Development of 100% biodegradable paper straws that do not become soggy

Korea Research Institute of Chemical Technology (KRICT) developed 100% biodegradable, eco-friendly paper straws that do not become soggy, Paper published on『Advanced Science (IF:17.52)』

Peer-Reviewed Publication

NATIONAL RESEARCH COUNCIL OF SCIENCE & TECHNOLOGY

 

IMAGE: WHEN USED TO STIR A BEVERAGE IN A CUP, A PAPER STRAW IS FREQUENTLY BENT SLIGHTLY OR DELAMINATED. DUE TO ITS HIGH MECHANICAL RIGIDITY IN WATER, ECO-FRIENDLY PAPER STRAW WAS OBSERVED TO WITHSTAND A RELATIVELY HEAVY WEIGHT FOR 60 SECONDS UNDER WET CONDITION. view more 

CREDIT: KOREA RESEARCH INSTITUTE OF CHEMICAL TECHNOLOGY (KRICT)

Eco-friendly paper straws that do not easily become soggy and are 100% biodegradable in the ocean and soil have been developed. The straws are easy to mass-produce and thus are expected to be implemented in response to the regulations on plastic straws in restaurants and cafés.

 

The paper straws that are currently available are not entirely made of paper alone. Straws made with 100% paper become too soggy when they come in contact with liquids and cannot function as straws. Accordingly, their surface should be coated. The most commonly used coating materials for paper straws are polyethylene (PE) or acrylic resin—the same materials used for making plastic bags and adhesives. Paper cups are also coated with the same materials as paper straws. A large number of previous studies have reported that polyethylene coating on discarded paper cups can disintegrate into small particles without being fully decomposed and become microplastics. Moreover, these paper products are made with paper and plastics (two very different materials) and thus it is difficult to recycle them.

 

Conventional paper straws are inconvenient to use. Upon prolonged contact with a liquid, they become soggy. Also, when these straws are used to drink carbonated beverages, many bubbles may form owing to their surface properties. Currently, polylactic acid (PLA) straws and rice straws are available in the market as alternatives to paper straws. However, PLA straws—also known as corn plastic straws—do not decompose well in the ocean. While rice straws decompose well in the environment, they have disadvantages, including higher prices, due to difficulties in their mass-production and their sharp cross-sections.

 

The joint research team of Dr. Oh Dongyeop and Dr. Kwak Hojung of KRICT and Professor Park Jeyoung of Sogang University have developed eco-friendly paper straws that are 100% biodegradable, perform better than conventional paper straws, and can be easily mass-produced.

 

Using their technology, the research team synthesized a well-known biodegradable plastic, polybutylene succinate (PBS)*, by adding a small amount of cellulose nanocrystals to create a coating material. The added cellulose nanocrystals are the same material as the main component of paper, and this allows the biodegradable plastic to firmly attach to the paper surface during the coating process.

* PBS (polybutylene succinate): Polyester-based biodegradable bioplastic with similar properties to those of petroleum-based polypropylene.

 

Conventional paper straws do not incorporate a material that will strongly attach the plastic coating to the surface of the straws. The surface of the straws thus is not uniformly coated with plastic, impeding their use. The most significant limitations this creates are that the straws become soggy when a liquid touches the uncoated part and bubbles extensively form when paper straws are left in carbonated beverages. This is because the uncoated part easily combines with water, whereas the coated plastic part has the property of repelling water, causing the carbonated drink to contact the uneven surface of the paper straws.

 

These limitations are overcome by the new paper straws developed by our research team; they do not become soggy easily or cause bubble formation in carbonated drinks because the coating material uniformly and strongly covers the surface of the straws. Also, the coating material is made of paper and biodegradable plastic and therefore will decompose and degrade completely.

 

The research team found that these eco-friendly paper straws maintain their physical integrity in not only cold drinks but also hot drinks. The team also found that the straws did not become soggy when used to stir various beverages such as water, tea, carbonated drinks, milk, and other drinks containing lipids, or upon prolonged contact with liquids. The degree of sogginess of the as-prepared paper straws and conventional paper straws was compared. The conventional paper straw was severely bent when a weight of approximately 25g was suspended after the straw was dipped in cold water at 5°C for 1 min. In contrast, the as-prepared paper straw did not bend as much even when the weight was more than 50g under the same conditions.

