Need a new supplier for a filtration product or service? Let the AFS Buyer's Guide be the first place you look. We have cross-refenced the goods and services of our corporate sponsors into an easy-to-explore catalog.
Our Buyer’s Guide is organized first by primary categories:
The new AFS Learning Center recently announced four two-hour live virtual courses now available for registration. All courses are $195/members and $295/nonmembers, and all employees of AFS Corporate Sponsors (see list here) can register at the member rate.
The upcoming courses include:
By Wallace Leung, Chair of World Filtration Congress 13; and past Chair Professor of Innovative Products & Technologies in Mechanical Engineering and past Director, Research Institute of Innovative Products & Technologies at the Hong Kong Polytechnic University, Hung Hom, Hong KongThe recent outbreak of novel coronavirus, also known as 2019-nCoV, has caused a worldwide concern about a potential pandemic. On January 30, the World Health Organization (WHO) declared the new coronavirus outbreak as a global health emergency. As of the writing of this article, the nCoV has infected more than 20,000 people in 24 countries and killed 426, according to official WHO reports.
The virus can spread from human to human. According to the Chinese Center for Disease Control and Prevention, the size of this virus is about 100nm. When airborne or aerosolized, the virus can be attached to nuclei particles, which can be fine particles in the respiratory tracts or saliva and nasal droplets of an infected person, as well as fine particles suspended in air. Regardless, the minimum size of airborne nCoV is about 100nm when attached to a nano-size particle. The 100nm size airborne particle is referred to as nanoaerosol (also known as nanoparticle or ultrafine particle). While the National Institute for Occupational Safety and Health has standardized N95 and N98 at 300nm, there is no standard filtration test for nanoaerosols at 100nm.
The International Delegation on Filtration (INDEFI) was founded by filtration professionals in France, UK and the United States and created the first World Filtration Congress in 1974. Its prime mission is to share information and keep up with the increasing problem-solving demands of filtration and separations technology. INDEFI now includes 13 member countries – Austria, Australia, China, Chinese Taipei, France, Germany, Hungary, India, Japan, Korea, Nordics (Denmark, Finland, Norway, Sweden), UK and the Unites States. Held every four years, this gathering is like no other filtration event due to the extraordinary array of technical and educational offerings and based on the number of countries and industries represented among the thousands of attendees.
Now approaching its 13th Congress (September 20-24, 2021 in San Diego), this exceptional technical forum attracts a wide variety of professionals, including scientists, researchers, academic professors, engineers, practitioners, entrepreneurs, end-users, university students of different disciplines and legislators.
Guest blog by Paul Marold, President of Lydall Performance Materials
Clean air is the most essential resource for life. One could live without food for a few weeks, and without water for a few days; but without air, one would only survive a few minutes, if that.
Commercial membranes are currently made of polymers. These membrane channels are hard to control and therefore have low monovalent ion rejection. Furthermore, some of them have a low tolerance for the chlorine used for sterilization and anti-biofouling. Compared with traditional polymer cross-linked membranes, two-dimensional graphene oxide (GO) based membranes have higher chemical and physical stability. GO nanosheets, which act as an important part, can naturally form a well-packed layer-by-layer membrane structure. This kind of unique membrane structure promotes water permeance via low surface friction while maintaining high salt rejection via edge functional groups of GO nanosheets. Hence, the GO membrane has great potential for industrial water treatment applications. GO nanosheet functionalization can greatly improve membrane performance through channel modification. These characteristics are hard to accurately study via experimental methods because of the nanoscale. Therefore, numerical molecular dynamics (MD) simulations are used to zoom into the nanoscale membranes.
Using MD simulation, surface friction of layer-by-layer membrane with various surface oxidation has been widely investigated. Higher surface oxidation has been proved to improve water slip length inside membrane channels. Furthermore, this higher surface attraction can also increase ion adsorption on the surface of channels that additionally increases the ion rejection rate. The edge functionalization on the layer-by-layer GO-based membrane, whose sieving effect has been proposed from experimental works, is rarely studied. It has been reported that edge functional groups have a significant influence on water permeance. Both interaction and geometric effects of edge functional groups were identified with different GO membrane structures. The study of edge functionalization effects is only limited to water transport performance at present. No work about their desalination performance has been reported, although similar researches have been widely studied on single-layer porous GO membranes. In real experiments, however, it’s very hard to prepare membranes with uniform pore size and keep membranes to a single layer structure in atomic thickness. Layer-by-layer membrane structure assembled by functionalized GO nanosheets is much easier. In addition, filtration efficiency can be largely decreased if the pore size is not well-controlled. Therefore, a study of desalination effects of edge functional groups on layer-by-layer GO membrane is still left untouched but necessary to be processed.
