HOCHLEITNER - INSIGHTS #Antifouling paints

Development of Anti-fouling Coating Using in Marine Environment

Wed, 18 May 2022 22:58:00 +0000

Chen Liu. Development of Anti-fouling Coating Using in Marine Environment. International Journal of Environmental Monitoring

The marine organism attaching to the ship hull would slow down the ship and increasing fuel consumption. In order to prevent the problem, anti-fouling paints are used to coat the bottoms of ships. At the same time, the harmful environmental effects of these paints such as tributyltin have been recognized. The International Convention on the Control of Harmful Anti-fouling Systems on Ships was adopted by the IMO in 2001 to prohibit the use of harmful organotins in anti-fouling paints used on ships. As the invention entered into force internationally, the most important work is to develop new material to replace the traditional coating. In this work, we summarize the development of anti-fouling paints all over the world and introduce the progress of the latest research.

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MARINE BIOFOULING TESTING

Wed, 18 May 2022 22:58:00 +0000

MARINE BIOFOULING TESTING:TECHNICAL CONSIDERATIONS ON METHODS,SITE SELECTION AND DYNAMIC TESTS

There is need to optimize testing protocols for marine coatings and develop improved accelerated test systems that best simulate the erosion process on marine paints as ships travel. The selection of a marine environment with aggressive biofouling conditions is necessary to obtain early results on the performance of experimental antifouling coatings. Simulation of the erosion of the coatings on the hull is an important tool in evaluating the efficacy of novel formulations.
Procedures in marine exposure testing, criteria in the selection of ideal sites with aggressive fouling conditions and a proposal for a modified dynamic test system are described.

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Innovative paint solution to help protect ships from marine biofouling

Tue, 08 Mar 2022 22:41:00 +0000

European researchers have pioneered an ecologically friendly and sustainable antifouling paint solution that is based neither on biocide emission nor low adhesion.

The EU-funded Low Emission Antifouling (LEAF) project has developed an environmentally- friendly and fully sustainable prototype paint to minimise the damage to cruising ships and static constructions from marine biofouling.

The presence of micro and macroscopic fouling organisms, such as barnacles, on a ship's hull can become a major challenge for seafarers. As they multiply, they build up calcium deposits under a boat's paint, which in turn interferes with smooth fluid flow and can decrease fuel efficiency by up to 40 %, as well as result in higher carbon emissions. This is a major problem in particular for larger vessels and marine constructions.

Traditionally, a biocide-based poison, such as copper oxide, has been applied to hull paint to kill any fouling organisms attached, with 90 % of the world's marine fleet being coated in such a copper-based antifouling system.

However, coating a ship's hull in such a substance significantly increases the risk of toxins being released into the surrounding water, killing other marine life. Additionally, low adhesion coatings suffer from drawbacks of low durability and associated high material and maintenance costs.

In order to significantly reduce ecological damage and provide a solution that is both sustainable and cost-efficient, the innovative approach taken by the LEAF project does not rely on the exposure and release of biocides into the water.

Instead, the prototype paint's antifouling effect is based on the direct contact of a fouling organism with biocide that resides within the coating itself. This will also have the additional benefit of providing longer service life and fewer maintenance costs.

Promising tests held across European waters

After less than three years of development and testing in both the lab and in the field, the LEAF project has recorded successful results over the sustainability and durability of the prototype paint. Highly promising tests have been conducted in Scandinavian, Mediterranean and Caribbean waters.

During a test that took place in Grado's Lagoon, Italy, the hull of a boat that had been launched two and a half months earlier was fully colonised by tubeworms, indicating a high fouling pressure. Additionally, the white paint on the engine anchoring structures was suffering from significant marine biofouling.

Following the application of the prototype LEAF paint, in the same warm waters of the lagoon, the result three weeks later showed that the boat had a high level of antifouling efficacy. The boat owner also confirmed that the LEAF paint performed substantially better than the commercial products that had been used in previous seasons.

Additionally, human exposure and aquatic risk assessments performed within the project have shown that the LEAF paint is likely to comply with the most stringent global regulation systems, such as the European Biocidal Products Regulation (BPR).

The LEAF team is now currently working with external partners on the next steps required to fully commercialise the new technology and successfully bring it to market for all interested end-users.

