Tag Archives: aquaporins

Oil spill cleanup nanotechnology-enabled solution from A*STAR

A*STAR (Singapore’s Agency for Science Technology and Research) has developed a new technology for cleaning up oil spills according to an Oct. 11, 2016 news item on Nanowerk,

Oceanic oil spills are tough to clean up. They dye feathers a syrupy sepia and tan fish eggs a toxic tint. The more turbulent the waters, the farther the slick spreads, with inky droplets descending into the briny deep.

Now technology may be able to succeed where hard-working volunteers have failed in the past. Researchers at the A*STAR Institute of Bioengineering and Nanotechnology (IBN) are using nanotechnology to turn an oil spill into a floating mass of brown jelly that can be scooped up before it can make its way into the food chain.

“Nanoscience makes it possible to tailor the essential structures of materials at the nanometer scale to achieve specific properties,” says chemist Yugen Zhang at IBN, who is developing some of the technologies. “Structures and materials in the nanometer size range often take on distinctive properties that are not seen in other size ranges,” adds Huaqiang Zeng, another chemist at IBN.

An Oct. 11, 2016 A*STAR press release, which originated the news item, describes some of problematic solutions before describing the new technology,

There are many approaches to cleaning an oil spill, and none are completely effective. Fresh, thick grease can be set ablaze or contained by floating barriers for skimmers to scoop out. The slick can also be inefficiently hardened, messily absorbed, hazardously dispersed, or slowly consumed by oil-grazing bacteria. All of these are deficient on a large scale, especially in rough waters.

Organic molecules with special gelling abilities offer a cheap, simple and environmentally friendly alternative for cleaning up the mess. Zeng has developed several such molecules that turn crude oil into jelly within minutes.

To create his ‘supergelators’, Zeng designed the molecules to associate with each other without forming physical bonds. When sprayed on contaminated seawater, the molecules immediately bundle into long fibers between 40 and 800 nanometers wide. These threads create a web that traps the interspersed oil in a giant blob that floats on the water’s surface. The gunk can then be swiftly sieved out of the ocean. Valuable crude oil can later be reclaimed using a common technique employed by petroleum refineries called fractional distillation.

Zeng tested the supergelators on four types of crude oil with different densities, viscosities and sulfur levels in a small round dish. The results were impressive. “The supergelators solidified both freshly spilled crude oil and highly weathered crude oil 37 to 60 times their own weight,” says Zeng. The materials used to produce these organic molecules are cheap and non toxic, which make them a commercially viable solution for managing accidents out at sea. Zeng hopes to work with industrial partners to test the nanomolecules on a much larger scale.

Zeng and his colleagues have developed other other ‘water’ applications as well,

Unsalty water

Scientists at IBN are also using nanoscience to remove salt from seawater and heavy metals from contaminated water.

With dwindling global fresh and ground water reserves, many countries are looking to desalination as a viable source of drinking water. Desalination is expected to meet 30 per cent of the water demand of Singapore by 2060, which will mean tripling the country’s current desalination capacity. But desalination demands huge energy consumption and reverse osmosis, the mainstream technology it depends on, has a relatively high cost. Reverse osmosis works by using extreme pressures to squeeze water molecules through tightly knit membranes.

An emerging alternative solution mimics the way proteins embedded in cell membranes, known as aquaporins, channel water in and out. Some research groups have even created membranes made of fatty lipid molecules that can accommodate natural aquaporins. Zeng has developed a cheaper and more resilient replacement.

His building blocks consist of helical noodles with sticky ends that connect to form long spirals. Water molecules can flow through the 0.3 nanometer openings at the center of the spirals, but all the other positively and negatively charged ions that make up saltwater are too bulky to pass. These include sodium, potassium, calcium, magnesium, chlorine and sulfur oxide. “In water, all of these ions are highly hydrated, attached to lots of water molecules, which makes them too large to go through the channels,” says Zeng.

The technology could lead to global savings of up to US$5 billion a year, says Zeng, but only after several more years of testing and tweaking the lipid membrane’s compatibility and stability with the nanospirals. “This is a major focus in my group right now,” he says. “We want to get this done, so that we can reduce the cost of water desalination to an acceptable level.”

Stick and non-stick

Nanomaterials also offer a low-cost, effective and sustainable way to filter out toxic metals from drinking water.

Heavy metal levels in drinking water are stringently regulated due to the severe damage the substances can cause to health, even at very low concentrations. The World Health Organization requires that levels of lead, for example, remain below ten parts per billion (ppb). Treating water to these standards is expensive and extremely difficult.

Zhang has developed an organic substance filled with pores that can trap and remove toxic metals from water to less than one ppb. Each pore is ten to twenty nanometers wide and packed with compounds, known as amines that stick to the metals.

Exploiting the fact that amines lose their grip over the metals in acidic conditions, the valuable and limited resource can be recovered by industry, and the polymers reused.

