PLASTICS
Oct 6, 2021
Business Insider
Presented by BASF
A company in Nairobi wants to install bricks made from plastic trash across Kenya’s capital. Could they become a solution for a country where 90% of roads have never been paved? And are roads made from plastic really a good idea?
Commercially viable production of climate-neutral plastic is possible
Peer-Reviewed PublicationSince the early 1950s, plastics have found their way into almost every area of modern life. Between 1964 and 2014, plastic consumption increased twentyfold, from 15 to 311 million tonnes per year. Not only has environmental pollution from plastic waste increased during this time, but the amount of petroleum its manufacture consumes is large, as are the associated greenhouse gas emissions.
Researchers from ETH Zurich, RWTH Aachen University and the University of California, Santa Barbara have created a new computational model of global plastic production and disposal. The team was led by André Bardow, formerly of RWTH Aachen University and now Professor of Energy and Process Systems Engineering at ETH Zurich. With their model, the scientists demonstrate that it is possible to economically produce plastics that have a net-zero greenhouse gas emissions balance over their entire life cycle.
This is made possible by a clever combination of three technologies that already exist: plastic recycling and plastic production from biomass and from CO2 through carbon capture and utilisation (CCU). The researchers published their study in the latest issue of the journal Science [https://doi.org/10.1126/science.abg9853].
Increased plastic recycling
As the calculations showed, the key is to use as much recycled plastic as possible, supplemented by the other two manufacturing methods. These three types of manufacturing correspond to the principle of the circular economy. By optimally combining the three technologies, the quantity of energy required can be reduced by 34 to 53 percent compared with the current fossil-based manufacturing practice, supplemented with extensive carbon capture and storage (CCS) – particularly in waste incineration plants, where plastic products are burned at the end of their life cycle.
The cost of the newly proposed manufacturing method is on a par with that of this alternative fossil manufacturing scenario. Under favourable conditions, by 2050 the cost of global plastic production can be reduced by as much as 288 billion dollars per year compared to the alternative scenario. To achieve this, biomass, CO2 and renewable electricity must be available at low cost, the extraction and supply of petroleum must become more expensive, and incentives must be provided for investment in recycling. “The lower energy demand may seem counterintuitive, but it results from the amount of energy that recycling saves over the entire life cycle,” ETH Professor Bardow says.
Policymakers can promote the path to climate-neutral plastics by offering incentives for more plastic recycling and increased use of biomass and CCU, the authors conclude in the study. “We shouldn’t think of the different technologies for plastic manufacture individually, because there is great potential in combining them in a clever way,” Bardow says.
This text is a revised version of a press release from RWTH Aachen University.
JOURNAL
Science
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Commercially viable production of climate-neutral plastic is possible
ARTICLE PUBLICATION DATE
30-Sep-2021
Effective deconstruction of polyurethane by catalyst based on earth-abundant metal
New manganese-based catalyst shows to be efficient in the recycling of polyurethane (PU), which paves the way for the circular plastic economy for PU.
Peer-Reviewed PublicationIMAGE: RESEARCHERS FROM AARHUS UNIVERSITY AND THE REPURPOSE PROJECT DEVELOP AN EFFECTIVE METHOD FOR THE DECONSTRUCTION OF POLYURETHANE BY USING A CATALYST BASED ON MANGANESE, AN EARTH-ABUNDANT METAL. view more
CREDIT: ILLUSTR.: CHEMSUSCHEM, SEP 12, 2021
Polyurethane (PU) is one of the most versatile thermoset synthetic polymers which through careful choice of monomer and formulation, can be seen in a myriad of different forms ranging from rigid-, flexible and molded foams to adhesives and elastomers just to name a few. Through its many forms, PU is seen in a plethora of different product like shoes, mattresses, and insolation material but also in more sophisticated products like wind turbine blades and components within aircrafts and cars. With a global production estimated to be above 22 million tons, increasing demand and production results in an ever-increasing amount of PU-waste, but here, the lack of good recycling methods means that most PU is send for energy recovery through incineration or is landfilled.
New research by the RePURpose consortium in ChemSusChem spearheaded by Prof Troels Skrydstrup and Ass. Prof. Steffan Kvist Kristensen has now shown that commercial and end-of-life PU-materials can be depolymerized into monomeric building blocks through chemical recycling. Where current PU‑recycling methods generate a secondary PU-material with other characteristics than the original material, this newly developed methodology has the potential to create virgin polymeric material with the same characteristics as the original material.
In the present study, researchers from the Interdisciplinary Nanoscience Center, iNANO, and Department of Chemistry at Aarhus University, reports that a catalytic system based on the earth-abundant base metal manganese, dihydrogen and isopropyl alcohol is effective for deconstructing different PU-materials into a polyol and an amine fraction representing the original monomeric compositions. The authors go to show, that the system can be used on gram scale even at low catalyst loading without diminishing the activity.
