Tag Archives: Huaqiang Zeng

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.

Oil spill cleanups with supergelators

Researchers in Singapore have proposed a new technology for cleaning up oil spills, according to a June 17, 2016 news item on Nanowerk,

Large-scale oil spills, where hundreds of tons of petroleum products are accidentally released into the oceans, not only have devastating effects on the environment, but have significant socio-economic impact as well [1].

Current techniques of cleaning up oil spills are not very efficient and may even cause further pollution or damage to the environment. These methods, which include the use of toxic detergent-like compounds called dispersants or burning of the oil slick, result in incomplete removal of the oil. The oil molecules remain in the water over long periods and may even be spread over a larger area as they are carried by wind and waves. Further, burning can only be applied to fresh oil slicks of at least 3 millimeters thick, and this process would also cause secondary environmental pollution.

In a bid to improve the technology utilized by cleanup crews to manage and contain such large spills, researchers from the Institute of Bioengineering and Nanotechnology (IBN) of A*STAR [located in Singapore] have invented a smart oil-scavenging material or supergelators that could help clean up oil spills efficiently and rapidly to prevent secondary pollution.

These supergelators are derived from highly soluble small organic molecules, which instantly self-assemble into nanofibers to form a 3D net that traps the oil molecules so that they can be removed easily from the surface of the water.

A June 17, 2016 IBN A*STAR media release, which originated the news item, provides more detail,

“Marine oil spills have a disastrous impact on the environment and marine life, and result in an enormous economic burden on society. Our rapid-acting supergelators offer an effective cleanup solution that can help to contain the severe environmental damage and impact of such incidents in the future,” said IBN Executive Director Professor Jackie Y. Ying.

Motivated by the urgent need for a more effective oil spill control solution, the IBN researchers developed new compounds that dissolve easily in environmentally friendly solvents and gel rapidly upon contact with oil. The supergelator molecules arrange themselves into a 3D network, entangling the oil molecules into clumps that can then be easily skimmed off the water’s surface.

“The most interesting and useful characteristic of our molecules is their ability to stack themselves on top of each other. These stacked columns allow our researchers to create and test different molecular constructions, while finding the best structure that will yield the desired properties,” said IBN Team Leader and Principal Research Scientist Dr Huaqiang Zeng. (Animation: Click to see how the supergelators stack themselves into columns.)

IBN’s supergelators have been tested on various types of weathered and unweathered crude oil in seawater, and have been found to be effective in solidifying all of them. The supergelators take only minutes to solidify the oil at room temperature for easy removal from water. In addition, tests carried out by the research team showed that the supergelator was not toxic to human cells, as well as zebrafish embryos and larvae. The researchers believe that these qualities would make the supergelators suitable for use in large oil spill areas.

The Institute is looking for industrial partners to further develop its technology for commercial use. [emphasis mine]

Video: Click to watch the supergelators in action

  1. The well documented BP Gulf of Mexico oil well accident in 2010 was a catastrophe on an unprecedented scale, with damages amounting to hundreds of billions of dollars. Its wide-ranging effects on the marine ecosystem, as well as the fishing and tourism industries, can still be felt six years on.

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

Instant Room-Temperature Gelation of Crude Oil by Chiral Organogelators by Changliang Ren, Grace Hwee Boon Ng, Hong Wu, Kiat-Hwa Chan, Jie Shen, Cathleen Teh, Jackie Y. Ying, and Huaqiang Zeng. Chem. Mater., 2016, 28 (11), pp 4001–4008 DOI: 10.1021/acs.chemmater.6b01367 Publication Date (Web): May 10, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

I have featured other nanotechnology-enabled oil spill cleanup solutions here. One of the more recent pieces is my Dec. 7, 2015 post about boron nitride sponges. The search terms: ‘oil spill’ and ‘oil spill cleanup’ will help you unearth more.

There have been some promising possibilities and I hope one day these clean up technologies will be brought to market.