic membranes perform better in handling challenging liquids, as strong physical or chemical cleaning methods can be used to restore membrane performance. Nowadays, news is filled with reports of extreme weather events, localized floods, peak turbidity, and algal blooms. These events are the long-term predictions of climate change and are now becoming a reality. For end users, ceramic membrane systems are much better at restoring their performance through cleaning and maintenance when the feeding conditions are beyond normal than relying solely on a non functional warranty. Another issue is that ceramic membrane systems take up less space. Due to high traffic, this has a direct impact on the land area. In addition, the ceramic membrane treatment process is usually simpler and therefore more compact. The advantage of ceramic membrane may mean the end of PVDF membrane Ceramic membranes are undoubtedly seizing the opportunity brought by the difficulties in the polymer membrane market. It is likely that restricting the use of PVDF membranes will take several years to be implemented. However, although fluorocarbon compounds, especially PFAS, have had a significant positive impact on society overall, their negative environmental and health effects will ultimately mean that their use will be limited to truly necessary areas. The membranes currently used for water treatment are unlikely to become one of these basic uses, as ceramics can economically and effectively replace them. As an industry, we need to consider the wider use of ceramic membranes and accelerate their application. This will ensure that we promptly learn from undeniable application lessons and gain better experience than in the early days of polymer membranes. Dr. Graeme K Pearce is a membrane technology expert with 40 years of experience in the membrane industry. He is the head of Membrane Consultancy Associates. Original link:https://www.aquatechtrade.com/news/wastewater/pvdf-pfas-ceramics-membranes-restrictions-uptake?tid=TIDP9737113X21F07B18E65B462A890C48939C1CF660YI2&noactioncode=1&utm_term=&utm_content=AQD2024_NB_28_A_EN&utm_medium=email&utm_campaign=Nieuwsbrieven_2024&utm_source=RE_Email__
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