In an effort to reduce our plastic footprint and dependency on fossil fuels a change from the current linear model (make-use-dispose) towards a circular plastic economy, where PU is produced, used, recovered and recycled into new PU-materials is needed. The usage of an earth-abundant metal, a green solvent and the potential adaption towards green hydrogen could pave the way towards a circular plastic economy for PU.
For more information go to www.repurpose.nu.
READ ALSO: Newly found way to recycle polyurethane, a ubiquitous though complicated plastic material
CAPTION
The new method for recycling PU is based on a first row transition metal catalyst, a green and cheap base, and a green solvent.
CREDIT
Illustr.: Lise R. L. Pedersen
Read the scientific article in ChemSusChem:
”Evaluation of Manganese Catalysts for the Hydrogenative Deconstruction of Commercial and End-of-Life Polyurethane Samples” by Laurynas Gausas, Bjarke Donslund, Steffan Kristensen, and Troels Skrydstrup. ChemSusChem. 2021.
The research has been carried out by scientists from Interdisciplinary Nanoscience Centre (iNANO) and Department of Chemistry at Aarhus University in collaboration with the RePURpose consortium, incl. Plixxent A/S, T. Dan-Foam ApS, ECCO SKO A/S, H. J. Hansen Genvindingsindustri A/S, Logstor A/S, N. Tinby A/S, and the Danish Technological Institute. Professor Troels Skrydstrup is in charge of the research team behind the study.
The work was generously supported by the Carlsberg Foundation, Innovation Fund Denmark, and the Danish National Research Foundation.
For further information, please contact
Professor Troels Skrydstrup
Interdisciplinary Nanoscience Center (iNANO) & Department of Chemistry
Aarhus University
Denmark
Email: ts@chem.au.dk
JOURNAL
ChemSusChem
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Evaluation of Manganese Catalysts for the Hydrogenative Deconstruction of Commercial and End-of-Life Polyurethane Samples
ARTICLE PUBLICATION DATE
12-Sep-2021
Research reveals how much plastic
debris is currently floating in the
Mediterranean Sea
A team of researchers have developed a model to track the pathways and fate of plastic debris from land-based sources in the Mediterranean Sea. They show that plastic debris can be observed across the Mediterranean, from beaches and surface waters to seafloors, and estimate that around 3,760 metric tons of plastics are currently floating in the Mediterranean.
Global plastic production has been increasing each year since the 1950s, with 368m tons of plastic produced in 2019. A high proportion of plastic waste ends up in seas and oceans – estimates suggest that more than 250,000 tons of plastic debris are currently floating around in oceans all over the world.
A new study published in Frontiers in Marine Science shows that a shocking amount of micro- and macroplastic debris is currently floating in the Mediterranean Sea.
The Mediterranean Sea is considered a hot spot for plastic pollution. This is likely due to its densely populated coastlines, fishing, shipping, tourism, and a limited outflow of surface water to the Atlantic. At the same time, the Mediterranean is rich in biodiversity, making it an area of concern for the conservation of marine ecosystems.
Plastic pollution affects all levels of marine biodiversity, with micro- and macroplastic particles found at the sea surface, beaches, the seafloor, and within the bodies of big and small marine animals. It has also been reported that humans ingest plastic through seafood consumption.
Modelling plastic pollution
A new model developed by researchers from the Hellenic Centre for Marine Research, Greece, tracked the pathways and ultimate fate of plastic debris in the Mediterranean Sea. The model performed a simulation over the period from 2010 to 2017, tracking plastics from land-based sources such as rivers and coastal cities, while taking into account important dispersion processes such as sinking, vertical/horizontal mixing, wind, and currents. It also identified potential accumulation patterns of micro- and macroplastics in the surface layer, water column, seafloor, and on beaches.
This revealed that the total annual plastics load going into the Mediterranean is approximately 17,600 tons, of which 3,760 tons are currently floating in the Mediterranean. Of the total, 84% ends up on beaches and the remaining 16% ends up in the water column or the sea floor.
“Simulations of plastic distribution in marine environments are currently characterized by a large degree of uncertainty. Experimental data on several processes that affect the fate of plastics, such as sinking, ingestion by marine organisms and fragmentation into smaller pieces are still quite limited,” said lead author Dr Kostas Tsiaras.
“Our model showed a reasonable skill in reproducing the observed distributions of plastics in the marine environment and thus can be used to assess the current status of plastic pollution in the Mediterranean and evaluate the impact of future cleaning actions and management plans.”
The model also described biofouling as a potential mechanism for the removal of microplastics from the sea water surface. Biofouling happens when micro-organisms such as algae accumulate on floating and submerged objects, including plastic debris.
Plastics are taking over the oceans
“Microplastics are less abundant in the sea surface due to their faster sinking from the attachment of heavier marine organisms (biofouling) and accumulate deeper in the water column and seafloor. On the other hand, macroplastics, such as plastic bags and styrofoam may float around for longer time periods, and travel long distances from their sources,” said Tsiaras.
Sources of microplastics (such as wastewater treatment plants) were mainly found near metropolitan cities and heavily populated areas along French, Spanish, and Italian coasts. Larger sized microplastics were found in areas with high untreated wastewater, such as the coasts off Greece and Turkey.
