Granular beds with asymmetric wettability enhances migration and separation of petroleum hydrocarbon pollutants

KeAi Communications Co., Ltd.

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Graphical Abstract

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Credit: Danhui Yang et al

A research team led by Wenjie Lv from East China University of Science and Technology proposed an asymmetric wettability microchannel structure to treat refinaery wastewater containing highly viscous and easily emulsified petroleum hydrocarbons that are difficult to separate.

By combining oleophilic and oleophobic surfaces, the granular beds with an asymmetric wettability microchannel directs oil droplets to migrate more efficiently, reducing blockages and energy consumptions. The findings were recently published in Water & Ecology.

“Through numerical simulations and high-speed camera tests, we systematically examined oil droplet adhesion, migration and separation in microchannels, as well as quantitatively correlated oil droplet migration rates with pressure drop distribution in combined wettability systems,” shares Lv.

Furthermore, by applying the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory, the research team elucidated the microscopic adhesion and migration mechanisms from an interfacial energy perspective.

The difference in wettability difference plays a crucial role in determining interfacial fluid behavior. On the OB (oleophobic media) surface, a stable water film forms due to the strong water-solid attraction.

“When the oil phase encounters the OB surface, the water film minimizes oil adhesion, often causing the oil droplets to slip or rebound–guiding them towards the OL (oleophilic-media),” explains LV. “Conversely, on the OL surface, the oil phase replaces the weak water–solid interaction to form a stable oil film.”

In OL-OB microchannels, the oil-solid contact forms a liquid bridge that blocks the pores, leading to an increase in bed pressure drop. In OL-OB media microchannels, the oil film selectively adheres to the OL surface, avoiding pore blockage, ensuring smooth flow of the continuous water phase, and reducing the pressure drop.

“The wettability gradient between the OL and OB surfaces also induces a wetting force that drives the oil phase to migrate from the OB surface to the OL surface, promoting effective coalescence,” adds Lv. “Therefore, the combined use of OL and OB can achieve synergistic effects: the high oil affinity of OL enhances wetting and coalescence efficiency, while the high water affinity of OB promotes water film formation, which not only improves water flux but also reduces bed pressure drop.”

Notably, the study identified the optimal operating conditions for operating the asymmetric microchannels. Compared to 30° and 120° or 30° and 150°, the microchannel combinations with oil phase contact angles of 30° and 90° significantly improved oil phase migration rate by 31.4% to 66.7%, while reducing flow field pressure drop by 25% with optimal velocity at 0.015 m/s.

Using the extended Derjaguin-Landau-Verwey-Overbeek theory, the team further revealed OL parts promote coalescence while OB parts form water films, enabling efficient separation. The findingsoffer a reliable technical pathway for optimizing energy consumption and scaling up the engineering application of oily wastewater pretreatment processes.

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Contact the author:

Dr. Danhui Yang, yangdh@ecust.edu.cn

-Ministry of Education's Hydrogen Energy Green Manufacturing and Utilization Key Core Technology Integration Research Platform, East China University of Science and Technology, Shanghai 200237, China

Dr. Wenjie Lv, lvwj@ecust.edu.cn

-National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, East China University of Science and Technology, Shanghai 200237, China

The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 200 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).

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Journal

Water & Ecology

DOI

10.1016/j.wateco.2025.100019 

Article Title

Granular beds with asymmetric wettability promote the migration and separation behavior of petroleum hydrocarbon pollutants: Migration rate and pressure drop distribution

Pollutants move through food chain affecting organ growth

KeAi Communications Co., Ltd.

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Potential developmental threats of long-term combined pollutant exposure to higher trophic levels.

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Credit: Zhang, Y., et al.

Pollution in our waters may be doing more harm than we think. A new study published in Environmental Chemistry and Ecotoxicology reveals that tiny aquatic organisms can pass a dangerous mix of microplastics and heavy metals up the food chain, disrupting organ development and hormone balance in higher-level species. The findings raise critical concerns for both ecosystem health and food safety.

“We used zebrafish as a model to trace how combined pollutants move through aquatic food webs,” shares lead author Yan Zhang. “Over a 90-day experiment, zebrafish exposed to microplastics and cadmium—first absorbed by protozoa—showed delayed growth in the heart, liver and reproductive organs.”

Notably, hormone levels were off balance, and deeper molecular analysis showed that crucial signaling pathways for growth and reproduction were disturbed.

“What surprised us most was the strength of the combined effect,” says Dr. Zhang. “Microplastics and cadmium are harmful on their own, but together they caused much more severe and lasting damage than expected, highlighting the hidden risks of pollutant mixtures in real-world environments.”

While previous studies often looked at individual pollutants or short-term effects, the current findings demonstrate how mixtures of pollutants can accumulate over time and pass through food webs, with long-term consequences. “This work helps connect the dots between environmental contamination and human food safety. What happens in aquatic ecosystems does not stay there—it can ultimately affect us too,” adds Zhang.

