Tag Archives: wastewater

Eco-friendly nanocomposite catalyst and ultrasound to remove pollutants from water

The best part of this story is that they’re using biochar from rice hulls to create the nanocomposite catalyst. A July 19, 2019 news item on ScienceDaily reveals a few details about the research without discussing the rice hulls,

The research team of Dr. Jae-woo Choi and Dr. Kyung-won Jung of the Korea Institute of Science and Technology’s (KIST, president: Byung-gwon Lee) Water Cycle Research Center announced that it has developed a wastewater treatment process that uses a common agricultural byproduct to effectively remove pollutants and environmental hormones, which are known to be endocrine disruptors.

A July 19, 2019 Korea National Research Council of Science & Technology news release on EurekAlert, which originated the news item, provides more detail,

The sewage and wastewater that are inevitably produced at any industrial worksite often contain large quantities of pollutants and environmental hormones (endocrine disruptors). Because environmental hormones do not break down easily, they can have a significant negative effect on not only the environment but also the human body. To prevent this, a means of removing environmental hormones is required.

The performance of the catalyst that is currently being used to process sewage and wastewater drops significantly with time. Because high efficiency is difficult to achieve given the conditions, the biggest disadvantage of the existing process is the high cost involved. Furthermore, the research done thus far has mostly focused on the development of single-substance catalysts and the enhancement of their performance. Little research has been done on the development of eco-friendly nanocomposite catalysts that are capable of removing environmental hormones from sewage and wastewater.

The KIST research team, led by Dr. Jae-woo Choi and Dr. Kyung-won Jung, utilized biochar,** which is eco-friendly and made from agricultural byproducts, to develop a wastewater treatment process that effectively removes pollutants and environmental hormones. The team used rice hulls [emphasis mine] which are discarded during rice harvesting, to create a biochar that is both eco-friendly and economical. The surface of the biochar was coated with nano-sized manganese dioxide to create a nanocomposite. The high efficiency and low cost of the biochar-nanocomposite catalyst is based on the combination of the advantages of the biochar and manganese dioxide.

**Biochar: a term that collectively refers to substances that can be created through the thermal decomposition of diverse types of biomass or wood under oxygen-limited condition

The KIST team used the hydrothermal method, which is a type of mineral synthesis that uses high heat and pressure, when synthesizing the nanocomposite in order to create a catalyst that is highly active, easily replicable, and stable. It was confirmed that giving the catalyst a three-dimensional stratified structure resulted in the high effectiveness of the advanced oxidation process (AOP), due to the large surface area created.

When used under the same conditions in which the existing catalyst can remove only 80 percent of Bisphenol A (BPA), an environmental hormone, the catalyst developed by the KIST team removed over 95 percent in less than one hour. In particular, when combined with ultrasound (20kHz), it was confirmed that all traces of BPA were completely removed in less than 20 minutes. Even after many repeated tests, the BPA removal rate remained consistently at around 93 percent.

Dr. Kyung-won Jung of KIST’s Water Cycle Research Center said, “The catalyst developed through this study makes use of a common agricultural byproduct. Therefore, we expect that additional research on alternative substances will lead to the development of catalysts derived from various types of organic waste biomass.” Dr. Jae-woo Choi, also of KIST’s Water Cycle Research Center, said, “We have high hopes that future studies aimed at achieving process optimization and increasing removal rates will allow for the development an environmental hormone removal system that is both eco-friendly and low-cost.”

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

Ultrasound-assisted heterogeneous Fenton-like process for bisphenol A removal at neutral pH using hierarchically structured manganese dioxide/biochar nanocomposites as catalysts by Kyung-Won Jung, Seon Yong Lee, Young Jae Lee, Jae-Woo Choi. Ultrasonics Sonochemistry
Volume 57, October 2019, Pages 22-28 DOI: https://doi.org/10.1016/j.ultsonch.2019.04.039 Available online 29 April 2019

This paper is behind a paywall.

Panning for silver nanoparticles in your clothes washer

A March 20, 2018 news item on phys.org describes a new approach to treating wastewater (Note: Links have been removed),

Humans have known since ancient times that silver kills or stops the growth of many microorganisms. Hippocrates, the father of medicine, is said to have used silver preparations for treating ulcers and healing wounds. Until the introduction of antibiotics in the 1940s, colloidal silver (tiny particles suspended in a liquid) was a mainstay for treating burns, infected wounds and ulcers. Silver is still used today in wound dressings, in creams and as a coating on medical devices.

Since the 1990s, manufacturers have added silver nanoparticles to numerous consumer products to enhance their antibacterial and anti-odor properties. Examples include clothes, towels, undergarments, socks, toothpaste and soft toys. Nanoparticles are ultra-small particles, ranging from 1 to 100 nanometers in diameter – too small to see even with a microscope. According to a widely cited database, about one-fourth of nanomaterial-based consumer products currently marketed in the United States contain nanosilver.

Multiple studies have reported that nanosilver leaches out of textiles when they are laundered. Research also reveals that nanosilver may be toxic to humans and aquatic and marine organisms. Although it is widely used, little is understood about its fate or long-term toxic effects in the environment.

We are developing ways to convert this potential ecological crisis into an opportunity by recovering pure silver nanoparticles, which have many industrial applications, from laundry wastewater. In a recently published study, we describe a technique for silver recovery and discuss the key technical challenges. Our approach tackles this problem at the source – in this case, individual washing machines. We believe that this strategy has great promise for getting newly identified contaminants out of wastewater.

A March 20, 2018 essay by Sukalyan Sengupta, Professor of Wastewater Treatment, and Tabish Nawaz. Doctoral Student, both at University of Massachusetts at Dartmouth on The Conversation website, which originated the news item, expands on the theme (Note: Links have been removed),

Use of nanosilver in consumer products has steadily risen in the past decade. The market share of silver-based textiles rose from 9 percent in 2004 to 25 percent in 2011.

Several investigators have measured the silver content of textiles and found values ranging from 0.009 to 21,600 milligrams of silver per kilogram of textile. Studies show that the amount of silver leached in the wash solution depends on many factors, including interactions between detergent and other chemicals and how silver is attached to the textiles.

