Tag Archives: Pedro Alvarez

Let them (Rice University scientists) show you how to restore oil-soaked soil

I did not want to cash in (so to speak) on someone else’s fun headline so I played with it. Hre is the original head, which was likely written by either David Ruth or Mike Williams at Rice University (Texas, US), “Lettuce show you how to restore oil-soaked soil.”

A February 1, 2019 news item on ScienceDaily on the science behind lettuce and oil-soaked soil,

Rice University engineers have figured out how soil contaminated by heavy oil can not only be cleaned but made fertile again.

How do they know it works? They grew lettuce.

Rice engineers Kyriacos Zygourakis and Pedro Alvarez and their colleagues have fine-tuned their method to remove petroleum contaminants from soil through the age-old process of pyrolysis. The technique gently heats soil while keeping oxygen out, which avoids the damage usually done to fertile soil when burning hydrocarbons cause temperature spikes.

Lettuce growing in once oil-contaminated soil revived by a process developed by Rice University engineers. The Rice team determined that pyrolyzing oil-soaked soil for 15 minutes at 420 degrees Celsius is sufficient to eliminate contaminants while preserving the soil’s fertility. The lettuce plants shown here, in treated and fertilized soil, showed robust growth over 14 days. Photo by Wen Song

A February 1, 2019 Rice University news release (also on EurekAlert), which originated the news item, explains more about the work,

While large-volume marine spills get most of the attention, 98 percent of oil spills occur on land, Alvarez points out, with more than 25,000 spills a year reported to the Environmental Protection Agency. That makes the need for cost-effective remediation clear, he said.

“We saw an opportunity to convert a liability, contaminated soil, into a commodity, fertile soil,” Alvarez said.

The key to retaining fertility is to preserve the soil’s essential clays, Zygourakis said. “Clays retain water, and if you raise the temperature too high, you basically destroy them,” he said. “If you exceed 500 degrees Celsius (900 degrees Fahrenheit), dehydration is irreversible.

The researchers put soil samples from Hearne, Texas, contaminated in the lab with heavy crude, into a kiln to see what temperature best eliminated the most oil, and how long it took.

Their results showed heating samples in the rotating drum at 420 C (788 F) for 15 minutes eliminated 99.9 percent of total petroleum hydrocarbons (TPH) and 94.5 percent of polycyclic aromatic hydrocarbons (PAH), leaving the treated soils with roughly the same pollutant levels found in natural, uncontaminated soil.

The paper appears in the American Chemical Society journal Environmental Science and Technology. It follows several papers by the same group that detailed the mechanism by which pyrolysis removes contaminants and turns some of the unwanted hydrocarbons into char, while leaving behind soil almost as fertile as the original. “While heating soil to clean it isn’t a new process,” Zygourakis said, “we’ve proved we can do it quickly in a continuous reactor to remove TPH, and we’ve learned how to optimize the pyrolysis conditions to maximize contaminant removal while minimizing soil damage and loss of fertility.

“We also learned we can do it with less energy than other methods, and we have detoxified the soil so that we can safely put it back,” he said.

Heating the soil to about 420 C represents the sweet spot for treatment, Zygourakis said. Heating it to 470 C (878 F) did a marginally better job in removing contaminants, but used more energy and, more importantly, decreased the soil’s fertility to the degree that it could not be reused.

“Between 200 and 300 C (392-572 F), the light volatile compounds evaporate,” he said. “When you get to 350 to 400 C (662-752 F), you start breaking first the heteroatom bonds, and then carbon-carbon and carbon-hydrogen bonds triggering a sequence of radical reactions that convert heavier hydrocarbons to stable, low-reactivity char.”

The true test of the pilot program came when the researchers grew Simpson black-seeded lettuce, a variety for which petroleum is highly toxic, on the original clean soil, some contaminated soil and several pyrolyzed soils. While plants in the treated soils were a bit slower to start, they found that after 21 days, plants grown in pyrolyzed soil with fertilizer or simply water showed the same germination rates and had the same weight as those grown in clean soil.

“We knew we had a process that effectively cleans up oil-contaminated soil and restores its fertility,” Zygourakis said. “But, had we truly detoxified the soil?”

To answer this final question, the Rice team turned to Bhagavatula Moorthy, a professor of neonatology at Baylor College of Medicine, who studies the effects of airborne contaminants on neonatal development. Moorthy and his lab found that extracts taken from oil-contaminated soils were toxic to human lung cells, while exposing the same cell lines to extracts from treated soils had no adverse effects. The study eased concerns that pyrolyzed soil could release airborne dust particles laced with highly toxic pollutants like PAHs.

