Tag Archives: water-repellen

Oil-absorbing hairy fern leaves lead to ‘nanofur’ for oil spill cleanups

German researchers have developed a biomimetic material branded as ‘nanofur’ for oil spill cleanups, according to an Aug. 23, 2016 news item on Nanowerk (Note: A link has been removed),

Some water ferns can absorb large volumes of oil within a short time, because their leaves are strongly water-repellent and, at the same time, highly oil-absorbing. Researchers of Karlsruhe Institute of Technology, together with colleagues of Bonn University, have found that the oil-binding capacity of the water plant results from the hairy microstructure of its leaves (Bioinspiration & Biomimetics, “Microstructures of superhydrophobic plant leaves – inspiration for efficient oil spill cleanup materials”). It is now used as a model to further develop the new Nanofur material for the environmentally friendly cleanup of oil spills.

An Aug.(?) 23 (?), 2016 Karlsruhe Institute of Technology (KIT) press release on EurekAlert, which originated the news item, explains the interest in improving technology for oil spill cleanups and provides insight into this  innovation,

Damaged pipelines, oil tanker disasters, and accidents on oil drilling and production platforms may result in pollutions [sic] of water with crude or mineral oil. Conventional methods to clean up the oil spill are associated with specific drawbacks. Oil combustion or the use of chemical substances to accelerate oil decomposition cause secondary environmental pollution. Many natural materials to take up the oil, such as sawdust or plant fibers, are hardly effective, because they also absorb large amounts of water. On their search for an environmentally friendly alternative to clean up oil spills, the researchers compared various species of aquatic ferns. “We already knew that the leaves of these plants repel water, but for the first time now, we have studied their capacity to absorb oil,” Claudia Zeiger says. She conducted the project at KIT’s Institute of Microstructure Technology.

Damaged pipelines, oil tanker disasters, and accidents on oil drilling and production platforms may result in pollutions of water with crude or mineral oil. Conventional methods to clean up the oil spill are associated with specific drawbacks. Oil combustion or the use of chemical substances to accelerate oil decomposition cause secondary environmental pollution. Many natural materials to take up the oil, such as sawdust or plant fibers, are hardly effective, because they also absorb large amounts of water. On their search for an environmentally friendly alternative to clean up oil spills, the researchers compared various species of aquatic ferns. “We already knew that the leaves of these plants repel water, but for the first time now, we have studied their capacity to absorb oil,” Claudia Zeiger says. She conducted the project at KIT’s Institute of Microstructure Technology.

Aquatic ferns originally growing in tropical and subtropical regions can now also be found in parts of Europe. As they reproduce strongly, they are often considered weed. However, they have a considerable potential as low-cost, rapid, and environmentally friendly oil absorbers, which is obvious from a short video (see below). ”The plants might be used in lakes to absorb accidental oil spills,” Zeiger says. After less than 30 seconds, the leaves reach maximum absorption and can be skimmed off together with the absorbed oil. The water plant named salvinia has trichomes on the leaf surface – hairy extensions of 0.3 to 2.5 mm in length. Comparison of different salvinia species revealed that leaves with the longest hairs did not absorb the largest amounts of oil. “Oil-absorbing capacity is determined by the shape of the hair ends,” Zeiger emphasizes. The largest quantity of oil was absorbed by leaves of the water fern salvinia molesta, whose hair ends are shaped like an eggbeater.

Based on this new knowledge on the relationship between surface structure of leaves and their oil-absorbing capacity, the researchers improved the ‘Nanofur’ material developed at their institute. This plastic nanofur mimics the water-repellent and oil-absorbing effect of salvinia to separate oil and water. “We study nanostructures and microstructures in nature for potential technical developments,” says Hendrik Hölscher, Head of the Biomimetic Surfaces Group of the Institute of Microstructure Technology of KIT. He points out that different properties of plants made of the same material frequently result from differences of their finest structures.

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

Microstructures of superhydrophobic plant leaves – inspiration for efficient oil spill cleanup materials by Claudia Zeiger, Isabelle C Rodrigues da Silva, Matthias Mail, Maryna N Kavalenka, Wilhelm Barthlott, and Hendrik Hölscher. Bioinspiration & Biomimetics, Volume 11, Number 5 DOI: http://dx.doi.org/10.1088/1748-3190/11/5/056003

Published 16 August 2016, © 2016 IOP Publishing Ltd

This article appears to be open access.

There is also a video demonstration of the material,

Enjoy!