In humans, exposure to silver can harm liver cells, skin and lungs. Prolonged exposure or exposure to a large dose can cause a condition called Argyria, in which the victim’s skin turns permanently bluish-gray.

Once silver goes down the drain and ends up at wastewater treatment plants, it can potentially harm bacterial treatment processes, making them less efficient, and foul treatment equipment. More than 90 percent of silver nanoparticles released in wastewater end up in nutrient-rich biosolids left over at the end of sewage treatment, which often are used on land as agricultural fertilizers.

Silver is toxic in aquatic environments, a concern that’s becoming more serious with the increased use of silver nanoparticles and awareness that oceans, rivers, and lakes are dangerously stressed.

Sengupta and Nawaz go on to describe their proposed solution (Note: Links have been removed),

Our research shows that the most efficient way to remove silver from wastewater is by treating it in the washing machine. At this point silver concentrations are relatively high, and silver is initially released from treated clothing in a chemical form that is feasible to recover.

A bit of chemistry is helpful here. Our recovery method employs a widely used chemistry process called ion exchange. Ions are atoms or molecules that have an electrical charge. In ion exchange, a solid and a liquid are brought together and exchange ions with each other.

For example, household soaps do not lather well in “hard” water, which contains high levels of ions such as magnesium and calcium. Many home water filters use ion exchange to “soften” the water, replacing those materials with other ions that do not affect its properties in the same way.

For this process to work, the ions that switch places must both be either positively or negatively charged. Nanosilver is initially released from textiles as silver ion, which is a cation – an ion with a positive charge (hence the plus sign in its chemical symbol, Ag+).

Even at the source, removing silver from washwater is challenging. Silver concentrations in the wash solution are relatively low compared to other cations, such as calcium, that could interfere with the removal process. Detergent chemistry complicates the picture further because some detergent components can potentially interact with silver.

To recover silver without picking up other chemicals, the recovery process must use materials that have a chemical affinity for silver. In a previous study, we described a potential solution: Using ion-exchange materials embedded with sulfur-based chemicals, which bind preferentially with silver.

In our new study, we passed washwater through an ion-exchange resin column and analyzed how each major detergent ingredient interacted with silver in the water and affected the resin’s ability to remove silver from the water. By manipulating process conditions such as pH, temperature and concentration of nonsilver cations, we were able to identify conditions that maximized silver recovery.

We found that pH and the levels of calcium ions (Ca2+) were critical factors. Higher levels of hydrogen or calcium ions bind up detergent ingredients and prevent them from interacting with silver ions, so the ion-exchange resin can remove the silver from the solution. We also found that some detergent ingredients – particularly bleaching and water-softening agents – made the ion-exchange resin work less efficiently. Depending on these conditions, we recovered between 20 percent and 99 percent of the silver in the washwater.

The researchers go on to propose a new approach to treating wastewater (Note: A link has been removed),

Today wastewater is collected from multiple sources, such as homes and businesses, and piped over long distances to centralized wastewater treatment plants. But increasing evidence shows that these facilities are ill-equipped to keep newly identified contaminants out of the environment, since they use one common treatment scheme for many different waste streams.

We believe the future is in decentralized systems that can treat different types of wastewater with specific technologies designed specifically for the materials they contain. If wastewater from laundromats contains different contaminants than wastewater from restaurants, why treat them the same way?

Interesting, non? In any event, here’s a link to and a citation for what I believe is the researchers’ latest paper on this subject,

Silver Recovery from Laundry Washwater: The Role of Detergent Chemistry by Tabish Nawaz and Sukalyan Sengupta. ACS Sustainable Chem. Eng., 2018, 6 (1), pp 600–608 DOI: 10.1021/acssuschemeng.7b02933 Publication Date (Web): November 21, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall. For anyone who can’t get access, Karla Lant provides a bit more technical detail about the work in her February 2, 2018 article for fondriest.com.

Not enough silver nanoparticles in water supply to be harmful?

While the news of a low concentration of silver nanoparticles in the water supply seems good in the short term, one can’t help wondering what will happen as more of them end up in the our water. As for the news itself, here’s the announcement concerning a review of some 300 papers, from an Oct. 13, 2016 news item on Nanowerk,

Silver nanoparticles have a wide array of uses, one of which is to treat drinking water for harmful bacteria and viruses. But do silver nanoparticles also kill off potentially beneficial bacteria or cause other harmful effects to water-based ecosystems? A new paper from a team of University of Missouri College of Engineering researchers says that’s not the case.

An Oct. 12, 2016 University of Missouri news release (also on EurekAlert), which originated the news item, expands on the theme (Note: Links have been removed),

In their paper, “Governing factors affecting the impacts of silver nanoparticles on wastewater treatment,” recently published in Science of the Total Environment, Civil and Environmental Engineering Department doctoral students Chiqian Zhang and Shashikanth Gajaraj and Department Chair and Professor Zhiqiang Hu worked with Ping Li of the South China University of Technology to analyze the results of approximately 300 published works on the subject of silver nanoparticles and wastewater. What they found was while silver nanoparticles can have moderately or even significantly adverse effects in large concentrations, the amount of silver nanoparticles found in our wastewater at present isn’t harmful to humans or the ecosystem as a whole.

“If the concentration remains low, it’s not a serious problem,” Zhang said.

Silver nanoparticles are used in wastewater treatment and found increasingly in everyday products in order to combat bacteria. In terms of wastewater treatment, silver nanoparticles frequently react with sulfides in biosolids, vastly limiting their toxicity.

Zhang said many of the studies looked at high concentrations and added that if, over time, the concentration rose to much higher levels of several milligrams per liter or higher), toxicity could become a problem. But he explained that it would take decades or even longer potentially to get to that point.

“People evaluate the toxicity in a small-scale system,” he said. “But with water collection systems, much of the silver nanoparticles become silver sulfide and not be harmful.”

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

Governing factors affecting the impacts of silver nanoparticles on wastewater treatment by Chiqian Zhang, Zhiqiang Hu, Ping Li, Shashikanth Gajaraj. Science of The Total Environment http://dx.doi.org/10.1016/j.scitotenv.2016.07.145 Available online 16 August 2016

This study is behind a paywall.