”One important lesson we learned is that different treatment objectives for regulatory compliance, detoxification and soil-fertility restoration need not be mutually exclusive and can be simultaneously achieved,” Alvarez said.

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

Pilot-Scale Pyrolytic Remediation of Crude-Oil-Contaminated Soil in a Continuously-Fed Reactor: Treatment Intensity Trade-Offs by Wen Song, Julia E. Vidonish, Roopa Kamath, Pingfeng Yu, Chun Chu, Bhagavatula Moorthy, Baoyu Gao, Kyriacos Zygourakis, and Pedro J. J. Alvarez. Environ. Sci. Technol., 2019, 53 (4), pp 2045–2053 DOI: 10.1021/acs.est.8b05825 Publication Date (Web): January 25, 2019

Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Crypton and NANO-TEX together at last

A Jan. 6, 2014 news item on Nanowerk notes that Crypton Fabrics has purchased NANO-TEX,

CRYPTON INC. has acquired NANO-TEX®, announced Randy Rubin, Chairman of The Crypton Companies. The privately held, 20-year-old Crypton Fabrics, based in Bloomfield Hills, Michigan, recently purchased NANO-TEX from private equity and venture capital investors; WL Ross and Co. LLC as major stockholders, in addition to Norwest Venture Partners, Masters Capital Nanotechnology Fund, Firelake Capital Management and Masters Capital Management.

NANO-TEX is a textile technology company whose performance finishes have enhanced leading consumer brands such as GAP, TARGET, MAIDENFORM, BASS PRO SHOPS, NORDSTROM, LAND’S END, FISHER-PRICE and many more.

The Jan. 6, 2014 Crypton (there has to be a Superman or inert gas enthusiast in that company) press release, which can be found on this page under this title: Silicon Valley to Motown, Performance Textile Leader Crypton Purchases Nano-Tex, explains why the NANO-TEX acquisition was so attractive and what it means to NANO-TEX’s major stockholders,

NANO‐TEX employs a proprietary nanotechnology approach to enhance textiles at the molecular level that provides permanent performance attributes such as stain and water resistance, moisture wicking, odor control, static elimination and wrinkle free properties. The end result is performance fabrics that maintain the original comfort, look and feel of the fabric and perform for the life of the product.

In 2013, NANO‐TEX technologies were on $280 million in branded finished products at retail worldwide.

Wilbur Ross, Jr., Chairman of WL Ross said, “We are extremely pleased by Crypton’s acquisition. This assures that NANO‐TEX will continue on a strong growth trajectory. Its expanding market reach and prominence will further enhance the competitiveness of WL Ross’s companies in the consumer and industrial fabrics industries, too; the goal that sparked our initial investment interest in NANO‐TEX eight years ago.”

It seems there was a specific product which attracted the Crypton team’s attention,

“This is a strategic acquisition as we extend our market share with apparel throughout the world. The intellectual properties and latest development, Aquapel®, a non‐fluorinated repellency treatment, is very exciting to our research team,” said Rubin.

There’s more about this product on the NANO-TEX Aquapel® page.

On a completely other note, at least one NANO-TEX product has silver in it according to a 2007 entry on the Consumer Products Inventory (Project on Emerging Nanotechnologies),

They Say:

“Nano-Tex™’s revolutionary technology fundamentally transforms fabric at the nano-level to dramatically improve your favorite everyday clothing.”



Potential Exposure Pathways:


How much we know:

Category 4 (Unsupported claim)

Additional Information:

Generic Product

Crypton too has silver in at least one product (from the INCASE Fabric Protection FAQs),

Q:  How does INCASE™ resist bacterial growth?
A: Silver Ion technology is used in INCASE to inhibit the growth of a broad spectrum of medically relevant microorganisms, including bacteria. Silver is one of nature’s original antimicrobials. Used thousands of years ago by Greeks in vessels to preserve water and wine, the natural benefits of silver have now been tapped to keep fabrics odor-free.