The research stands out for its multi-level approach, combining physical observations with hormonal testing and genetic analysis. By integrating these perspectives, the study paints a clearer picture of how pollution interacts within living systems—and why it matters.

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Contact the author: Yan Zhang, Key Laboratory of Evolution & Marine Biodiversity (Chinese Ministry of Education), College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, yanzhang1997@stu.ouc.edu.cn

The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 200 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).

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Journal

Environmental Chemistry and Ecotoxicology

DOI

10.1016/j.enceco.2025.09.004 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Protozoan-mediated long-term trophic transfer of combined pollutants: Implications for organ development in higher-trophic-level predator

 

Hotter does mean wetter

As climate change intensifies, so will precipitation --much of the time

Kyoto University

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How rising temperatures will affect rainfall in Japan. 

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Credit: KyotoU / Takemi lab

Kyoto, Japan -- Around the world, we are already witnessing the detrimental effects of climate change, which we know will only become more severe. Extreme weather events such as heavy rainfall, tropical cyclones, and heat waves are projected to intensify, and this will negatively impact both human society and natural ecosystems.

Assessing how climate change affects extreme weather is important not only from a scientific point of view, but also from a practical perspective. It is critical that we start adapting to climate change and mitigating the effects of potential disasters.

This situation has motivated a team of researchers at Kyoto University to investigate how climate change -- in particular, rising temperatures -- affects precipitation in Japan. The team has focused on heavy rainfall patterns and what kind of atmospheric conditions influence their characteristics.

"We know that the saturation of water vapor increases with temperature at a rate of about 7% per degree Celsius, but not all that water vapor is converted to rainfall, so we weren't sure this temperature scaling applies to the rainfall amount," says first author Sridhara Nayak.

Using climate change data generated by climate models from the Japan Meteorological Agency's Meteorological Research Institute, the team examined precipitation data for Japan, dividing the Japanese islands into seven regions to account for regional variations. They then analyzed the precipitation intensity and atmospheric conditions over Japan both in the present climate and in the projected future climate with a global average temperature increase of 4 degrees Celsius.

The findings revealed that a 4 degree global temperature increase will not only intensify extreme precipitation, but that it will indeed become stronger at a rate of 7% per degree of warming.

However, the atmospheric humidity, or amount of water vapor, plays a vital role in characterizing favorable conditions for an extreme precipitation occurrence. The heat to precipitation connection is applicable not on the hottest days, but at times when atmospheric moisture is sufficient. When the temperatures are at their hottest, the atmosphere becomes drier, and rainfall weakens. Therefore, extreme precipitation occurs not on the hottest days, but on days within the second highest temperature range of the year.

"With this in mind, we need to be prepared for the severe impacts of heavy rainfall in the future by creating a plan for climate change adaptation," says team leader Tetsuya Takemi.

Of course, there is more investigating to be done. This study utilized climate prediction data with a spatial resolution of 20 km, which is not sufficient to capture clouds that produce extreme precipitation. The researchers say that future studies should investigate the mechanisms for the occurrence of extreme precipitation using higher-resolution datasets.

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The paper "Regional and vertical scaling of water vapor with temperature over Japan during extreme precipitation in a changing climate" appeared on 15 October 2025 in Scientific Reports, with doi: 10.1038/s41598-025-22287-6

About Kyoto University

Kyoto University is one of Japan and Asia's premier research institutions, founded in 1897 and responsible for producing numerous Nobel laureates and winners of other prestigious international prizes. A broad curriculum across the arts and sciences at undergraduate and graduate levels complements several research centers, facilities, and offices around Japan and the world. For more information, please see: http://www.kyoto-u.ac.jp/en

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Journal

Scientific Reports

DOI

10.1038/s41598-025-22287-6 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Regional and vertical scaling of water vapor with temperature over Japan during extreme precipitation in a changing climate

Article Publication Date

15-Oct-2025

 

Leopoldina and Stifterverband honor atmospheric researcher Johannes Lelieveld with the 2024 Carl-Friedrich-von-Weizsäcker-Prize