For the curious, I have a Feb. 28, 2013 posting where I contrasted two silver nanoparticle studies one of which found little risk and the other which raised serious concerns. Scroll down about about 60% of the way for the ‘cautionary’ study.

Personally, I’m inclined to agree silver nanoparticles are not an immediate concern but since no one knows what the tipping point might be, now would be a good time to get serious about research, policies, and regulation.

Silver nanoparticles and wormwood tackle plant-killing fungus

I’m back in Florida (US), so to speak. Last mentioned here in an April 7, 2015 post about citrus canker and zinkicide, a story about a disease which endangers citrus production in the US, this latest story concerns a possible solution to the problem of a fungus, which attacks ornamental horticultural plants in Florida. From a May 5, 2015 news item on Azonano,

Deep in the soil, underneath more than 400 plant and tree species, lurks a lethal fungus threatening Florida’s $15 billion a year ornamental horticulture industry.

But University of Florida plant pathologist G. Shad Ali has found an economical and eco-friendly way to combat the plant destroyer known as phytophthora before it attacks the leaves and roots of everything from tomato plants to oak trees.

Ali and a team of researchers with UF’s Institute of Food and Agricultural Sciences, along with the University of Central Florida and the New Jersey Institute of Technology, have found that silver nanoparticles produced with an extract of wormwood, an herb with strong antioxidant properties, can stop several strains of the deadly fungus.

A May 4, 2015 University of Florida news release, which originated the news item, describes the work in more detail,

“The silver nanoparticles are extremely effective in eliminating the fungus in all stages of its life cycle,” Ali said. “In addition, it has no adverse effects on plant growth.” [emphasis mine]

The silver nanoparticles measure 5 to 100 nanometers in diameter – about one one-thousandth the width of a human hair. Once the nanoparticles are sprayed onto a plant, they shield it from fungus. Since the nanoparticles display multiple ways of inhibiting fungus growth, the chances of pathogens developing resistance to them are minimized, Ali said. Because of that, they may be used for controlling fungicide-resistant plant pathogens more effectively.

That’s good news for the horticulture industry. Worldwide crop losses due to phytophthora fungus diseases are estimated to be in the multibillion dollar range, with $6.7 billion in losses in potato crops due to late blight – the cause of the Irish Potato Famine in the mid-1800s when more than 1 million people died – and $1 billion to $2 billion in soybean loss.

Silver nanoparticles are being investigated for applications in various industries, including medicine, diagnostics, cosmetics and food processing.  They already are used in wound dressings, food packaging and in consumer products such as textiles and footwear for fighting odor-causing microorganisms.

Other members of the UF research team were Mohammad Ali, a visiting doctoral student from the Quaid-i-Azam University, Islamabad, Pakistan; David Norman and Mary Brennan with the University of Florida’s Plant Pathology-Mid Florida Research and Education Center; Bosung Kim with the University of Central Florida’s chemistry department; Kevin Belfield with the College of Science and Liberal Arts at the New Jersey Institute of Technology and the University of Central Florida’s chemistry department.

Ali’s comment about silver nanoparticles not having any adverse effects on plant growth is in contrast to findings by Mark Wiesner and other researchers at  Duke University (North Carolina, US). From my Feb. 28, 2013 posting (which also features a Finnish-Estonia study showing no adverse effects from silver nanoparticles  in crustaceans),

… there’s a study from Duke University suggests that silver nanoparticles in wastewater which is later put to agricultural use may cause problems. From the Feb. 27, 2013 news release on EurekAlert,

In experiments mimicking a natural environment, Duke University researchers have demonstrated that the silver nanoparticles used in many consumer products can have an adverse effect on plants and microorganisms.

The main route by which these particles enter the environment is as a by-product of water and sewage treatment plants. [emphasis] The nanoparticles are too small to be filtered out, so they and other materials end up in the resulting “sludge,” which is then spread on the land surface as a fertilizer.

The researchers found that one of the plants studied, a common annual grass known as Microstegium vimeneum, had 32 percent less biomass in the mesocosms treated with the nanoparticles. Microbes were also affected by the nanoparticles, Colman [Benjamin Colman, a post-doctoral fellow in Duke’s biology department and a member of the Center for the Environmental Implications of Nanotechnology (CEINT)] said. One enzyme associated with helping microbes deal with external stresses was 52 percent less active, while another enzyme that helps regulate processes within the cell was 27 percent less active. The overall biomass of the microbes was also 35 percent lower, he said.

“Our field studies show adverse responses of plants and microorganisms following a single low dose of silver nanoparticles applied by a sewage biosolid,” Colman said. “An estimated 60 percent of the average 5.6 million tons of biosolids produced each year is applied to the land for various reasons, and this practice represents an important and understudied route of exposure of natural ecosystems to engineered nanoparticles.”

“Our results show that silver nanoparticles in the biosolids, added at concentrations that would be expected, caused ecosystem-level impacts,” Colman said. “Specifically, the nanoparticles led to an increase in nitrous oxide fluxes, changes in microbial community composition, biomass, and extracellular enzyme activity, as well as species-specific effects on the above-ground vegetation.”

Getting back to Florida, you can find Ali’s abstract here,

Inhibition of Phytophthora parasitica and P. capsici by silver nanoparticles synthesized using aqueous extract of Artemisia absinthium by Mohammad Ali, Bosung Kim, Kevin Belfield, David J. Norman, Mary Brennan, & Gul Shad Ali. Phytopathology  http://dx.doi.org/10.1094/PHYTO-01-15-0006-R Published online April 14, 2015

This paper is behind a paywall.

For anyone who recognized that wormwood is a constituent of Absinthe, a liquor that is banned in many parts of the world due to possible side effects associated with the wormwood, here’s more about it from the Wormwood overview page on WebMD (Note: Links have been removed),

Wormwood is an herb. The above-ground plant parts and oil are used for medicine.