Cyrpton’s INCASE product uses sliver ions, which according to some research at Rice University (based in Texas, US), are more toxic than silver nanoparticles, from my July 13, 2012 posting,

He [Pedro Alvarez, George R. Brown Professor and chair of Rice’s Civil and Environmental Engineering Department] said the finding should shift the debate over the size, shape and coating of silver nanoparticles. [emphasis mine] “Of course they matter,” Alvarez said, “but only indirectly, as far as these variables affect the dissolution rate of the ions. The key determinant of toxicity is the silver ions. So the focus should be on mass-transfer processes and controlled-release mechanisms.”

Crypton’s About page strongly suggests an environmentally friendly and health conscious company (Note: Links have been removed),

Innovation. Industry leadership. A deep commitment to product excellence. These core elements are at the heart of the Crypton DNA – a labor of love that began in 1993 when founders Craig and Randy Rubin set out to create a new generation of stylish fabrics that were moisture-resistant and easy-to-clean, yet soft, comfortable and breathable.

From the basement of their Michigan home, a textile revolution was born.

Now based in West Bloomfield Michigan, with a green manufacturing facility in Kings Mountain, North Carolina, Crypton is the only textile solution in the world offering complete stain, moisture, mildew, bacteria and odor-resistant protection thanks to a patented process developed by some of the leading minds in the textile industry.

Early on, by offering a fabric – not a vinyl or plastic – that was capable of resisting stains, moisture, odors and bacteria, Crypton proved to be the perfect solution for the health care market. Following this initial success, Crypton solutions rapidly expanded into some of the finest restaurants, hotels, cruise ships around the world, as well as government complexes, schools and health care facilities.

Now trusted and relied on by over 90% of contract designers, there are more than 20,000 patterns of Crypton fabric available today. Crypton is the only fabric deemed a non-porous surface and can be disinfected when used in conjunction with our U.S. EPA-approved Crypton Disinfectant & Deodorizer.

From fabric, carpet, leather, wall and mattress to pet beds, home accessories, bags and luggage – our mission is to give customers more ways to live healthy, live beautifully and Live Clean®.

While there is no incontrovertible proof that silver nanoparticles and/or silver ions are a serious threat to the environment, it would be nice to see companies acknowledge some of the concerns.

The relationship of silver ions & nanoparticles, Nietzsche, and Rice University

My hat’s off to Mike Williams for introducing Nietzsche into a news item about silver nanoparticles and toxicity. Here’s the line from his July 11, 2012 Rice University news release (Note: I have removed some links),

Their work comes with a Nietzsche-esque warning: Use enough. If you don’t kill them, you make them stronger.

Scientists have long known that silver ions, which flow from nanoparticles when oxidized, are deadly to bacteria. Silver nanoparticles are used just about everywhere, including in cosmetics, socks, food containers, detergents, sprays and a wide range of other products to stop the spread of germs.

But scientists have also suspected silver nanoparticles themselves may be toxic to bacteria, particularly the smallest of them at about 3 nanometers. Not so, according to the Rice team that reported its results this month in the American Chemical Society journal Nano Letters.

This next bit describing the research is an example of what I find so compelling (curiosity and persistence) about science,

To figure that out, the researchers had to strip the particles of their powers. “Our original expectation was that the smaller a particle is, the greater the toxicity,” said Zongming Xiu, a Rice postdoctoral researcher and lead author of the paper. Xiu set out to test nanoparticles, both commercially available and custom-synthesized from 3 to 11 nanometers, to see whether there was a correlation between size and toxicity.

“We could not get consistent results,” he said. “It was very frustrating and really weird.”

Here’s what they did next, what they found, and the implications of their findings,

Xiu decided to test nanoparticle toxicity in an anaerobic environment – that is, sealed inside a chamber with no exposure to oxygen — to control the silver ions’ release. He found that the filtered particles were a lot less toxic to microbes than silver ions.

Working with the lab of Rice chemist Vicki Colvin, the team then synthesized silver nanoparticles inside the anaerobic chamber to eliminate any chance of oxidation. “We found the particles, even up to a concentration of 195 parts per million, were still not toxic to bacteria,” Xiu said. “But for the ionic silver, a concentration of about 15 parts per billion would kill all the bacteria present. That told us the particle is 7,665 times less toxic than the silver ions, indicating a negligible toxicity.”

“The point of that experiment,” Alvarez [Pedro Alvarez, George R. Brown Professor and chair of Rice’s Civil and Environmental Engineering Department] said, “was to show that a lot of people were obtaining data that was confounded by a release of ions, which was occurring during exposure they perhaps weren’t aware of.”