Paints and coatings containing bactericidal agent nanoparticles combat marine fouling

Thu, 24 Feb 2022 22:57:00 +0000

Scientists have discovered that tiny vanadium pentoxide nanoparticles can inhibit the growth of barnacles, bacteria, and algae on surfaces in contact with water, such as ship hulls, sea buoys, or offshore platforms. Their experiments showed that steel plates to which a coating containing dispersed vanadium pentoxide particles had been applied could be exposed to seawater for weeks without the formation of deposits of barnacles, bacteria, and algae.

Scientists at Johannes Gutenberg University Mainz (JGU) in Germany have discovered that tiny vanadium pentoxide nanoparticles can inhibit the growth of barnacles, bacteria, and algae on surfaces in contact with water, such as ship hulls, sea buoys, or offshore platforms. Their experiments showed that steel plates to which a coating containing dispersed vanadium pentoxide particles had been applied could be exposed to seawater for weeks without the formation of deposits of barnacles, bacteria, and algae. In comparison, plates that were coated only with the ship's normal paint exhibited massive fouling after exposure to seawater for the same period of time. The discovery could lead to the development of new protective, antifouling coatings and paints that are less damaging to the environment than the ship coatings currently used.

Marine fouling is a problem that costs the shipping industry more than 200 billion dollars per year. The accumulation of organisms such as algae, mussels, and barnacles increases the objects' water resistance and, in consequence, fuel consumption. This means additional costs for shipping companies and, even worse, increased environmental damage due to extra CO2 emissions. Within only a few months, an underwater boat hull can be completely covered and overgrown with organisms. According to Lloyds, this means an increase in fuel consumption of up to 28 percent and about 250 million tons of additional CO2 emissions per year. While it is possible to counteract this effect to some extent by means of the use of antifouling paints, conventional biocides are less effective and can have adverse environmental consequences. In addition, microorganisms can develop resistance to them.

It was one of nature's own defense mechanisms that provided the inspiration for the approach now taken by the team of scientists working under Professor Dr. Wolfgang Tremel of the Institute of Inorganic Chemistry and Analytical Chemistry at JGU. Certain enzymes found in brown and red algae produce halogen compounds that have a biocidal potential. It is assumed that these are synthesized by the algae to protect them against microbial attack and predators. The chemists at Mainz University decided to mimic this process using vanadium pentoxide nanoparticles. According to their article published in Nature Nanotechnology, vanadium pentoxide (V2O5) nanoparticles have "an intrinsic biomimetic bromination activity […] which makes them a practical and cost-efficient alternative for conventional chemical biocides." Vanadium pentoxide functions as a catalyst so that hydrogen peroxide and bromide combine to form small quantities of hypobromous acid, which is highly toxic to many microorganisms and has a pronounced antibacterial effect. The required reactants are present in seawater: This already contains bromide ions, while small quantities of hydrogen peroxide are formed when it is exposed to sunlight.

The process has been demonstrated both under laboratory conditions and in natural seawater. It has only very minimal consequences for the environment because the effect is restricted to micro-surfaces. The metallic oxide is particularly potent when it is present in the form of nanoparticles because then, due to the larger surface area, there is an enhanced catalytic effect.

"Vanadium pentoxide nanoparticles, due to their poor solubility and the fact that they are embedded in the coating, are considerably less toxic to marine life than are the tin- and copper-based active substances used in the commercially available products," explains Wolfgang Tremel. In his view, ships' coatings based on vanadium pentoxide could be a practical and cost-effective alternative to conventional chemical biocides. "Here we have an environmentally-compatible component for a new generation of antifouling paints that employ the natural defense mechanism used by marine organisms."

Ron Wever, the team's Dutch cooperation partner from the University of Amsterdam, has been investigating such natural defense mechanisms for the last 15 years. He suggested adding the enzyme involved, i.e., vanadium haloperoxidase, to antifouling paints. The chemists in Mainz are now working together with Wever to develop vanadium pentoxide nanoparticles. "Vanadium pentoxide particles are considerably cheaper and also more stable than genetically produced enzymes," he adds.