Wormwood is used in some alcoholic beverages. Vermouth, for example, is a wine beverage flavored with extracts of wormwood. Absinthe is another well-known alcoholic beverage made with wormwood. It is an emerald-green alcoholic drink that is prepared from wormwood oil, often along with other dried herbs such as anise and fennel. Absinthe was popularized by famous artists and writers such as Toulouse-Lautrec, Degas, Manet, van Gogh, Picasso, Hemingway, and Oscar Wilde. It is now banned in many countries, including the U.S. But it is still allowed in European Union countries as long as the thujone content is less than 35 mg/kg. Thujone is a potentially poisonous chemical found in wormwood. Distilling wormwood in alcohol increases the thujone concentration.

Returning to the matter at hand, as I’ve noted previously elsewhere, research into the toxic effects associated with nanomaterials (e.g. silver nanoparticles) is a complex process.

Copper nanoparticles, toxicity research, colons, zebrafish, and septic tanks

Alicia Taylor, a graduate student at UC Riverside, surrounded by buckets of effluent from the septic tank system she used for her research. Courtesy: University of California at Riverside

Alicia Taylor, a graduate student at UC Riverside, surrounded by buckets of effluent from the septic tank system she used for her research. Courtesy: University of California at Riverside

Those buckets of efflluent are strangely compelling. I think it’s the abundance of orange. More seriously, a March 2, 2015 news item on Nanowerk poses a question about copper nanoparticles,

What do a human colon, septic tank, copper nanoparticles and zebrafish have in common?

They were the key components used by researchers at the University of California, Riverside and UCLA [University of California at Los Angeles] to study the impact copper nanoparticles, which are found in everything from paint to cosmetics, have on organisms inadvertently exposed to them.

The researchers found that the copper nanoparticles, when studied outside the septic tank, impacted zebrafish embryo hatching rates at concentrations as low as 0.5 parts per million. However, when the copper nanoparticles were released into the replica septic tank, which included liquids that simulated human digested food and household wastewater, they were not bioavailable and didn’t impact hatching rates.

A March 2, 2015 University of California at Riverside (UCR) news release (also on EurekAlert), which originated the news item, provides more detail about the research,

“The results are encouraging because they show with a properly functioning septic tank we can eliminate the toxicity of these nanoparticles,” said Alicia Taylor, a graduate student working in the lab of Sharon Walker, a professor of chemical and environmental engineering at the University of California, Riverside’s Bourns College of Engineering.

The research comes at a time when products with nanoparticles are increasingly entering the marketplace. While the safety of workers and consumers exposed to nanoparticles has been studied, much less is known about the environmental implications of nanoparticles. The Environmental Protection Agency is currently accessing the possible effects of nanomaterials, including those made of copper, have on human health and ecosystem health.

The UC Riverside and UCLA [University of California at Los Angeles] researchers dosed the septic tank with micro copper and nano copper, which are elemental forms of copper but encompass different sizes and uses in products, and CuPRO, a nano copper-based material used as an antifungal agent to spray agricultural crops and lawns.

While these copper-based materials have beneficial purposes, inadvertent exposure to organisms such as fish or fish embryos has not received sufficient attention because it is difficult to model complicated exposure environments.

The UC Riverside researchers solved that problem by creating a unique experimental system that consists of the replica human colon and a replica two-compartment septic tank, which was originally an acyclic septic tank. The model colon is made of a custom-built 20-inch-long glass tube with a 2-inch diameter with a rubber stopper at both ends and a tube-shaped membrane typically used for dialysis treatments within the glass tube.

To simulate human feeding, 100 milliliters of a 20-ingredient mixture that replicated digested food was pumped into the dialysis tube at 9 a.m., 3 p.m. and 9 p.m. for five-day-long experiments over nine months.

The septic tank was filled with waste from the colon along with synthetic greywater, which is meant to simulate wastewater from sources such as sinks and bathtubs, and the copper nanoparticles. The researchers built a septic tank because 20 to 30 percent of American households rely on them for sewage treatment. Moreover, research has shown up to 40 percent of septic tanks don’t function properly. This is a concern if the copper materials are disrupting the function of the septic system, which would lead to untreated waste entering the soil and groundwater.

Once the primary chamber of the septic system was full, liquid began to enter the second chamber. Once a week, the effluent was drained from the secondary chamber and it was placed into sealed five-gallon containers. The effluent was then used in combination with zebrafish embryos in a high content screening process using multiwall plates to access hatching rates.

The remaining effluent has been saved and sits in 30 five-gallon buckets in a closet at UC Riverside because some collaborators have requested samples of the liquid for their experiments.

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

Understanding the Transformation, Speciation, and Hazard Potential of Copper Particles in a Model Septic Tank System Using Zebrafish to Monitor the Effluent* by Sijie Lin, Alicia A. Taylor, Zhaoxia Ji, Chong Hyun Chang, Nichola M. Kinsinger, William Ueng, Sharon L. Walker, and André E. Nel. ACS Nano, 2015, 9 (2), pp 2038–2048 DOI: 10.1021/nn507216f
Publication Date (Web): January 27, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

* Link added March 10, 2015.

Canadian nanobusiness news bitlets: NanoStruck and Lomiko Metals

The two items or ‘news bitlets’ about Canadian nano business don’t amount to much; one concerns a letter of intent and the other, an offer of warrants (like stock options) which likely expired today (March 13, 2014).

It seems NanoStruck Technologies is continuing to make headway in Mexico (as per my Feb. 19, 2014 posting about the company’s LOI and gold mine tailings in Zacatecas state) as the company has signed another letter of intent (LOI), this time, to treat wastewater in the region of Cabo Corrientes. From a March 11, 2014 news item on Azonano,

NanoStruck Technologies Inc. (the “Company” or “NanoStruck”) announces the signing of a Letter of Intent (LOI) with the town of El Tuito to use the Company’s NanoPure technology to treat wastewater from the municipality of Cabo Corrientes in Mexico.

The parties are in dialogue for the treatment of household residual water, which contains food, biodegradable matter, kitchen waste and organic materials. The Company’s NanoPure solution uses chemical-free processes and proprietary nano powders that can be customised to remove such contaminants.