 

The newly developed straws decompose well, even in the ocean. In general, paper or plastic decomposes much more slowly in the ocean than in soil because of the ocean’s low temperature and high salinity, which impede growth of microbes. The research team performed a decomposition test in a marine environment by immersing the straw samples at a depth of 1.5–2 m on the coast near Pohang, South Korea.

 

Regular plastic straws and corn plastic straws did not decompose after 120 days. Conventional paper straws preserved their shape and lost only 5% of their total weight. In contrast, the straws developed by the research team lost more than 50% of their weight after 60 days and decomposed completely after 120 days.

 

“This technology is but a small step toward the direction we need to take in this era of plastic. Turning a plastic straw we often use into a paper straw will not immediately impact our environment, but the difference will be profound over time. If we gradually change from using convenient disposable plastic products to various eco-friendly products, our future environment will be much safer than what we now worry about,” said the head researcher, Dr. Oh Dongyeop.

Degree of decomposition of the straw samples after being immersed in the ocean for 120 days. 

Conventional plastic straws and corn plastic straws did not decompose after 120 days under marine conditions. They have preserved their shape and lost only 5% of their total weight. In the meantime, eco-friendly straws developed by the research team lost more than 50% of their weight after 60 days and decomposed completely after 120 days.

CREDIT

Korea Research Institute of Chemical Technology (KRICT

Interview Q&A session with the [VIDEO] | 

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KRICT was established as a government-funded research institute in 1976. KRICT has played a leading role in the development of the national chemical industry as it developed technologies for chemical and related fields of convergence, transferred chemical technologies to industries, produced professionals in the chemical field, and provided tremendous support for a variety of chemical infrastructures. Now we promise to reach new heights in chemistry and chemical engineering and continue our role in facilitating increased use of the knowledge from research. For more information, please visit KRICT’s website at https://www.krict.re.kr/eng/

 

This achievement was supported by the Nano·Material Technology Development Program through the Ministry of Science and ICT, the Basic Science Research Program through KRICT, and the Biodegradable Bioplastics Commercialization and Demonstration Project through the Ministry of Trade, Industry and Energy.

The research results were published in the international academic journal Advanced Science (IF:17.52) under the title ‘Biodegradable, Water-resistant, Anti-fizzing, Polyester Nanocellulose Composite Paper Straws’ on November 21, 2022, and are accessible to the public.

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JOURNAL

Advanced Science

DOI

10.1002/advs.202205554 

ARTICLE TITLE

Biodegradable, Water-resistant, Anti-fizzing, Polyester Nanocellulose Composite Paper Straws

Passive radiative cooling can now be controlled electrically

Peer-Reviewed Publication

LINKÖPING UNIVERSITY

 

IMAGE: MINGNA LIAO PHOTOGRAPHED THROUGH THE SKY SIMULATOR BUILT BY THE RESEARCHERS. view more 

CREDIT: THOR BALKHED

Energy-efficient ways of cooling buildings and vehicles will be required in a changing climate. Researchers at Linköping University have now shown that electrical tuning of passive radiative cooling can be used to control temperatures of a material at ambient temperatures and air pressure. The results have been published in Cell Reports Physical Science.

"To cool buildings, for example, traditional air conditioning is mainly used today, which requires large amounts of energy and uses environmentally hazardous refrigerants. With the help of passive radiative cooling, the cold of outer space could be used to complement normal ACs and reduce energy consumption," says Magnus Jonsson, professor and leader of the Organic Photonics and Nano-Optics group at Linköping University.

Passive radiative cooling utilizes that thermal energy can leave an object in the form of infrared radiation. All objects emit heat as infrared light – trees, buildings, water and even humans. 

Different types of materials emit different amounts of infrared heat. This depends on the ability of the material to absorb infrared radiation – the better it is at absorbing infrared heat, the better the material is at emitting the heat. For example, ordinary white writing paper is good at absorbing infrared heat and, consequently, at emitting it. By contrast, metals are rather bad at it, as most of the heat is reflected.

Due to the atmosphere's ability to transmit light in the infrared wavelength range, coldness in outer space, where the temperature is about –270 degrees Celsius, can be used to remove heat from objects on earth. As a result of the temperature difference, there can be a net transport out. An object can therefore get a lower temperature than the ambient temperature with the help of passive radiative cooling.