A research group headed by Dr. Klaus Peter Jochum of the Max Planck Institute for Chemistry in Mainz has been conducting experiments to determine whether the use of vanadium pentoxide might have a negative effect on the environment. Using a highly sensitive ICP mass spectrometer, the scientists determined the concentration of vanadium in various samples of seawater that had been exposed to the coated material for different lengths of time. The results showed that levels were only slightly elevated above the normal average vanadium concentration in seawater. It can thus be concluded that only very tiny amounts of vanadium migrate from the coating into seawater and will thus have no negative impact on the environment.

Journal Reference:

Filipe Natalio, Rute André, Aloysius F. Hartog, Brigitte Stoll, Klaus Peter Jochum, Ron Wever, Wolfgang Tremel. Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation. Nature Nanotechnology, 2012; DOI: 10.1038/NNANO.2012.91

Ships may soon be able to shed bacteria and marine growth

Tue, 15 Feb 2022 23:07:00 +0000

Duke University engineers have developed a material that can be applied like paint to the hull of a ship and will literally be able to dislodge bacteria, keeping it from accumulating on the ship's surface. This buildup on ships increases drag and reduces the energy efficiency of the vessel, as well as blocking or clogging undersea sensors.

The material works by physically moving at the microscopic level, knocking the bacteria away. This avoids the use of bacteria-killing paints, which can contain heavy metals or other toxic chemicals that might accumulate in the environment and unintentionally harm fish or other marine organisms.

The Duke researchers also say that similar types of materials could be used in other settings where the buildup of bacteria -- known as biofilms -- presents problems, such as on the surfaces of artificial joint implants or water purification membranes.

"We have developed a material that 'wrinkles,' or changes it surface in response to a stimulus, such as stretching or pressure or electricity," said Duke engineer Xuanhe Zhao, assistant professor in Duke's Pratt School of Engineering. "This deformation can effectively detach biofilms and other organisms that have accumulated on the surface."

The results of the Duke studies were published online in the journal Advanced Materials.

Zhao has already demonstrated the ability of electric current to deform, or change, the surface of polymers.

"Nature has offered many solutions to deal with this buildup of biological materials that we as engineers can try to recreate," said Gabriel López, professor of biomedical engineering and mechanical engineering and materials science. He also serves as director of Research Triangle Materials Research Science and Engineering Center (MRSEC), which is funded by the National Science Foundation.

"For example, the hair-like structures known as cilia can move foreign particles from the lungs and respiratory tract," Lopez said. "In the same manner, these types of structures are used by mollusks and corals to keep their surfaces clean. To date, however, it is been difficult to reproduce the cilia, but controlling the surface of a material could achieve the same result."

The researchers tested their approach in the laboratory with simulated seawater, as well as on barnacles. These experiments were conducted in collaboration with Daniel Rittschof the Duke University Marine Lab in Beaufort, N.C.

Keeping bacteria from attaching to ship hulls or other submerged objects can prevent a larger cascade of events that can reduce performance or efficiency. Once they have taken up residence on a surface, bacteria often attract larger organisms, such as seaweed and larva of other marine organisms, such as worms, bivalves, barnacles or mussels.

"It is known that bacterial films can recruit other organisms, so stopping the accumulation process from the beginning in the first place would make a lot of sense," Lopez said.

The project is funded by the U.S. Office of Naval Research and the MRSEC. Other members of the Duke team are Phanindhar Shivapooja, Qiming Wang and Beatriz Orihuela.

Journal Reference:

Phanindhar Shivapooja, Qiming Wang, Beatriz Orihuela, Daniel Rittschof, Gabriel P. López, Xuanhe Zhao. Bioinspired Surfaces with Dynamic Topography for Active Control of Biofouling. Advanced Materials, 2013; DOI: 10.1002/adma.201203374

Marine paints: The particular case of antifouling paints

Sun, 13 Feb 2022 22:27:00 +0000

Elisabete Almeida^,Teresa C. Diamantino^,Orlando de Sousa

Abstract

The authors present a general overview of marine paints, paying particular attention to the case of antifouling paints. After locating these paints in the anticorrosive protection systems used on the underwater parts of ships and/or other moving structures, a summary is made of the main types of antifouling products used through history up to the present time. This is complemented by a systematic assessment of the main types of living organisms that fix themselves to the underwater parts of ships. Consideration is also briefly made of the main basic mechanisms by which the different types of antifouling paints work. Finally a number of current research lines on antifouling technologies are mentioned.