The March 10, 2014 NanoStruck Technologies news release (which originated the news item) link on the company website leads to the full text here on heraldonline.com (Note: Links have been removed),

Homero Romero Amaral, President of the Municipality of Cabo Corrientes said: “NanoStruck’s NanoPure technology is a proven solution for the treatment of residual water in an environmentally friendly way. Its low energy consumption means it also maintains a low carbon footprint.”

Bundeep Singh Rangar, Interim CEO and Chairman of the Board said: “We are privileged to be given the opportunity to work with the Cabo Corrientes municipality to create a long-term residual wastewater treatment solution.”

El Tuito is the capital of Cabo Corrientes, a cape on the Pacific coast of the Mexican state of Jalisco. It marks the southernmost point of the Bahía de Banderas (Bay of Flags), where the port and resort city of Puerto Vallarta is situated.

The Municipality and NanoStruck have commenced negotiation of a definitive agreement regarding the use of the NanoPure technology and hope to complete a binding agreement within 90 days.

My next bitlet concerns, Lomiko Metals and its short form prospectus and offering. From the company’s March 7, 2014 news release (also available on MarketWired),

LOMIKO METALS INC. (TSX VENTURE:LMR) (the “Company” or “Lomiko”) is pleased to announce that it has obtained a final receipt for its short form prospectus (the “Prospectus”) in each of the provinces of British Columbia, Alberta and Ontario, which qualifies the distribution (the “Public Offering”) of (i) a minimum of 6,818,182 units (the “Units”) and a maximum of 27,272,727 Units of the Company at a price of $0.11 per Unit, and (ii) a maximum of 7,692,308 flow-through units (the “Flow-Through Units”) of the Company at a price of $0.13 per Flow-Through Unit, for minimum total gross proceeds of $750,000 and maximum total gross proceeds of $4,000,000.

Each Unit consists of one common share of the Company (each, a “Common Share”) and one-half of one common share purchase warrant (each whole warrant being a “Unit Warrant”). Each Flow-Through Unit consists of one Common Share to be issued on a “flow-through” basis within the meaning of the Income Tax Act (Canada) (each a “Flow-Through Share”) and one-half of one common share purchase warrant (each whole warrant being a “Flow-Through Unit Warrant”).

Each Unit Warrant will entitle the holder thereof to purchase one common share of the Company (the “Unit Warrant Shares”) at a price of $0.15 per Unit Warrant Share at at any time before the date that is 18 months following the closing date of the Public Offering. Each Flow-Through Unit Warrant will entitle the holder thereof to purchase one common share of the Company (the “Flow-Through Unit Warrant Shares”) at a price of $0.20 per Flow-Through Unit Warrant Share at at any time before the date that is 18 months following the closing date of the Public Offering. The Public Offering will be conducted on a “best effort” agency basis through Secutor Capital Management Corporation (the “Agent”), pursuant to an agency agreement dated March 6, 2014 (the “Agency Agreement”) between the Company and the Agent in respect of the Public Offering.

Pursuant to the Agency Agreement, the Company has also granted an over-allotment option to the Agent, exercisable for a period of 30 days following the closing of the Public Offering, in whole or in part, to purchase additional Units and Flow-Through Units in a maximum number equal to up to 15% of the number of Units and Flow-Through Units respectively sold pursuant to the Public Offering. In connection with the Public Offering, the Company will pay the Agent a cash commission equal to 8% of the gross proceeds of the Public Offering and grant compensation options to the Agent entitling it to purchase that number of common shares of the Company equal to 6% of the aggregate number of Units and Flow-Through Units issued and sold under the Public Offering (including the over-allotment option) for a period of 18 months following the closing date of the Public Offering, at a price of $0.11 per common share.

The Company is also pleased to announce it has received conditional approval from the TSX Venture Exchange for its previously announced concurrent non-brokered offering of up to 15,346,231 flow-through units (the “Private Placement Units”) for additional gross proceeds of $2,000,000 (the “Private Placement”). The securities underlying the Private Placement Units will be issued on the same terms as the securities underlying the Flow-Through Units to be issued under the Public Offering. The Company has agreed to pay to Secutor Capital Management Corporation a finder’s fee of 8% in cash and the issuance of a warrant to purchase the number of common shares of the Company equal to 6%, exercisable at $0.13 per share for 18 months from the date of issuance. The securities to be issued under the Private Placement will be subject to a four-month hold period from the closing date of the Private Placement.

The net proceeds from the Public Offering and the Private Placement will be used by Lomiko primarily in connection with the exploration program on the Quatre-Milles East and West mineral properties (Quebec), for business development and for working capital and general corporate purposes. In particular, the proceeds of the flow-through shares under the Public Offering and the Private Placement will be used by the Company to incur eligible Canadian Exploration Expenses as defined by the Income Tax Act (Canada).

Closing of the Public Offering and of the Private Placement is expected to occur on or about March 13, 2014, or such other date as the Agent and the Company may determine. The TSX Venture Exchange has conditionally approved the listing of the securities to be issued pursuant to the Public Offering and the Private Placement. The Public Offering and the Private Placement are subject to customary conditions and the final approval of the TSX Venture Exchange.

The Units, the Flow-Through Units and the Private Placement Units have not been, nor will they be, registered under the United States Securities Act of 1933, as amended (the “1933 Act”), and may not be offered, sold or delivered, directly or indirectly, within the United States, or to or for the account or benefit of U.S. persons unless the Units, the Flow-Through Units and the Private Placement Units are registered under the 1933 Act or pursuant to an applicable exemption from the registration requirements of the 1933 Act. This press release does not constitute an offer to sell, nor it is a solicitation of an offer of securities, nor shall there be any sale of securities in any state of the United States in which such offer, solicitation or sale would be unlawful.

You’re on your own with regard to determining how good an investment this company might be. The company’s March 10, 2014 newsletter does point to two analyses (although, again, you’re on your own as to whether or not these are reputable analysts), The first analyst is Gary Anderson (self-described as a Investor, trader, researcher, and writer- exclusively in 3D Printing Stocks.). He writes this in a Dec. 27, 2013 posting on 3DPrintingStocks.com,

I spend a great deal of time looking for what I believe are legitimate, undiscovered stocks in the 3D printing space because I believe that’s where the major gains will be over a 3-6 month period as they undergo discovery by the broader market.