Leopoldina

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The chemist Johannes Lelieveld uses innovative measurement methods and computer models to examine how chemical and meteorological processes impact Earth’s atmosphere. His research offers vital insights into the atmosphere’s self-cleaning capacity as well as into the influence of different kinds of emissions on climate and human health. The German National Academy of Sciences Leopoldina and the Stifterverband are honouring his achievements with the 2024 Carl-Friedrich-von-Weizsäcker-Prize. The prize, endowed with 30,000 euros, is awarded for scientific achievements that deal with important challenges facing society. It is thus the German award for scientists working in the area of science-based policy advice. “Johannes Lelieveld’s research has played an important role in helping us better understand the interaction between the atmosphere and processes on Earth,” says Leopoldina President Professor Dr Bettina Rockenbach. “Humans influence the atmosphere via pollutants such as particulate matter and ozone. At the same time, these pollutants negatively impact human health. Johannes Lelieveld’s research shows that air pollution and climate change cannot be considered separately. He is also frequently involved in advising policy-makers and society, not least via his involvement in the Leopoldina ‘Clean Air’ Ad hoc statement.” “With this award to Johannes Lelieveld, the Stifterverband and the Leopoldina are honouring a scientist whose work has clearly demonstrated how excellent research can help solve urgent issues facing society,” says Professor Dr Michael Kaschke, President of the Stifterverband. “His latest research on air quality and the impact of emissions on health not only provides new scientific insight but also creates a solid basis for specific and workable policy decisions. He thus exemplifies the principle behind the Carl-Friedrich-von-Weizsäcker-Prize: placing science at the service of society.” Professor Dr Johannes Lelieveld is a Dutch atmospheric researcher who has served as Director at the Max Planck Institute for Chemistry in Mainz/Germany since 2000. He has developed aircraft-based measurement programmes and computer models that simulate the interaction of chemical and meteorological processes. For example, he has managed to describe how clouds influence the chemistry of the ozone, how Asian monsoons impact the atmosphere’s ability to regenerate, as well as what risks arise due to nuclear catastrophes such as at Fukushima in Japan and Chernobyl in Ukraine. More recently, he has examined the effects of air pollution on human health and how emissions impact human mortality rates. Lelieveld has also used his expertise to advise policy-makers and society, for example when it comes to prioritising which emissions should be reduced in order to lessen risks to health. He has also created guidelines to reduce the risks to human health caused by air pollution and environmental changes. After obtaining his doctorate in atmospheric physics from the University of Utrecht/The Netherlands in 1990, and following research stays at the University of Stockholm/Sweden and the University of California in San Diego/USA, Johannes Lelieveld was appointed Professor of Atmospheric Physics and Atmospheric Chemistry at the universities in Wageningen/The Netherlands and Utrecht in 1993. He has been Director at the Max Planck Institute for Chemistry in Mainz/Germany since 2000, and Professor of Atmospheric Physics at the University of Mainz/Germany since 2002. Johannes Lelieveld is also a member of numerous academies and scientific organisations, including the Royal Society of Chemistry and the American Geophysical Union. He became a member of the Leopoldina Geosciences Section in 2015. His research has been honoured with numerous awards, including the Vilhelm Bjerknes Medal from the European Geosciences Union, and the Cardiovascular research high impact award from the European Society of Cardiology. Lelieveld was also one of the first researchers to receive an “Advanced Research Grant” from the European Research Council (ERC). The Carl-Friedrich-von-Weizsäcker-Prize is the science prize from the Stifterverband and is endowed with 30,000 euros. Together with the Leopoldina, the Stifterverband awards the prize every two years to scientists or research teams who have made a valuable scientific contribution to tackling the challenges facing society today. The first Weizsäcker-Prize was awarded to Professor Dr Jens Reich, scientist and civil rights activist, in 2009. Other recipients include the marine researcher Professor Dr Antje Boetius, the economist Professor Dr Christian Dustmann and the neuropsychologist Professor Dr Thomas Elbert. The award ceremony will take place on Tuesday 25 November 2025 in Halle (Saale)/Germany as part of the Leopoldina’s traditional Christmas Lecture, which will be held by this years’ prize winner on the topic of “Air Quality, Climate Change and Health”. Further information on the Christmas Lecture programme is available here: https://www.leopoldina.org/en/events/event/event/3288/ The Leopoldina on Bluesky: https://bsky.app/profile/leopoldina.org       The Leopoldina on LinkedIn: https://www.linkedin.com/company/nationale-akademie-der-wissenschaften-leopoldina    The Leopoldina on YouTube: https://www.youtube.com/@nationalakademieleopoldina    The Leopoldina on X: https://www.twitter.com/leopoldina About the German National Academy of Sciences Leopoldina As the German National Academy of Sciences, the Leopoldina provides independent science-based policy advice on matters relevant to society. To this end, the Academy develops interdisciplinary statements based on scientific findings. In these publications, options for action are outlined; making decisions, however, is the responsibility of democratically legitimized politicians. The experts who prepare the statements work in a voluntary and unbiased manner. The Leopoldina represents the German scientific community in the international academy dialogue. This includes advising the annual summits of Heads of State and Government of the G7 and G20 countries. With around 1,700 members from more than 30 countries, the Leopoldina combines expertise from almost all research areas. Founded in 1652, it was appointed the National Academy of Sciences of Germany in 2008. The Leopoldina is committed to the common good.  About the Stifterverband Around 3,000 companies, company associations, foundations and private persons work together as the Stifterband to further advance education, science and innovation. With improvement programmes, analyses and recommendations for action, the Stifterverband safeguards the infrastructure of innovation: high-performance universities, strong research institutions, and productive discussion between business, science and general society.