Macroplastics were abundant in areas with important riverine input such as Algerian, Albanian, and Turkish coasts, and close to metropolitan cities and highly populated coasts (Spain, France, Italy).
Policy recommendations
“The model outputs can be used to identify ecologically (bird and cetacean habitats) or commercially (aquaculture and fisheries) important areas that are potentially threatened by plastic pollution. This is important for the design of ecosystem-based management plans and policies for the mitigation of plastic pollution, which is often a trans-boundary environmental problem, as floating plastics may travel long distances from their sources,” according to Tsiaras.
The social, political, and cultural variety of inhabited countries along the coastline of the Mediterranean makes the implementation of a common marine ecosystem management policy difficult. But models such as the one from the study can help mitigate this problem.
“The use of predictive models, like the one presented here, that can connect observed plastic concentrations with their sources, is critical for the designation of successful management plans.”
JOURNAL
Frontiers in Marine Science
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
Not applicable
Reducing plastics in gardens
Packaging and other rubbish contaminate soil
Peer-Reviewed PublicationIMAGE: FLINDERS UNIVERSITY PROFESSOR YOUHONG TANG, LEFT, WITH CRC CARE AND UNIVERSITY OF NEWCASTLE RESEARCHER DR CHENG FANG AND DR CHRISTOPHER GIBSON, FROM THE FLINDERS MICROSCOPY AND MICROANALYSIS, HAVE BEEN WORKING ON MICROPLASTIC DECOMPOSITION AND POSSIBLE REMEDIATION AND RECYCLING IDEAS. view more
CREDIT: FLINDERS UNIVERSITY
With plastic waste a worldwide problem, consumers are taking steps to reduce use and recycle more household packaging – including in their own backyard.
A new Australian study, studying microplastic contamination in backyard soil samples, suggests plastic landscape garden bed linings, commercially produced mulch and remnants of discarded soft plastics are commonly found after seven or more years of regular degradation.
Sampling of backyard soil, by scientists from The University of Newcastle, Flinders University and CRC CARE, says the microplastics from various sources in the garden soil experiment highlights that “plastic is everywhere”.
“Plastic is everywhere so sooner or later there will be microplastic, in this case with bubble wrap left in mulch used in a backyard garden and other possible sources,” says lead author Dr Cheng Fang, senior research fellow, Global Centre for Environmental Remediation at The University of Newcastle.
“Microplastic is receiving increased attention as an emerging contaminant. Even after seven years of natural decomposition, people will find it in their garden from these common gardening sources.”
Flinders University collaborator Professor Youhong Tang says although the results are concerning, they also show that contamination can be reduced in suburban backyards and other areas by more careful design, planting and gardening practices.
“People may be trying to recycle and make the right environmental decisions, but also need to remove as much plastic as possible to avoid future microplastic contamination,” Professor Tang says.
Accumulation of plastic waste is increasing in marine and terrestrial ecosystems, released into the environment in different sizes ranging from macroscale to nanoscale.
Plastic fragments between 0.5mm and up to 5mm were found in the experiment.
CRC Contamination Assessment and Remediation of the Environment (CARE) CEO Laureate Professor Ravi Naidu says the study “gives us a clear idea of potential exposure to microplastics in a household setting.”
“Now we can work on understanding the risk that this poses, as well as ways to reduce that risk, clean up existing pollution, and prevent microplastics entering our environment in the first place,” Professor Naidu says.
Using logic-based algorithms and Raman imaging at Flinders University Microscopy and Microanalysis, the scientists were able to characterise and show how microplastics are released after about seven years due to normal degradation, weathering or abrasion conditions.
Dr Christopher Gibson, from the Flinders Microscopy and Microanalysis laboratory, says that high-resolution Raman imaging “has great potential in the detection and characterisation of plastics – not just at the microscale but at nanoscale”.
For example, the imaging suggest the nanoplastics amount release from a piece of plastic at size of 5 mm x 5 mm x 5 mm is equivalent, in mass or weight, to 1 x 109 pieces of microplastics at size of 5 μm x 5 μm x 5 μm, or equivalent to 1 x 1018 pieces of nanoplastics at size of 5 nm x 5 nm x 5 nm.
“Therefore, if we care about the contamination from the microplastics and nanoplastics, we must be very cautious about the use of plastic items in our garden,” the new paper in Frontiers in Environmental Science concludes.
The paper, Catching microplastics in gardens: case study (i) of soil (2021), by Zahra Sobhani, Yunlong Luo, Christopher T Gibson, Youhong Tang, Ravi Naidu, Mallavarapu Megharaj and Cheng Fang has been published in Frontiers in Environmental Science DOI: 10.3389/fenvs.2021.739775,
JOURNAL
Frontiers in Environmental Science
METHOD OF RESEARCH
Imaging analysis
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Catching microplastics in gardens: case study (i) of soil
ARTICLE PUBLICATION DATE
30-Sep-2021
COI STATEMENT
The authors declare no conflict of Interest
