Tag Archives: Patrick Lejtenyi

Powerful tool for coastal oil spill cleanup? Paper examines nanomaterial remediation studies

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A February 4, 2025 news item on ScienceDaily announces an analysis (meta analysis) of over 40 studies into using nanomaterials for cleaning up pollution,

Cleaning up after a major oil spill is a long, expensive process, and the damage to a coastal region’s ecosystem can be significant. This is especially true for the world’s Arctic region, where newly opened sea lanes will expose remote shorelines to increased risks due to an anticipated rise in sea traffic.

Current mitigation techniques even in heavily populated regions face serious limitations, including low oil absorption capacity, potential toxicity to marine life and a slow remediation process.

However, advances in nanotechnology may provide solutions that are more effective, safer and work much faster than current methods. That’s according to a new paper in Environmental Science: Nano by a Concordia-led team of researchers.

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A February 4, 2025 Concordia University news release (also on EurekAlert) by Patrick Lejtenyi, which originated the news item, delves further into the topic, Note: Links have been removed,

“Using nanomaterials as a response method has emerged as a promising sustainable approach,” says lead author Huifang Bi, a PhD candidate in the Department of Building, Civil and Environmental Engineering at the Gina Cody School of Engineering and Computer Science.

“This paper synthesizes, reviews and analyzes between 40 and 50 studies on the subject to give us a big-picture look of the status of nanotechnologies in coastal oil spill response. At the same time, we are also presenting our own suggestions and identifying research gaps between using nanomaterials in the lab and how they can be used in real-world applications.”

She adds that nanomaterials are being widely studied to combat marine oil spills, but she is focusing specifically on coastline remediation. She estimates that more than 90 per cent of the papers she reviewed were exclusively lab-based and not yet available for field use.

Encouraging results need field testing

The unique properties found in nanomaterials can help mitigation across different remediation efforts. These include surface washing agents, dispersants, sorbents and bioremediation. Each method has its own strengths and drawbacks that can be improved with the use of nanomaterials.

For instance, replacing synthetic surfactants and organic solvents with bio-based nanomaterials has shown to be both highly effective at removing oil and to produce less toxic substances that can harm coastal biotas.

Nanomaterials can also be used in dispersants. Clay-based nanomaterials can stabilize oil particles in an emulsion, resulting in a larger area for oil-eating bacteria to grow and accelerating oil disappearance. In sorbents like aerogels or foams, nanomaterials can improve the removal of oil from water by absorption, adsorption or a combination thanks to large surface areas and a high number of sorption sites.

Finally, they can also be used to accelerate bioremediation, a technique that uses microorganisms to break down harmful pollutants like oil into less harmful or harmless substances.

“While these lab-based results are encouraging, we need to exercise caution,” warns Bi, winner of a 2023 Vanier Canada Graduate Scholarship. “We should prioritize the use of sustainable and eco-friendly nanomaterials to minimize environmental risks and ensure the responsible application of nanotechnology in coastal oil spill response. We also need to scale up testing to measure this efficacy in field tests.”

According to Bi’s thesis supervisor Chunjiang An, an associate professor in the same department, the emergence of nanomaterials as oil spill remediation tools is coming at a critical time.

“We are facing many new challenges, with threats of oil spills now affecting both traditional and new regions, including the Arctic,” he says. “We need to work with governments and the private sector to ensure that they are aware of these technologies and can further include them in their future remediation guidelines.”

Here’s a link to and a citation for the paper,

Nanotechnology for oil spill response and cleanup in coastal regions by Huifang Bi, Catherine N. Mulligan, Kenneth Lee, Baiyu Zhang, Zhi Chen and Chunjiang An. Environ. Sci.: Nano, 2025,12, 41-47 DOI: https://doi.org/10.1039/D4EN00954A First published: 18 Nov 2024

This paper appears to be open access.

Using carbon dots (organic nanosensors) to detect pesticides

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Before getting to the latest about carbon dots, there’s something to be clarified (and it was news to me), a carbon dot is not a quantum dot. So says this 2020 paper, “Advances in carbon dots: from the perspective of traditional quantum dots” by Yanhong Liu, Hui Huang, Weijing Cao, Baodong Mao, Yang Liu, and Zhenhui Kang. Mater. Chem. Front., 2020,4, 1586-1613 First published March 17, 2020.