The little-known penny stock [Lomiko Metals] I’m introducing today has legitimate upside potential for 3D printing investors based on four factors:

  1. The market for their product
  2. Current and potential future value of existing assets
  3. Supply and demand imbalance predicted
  4. Entrance into 3D printing materials market with an established leader

….

3D printing investors looking for a materials supplier as part of their 3D printing portfolio may want to consider Lomiko Metals.  I believe there is limited downside risk at current levels due to the intrinsic value of the company’s hard assets in their Quatre Milles graphite property, and potential for significant share price appreciation due to the four factors discussed above.

Graphene has extraordinary potential as a game-changing material for 3D printing.  Early movers like Lomiko Metals in partnership with Graphene Labs could become the beneficiaries of this amazing material’s potential as it becomes commercialized and utilized in 3D printed components and products that contain revolutionary properties.

Disclosure:    I am long shares of Lomiko Metals.  I received no compensation from Lomiko Metals or any third party for this article.

Silver ions in the environment

Earlier this week (Feb. 24, 2014), I published a post featuring Dr. Andrew Maynard, Director of the University of Michigan’s Risk Science Center in an introductory video describing seven surprising facts about silver nanoparticles. For those who want to delve more deeply, there’s a Feb. 25, 2014 news item on Nanowerk describing some Swiss research into silver nanoparticles and ions in aquatic environments,

It has long been known that, in the form of free ions, silver particles can be highly toxic to aquatic organisms. Yet to this day, there is a lack of detailed knowledge about the doses required to trigger a response and how the organisms deal with this kind of stress. To learn more about the cellular processes that occur in the cells, scientists from the Aquatic Research Institute, Eawag [Swiss Federal Institute of Aquatic Science and Technology], subjected algae to a range of silver concentrations.

In the past, silver mostly found its way into the environment in the vicinity of silver mines or via wastewater [emphasis mine] emanating from the photo industry. More recently, silver nanoparticles have become commonplace in many applications – as ingredients in cosmetics, food packaging, disinfectants, and functional clothing. Though a recent study conducted by the Swiss National Science Foundation revealed that the bulk of silver nanoparticles is retained in wastewater treatment plants, only little is known about the persistence and the impact of the residual nano-silver in the environment.

The Feb. 25, 2014 Eawag media release, which originated the news item, describes the research in further detail,

Smitha Pillai from the Eawag Department of Environmental Toxicology and her colleagues from EPF Lausanne and ETH Zürich studied the impact of various concentrations of waterborne silver ions on the cells of the green algae Chlamydomonas reinhardtii. Silver is chemically very similar to copper, an essential metal due to its importance in several enzymes. Because of that, silver can exploit the cells’ copper transport mechanisms and sneak into them undercover. This explains why, already after a short time, concentrations of silver in the intracellular fluid can reach up to one thousand times those in the surrounding environment.

A prompt response

Because silver damages key enzymes involved in energy metabolism, even low concentrations can cut photosynthesis and growth rates by a half in just 15 minutes. Over the same time period, the researchers also detected changes in the activity of about 1000 other genes and proteins, which they interpreted as a response to the stressor – an attempt to repair silver-induced damage. At low concentrations, the cells’ photosynthesis apparatus recovered within five hours, and recovery mechanisms were sufficient to deal with all but the highest concentrations tested.

A number of unanswered questions

At first glance, the results are reassuring because the silver concentrations that the algae are subject to in the environment are rarely as high as those applied in the lab, which allows them to recover quickly – at least externally. But the experiments also showed that even low silver concentrations have a significant effect on intracellular processes and that the algae divert their energy to repairing damage incurred. This can pose a problem when other stressors act in parallel, such as increased UV-radiation or other chemical compounds. Moreover, it remains unknown to this day whether the cells have an active mechanism to shuttle out the silver. Lacking such a mechanism, the silver could have adverse effects on higher organisms, given that algae are at the bottom of the food chain.

You can find the researchers’ paper here,

Linking toxicity and adaptive responses across the transcriptome, proteome, and phenotype of Chlamydomonas reinhardtii exposed to silver by Smitha Pillai, Renata Behra, Holger Nestler, Marc J.-F. Suter, Laura Sigg, and Kristin Schirmer. Proceedings of the National Academy of Sciences (PNAS) – early edition 18.February 2014, www.pnas.org/cgi/doi/10.1073/pnas.1319388111

The paper is available through the PNAS open access option.

I have published a number of pieces about aquatic enviornments and wastewater and nanotechnology-enabled products as useful for remediation efforts and as a source of pollution. Here’s a Feb. 28, 2013 posting where I contrasted two pieces of research on silver nanoparticles. The first was research in an aquatic environment and the other concerned wastewater.

Luminous bacteria sense pharmaceuticals and metals in wastewater

Scientists at the Helmholtz Association of German Research Centres have conceptualized a technique using luminescent bacterial proteins for sensing pharmaceuticals and metals in waste water. From the Helmholtz Association of German Research Centres June 12, 2013 press release,

While residual medications don’t belong in the water, trace metals from industrial process waters handled by the recycling industry are, in contrast, valuable resources. Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have developed a simple color sensor principle which facilitates the easy detection of both materials as well as many other substances. This is the concept: If the analyzed sample shines red, then the water is ‘clean;’ if its color turns green, however, then it contains the substances the scientists wish to detect. The researchers recently published their concept in the scientific journal Sensors and Actuators B: Chemical (DOI: 10.1016/j.snb.2013.05.051).

Here’s the concept, from the press release,

The sensor principle is based on a red and a green fluorescent dye. If a substance to be detected is present in a water sample, then the sensor shines green; a red color, however, indicates that the substance is not present. What is the reason for the color difference? “The color molecules are located on a nanostructured surface consisting of bacterial proteins. The dyes are so close to one another that energy is transferred from the green to the red dye if these dyes are irradiated with light at a specific wavelength, for example, the light emitted by a laser. Then the sample shines red. This energy transfer, though, only occurs if the water sample is ‘clean.’ If, however, any foreign substances such as, for example, the pharmaceuticals or pollutants to be detected accumulate between the color molecules at specific binding sites, then the transfer is interrupted and only the green dyes shine,” explains Ulrike Weinert. Her doctoral dissertation revolves around the binding of color molecules on nano surfaces.