This effect has been used far back in history, such as to make ice in warmer climates. However, in recent years, materials science research has taken an increasing interest in the phenomenon, and has developed new materials with a high capacity to emit infrared heat while not being warmed up by the rays of the sun. 

Researchers at Linköping University have now shown that the temperature of a device can be regulated by electrically tuning the extent to which it emits heat through passive radiative cooling. The concept uses a conducting polymer to electrochemically tune the emissivity of the device. 
The results have been published in the journal Cell Reports Physical Science.

"You can liken it to a thermostat. Currently, we can adjust the temperature by 0.25 degrees Celsius. It may not sound like much, but the point is that we have shown that it is possible to carry out this tuning at room temperature and normal pressure," says Debashree Banerjee, principal research engineer at Linköping University and principal author of the study.

The researchers believe that, now that they have shown that it is possible, there is potential to further develop both materials and devices. In the long term, it is possible to envisage systems that can be laid on a roof, much like a solar cell, thus controlling the infrared thermal radiation from the house and cooling when needed. The method requires extremely little energy consumption and causes minimal pollution. Other areas of application can also include tunable clothing and wallpaper to thermal flows and improve thermal comfort indoors at lowered energy consumption. 

In another study published in Advanced Science, the same research group has developed a thermoelectric device that is powered by the same principle of radiative cooling, also complemented by solar heating. It is based on generating a temperature difference between two cellulose materials, one of which contains carbon black to also absorb the heat of the sun. The materials are connected to a material that converts the temperature difference into an electrical potential. Exposing the device to the sky induced an electrical voltage of 60 mV already at moderate solar radiation, but the concept even works at night since the two wood-based materials are designed to have different abilities to radiate heat. 

"We use not only the sun, but also outer space as an energy source," says Mingna Liao, PhD doctoral student in the group and principal author of the article in Advanced Science.

In order to perform controlled measurements for both studies, the researchers built a sky simulator. In this way, the measurements were not affected by changes in the environment in the same way as they would be outdoors. The sky simulator consists of a tube with aluminium-coated sides that reflect the radiation. A receptacle placed at the bottom contains a material that absorbs the heat radiation and is cooled with liquid nitrogen to simulate the coldness of outer space. 

The research has been funded by the Knut and Alice Wallenberg Foundation, the Wallenberg Wood Science Center, the Swedish Defence Research Agency (FOI), the Swedish Research Council, and the strategic research area for Advanced Functional Materials (AFM) at Linköping University.

Debashree Banerjee (left) prepares a device with passive radiative cooling that can be controlled electrically. Magnus Jonsson in the middle and Mingna Liao in the background.

An electrically controllable passive radiant cooling device. It is based on a controllable conductive polymer on top of a porous paper with an electrolyte.

CREDIT

Thor Balkhed

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JOURNAL

Cell Reports Physical Science

DOI

10.1016/j.xcrp.2023.101274 

ARTICLE TITLE

Electrical Tuning of Radiative Cooling at Ambient Conditions

ARTICLE PUBLICATION DATE

1-Feb-2023

Kobe University and AGC successfully convert dry cleaning solvent into useful chemical compounds

Safe, simple and inexpensive: New organic synthesis method efficiently produces pharmaceutical intermediates and polyurethane from perchloroethylene

Peer-Reviewed Publication

KOBE UNIVERSITY

 

IMAGE: PHOTO-ON-DEMAND ORGANIC SYNTHESIS WITH PERCHLOROETHYLENE. view more 

CREDIT: AKIHIKO TSUDA

A collaboration between Associate Professor TSUDA Akihiko’s research group at Kobe University’s Graduate School of Science and AGC Incorporated has succeeded in synthesizing various useful compounds from perchloroethylene (also known as tetrachloroethylene), a solvent commonly used to dry clean clothes. The compounds they synthesized include pharmaceutical intermediates (trichloroacetamide, urea derivatives and urethane derivatives) as well as a novel polyurethane containing a fluoroalkyl group. These useful chemical compounds are vital building blocks for manufacturing medicines, plastics and other products.

Utilizing Kobe University’s previously invention: the ‘photo-on-demand’ organic synthesis method, the research collaboration developed a new photo-oxidation method (chemical reaction and process) for perchloroethylene. This simple, safe and low cost method places less burden on the environment and can efficiently synthesize the aforementioned useful compounds.