Alvarez suggested the team’s anaerobic method may be used to test many other kinds of metallic nanoparticles for toxicity and could help fine-tune the antibacterial qualities of silver particles. In their tests, the Rice researchers also found evidence of homesis; [e.g..,] E. coli became stimulated by silver ions when they encountered doses too small to kill them.

“Ultimately, we want to control the rate of (ion) release to obtain the desired concentrations that just do the job,” Alvarez said. “You don’t want to overshoot and overload the environment with toxic ions while depleting silver, which is a noble metal, a valuable resource – and a somewhat expensive disinfectant. But you don’t want to undershoot, either.”

He said the finding should shift the debate over the size, shape and coating of silver nanoparticles. [emphasis mine] “Of course they matter,” Alvarez said, “but only indirectly, as far as these variables affect the dissolution rate of the ions. The key determinant of toxicity is the silver ions. So the focus should be on mass-transfer processes and controlled-release mechanisms.”

Interestingly, this is a joint US-UK effort (US Environmental Protection Agency and the U.K. Natural Environment Research Council). H/T to Will Soutter’s July 12, 2012 news item on Azonano for the information about this latest silver nanoparticle research from Rice University. The July 11, 2012 news item on Nanowerk also features information about the silver nanoparticles, ions, and Rice University.

I have mentioned Vicki Colvin’s work previously including this Jan. 28, 2011 posting about a UK/US joint environmental research effort. I have also mentioned Pedro Alvarez a few times including this Aug. 2, 2010 posting about nanomaterials and the construction industry.

Nanotechnology reaches its adolescence?

They (American Association for the Advancement of Science [AAAS], the American Chemical Society [ACS], and the Georgetown University Program on Science in the Public Interest) will be hosting a discussion, Nanotechnology in the 2010s: The Teen Years, on Nov. 21, 2011 in Washington, DC.

This is part of a series, Science & Society: Global Challenges, hosted at the AAAS auditorium at 1200 New York Avenue. The reception starts at 5 pm EST, and the discussion begins at 6:00 pm and finishes at 7:30 pm. You do need to RSVP if you are attending at the AAAS  ‘Global Challenges’ webpage, which specifies, No powerpoint. No notes. Just candid conversations …

I did get a copy of the media release from the ACS, which you can view here in the Nov. 15, 2011 news item on Nanowerk.

From the media release, here’s a list of the expert discussants,

Experts:   Pedro Alvarez, Department of Civil and
Environmental Engineering, Rice  University

                    Omid Farokhzad, Brigham and Women’s
Hospital, Harvard Medical School

                    Debra Kaiser, Ceramics Division, National
Institute of Standards and Technology (NIST)

Host:         David Kestenbaum, NPR [National Public

Here are the questions they will be discussing (from the ACS media release),

Since the 1990s, nanotechnology has been lauded as the key to transforming a wide array of innovative fields from biomedicine and electronics to energy, textiles and transportation, inspiring the National Nanotechnology Initiative (NNI) in 2000.

Now in the 2010s, is nanotechnology coming of age? Is the anticipated explosion of new products such as lighting, electronic displays, pharmaceuticals, solar photovoltaic cells and water treatment systems coming to fruition, or is NNI still in its research and development infancy? How should the United States allocate funds for research with such a strong potential to deliver economic innovations? These questions and others will be addressed Monday, Nov. 21, as part of the 2011 Science & Society: Global Challenges Discussion Series.

The ACS podcasts these discussions but you may have to wait a few weeks before viewing the nanotechnology discussion. The most recent available podcast of a Global Challenges discussion is the Oct. 3, 2011 discussion about Cyber Attack. The Oct. 24 discussion about Fukushima and the Nov. 7 discussion about Infectious Diseases have not been posted as of 11 am PST, Nov. 16, 2011.

Omid Farokhzad, one of the Global Challenges nanotechnology experts, was last mentioned on this blog in conjunction with a deal his companies (BIND and Selecta) made with RUSNANO (Russian Nanotechnologies Corporation) in my Oct. 28, 2011 posting. He was also featured in part 2 (More than Human, which is available for viewing online) of The Nano Revolution series broadcast, Oct. 20, 2011, by the Canadian Broadcasting Corporation as part of The Nature of Things programming. I did comment on the episode in my Oct. 26, 2011 posting but did not mention Farokhzad.

