Author Archive

Green-er gold nanoparticles

gold nano synthesis

Working in a university research laboratory, I am made aware, almost on a daily basis, of the amount of energy and chemicals we use and the amounts of—sometimes hazardous—waste we produce. Working in an environmental engineering research lab that has the word “sustainable” as part of its name, I am also well aware of how ironic that may seem.

As scientists, we want to be able to create the best, most precisely controlled, most reproducible nanoparticles and nanoparticle-containing experiments. Sometimes the cost for those conditions is high temperatures and large amounts of (sometimes harsh) chemicals (e.g., excess precursors and stabilizers). So even though the core motivation for our research is to benefit the environment, sometimes the methods we have to use in the lab are not completely environmentally friendly.

Researchers are becoming increasingly conscious that their research should also incorporate sustainability principles. It may not be possible to do research that is completely void of environmental impacts, but it’s very possible to make an effort into minimizing those impacts. This led to the establishment of the Twelve Principles of Green Chemistry, established in 1998 by Paul Anastas and John Warner.

Of these 12 principles, number six refers to energy efficiency. This work done by my colleagues Leng, Pati, and Vikesland addresses that principle by demonstrating the growth of gold nanoparticles at room temperature, resulting in significant energy savings.

By using gold seeds of about 18 nm in diameter as a starting point, they were able to produce gold nanoparticles of different sizes, ranging from 20 – 110 nm, at room temperature. The fact that nanoparticle growth happens slower at room temperature can be viewed simultaneously as a negative point (it takes longer to manufacture them) and a positive point (with a slower reaction rate, it may be possible to better understand the complicated mechanisms behind nanoparticle growth).

This work shows that we need to continue incorporating the principles of green chemistry and engineering into nanomaterial design to improve our current energy-intensive nanomaterial production practices.

To access the full article, download a copy for free by clicking the link below:

Room temperature seed mediated growth of gold nanoparticles: mechanistic investigations and life cycle assessment.
Weinan Leng , Paramjeet Pati and Peter J. Vikesland
Environ. Sci.: Nano, 2015,2, 440-453
DOI: 10.1039/C5EN00026B

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About the webwriter

Marina Vance is a PhD research scientist at Virginia Tech and Associate Director of @VTSuN. She is interested in air quality and environmental nanotechnology. You can find more information about her at mevance.com and you can find more articles by Nina in her author archive.

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Nanotechnology – old or new?

Summer is almost over and so is a whirlwind of environmental engineering- and nanotechnology-related conferences. At a previous environmental nanotechnology-related conference, I had the great experience to participate in a lively debate on a very fundamental, albeit not often asked question in our field: is nanotechnology novel?

At first, one may think this question should not even be open for debate, since the very idea of nanotechnology evokes exciting futuristic thoughts about the future of medicine, solar energy, nanorobots, and even science fiction.

In this recently published paper, Hochella, Spencer, and Jones present an overview of this unexpected debate. Jones moderated a discussion in which Hochella and Spencer, two experts in their respective fields of nanogeoscience and electrical engineering/material science, brought their arguments for and against the following statement:

“The magic of nanomaterials is not new: nature has been playing these tricks for billions of years.”

In my view, nature’s nanostructures can be informative of how the environment responds to nanomaterials and their study is instrumental for informing environmental nanoscience and technology. However, the potential existence of natural analogues to engineered nanostructures is no evidence that there is reduced likelihood of adverse environmental effects, since after all, with the exception of a few synthetic compounds (e.g., CFC), most environmental pollutants exist in nature. We just happen to place them where they don’t belong (e.g., lead in the atmosphere).

The untended meadow of nature’s nanostructures and the
English-style garden of engineered nanomaterials

This work takes you around the universe and back to demonstrate the importance of determining whether naturally-occurring nanomaterials are representative of the novel and well-controlled structures engineered by man.


To access the full article, download a copy for free by clicking the link below:

Nanotechnology: nature’s gift or scientists’ brainchild?
Michael F. Hochella, Jr., Michael G. Spencer and Kimberly L. Jones
Environ. Sci.: Nano, 2015, 2, 114-119
DOI: 10.1039/C4EN00145A

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About the webwriter

Marina Vance is a PhD research scientist at Virginia Tech and Associate Director of @VTSuN. She is interested in air quality, nanotechnology and health. You can find more information about her in mevance.com.

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Great balls of fire

Environmental Science Nano Cover VejeranoPeople in modern societies produce a lot of waste. I propose that you think about it next time you buy something. How much of it is comprised of packaging? How much of that packaging is recyclable? How much of it will become waste after a short while?

With the fast advancement of nanotechnological applications to enhance consumer products, we can expect nanomaterials to become ubiquitous in our domestic waste. So what happens when we burn nanotechnology-enhanced waste (or nanowaste)? Unlike that great Jerry Lee Lewis song that everybody knows, the answer to this question is a little bit more complex.

Most modern incinerator facilities are equipped to minimize the emission of air pollutants from the incineration process, especially particulate matter (also known as fly ash).

But what if some nanomaterials lead to the production of different pollutants during the incineration process? As we know from this blog, nanomaterials are multi-talented. Some have the ability to catalyze reactions, which can lead to the production of potentially toxic combustion by-products.

There are many locations around the world that perform open burning to dispose of waste. Therefore, it is possible that air pollutants generated may be slightly different if the waste contains nanomaterials.

In their most recent work—and ES Nano cover articleVejerano and colleagues evaluated the toxic response of fly ash from waste that contained a wide variety of nanomaterials, such as nanosilver, titania, ceria, fullerenes, quantum dots, and more.

They found that waste that contained nanosilver, titania, and C60 fullerenes led to a toxic response in human lung epithelial cells, which is signalled by an increase in the production of reactive oxygen species (ROS). But, in addition to that, this study also shows that the presence of nanomaterials in waste is not expected to significantly alter the environmental and health risk of the fly ash emitted from combustion processes.


To access the full article, download a copy for free* by clicking the link below:

Toxicity of particulate matter from incineration of nanowaste
Eric P. Vejerano, Yanjun Ma, Amara L. Holder, Amy Pruden, Subbiah Elankumaran and Linsey C. Marr
Environ. Sci.: Nano, 2014, 2, 143-154
DOI: 10.1039/C4EN00182F

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About the webwriter

Marina is a PhD research scientist at Virginia Tech and Assoc. Director of @VTSuN. She is interested in air quality, nanotechnology and health. You can find more information about her in her website mevance.com.

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