Perchloroethylene is already used in large quantities for dry cleaning and other applications. As the world moves towards carbon neutral efforts and sustainability, this research development has gained attention as a novel way of using perchloroethylene and as method for recycling chemicals.

Patents were filed in relation to these research findings in March 2019 (domestic) and March 2020 (international). The academic paper was published online in ACS Omega on January 4, 2023.

Main Points

• Successful joint research collaboration combined the strengths of Kobe University, with its photo-on-demand synthesis method, and AGC Inc.’s experience as a producer of perchloroethylene.
• They developed a new organic synthesis method using perchloroethylene as raw material for the synthesis of chemical products. Perchloroethylene is commonly used for dry cleaning clothes (In 2018, Japan exported 6300 tons and imported 20 tons. Source: The Chemical Daily Co., Ltd.).
• The research group succeeded in synthesizing a ~97% yield of trichloroacetamide (a precursor for pharmaceuticals and polymers) by merely irradiating a mixture of perchloroethylene and a reactant (amine) with light. They managed to synthesize 21 chemicals on a scale of up to ten grams (and this can be scaled up).
• Using the above product, they successfully synthesized 11 pharmaceutical urea derivatives, 8 urethane derivatives and 1 fluorinated polyurethane on a gram scale.
• Expensive specialized apparatus and agents are not required. These useful chemical products can be synthesized in large quantities on demand using light in a safe, inexpensive and simple manner, which has a low impact on the environment.
• This could be utilized as a new method of recycling perchloroethylene.
• It is hoped that this new chemical synthesis method will greatly contribute towards efforts to become carbon neutral and realize sustainable societies.

Research Background
Perchloroethylene is mainly used as a dry cleaning solvent and metal degreaser. Even though perchloroethylene is inflammable and chemically highly stable, various substances are produced if it is photo-oxidized under ultraviolet light. These include trichloroacetyl chloride, phosgene, carbon monoxide and chlorine (Figure 2). These substances are highly damaging to the environment due to their extremely toxic or corrosive properties, however they are valuable raw materials for organic synthesis. In light of current environmental pollution issues, the development of a method to recycle perchloroethylene would be beneficial. Despite this, there are hardly any examples of using photo-oxidation products specifically from perchloroethylene for organic synthesis.

Associate Professor Tsuda et al.’s research group were global pioneers in this regard, successfully synthesizing numerous useful chemical compounds using perchloroethylene’s photo-oxidation products. In 2012, they applied for a patent (patent number 5900920) and published a paper (Organic Syntheses with Photochemically Generated Chemicals from Tetrachloroethylene) on this innovation. However, there were two remaining issues with this previous method, one scientific and one safety-related, respectively: 1. The reaction efficiency was low, and 2. It was necessary to temporarily take the toxic and corrosive photo-oxidation products out of the reaction chamber to use them to synthesize the target compound. To resolve these issues, this research group began working with AGC Inc. This research collaboration between industry and academia led to the joint development of an organic synthesis method that could safely, inexpensively and easily turn perchloroethylene into high yields of organic chemical compounds at low cost to the environment.

Research Methodology
The researchers hoped that it would be possible to develop a novel organic synthesis method that resolved the previously mentioned safety issues. This would involve using a mixture of perchloroethylene and an amine, and would require an instant reaction to occur in situ between the perchloroethylene’s photo-oxidation products and the amine upon direct irradiation with ultraviolet light. However, the researchers hypothesized that perchloroethylene photooxidation would not occur based on the common scientific knowledge that amines absorb ultraviolet light. Even if the photoxidation did take place, they predicted that the subsequent reaction would not progress as hoped. This is because the hydrochloric acid (HCl) produced in the reaction between the photooxidation products and the amine would turn the amine into hydrochloride salt. In experiments under normal reaction conditions (below room temperature), the researchers found that the photooxidation of perchloroethylene proceeded slowly and the amine formed into hydrochloride salt at the same time. A long period of exposure caused part of the amine to photodecompose, resulting in strong coloration. These experiments showed that perchloroethylene photooxidation results in a highly complex series of chemical reactions.

Therefore, the research group heated a mixed solution of perchloroethylene and amine to over 70°C in the hope that (1) the gas-phase reaction rate would be increased by partially vaporizing the perchloroethylene and (2) the reaction would proceed even if the amine formed into hydrochloride salt. The researchers found that the expected reaction proceeded in a short amount of time and a single product was obtained.