The network project (“AptaSens”) was subsidized by the Federal Ministry of Education and Research (BMBF). Nanostructured surfaces are an important part of the project. They are extracted from the envelope proteins of bacteria which are cultivated by the researchers in a lab. “The proteins form regular lattice structures at the nano level. They are ideally suited to evenly arrange functional groups and other molecules,” notes Weinert.

Another essential component of the sensor principle are the binding sites on the nano surface of the substances which are to be detected. That’s why so-called aptamers are used. These aptamers are short, single-stranded DNA oligonucleotides; the DNA segments can be designed in such a way that they are capable of specifically binding the most diverse substances such as the pharmaceuticals or the pollutants mentioned above. Dr. Beate Strehlitz from the Leipzig-based Helmholtz Centre for Environmental Research (UFZ) has specialized in this field. Within the scope of the AptaSens project, her team developed such a receptor for the antibiotic kanamycin which is used, for example, for the treatment of such bacterial infections of the eye as conjunctivitis, or in veterinary medicine.

The next step will be testing, from the press release,

What remains to be done now is to combine the kanamycin receptor with the dyes to test the color sensor principle with a sample substance. “From there, it’s just a small step to the development of a complete color sensor,” notes Katrin Pollmann [Dr. Katrin Pollmann, Team Leader Biotechnology at the HZDR {Holtzman Centres}]. For this, the researchers need to integrate the individual components – which include bacterial proteins, dyes, and aptamers – into a sensor chip. They have actually conducted a number of experiments with suitable substrates such as, for example, glass or silicon dioxide. “The sensor chip could be as small as a thumbnail. It could be wetted on site with the water sample to be analyzed. This would also include a laser light source which activates the chip as well as a detector that measures the change in color,” adds Pollmann. The scientists are now applying for a follow-up project.

I’d love to get a little more information about which metals (gold nanoparticles? silver nanoparticles? zinc oxide nanoparticles? etc.) could be detected in the water. If the information is in the research team’s published paper, that is available only behind a paywall.  H/T to Nanowerk (June 12, 2013 news item) for alerting me to this research work.

Here’s a citation (the link was provided earlier in this post),

U. Weinert, K. Pollmann, J. Raff. “Fluorescence Resonance Energy Transfer by S-layer coupled fluorescence dyes”, in Sensors and Actuators B: Chemical (2013), DOI: 10.1016/j.snb.2013.05.051

For anyone who’s interested in more information about aptamers, there’s my Oct. 25, 2011 posting which featured an interview with Dr. Maria DeRosa about her work with them.

Silver nanoparticles, water, the environment, and toxicity

I am contrasting two very different studies on silver nanoparticles in water and their effect on the environment to highlight the complex nature of determining the risks and environmental effects associated with nanoparticles in general. One piece of research suggests that silver nanoparticles are less dangerous than other commonly used forms of silver while the other piece raises some serious concerns.

A Feb. 28, 2013 news item on Nanowerk features research about the effects that silver nanoparticles have on aquatic ecosystems (Note: A link has been removed),

According to Finnish-Estonian joint research with data obtained on two crustacean species, there is apparently no reason to consider silver nanoparticles more dangerous for aquatic ecosystems than silver ions.

The results were reported in the journal Environmental Science and Pollution Research late last year (“Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus”). Jukka Niskanen has utilised the same polymerisation and coupling reactions in his doctoral dissertation studying several hybrid nanomaterials, i.e. combinations of synthetic polymers and inorganic (gold, silver and montmorillonite) nanoparticles. Niskanen will defend his doctoral thesis at the University of Helsinki in April.

The University of Helsikinki Feb. 28, 2013 press release written by Minna Merilainen and which originated the new item provides details about the research,

“Due to the fact that silver in nanoparticle form is bactericidal and also fungicidal and also prevents the reproduction of those organisms, it is now used in various consumer goods ranging from wound dressing products to sportswear,” says Jukka Niskanen from the Laboratory of Polymer Chemistry at the University of Helsinki, Finland.A joint study from the University of Helsinki and the National Institute of Chemical Physics and Biophysics (Tallinn, Estonia), Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus, shows that silver nanoparticles are apparently no more hazardous to aquatic ecosystems than a water-soluble silver salt. The study compared the ecotoxicity of silver nanoparticles and a water-soluble silver salt.

“Our conclusion was that the environmental risks caused by silver nanoparticles are seemingly not higher than those caused by a silver salt. However, more research is required to reach a clear understanding of the safety of silver-containing particles,” Niskanen says.

Indeed, silver nanoparticles were found to be ten times less toxic than the soluble silver nitrate - a soluble silver salt used for the comparison.

The bioavailability of silver varies in different test media

To explain this phenomenon, the researchers refer to the variance in the bioavailability of silver to crustaceans in different tested media.

University lecturer Olli-Pekka Penttinen from the Department of Environmental Sciences of the University of Helsinki goes on to note that the inorganic and organic compounds dissolved in natural waters (such as humus), water hardness and sulfides have a definite impact on the bioavailability of silver. Due to this, the toxicity of both types of tested nanoparticles and the silver nitrate measured in the course of the study was lower in natural water than in artificial fresh water.

The toxicity of silver nanoparticles and silver ions was studied using two aquatic crustaceans, a water flea (Daphnia magna) and a fairy shrimp ( Thamnocephalus platyurus). Commercially available protein-stabilised particles and particles coated with a water-soluble, non-toxic polymer, specifically synthesised for the purpose, were used in the study. First, the polymers were produced utilising a controlled radical polymerization method. Synthetic polymer-grafted silver particles were then produced by attaching the water-soluble polymer to the surface of the silver with a sulfur bond.

Jukka Niskanen has utilised such polymerisation and coupling reactions in his doctoral dissertation. Polymeric and hybrid materials: polymers on particle surfaces and air-water interfaces, studying several hybrid nanomaterials , i.e., combinations of synthetic polymers and inorganic (gold, silver and montmorillonite) nanoparticles....

