Cleaning microplastics
New water microcleaners self-disperse, capture microplastics and float up for removal
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The system that captures microplastics from water functions in a single cycle.
view moreCredit: Image courtesy of Orlin Velev, NC State University.
In a new paper, researchers at North Carolina State University show proof of concept for a system that, in a single cycle, actively removes microplastics from water.
The findings, described in the journal Advanced Functional Materials, hold the potential for advances in cleansing oceans and other bodies of water of tiny plastics that may harm human health and the environment.
“The idea behind this work is: Can we make the cleaning materials in the form of soft particles that self-disperse in water, capture microplastics as they sink, and then return to the surface with the captured microplastic contaminants?” said Orlin Velev, the S. Frank and Doris Culberson Distinguished Professor of Chemical and Biomolecular Engineering at NC State and corresponding author of the paper.
“We demonstrated how multiple principles can be integrated into a system that works in a single cycle.”
The research starts with soft dendritic colloids – unique, hierarchically-branched soft particles with distinct properties such as the ability to stick to just about any surface – which can be created from a variety of polymers.
Velev and Ph.D. student Haeleen Hong, the paper’s first author, say these particles’ sticky nature can attract microplastics and grab them – even in wet and salty conditions, like ocean water.
“The cleansing particles in this research are made from chitosan, a biodegradable polymer originating from chitin, which comes from processed shellfish waste,” Velev said. He adds that using environmentally safe materials that already come from the sea makes the process more sustainable.
Soft dendritic colloids take the shape of small pellets when dried in droplets suspended over a water-repellent surface. When dropped into water, particles in the pellets separate and spread out to hunt microplastics. But first the researchers infuse a bit of eugenol, a plant-based oil, on one section of the pellet as a dispersant.
“This oil makes the pellets move in the water by the so-called ‘camphor boat effect,’ decreasing the surface tension on one side of the pellet and driving it forward. This allows our microcleaners to spread out across a larger area, capturing microplastics as they move and descend,” Hong said.
To make the return trip to the water’s surface, the microcleaners also contain small particles of magnesium, which makes them bubble up and rise to the surface when reacting with water.
To delay this return trip, the researchers coat the magnesium with an environmentally safe gelatin layer that blocks the magnesium’s reaction with water. Essentially, thicker coats of the gelatin delay the particles from rising to the surface, allowing the microcleaners to pick up more microplastics as they swirl and descend in water.
“As the gelatin dissolves, the magnesium generates bubbles and the microcleaners rise, bringing the captured plastics particles to the surface in a dense, scummy mixture,” Hong said. The paper shows that the particles can “swim” and collect microplastics for up to 30 minutes. The microplastic-laden microcleaners that have floated up to the water surface can then be collected by skimming.
“Potentially, the collected scum can be bioprocessed into more chitosan, which can then be used to create more microcleaners in order to capture more microplastics,” Velev said. Scaling up the process will take further investigations, the researchers say.
Former NC State Ph.D. student Rachel Bang co-authored the paper, along with current NC State Ph.D. student Lucille Verster.
Funding by the National Science Foundation under grants EFMA-2029327, CMMI-2233399 and DMR-2243104 supported the research.
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Note to editors: An abstract of the paper follows.
“Designing of self-dispersing soft dendritic microcleaners for microplastics capture and recovery”
Authors: Haeleen Hong, Rachel S. Bang, Lucille Verster and Orlin D. Velev, North Carolina State University
Published: March 25, 2025, in Advanced Functional Materials
DOI: 10.1002/adfm.202423494
Abstract: The recovery of persistent microplastics (MPs) from aquatic systems is a pressing environmental issue that is hard to address by conventional methods such as filtration or centrifugation. Strategies are investigated for the design of the self-dispersal and collection cycle of a class of active microcleaners comprising soft dendritic colloids (SDCs). The SDCs are made of chitosan and have a hierarchical fibrillar structure which enables adhesive collection of MP particles through van der Waals attraction. Wide-scale dispersion is achieved by agglomerating the SDCs into larger supraparticles, which self-propel on the water surface by the Marangoni effect driven by small amounts of organic oil. The cycle of propulsion, rehydration, and sinking enables efficient MP capture by the sedimenting SDCs. Further, magnesium hydrolysis reaction timed by encapsulation leads to vertical bubble propulsion and collection of the SDC-MPs aggregates on the surface. Overall, the results present a proof of concept of the potential of comprehensive MP cleanup methods based on sustainable self-dispersing microcleaners.
Microcleaners attract and capture microplastics in water.
Credit
Image courtesy of Haeleen Hong, NC State University.
Journal
Advanced Functional Materials
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Designing of self-dispersing soft dendritic microcleaners for microplastics capture and recovery
Article Publication Date
25-Mar-2025
New evidence links microplastics with chronic disease
Places with higher concentrations of microplastics see higher rates of hypertension, diabetes, stroke and other noncommunicable diseases
Tiny fragments of plastic have become ubiquitous in our environment and our bodies. Higher exposure to these microplastics, which can be inadvertently consumed or inhaled, is associated with a heightened prevalence of chronic noncommunicable diseases, according to new research being presented at the American College of Cardiology’s Annual Scientific Session (ACC.25).