Based on this discovery, the researchers synthesized ~97% yields of various N-Substituted Trichloroacetamides (NTCAs, which chemically protect isocyanates that serve as urethane precursors) (Figure 3). Therefore, it is thought that the mechanism behind perchloroethylene’s photooxidation is not merely a photooxidation reaction. Instead, it likely occurs as the result of a radical chain reaction caused by the chlorine radicals that are generated when the light cleaves the C-Cl bonds. The produced trichloroacetyl chloride instantly reacts in situ with amine and amine chloride, and this reaction is thought to be what causes NTCA to form.

The research group succeeded in synthesizing up to 10 grams of a total of 21 compounds including fluorinated ones, therefore this novel organic synthesis method can be applied to the production of a wide range of useful chemical compounds. Furthermore, it is possible to scale up the method merely by using larger reaction chamber.

The obtained NTCAs can be converted into urea derivatives and urethane derivatives through base-catalyzed substitution reactions with amines or alcohols. These reactions also produce chloroform as a by-product (which could be used as a recycled solvent or as a chemical precursor). It is thought that NTCA decomposes into isocyanates and then the subsequent addition of amines or alcohols progresses the reaction. In one application of this chemical reaction, the researchers successfully synthesized a new fluoroalkyl polyurethane from an NTCA containing fluorine. Fluoroalkyl compounds tend to have water repellent, oil repellent, flame retardant and weather resistant properties.

Further Research
Using the photo-on-demand synthesis method, the research group were able to synthesize various organic chemical compounds (including urea derivatives, urethane derivatives and polyurethane) from a solution of perchloroethylene and amine in a safe, inexpensive and relatively environmentally friendly manner. To develop this photoreaction method even further, Professor Tsuda et al. are currently using a flow reaction system in their efforts to develop a continuous organic synthesis method. With its potential to contribute towards the realization of a sustainable society, this research accomplishment is expected to be utilized in the future as a novel way of using the abundant chemical perchloroethylene and as a method to recycle chemicals.

Photochemical oxidation of perchloroethylene.

CREDIT

Akihiko Tsuda

Synthetic scheme for valuable organic compounds with the photooxidation products of perchloroethylene. DBU: Organic strong base

CREDIT

Akamatsu T.; Shele M.; Matsune A.; Kashiki Y.; Liang F.; Okazoe T.; Tsuda A.; Photo-on-Demand In Situ Synthesis of N-Substituted Trichloroacetamides with Tetrachloroethylene and Their Conversions to Ureas, Carbamates, and Polyurethanes, ACS Omega 2023, 8, 2, 2669–268

Acknowledgements
This research was supported by the Adaptable and Seamless Technology Transfer Program through Target-driven R&D (A-STEP) (seeds development type/academia and industry collaboration phase) from the Japan Science and Technology Agency (JST): ‘Developing highly functional and high added value polyurethane-materials through safe production processes using fluoroalkyl carbonates as key intermediates’ (Principle Researcher: Akihiko Tsuda).

Patent Information
Presentation Title: Method for Producing N-Substituted Trichloroacetamides
Patent application no. : 2019-060647 (Date of application: March 27, 2019).
International patent application no.: PCT/JP2020/013124 (Date of application: March 24, 2020).
Patent publication no.: WO/2020/196553 A1 (Date of publication: October 1, 2020).
Presenters: Akihiko Tsuda, Takashi Okazoe, Hiroshi Wada, Yoshitaka Sunayama, and Toshifumi Kakiuchi
Applicants: Kobe University and AGC Inc.

Journal Information
Title:
Photo-on-Demand In Situ Synthesis of N-Substituted Trichloroacetamides with Tetrachloroethylene and Their Conversions to Ureas, Carbamates, and Polyurethanes
DOI: doi.org/10.1021/acsomega.2c07233
Authors:
Toshiki Akamatsu1,§, Muge Shele1,§, Ayako Matsune1, Yoshiyuki Kashiki1, Fengying Liang1, Takashi Okazoe2, Akihiko Tsuda*,1
*Corresponding author, §equal contribution
1. Graduate School of Science, Kobe University
2. AGC Inc.
Journal:
ACS Omega

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JOURNAL

ACS Omega

DOI

10.1021/acsomega.2c07233 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Photo-on-Demand In Situ Synthesis of N-Substituted Trichloroacetamides with Tetrachloroethylene and Their Conversions to Ureas, Carbamates, and Polyurethanes

ARTICLE PUBLICATION DATE

4-Jan-2023

COI STATEMENT

The authors declare the following competing financial interest(s): This research was funded by AGC Inc.