It was previously known from other studies and research results that silver changes the functioning of proteins and enzymes. It has also been shown that silver ions can prevent the replication of DNA. Concerning silver nanoparticles, tests conducted on various species of bacteria and fungi have indicated that their toxicity varies. For example, gram-negative bacteria such as Escherichia coli are more sensitive to silver nanoparticles than gram-positive ones (such as Staphylococcus aureus). The difference in sensitivity is caused by the structural differences of the cell membranes of the bacteria. The cellular toxicity of silver nanoparticles in mammals has been studied as well. It has been suggested that silver nanoparticles enter cells via endocytosis and then function in the same manner as in bacterial cells, damaging DNA and hindering cell respiration. Electron microscope studies have shown that human skin is permeable to silver nanoparticles and that the permeability of damaged skin is up to four times higher than that of healthy skin.

While this Finnish-Estonian study suggests that silver nanoparticles do not have a negative impact on the tested crustaceans in an aquatic environment, there’s a study from Duke University suggests that silver nanoparticles in wastewater which is later put to agricultural use may cause problems. From the Feb. 27, 2013 news release on EurekAlert,

In experiments mimicking a natural environment, Duke University researchers have demonstrated that the silver nanoparticles used in many consumer products can have an adverse effect on plants and microorganisms.

The main route by which these particles enter the environment is as a by-product of water and sewage treatment plants. [emphasis] The nanoparticles are too small to be filtered out, so they and other materials end up in the resulting “sludge,” which is then spread on the land surface as a fertilizer.

The researchers found that one of the plants studied, a common annual grass known as Microstegium vimeneum, had 32 percent less biomass in the mesocosms treated with the nanoparticles. Microbes were also affected by the nanoparticles, Colman [Benjamin Colman, a post-doctoral fellow in Duke’s biology department and a member of the Center for the Environmental Implications of Nanotechnology (CEINT)] said. One enzyme associated with helping microbes deal with external stresses was 52 percent less active, while another enzyme that helps regulate processes within the cell was 27 percent less active. The overall biomass of the microbes was also 35 percent lower, he said.

“Our field studies show adverse responses of plants and microorganisms following a single low dose of silver nanoparticles applied by a sewage biosolid,” Colman said. “An estimated 60 percent of the average 5.6 million tons of biosolids produced each year is applied to the land for various reasons, and this practice represents an important and understudied route of exposure of natural ecosystems to engineered nanoparticles.”

“Our results show that silver nanoparticles in the biosolids, added at concentrations that would be expected, caused ecosystem-level impacts,” Colman said. “Specifically, the nanoparticles led to an increase in nitrous oxide fluxes, changes in microbial community composition, biomass, and extracellular enzyme activity, as well as species-specific effects on the above-ground vegetation.”

As previously noted, these two studies show just how complex the questions of risk and nanoparticles can become.  You can find out more about the Finish-Estonian study,

Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus by  Irina Blinova, Jukka Niskanen, Paula Kajankari, Liina Kanarbik, Aleksandr Käkinen, Heikki Tenhu, Olli-Pekka Penttinen, and Anne Kahru. Environmental Science and Pollution Research published November 11, 2012 online

The publisher offers an interesting option for this article. While it is behind a paywall, access is permitted through a temporary window if you want to preview a portion of the article that lies beyond the abstract.

Meanwhile here’s the article by the Duke researchers,

Low Concentrations of Silver Nanoparticles in Biosolids Cause Adverse Ecosystem Responses under Realistic Field Scenario by Benjamin P. Colman, Christina L. Arnaout, Sarah Anciaux, Claudia K. Gunsch, Michael F. Hochella Jr, Bojeong Kim, Gregory V. Lowry,  Bonnie M. McGill, Brian C. Reinsch, Curtis J. Richardson, Jason M. Unrine, Justin P. Wright, Liyan Yin, and Emily S. Bernhardt. PLoS ONE 2013; 8 (2): e57189 DOI: 10.1371/journal.pone.0057189

This article is open access as are all articles published by the Public Library of Science (PLoS) journals.

For anyone interested in the Duke University/CEINT mesocosm project, I made mention of it in an Aug. 15, 2011 posting.

Grey water and a short story from a GG winner

I mentioned Kate Pullinger when she won Canada’s 2009 Governor General’s (GG) award for fiction (Nov. 20, 2009 posting) and it seems a GG winner never gets to rest on her laurels. Last summer she was asked to write a short story celebrating the 75th anniversary of the GG awards. From the Canadian Broadcasting Corporation’s (CBC) Canada Writes web space (from the Nov. 24, 2011 posting about Kate Pullinger’s story, Grey Water Lady),

Last summer, to celebrate the 75th anniversary of the Governor General’s Awards and the CBC, we asked ten GG-winning authors write a story about winter.

Kate Pullinger tells the story of a jet-lagged and heartbroken waste-water specialist who seeks to inject some colour back in her life.

Here’s a brief excerpt from Kate’s story,

Domestic grey water – the recycling of waste water from the bath, sink, shower, washing machine, etc – had become her area of expertise almost by default. In the industry she was known as Grey Water Lady. Fondly.  But still. She’d been flown over by the government to have a look at Melbourne’s controversial desalination plant project, but as soon as she got off the plane she realised the clothes she’d packed were completely inappropriate and that she’d have to wear everything in her suitcase all at the same time in order to stay warm.

In addition to writing a story, Kate was asked to do something else,

We asked Kate to recommend a writer who she thinks is not as well known as they deserve to be. Come back on Tuesday [Nov. 29, 2011] to find out who she has chosen as her writer to watch.

As for Canada Writes, here’s more from the About Us page,

Canada Writes is Canada’s home for original writing of all kinds, including the CBC Literary Prizes. It’s a meeting place for writers- a place where you come to showcase your work through an ongoing series of writing challenges and competitions, and a resource to help you connect with other writers across the country. We also feature original stories from writers across the country, editorials, writing news and recommendations and writing workshops.

It is also home to the CBC Short Story Prize, the CBC Poetry Prize and the CBC Creative Nonfiction Prize.

Kate now lives in the UK but was born in British Columbia and grew up on Vancouver Island.