Nanomaterial use in construction, in coatings, in site remediation, and on invisible planes

Next to biomedical and electronics industries, the construction industry is expected to be the most affected by nanotechnology according to a study in ACS (American Chemical Society) Nano (journal). From the news item on Azonano,

Pedro Alvarez and colleagues note that nanomaterials likely will have a greater impact on the construction industry than any other sector of the economy, except biomedical and electronics applications. Certain nanomaterials can improve the strength of concrete, serve as self-cleaning and self-sanitizing coatings, and provide many other construction benefits. Concerns exist, however, about the potential adverse health and environmental effects of construction nanomaterials.

The scientists analyzed more than 140 studies on the benefits and risks of nanomaterials. …

The article in ACS Nano is titled, “Nanomaterials in the Construction Industry: A Review of Their Applications and Environmental Health and Safety Considerations.

Still on the construction theme but this time more focused on site remediation, here’s a story about sulfur-rich drywall which corrodes pipes and wiring while possibly causing respiratory illness. From the news item on Nanowerk,

A nanomaterial originally developed to fight toxic waste is now helping reduce debilitating fumes in homes with corrosive drywall.

Developed by Kenneth Klabunde of Kansas State University, and improved over three decades with support from the National Science Foundation, the FAST-ACT material has been a tool of first responders since 2003.

Now, NanoScale Corporation of Manhattan, Kansas–the company Klabunde co-founded to market the technology–has incorporated FAST-ACT into a cartridge that breaks down the corrosive drywall chemicals.

Homeowners have reported that the chemicals–particularly sulfur compounds such as hydrogen sulfide and sulfur dioxide–have caused respiratory illnesses, wiring corrosion and pipe damage in thousands of U.S. homes with sulfur-rich, imported drywall.

“It is devastating to see what has happened to so many homeowners because of the corrosive drywall problem, but I am glad the technology is available to help,” said Klabunde. “We’ve now adapted the technology we developed through years of research for FAST-ACT for new uses by homeowners, contractors and remediators.”

The company has already tested its new product and found that corrosion was reduced and odor levels dropped to almost imperceptible. There are plans to use the company’s technology in the Gulf Coast and elsewhere there are airborne toxic substances.

In Europe, Germany has plans to introduce new concrete paving slabs that reduce the quantity of nitrogen oxide in the air. From the news item on Nanowerk,

In Germany, ambient air quality is not always as good as it might be – data from the federal environment ministry makes this all too clear. In 2009, the amounts of toxic nitrogen oxide in the atmosphere exceeded the maximum permitted levels at no fewer than 55 percent of air monitoring stations in urban areas. The ministry reports that road traffic is one of the primary sources of these emissions.

In light of this fact, the Baroque city of Fulda is currently embarking on new ways to combat air pollution. Special paving slabs that will clean the air are to be laid the length of Petersberger Strasse, where recorded pollution levels topped the annual mean limit of 40 micrograms per cubic meter (µg/m3) last year. These paving slabs are coated with titanium dioxide (TiO2), which converts harmful substances such as nitrogen oxides into nitrates. Titanium dioxide is a photocatalyst; it uses sunlight to accelerate a naturallyoccurring chemical reaction, the speed of which changes with exposure to light.

They’ve already had success with this approach in Italy but Germany has fewer hours of sunshine and lower intensities of light so the product had to be optimized and tested in Germany. Testing has shown that the effect for Germany’s optimized paving slabs does not wear off quickly (it was tested again at 14 months and 23 months). Finally, there don’t seem to be any environmentally unpleasant consequences. If you’re curious about the details, do click on the link.

One last item, this time it’s about a nano-enabled coating that’s a paint. An Israeli company has developed a paint for airplanes that can make them invisible to radar. From Dexter Johnson’s July 14, 2010 posting on Nanoclast,

No, we’re not talking about a Wonder Woman-type of invisible plane, but rather one that becomes very difficult to detect with radar.

The Israel-based Ynetnews is reporting that an Israeli company called Nanoflight has successfully run a test on dummy missiles that were painted with the nano-enabled coating and have shown that radar could not pick them up as missiles.

The YnetNews article rather brutally points out that painting an aircraft with this nanocoating is far cheaper than buying a $5 billion US-made stealth aircraft. Of course, it should also be noted that one sale of a $5 billion aircraft employs a large number of aeronautical engineers, and the high price tag also makes it far more difficult for others to purchase the technology and possess the ability to sneak up on an enemy as well.

You can read more and see a picture of Wonder Woman’s invisible plane by following the link to Dexter’s posting.