Seawater split to produce green hydrogen

Peer-Reviewed Publication

UNIVERSITY OF ADELAIDE

Researchers have successfully split seawater without pre-treatment to produce green hydrogen.

The international team was led by the University of Adelaide’s Professor Shizhang Qiao and Associate Professor Yao Zheng from the School of Chemical Engineering.

“We have split natural seawater into oxygen and hydrogen with nearly 100 per cent efficiency, to produce green hydrogen by electrolysis, using a non-precious and cheap catalyst in a commercial electrolyser,” said Professor Qiao.

A typical non-precious catalyst is cobalt oxide with chromium oxide on its surface.

“We used seawater as a feedstock without the need for any pre-treatment processes like reverse osmosis desolation, purification, or alkalisation,” said Associate Professor Zheng.

“The performance of a commercial electrolyser with our catalysts running in seawater is close to the performance of platinum/iridium catalysts running in a feedstock of highly purified deionised water.

The team published their research in the journal Nature Energy.

“Current electrolysers are operated with highly purified water electrolyte. Increased demand for hydrogen to partially or totally replace energy generated by fossil fuels will significantly increase scarcity of increasingly limited freshwater resources,” said Associate Professor Zheng.

Seawater is an almost infinite resource and is considered a natural feedstock electrolyte. This is more practical for regions with long coastlines and abundant sunlight. However, it isn’t practical for regions where seawater is scarce.

Seawater electrolysis is still in early development compared with pure water electrolysis because of electrode side reactions, and corrosion arising from the complexities of using seawater.

“It is always necessary to treat impure water to a level of water purity for conventional electrolysers including desalination and deionisation, which increases the operation and maintenance cost of the processes,” said Associate Professor Zheng.

“Our work provides a solution to directly utilise seawater without pre-treatment systems and alkali addition, which shows similar performance as that of existing metal-based mature pure water electrolyser.”

The team will work on scaling up the system by using a larger electrolyser so that it can be used in commercial processes such as hydrogen generation for fuel cells and ammonia synthesis.

Researchers have successfully split seawater without pre-treatment to produce green hydrogen.

The international team was led by the University of Adelaide’s Professor Shizhang Qiao and Associate Professor Yao Zheng from the School of Chemical Engineering.

“We have split natural seawater into oxygen and hydrogen with nearly 100 per cent efficiency, to produce green hydrogen by electrolysis, using a non-precious and cheap catalyst in a commercial electrolyser,” said Professor Qiao.

A typical non-precious catalyst is cobalt oxide with chromium oxide on its surface.

“We used seawater as a feedstock without the need for any pre-treatment processes like reverse osmosis desolation, purification, or alkalisation,” said Associate Professor Zheng.

“The performance of a commercial electrolyser with our catalysts running in seawater is close to the performance of platinum/iridium catalysts running in a feedstock of highly purified deionised water.

The team published their research in the journal Nature Energy.

“Current electrolysers are operated with highly purified water electrolyte. Increased demand for hydrogen to partially or totally replace energy generated by fossil fuels will significantly increase scarcity of increasingly limited freshwater resources,” said Associate Professor Zheng.

Seawater is an almost infinite resource and is considered a natural feedstock electrolyte. This is more practical for regions with long coastlines and abundant sunlight. However, it isn’t practical for regions where seawater is scarce.

Seawater electrolysis is still in early development compared with pure water electrolysis because of electrode side reactions, and corrosion arising from the complexities of using seawater.

“It is always necessary to treat impure water to a level of water purity for conventional electrolysers including desalination and deionisation, which increases the operation and maintenance cost of the processes,” said Associate Professor Zheng.

“Our work provides a solution to directly utilise seawater without pre-treatment systems and alkali addition, which shows similar performance as that of existing metal-based mature pure water electrolyser.”

The team will work on scaling up the system by using a larger electrolyser so that it can be used in commercial processes such as hydrogen generation for fuel cells and ammonia synthesis.