The secret behind the success of Zhang’s polymers is the large surface area covered by the pores, which translates into more opportunities to interact with and trap the metals. “Other materials have a surface area of about 100 square meters per gram, but ours is 1,000 square meters per gram,” says Zhang. “It is 10 times higher.”

Zhang tested his nanoporous polymers on water contaminated with lead. He sprinkled a powdered version of the polymer into a slightly alkaline liquid containing close to 100 ppb of lead. Within seconds, lead levels reduced to below 0.2 ppb. Similar results were observed for cadmium, copper and palladium. Washing the polymers in acid released up to 93 per cent of the lead.

With many companies keen to scale these technologies for real-world applications, it won’t be long before nanoscience treats the Earth for its many maladies.

I wonder if the researchers have found industrial partners (who could be named) to bring these solutions for oil spill cleanups, desalination, and water purification to the market.

Earth Day, Water Day, and every day

I’m blaming my confusion on the American Chemical Society (ACS) which seemed to be celebrating Earth Day on April 15, 2014 as per its news release highlighting their “Chemists Celebrate Earth Day” video series  while in Vancouver, Canada, we’re celebrating it on April 26, 2014 and elsewhere it seems to be on April 20, this year. Regardless, here’s more about how chemist’s are celebrating from the ACS news release,

Water is arguably the most important resource on the planet. In celebration of Earth Day, the American Chemical Society (ACS) is showcasing three scientists whose research keeps water safe, clean and available for future generations. Geared toward elementary and middle school students, the “Chemists Celebrate Earth Day” series highlights the important work that chemists and chemical engineers do every day. The videos are available at http://bit.ly/CCED2014.

The series focuses on the following subjects:

  • Transforming Tech Toys– Featuring Aydogan Ozcan, Ph.D., of UCLA: Ozcan takes everyday gadgets and turns them into powerful mobile laboratories. He’s made a cell phone into a blood analyzer and a bacteria detector, and now he’s built a device that turns a cell phone into a water tester. It can detect very harmful mercury even at very low levels.
  • All About Droughts – Featuring Collins Balcombe of the U.S. Bureau of Reclamation: Balcombe’s job is to keep your drinking water safe and to find new ways to re-use the water that we flush away everyday so that it doesn’t go to waste, especially in areas that don’t get much rain.
  • Cleaning Up Our Water – Featuring Anne Morrissey, Ph.D., of Dublin City University: We all take medicines, but did you know that sometimes the medicine doesn’t stay in our bodies? It’s up to Anne Morrissey to figure out how to get potentially harmful pharmaceuticals out of the water supply, and she’s doing it using one of the most plentiful things on the planet: sunlight.

Sadly, I missed marking World Water Day which according to a March 21, 2014 news release I received was being celebrated on Saturday, March 22, 2014 with worldwide events and the release of a new UN report,

World Water Day: UN Stresses Water and Energy Issues 

Tokyo Leads Public Celebrations Around the World

Tokyo — March 21 — The deep-rooted relationships between water and energy were highlighted today during main global celebrations in Tokyo marking the United Nations’ annual World Water Day.

“Water and energy are among the world’s most pre-eminent challenges. This year’s focus of World Water Day brings these issues to the attention of the world,” said Michel Jarraud, Secretary-General of the World Meteorological Organization and Chair of UN-Water, which coordinates World Water Day and freshwater-related efforts UN system-wide.

The UN predicts that by 2030 the global population will need 35% more food, 40% more water and 50% more energy. Already today 768 million people lack access to improved water sources, 2.5 billion people have no improved sanitation and 1.3 billion people cannot access electricity.

“These issues need urgent attention – both now and in the post-2015 development discussions. The situation is unacceptable. It is often the same people who lack access to water and sanitation who also lack access to energy, ” said Mr. Jarraud.

The 2014 World Water Development Report (WWDR) – a UN-Water flagship report, produced and coordinated by the World Water Assessment Programme, which is hosted and led by UNESCO – is released on World Water Day as an authoritative status report on global freshwater resources. It highlights the need for policies and regulatory frameworks that recognize and integrate approaches to water and energy priorities.

WWDR, a triennial report from 2003 to 2012, this year becomes an annual edition, responding to the international community’s expression of interest in a concise, evidence-based and yearly publication with a specific thematic focus and recommendations.

WWDR 2014 underlines how water-related issues and choices impact energy and vice versa. For example: drought diminishes energy production, while lack of access to electricity limits irrigation possibilities.

The report notes that roughly 75% of all industrial water withdrawals are used for energy production. Tariffs also illustrate this interdependence: if water is subsidized to sell below cost (as is often the case), energy producers – major water consumers – are less likely to conserve it.  Energy subsidies, in turn, drive up water usage.