A basic rule of air filters is that the more effective they are at removing air contaminants, the more resistant to air flow they are. The air filtration industry has long battled the opposing goals of efficacy and air flow, because as a filter becomes more effective, the greater the energy required to move air through it. In a face mask situation, the more effective (resistant) a filter is, the harder it is to breathe – so you can understand the quandary that we have in developing masks that let in breathing air but not viruses.
The primary danger of wearing a mask that doesn’t do what the wearer thinks it is doing is that it provides a false sense of security, and the wearer might take risks he or she wouldn’t otherwise take, putting themselves or others at risk.
During the week of April 20, AFS will present the following courses:
Tuesday, April 21, 8:00 a.m. – 12:00 p.m. central time: Intro to Solids/Liquids I – Principles
Tuesday, April 21, 1:00 – 5:00 p.m. central time: Meltblown and Nanofiber Technologies
Friday, April 24, 8:00 a.m. – 12:00 p.m. central time: Intro to Solids/Liquids II – Equipment, Operation and Testing
We thank everyone for their patience as we worked with the Hilton to identify new dates. In these uncertain times, WFC 13 and AFS leadership agreed to confirm dates later in 2021 to hopefully reduce risk of a repeat pandemic. The Hilton Bayfront has implemented a number of updated processes regarding sanitation. As we negotiated with the hotel, we took into consideration our contracted space in case social distancing is still enforced at the time of the Congress. The safety of all WFC 13 participants is our primary concern.
AFS and WFC 13 staff are working with the confirmed WFC 13 speakers and exhibitors to re-confirm their availability. The content that was to be presented last month will be very similar to what will be presented in September, 2021. Speakers will have the opportunity to update abstracts in 2021 with new information and data. WFC 13’s technical program is unmatched.
Guest blog by Kathleen Owen, ASHRAE Fellow, ETF member and Air Pollution Control Engineer for Owen Air Filtration Consulting
Have you been asked how MERV filters catch PM2.5? Obviously, it’s easy to go to the ASHRAE Standard 52.2 MERV table and see that a MERV 13 filter is ≥ 85% in the 1-3 µm particle diameter size range. This is often the answer you need. Still the questions keep coming, including from ASHRAE SSPCs 62.1 and 62.2. With ISO 16890 providing an ePM and these ASHRAE committees deciding to specify filters using particulate matter efficiencies, it became clear that ASHRAE 52.2 needed to address this issue.
Three layers of respirator fabric
While the efficiency of face masks is measured by norms defined by ASTM or NIOSH, producers of nonwoven materials need to have insight into the pore size of their material as well.
This document briefly explains how the pore size distribution of these nonwoven materials can be measured using a gas liquid porometer with the ‘pressure scan’ method.
Our next Short Course is Aspects of Designing Media and Filters for Air Filtration, which will be presented on Thursday, July 30, 8:00 a.m. – 12:00 p.m. central time.
This course gives the basis for a better understanding of air filtration theory when applied to filter media and filters, and how other filter requirements, such as environmental regulations, durability and manufacturability have an impact on filter media design. The theoretical principles and practical knowledge gained during this course will allow the participant to be able to properly design and specify filters and filter media for specific applications.
Long-time AFS member and supporter Peter Tsai has recently received international attention for coming out of retirement to join the battle against Covid-19. As the inventor of the synthetic fabric used to make the N95 mask that is critical in protecting front-line healthcare workers and stemming the spread of coronavirus, Peter started receiving a barrage of requests in mid-March for his knowledge about the nonwoven electrostatically charged material.
With a massive global shortage of the N95 masks, scientists, engineers and clinicians primarily wanted to know: Can the material be sterilized and reused? – and – How can production be scaled up to meet demand? With a willing and curious spirit that has always defined his signature approach, Peter didn’t hesitate to leave the comforts of retirement to help answer these questions. He started working 20 hours a day and even built a lab in his own home to test his ideas.
Proper design of a solid-liquid tubular element filter requires a thorough understanding of all variables within a process. Most small-scale filtration studies are performed with either a downward flow nutsche pressure filter or vacuum filter due to simplicity and overall space and batch requirements. Although this may produce successful results in terms of quality and throughput, several other factors such as cake homogeneity, particle sedimentation, and cake discharge cannot be effectively assessed which can present inaccuracies in sizing and operating a commercial tubular element filter. This presentation examines the inaccuracies that can develop upon scaling to a tubular element filter.
Bradley Moakler holds a B.S. in Chemical Engineering from the University of Nevada, Reno. After graduating, he worked as a process engineer for three years in the separations circuit at Molycorp, a rare earth mineral processing mine. He is currently working as North American Regional Manager for DrM Inc., a subsidiary of DrM, Dr. Mueller AG Switzerland, and has been with the company for approximately five years. His work mainly involves sales engineering, process development, and business development.
The following active AFS committees and their respective chairs are currently seeking new volunteers:
To volunteer for a committee, please email Lyn Sholl, Executive Director