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JOURNAL

Nature Energy

DOI

10.1038/s41560-023-01195-x 

ARTICLE TITLE

Direct seawater electrolysis by adjusting the local reaction environment of a catalyst

ARTICLE PUBLICATION DATE

30-Jan-2023

Ancient fossils shed new light on evolution of sea worm

Peer-Reviewed Publication

DURHAM UNIVERSITY

 

IMAGE: COMPLETE SPECIMEN OF THE CAMBRIAN CAGE WORM IOTUBA FROM THE CHENGJIANG FOSSIL DEPOSIT. view more 

CREDIT: CREDIT: ZHANG ZHIFEI

Ancient fossils shed new light on evolution of sea worm 

-With pictures-

Ancient fossils have shed new light on a type of sea worm linking it to the time of an evolutionary explosion that gave rise to modern animal life.

Researchers at Durham University, UK, and Northwest University, Xi’an, China, examined 15 exceptionally preserved fossils of the annelid worm Iotuba chengjiangensis dating from the early Cambrian period 515 million years ago.

The fossilised remains included evidence of the worms’ guts and kidneys and revealed they had an unexpectedly complex structure similar to that of other annelid worms.

The researchers say this means that annelids – or segmented worms – diversified into different lineages some 200 million years earlier than previously thought and were part of the evolutionary leap known as the Cambrian explosion.

The Cambrian explosion saw a huge rise in organisms between 540 and 530 million years ago – as shown by fossil records – and saw the appearance of many of the major groups that make up animal life on Earth.

The findings are published in the journal Proceedings of the Royal Society B.

Study co-author Dr Martin R. Smith, in the Department of Earth Sciences, Durham University, said: “We know that the main animal lines we see today emerged during the Cambrian explosion, but we always thought annelid worms were late to the party, and their major subgroups didn’t begin to diversify until nearly 200 million years later.

“But the amazingly preserved fossils we have studied and the structure of these amazing little creatures challenge this picture, and show that annelid worms – including Iotuba chengjiangensis – seemed to follow the pattern of events initiated by the Cambrian explosion.

“Detailed fossils of this type of worm are extremely rare, so it was great to be able to study the fossilised record of this tiny animal in such detail.

“It turns out they weren’t late to the party at all, they were just hiding in a side room.”

The researchers say that Iotuba chengjiangensis was a cage worm able to move its head in and out of a cage made of bristly spines.

This makes the worm a close relative of families of annelid sea worms such as Flabelligeridae and Acrocirridae.

Dr Smith added: “These families are like the top rungs on an evolutionary ladder. For these groups to have appeared so early in the day, there must have been a dramatic unseen origin of modern annelid diversity in the heat of the Cambrian explosion.

“It turns out that many of the annelids we know and love today may have begun to evolve much sooner than we think.”

Research lead author Dr Zhifei Zhang, Northwest University, Xi'an, China said: “Annelids are one of the largest and most successful phyla of animals that are flourishing in both terrestrial and marine ecosystems with the most diversified living lineage, Polychaeta, living in the sea.

“The most well-known are, for example, earth worms, leeches and clam worms. There are also at least 20,000 species and 80 families of Polychaete in the modern sea.

“However, their earliest geological records of fossils in Cambrian deposits, even in the well-known Konservat-Lagerstätten are quite rare.

“Is this because the delicate worms didn’t exist, or simply didn’t preserve? Our research gives the first insightful answer: biodiversification of the segmented worms occurs much earlier than thought before.”

The research was funded by the National Natural Science Foundation of China and Changjiang Scholars Program of the Chinese Ministry of Education.

ENDS

Artist's reconstruction of Iotuba – complete organism.

Artist's reconstruction of Iotuba, showing front of body with everted head (with branchial filaments and mouth) surrounded by cage of spines (chaetae).

Head-on reconstruction of Iotuba, showing cage of spines (chaetae) surrounding everted head, with branchial filaments and mouth.

CREDIT

Credit: Zhang Zhifei

Specimen of the Cambrian cage worm Iotuba from the Chengjiang fossil deposit.

CREDIT

Credit: Martin R. Smith

JOURNAL

Proceedings of the Royal Society B Biological Sciences

DOI

10.1098/rspb.2022.2014 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

The Cambrian cirratuliform Iotuba denotes an early annelid radiation

ARTICLE PUBLICATION DATE

1-Feb-2023