Researchers said the new findings add to a small but growing body of evidence that microplastic pollution represents an emerging health threat. In terms of its relationship with stroke risk, for example, microplastics concentration was comparable to factors such as minority race and lack of health insurance, according to the results.
“This study provides initial evidence that microplastics exposure has an impact on cardiovascular health, especially chronic, noncommunicable conditions like high blood pressure, diabetes and stroke,” said Sai Rahul Ponnana, MA, a research data scientist at Case Western Reserve School of Medicine in Ohio and the study’s lead author. “When we included 154 different socioeconomic and environmental features in our analysis, we didn’t expect microplastics to rank in the top 10 for predicting chronic noncommunicable disease prevalence.”
Microplastics—defined as fragments of plastic between 1 nanometer and 5 millimeters across—are released as larger pieces of plastic break down. They come from many different sources, such as food and beverage packaging, consumer products and building materials. People can be exposed to microplastics in the water they drink, the food they eat and the air they breathe.
The study examines associations between the concentration of microplastics in bodies of water and the prevalence of various health conditions in communities along the East, West and Gulf Coasts, as well as some lakeshores, in the United States between 2015-2019. While inland areas also contain microplastics pollution, researchers focused on lakes and coastlines because microplastics concentrations are better documented in these areas. They used a dataset covering 555 census tracts from the National Centers for Environmental Information that classified microplastics concentration in seafloor sediments as low (zero to 200 particles per square meter) to very high (over 40,000 particles per square meter).
The researchers assessed rates of high blood pressure, diabetes, stroke and cancer in the same census tracts in 2019 using data from the U.S. Centers for Disease Control and Prevention. They also used a machine learning model to predict the prevalence of these conditions based on patterns in the data and to compare the associations observed with microplastics concentration to linkages with 154 other social and environmental factors such as median household income, employment rate and particulate matter air pollution in the same areas.
The results revealed that microplastics concentration was positively correlated with high blood pressure, diabetes and stroke, while cancer was not consistently linked with microplastics pollution. The results also suggested a dose relationship, in which higher concentrations of microplastic pollution are associated with a higher prevalence of disease. However, researchers said that evidence of an association does not necessarily mean that microplastics are causing these health problems. More studies are required to determine whether there is a causal relationship or if this pollution is occurring alongside another factor that leads to health issues, they said.
Further research is also needed to determine the amount of exposure or the length of time it might take for microplastics exposure to have an impact on health, if a causal relationship exists, according to Ponnana. Nevertheless, based on the available evidence, it is reasonable to believe that microplastics may play some role in health and we must take steps to reduce exposures, he said. While it is not feasible to completely avoid ingesting or inhaling microplastics when they are present in the environment, given how ubiquitous and tiny they are, researchers said the best way to minimize microplastics exposure is to curtail the amount of plastic produced and used, and to ensure proper disposal.
“The environment plays a very important role in our health, especially cardiovascular health,” Ponnana said. “As a result, taking care of our environment means taking care of ourselves.”
Ponnana will present the study, “Microplastic Concentration, Social, and Environmental Features and Their Association with Chronic Disease Prevalence: An Analysis Across U.S. Census Tracts,” Sunday, March 30, 2025, at 9:00 a.m. CT / 14:00 UTC in Moderated Poster Theater 2.
In a separate study presented at ACC.25, researchers from a different group reviewed the scientific literature and found that studies showed a strong correlation between microplastics in plaques in the heart’s arteries and the risk of adverse cardiovascular events, suggesting that the presence of microplastics could play a role in the onset or exacerbation of serious heart problems. Eesha Nachnani of the University School of Nashville will present the study, “Plastic Perils: The Hidden Threat of Microplastics in Cardiovascular Health,” on Monday, March 31, 2025, at 9:00 a.m. CT / 14:00 UTC in South Hall.
ACC.25 will take place March 29-31, 2025, in Chicago, bringing together cardiologists and cardiovascular specialists from around the world to share the newest discoveries in treatment and prevention. Follow @ACCinTouch, @ACCMediaCenter and #ACC25 for the latest news from the meeting.
The American College of Cardiology (ACC) is the global leader in transforming cardiovascular care and improving heart health for all. As the preeminent source of professional medical education for the entire cardiovascular care team since 1949, ACC credentials cardiovascular professionals in over 140 countries who meet stringent qualifications and leads in the formation of health policy, standards and guidelines. Through its world-renowned family of JACC Journals, NCDR registries, ACC Accreditation Services, global network of Member Sections, CardioSmart patient resources and more, the College is committed to ensuring a world where science, knowledge and innovation optimize patient care and outcomes. Learn more at ACC.org.
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