A group of scientists led by Nanyang Technological University, Singapore (NTU Singapore) has created a reusable, biodegradable sponge that may readily take in oil and different natural solvents from contaminated water sources, making it a promising different for tackling marine oil spills.

Made of sunflower pollen, the sponge is hydrophobic – it repels water – thanks to a coat of pure fatty acid on the sponge. In lab experiments, the scientists confirmed the sponge’s skill to soak up oil contaminants of varied densities, comparable to gasoline and motor oil, at a fee comparable to that of business oil absorbents.

Oil spills are troublesome to clear up, and lead to extreme long-lasting harm to the marine ecosystem. Conventional clean-up strategies, together with utilizing chemical dispersants to break oil down into very small droplets, or absorbing it with costly, unrecyclable supplies, might worsen the harm. 

So far, the researchers have engineered sponges that measure 5 cm in diameter. The analysis group, made up of scientists from NTU Singapore and Sungkyunkwan University in South Korea, believes that these sponges, when scaled up, could possibly be an eco-friendly different to tackle marine oil spills.

Professor Cho Nam-Joon from the NTU School of Materials Science and Engineering, who led the research, stated: “By finetuning the material properties of pollen, our team successfully developed a sponge that can selectively target oil in contaminated water sources and absorb it. Using a material that is found abundantly in nature also makes the sponge affordable, biodegradable, and eco-friendly.”

This research builds on NTU’s physique of labor on discovering new makes use of for pollen, generally known as the diamond of the plant kingdom for its onerous exterior, by remodeling its powerful shell into microgel particles. This smooth, gel-like materials is then used as a constructing block for a brand new class of environmentally sustainable supplies. 

Last yr, Prof Cho, along with NTU President Professor Subra Suresh, led a analysis group to create a paper-like materials from pollen as a greener different to paper created from bushes. This ‘pollen paper’ additionally bends and curls in response to altering ranges of environmental humidity, a trait that could possibly be helpful for smooth robots, sensors, and synthetic muscle tissues. 

Prof Cho, who additionally holds the Materials Research Society of Singapore Chair in Materials Science and Engineering, added: “Pollen that is not used for plant pollination is often considered biological waste. Through our work, we try to find new uses for this ‘waste’ and turn it into a natural resource that is renewable, affordable, and biodegradable. Pollen is also biocompatible. It does not cause an immunological, allergic or toxic reaction when exposed to body tissues, making it potentially suitable for applications such as wound dressing, prosthetics, and implantable electronics.”

The findings have been printed within the scientific journal Advanced Functional Materials in March.

Building a sponge from pollen

To kind the sponge, the NTU group first reworked the ultra-tough pollen grains from sunflowers right into a pliable, gel-like materials by way of a chemical course of akin to standard soap-making. 

This course of contains eradicating the sticky oil-based pollen cement that coats the grain’s floor, earlier than incubating the pollen in alkaline situations for 3 days. The ensuing gel-like materials was then freeze-dried.

These processes resulted within the formation of pollen sponges with 3D porous architectures. The sponges have been briefly heated to 200°C – a step that makes their kind and construction steady after repeatedly absorbing and releasing liquids. Heating additionally led to a two-fold enchancment within the sponge’s resistance to deformation, the scientists discovered.

To be sure that the sponge selectively targets oil and doesn’t soak up water, the scientists coated it with a layer of stearic acid, a kind of fatty acid discovered generally in animal and vegetable fats. This renders the sponge hydrophobic whereas sustaining its structural integrity.

The scientists carried out oil-absorption checks on the pollen sponge with oils and natural solvents of various densities, comparable to gasoline, pump oil, and n-hexane (a chemical present in crude oil). 

They discovered that the sponge had an absorption capability within the vary of 9.7 to over 29.3 g/g . This is comparable to industrial polypropylene absorbents, that are petroleum derivatives and have an absorption capability vary of 8.1 to 24.6 g/g.

They additionally examined the sponge for its sturdiness and reusability by repeatedly soaking it in silicone oil, then squeezing the oil out. They discovered that this course of may go on for no less than 10 cycles. 

In a ultimate proof-of-concept experiment, the group examined the flexibility of a sponge 1.5cm in diameter and 5mm in peak to soak up motor oil from a contaminated water pattern. The sponge readily absorbed the motor oil in lower than 2 minutes. 

“Collectively, these results demonstrate that the pollen sponge can selectively absorb and release oil contaminants and has similar performance levels to commercial oil absorbents while demonstrating compelling properties such as low cost, biocompatibility, and sustainable production,” stated Prof Cho, the corresponding writer of this research. 

Going ahead, the researchers plan to scale up the scale of pollen sponges to meet trade wants. They are additionally trying to collaborate with non-governmental organisations and worldwide companions to conduct pilot checks with pollen sponges in real-life environments. 

“We hope our innovative pollen materials can one day replace widely-used plastics and help to curb the global issue of plastic pollution,” stated Prof Cho.


Note to Editors:

Paper ‘Colloid-Mediated Fabrication of a 3D Pollen Sponge for Oil Remediation Applications’ printed in Advanced Functional Materials. 2021, 2101091.


Media contact:

Foo Jie Ying

Manager, Corporate Communications Office 

Nanyang Technological University

Email: [email protected]

About Nanyang Technological University, Singapore

A research-intensive public college, Nanyang Technological University, Singapore (NTU Singapore) has 33,000 undergraduate and postgraduate college students within the Engineering, Business, Science, Humanities, Arts, & Social Sciences, and Graduate faculties. It additionally has a medical college, the Lee Kong Chian School of Medicine, established collectively with Imperial College London.

NTU can be house to world-class autonomous institutes – the National Institute of Education, S Rajaratnam School of International Studies, Earth Observatory of Singapore, and Singapore Centre for Environmental Life Sciences Engineering – and varied main analysis centres such because the Nanyang Environment & Water Research Institute (NEWRI) and Energy Research Institute @ NTU ([email protected]).

Ranked amongst the world’s prime universities by QS, NTU has additionally been named the world’s prime younger college for the previous seven years. The University’s principal campus is ceaselessly listed among the many Top 15 most stunning college campuses on this planet and has 57 Green Mark-certified (equal to LEED-certified) buildings, of which 95% are licensed Green Mark Platinum. Apart from its principal campus, NTU additionally has a campus in Novena, Singapore’s healthcare district.

Under the NTU Smart Campus imaginative and prescient, the University harnesses the ability of digital know-how and tech-enabled options to help higher studying and residing experiences, the invention of recent information, and the sustainability of assets.

For extra data, go to http://www.ntu.edu.sg.


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