Abstract

Quantum dots (QDs) have been the core concept of nanoscience and nanotechnology since their inception, and play a dominant role in the development of the nano-field. Carbon dots (CDots), defined by a feature size of <10 nm, have become a rising star in the crossover field of carbon materials and traditional QDs (TQDs). CDots possess many unique structural, physicochemical and photochemical properties that render them a promising platform for biology, devices, catalysis and other applications. …

This story is about carbon dots but you can find out more about quantum dots in my October 6, 2023 posting concerning the 2023 Nobel prizes; scroll down to the ‘Chemistry’ subhead.

An August 30, 2023 news item on phys.org describes work from Concordia University (Montréal, Canada) on carbon dots,

Researchers at Concordia have developed a new system using tiny nanosensors called carbon dots to detect the presence of the widely used chemical glyphosate. Their research, titled “Ratiometric Sensing of Glyphosate in Water Using Dual Fluorescent Carbon Dots,” is published in Sensors.

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An August 30, 2023 Concordia University news release (also on EurekAlert) by Patrick Lejtenyi, which originated the news item, explains the importance of the work and provides more technical details, Note: Links have been removed,

Glyphosate is a pesticide found in more than 750 agricultural, forestry, urban and home products, including Monsanto’s popular weed-killer Roundup. It is also controversial: studies have linked its overuse to environmental pollution and cancer in humans. Its sale is banned or restricted in dozens of countries and jurisdictions, including Canada.

The researchers’ system relies on the carbon dots’ chemical interaction with glyphosate to detect its presence. Carbon dots are exceedingly small fluorescent particles, usually no more than 10 or 15 nanometres in size (a human hair is between 80,000 and 100,000 nanometres). But when they are added to water solutions, these nanomaterials emit blue and red fluorescence.

The researchers employed an analysis technique called a ratiometric self-referencing assay to determine glyphosate levels in a solution. The red fluorescence emitted by the carbon dots when exposed to varying concentrations of the chemical and different pH levels is compared with a control in which no glyphosate is present. In all the tests, the blue fluorescence remained unchanged, giving the researchers a common reference point across the different tests.

They observed that higher levels of glyphosate quenched the red fluorescence, which they accredited to the interaction of the pesticide with the carbon dots’ surface.

“Our system differs from others because we are measuring the area between two peaks—two fluorescent signatures—on the visible spectrum,” says Adryanne Clermont-Paquette, a PhD candidate in biology and the paper’s lead author. “This is the integrated area between the two curves. Ratiometric measurement allows us to ignore variables such as temperature, pH levels or other environmental factors. That allows us to just only look at the levels of glyphosate and carbon dots that are in the system.”

“By understanding the chemistry at the surface of these very small dots and by knowing their optical properties, we can use them to our advantage for many different applications,” says Rafik Naccache, an associate professor of chemistry and biochemistry and the paper’s supervising author.

Research assistants Diego-Andrés Mendoza and Amir Sadeghi, along with associate professor of biology Alisa Piekny, are co-authors.

Starting small

Naccache says the technique is designed to detect minute amounts of the pesticide. The technique they developed is sensitive enough to be able to detect the presence of pesticide at levels as low as 0.03 parts per million.

“The challenge is always in the other direction, to see how low we can go in terms of sensitivity and selectivity,” he says.

There remains much work to be done before this technology can be used widely. But as Clermont-Paquette notes, this paper represents an important beginning.

“Understanding the interaction between glyphosate and carbon dots is a first step. If we are to move this along further, and develop it into a real-life application, we have to start with the fundamentals.”

The researchers are supported by funding from the Natural Sciences and Engineering Research Council of Canada.

Here’s a link to and a citation for the paper,

Ratiometric Sensing of Glyphosate in Water Using Dual Fluorescent Carbon Dots
by Adryanne Clermont-Paquette, Diego-Andrés Mendoza, Amir Sadeghi, Alisa Piekny, and Rafik Naccache. Sensors 2023, 23(11), 5200; DOI: https://doi.org/10.3390/s23115200 Published: 30 May 2023

This paper is open access.