The report stresses the imperative of coordinating political governance and ensuring that water and energy prices reflect real costs and environmental impacts.

“Energy and water are at the top of the global development agenda,” said the Rector of United Nations University, David Malone, this year’s coordinator of World Water Day on behalf of UN-Water together with the United Nations Industrial Development Organization (UNIDO).

“Significant policy gaps exist in this nexus at present, and the UN plays an instrumental role in providing evidence and policy-relevant guidance. Through this day, we seek to inform decision-makers, stakeholders and practitioners about the interlinkages, potential synergies and trade-offs, and highlight the need for appropriate responses and regulatory frameworks that account for both water and energy priorities. From UNU’s perspective, it is essential that we stimulate more debate and interactive dialogue around possible solutions to our energy and water challenges.”

UNIDO Director-General LI Yong, emphasized the importance of water and energy for inclusive and sustainable industrial development.

“There is a strong call today for integrating the economic dimension, and the role of industry and manufacturing in particular, into the global post-2015 development priorities. Experience shows that environmentally sound interventions in manufacturing industries can be highly effective and can significantly reduce environmental degradation. I am convinced that inclusive and sustainable industrial development will be a key driver for the successful integration of the economic, social and environmental dimensions,” said Mr. LI.

Rather unusually, Michael Bergerrecently published two Nanowerk Spotlight articles about water (is there theme, anyone?) within 24 hours of each other. In his March 26, 2014 Spotlight article, Michael Berger focuses on graphene and water remediation (Note: Links have been removed),

The unique properties of nanomaterials are beneficial in applications to remove pollutants from the environment. The extremely small size of nanomaterial particles creates a large surface area in relation to their volume, which makes them highly reactive, compared to non-nano forms of the same materials.

The potential impact areas for nanotechnology in water applications are divided into three categories: treatment and remediation; sensing and detection: and pollution prevention (read more: “Nanotechnology and water treatment”).

Silver, iron, gold, titanium oxides and iron oxides are some of the commonly used nanoscale metals and metal oxides cited by the researchers that can be used in environmental remediation (read more: “Overview of nanomaterials for cleaning up the environment”).

A more recent entrant into this nanomaterial arsenal is graphene. Individual graphene sheets and their functionalized derivatives have been used to remove metal ions and organic pollutants from water. These graphene-based nanomaterials show quite high adsorption performance as adsorbents. However they also cause additional cost because the removal of these adsorbent materials after usage is difficult and there is the risk of secondary environmental pollution unless the nanomaterials are collected completely after usage.

One solution to this problem would be the assembly of individual sheets into three-dimensional (3D) macroscopic structures which would preserve the unique properties of individual graphene sheets, and offer easy collecting and recycling after water remediation.

The March 27, 2014 Nanowerk Spotlight article was written by someone at Alberta’s (Canada) Ingenuity Lab and focuses on their ‘nanobiological’ approach to water remediation (Note: Links have been removed),

At Ingenuity Lab in Edmonton, Alberta, Dr. Carlo Montemagno and a team of world-class researchers have been investigating plausible solutions to existing water purification challenges. They are building on Dr. Montemagno’s earlier patented discoveries by using a naturally-existing water channel protein as the functional unit in water purification membranes [4].

Aquaporins are water-transport proteins that play an important osmoregulation role in living organisms [5]. These proteins boast exceptionally high water permeability (~ 1010 water molecules/s), high selectivity for pure water molecules, and a low energy cost, which make aquaporin-embedded membrane well suited as an alternative to conventional RO membranes.

Unlike synthetic polymeric membranes, which are driven by the high pressure-induced diffusion of water through size selective pores, this technology utilizes the biological osmosis mechanism to control the flow of water in cellular systems at low energy. In nature, the direction of osmotic water flow is determined by the osmotic pressure difference between compartments, i.e. water flows toward higher osmotic pressure compartment (salty solution or contaminated water). This direction can however be reversed by applying a pressure to the salty solution (i.e., RO).

The principle of RO is based on the semipermeable characteristics of the separating membrane, which allows the transport of only water molecules depending on the direction of osmotic gradient. Therefore, as envisioned in the recent publication (“Recent Progress in Advanced Nanobiological Materials for Energy and Environmental Applications”), the core of Ingenuity Lab’s approach is to control the direction of water flow through aquaporin channels with a minimum level of pressure and to use aquaporin-embedded biomimetic membranes as an alternative to conventional RO membranes.

Here’s a link to and a citation for Montemagno’s and his colleague’s paper,

Recent Progress in Advanced Nanobiological Materials for Energy and Environmental Applications by Hyo-Jick Choi and Carlo D. Montemagno. Materials 2013, 6(12), 5821-5856; doi:10.3390/ma6125821

This paper is open access.

Returning to where I started, here’s a water video featuring graphene from the ACS celebration of Earth Day 2014,

Happy Earth Day!