Center of Excellence SOURCES

Prof Riina Aav: “Recycling rare earth elements is inevitable – without it we will not meet our green targets”

At the TeadusEST Forum, Tallinn University of Technology professor Riina Aav emphasized that the world is facing a critical resource crisis and that efficient recycling of rare earth elements is becoming an essential prerequisite for the development of green technologies. This is one of the central focuses of the research carried out at the circular economy centre of excellence SOURCES.

According to Aav, the actual demand for materials is already ten times higher than international trade volumes. “Many critical elements – including rare earth metals – are being used more and more, and they are expensive and difficult to obtain,” she explained.

Referring to international analyses, Aav noted that while recycling some materials is not economically viable, the situation is quite different for rare earth elements. “Neodymium and other rare earth metals are clearly moving towards a point where recycling will become unavoidable in the coming years,” she said.

Plastic recycling must also become more ambitious

In addition to rare earth elements, Aav highlighted the urgent need to increase the recycling of carbon-based materials, particularly plastics.

“To keep plastic production within the planet’s environmental boundaries, at least 70% of plastics should be recycled. The European average is currently only 40%,” she said. “If we want to stay within planetary limits, we must significantly raise recycling rates and develop new technologies.”

The centre of excellence strengthens the research community and fosters new enterprises

Within just two years, the SOURCES Centre of Excellence has published more than 25 scientific papers, organized conference with over 300 participants, and organized a joint state–scientist roundtable.

According to Aav, building a strong sense of community among researchers is crucial: “Seeing that your work matters and that others in your field are succeeding – that is the best motivation. That’s how new startups are born,” she said, pointing to emerging companies in areas such as lithium battery recycling.

“We are only at the beginning of this journey, but if we want to meet climate goals and ensure Estonia’s competitiveness in the green transition, we must invest in science, technology and collaboration,” Aav concluded.

Why is industry not moving as fast?

During the discussion, Estonian Research Council chair Anu Noorma asked why industry is not adopting new solutions faster, citing VKG’s recent decision to halt its plastic waste recycling project.

Aav explained that the issue is not the lack of scientific knowledge but the maturity of the technology:
“There simply was no technology at the required readiness level to process unsorted plastic packaging waste. Without economic viability, a company cannot make such an investment.”

Deputy Secretary General for Research and Higher Education at the Ministry of Education and Research, Renno Veinthal, asked what is currently hindering the centere’s progress and how intellectual property policies affect research.

Aav noted that university-centered intellectual property models can slow researchers down: “A researcher wants to publish, while the university needs to secure ownership – that adds an extra barrier. Developing large-scale industrial solutions takes at least ten years.”

Nevertheless, she sees encouraging signs. She highlighted the new magnet factory opened by Neo Performance Materials, which, she said, shows that Estonia is becoming an increasingly attractive location for developing green technologies.

On 4 December 2025, the TeadusEST Forum — organised by the Estonian Research Council — brought together researchers from 10 national Centres of Excellence, including the Circular Economy Centre of Excellence SOURCES, to present their work and share insights on the future of science and sustainability.

State–Science Cooperation Roundtable Focused on Key Circular Economy Challenges and Protecting Estonia’s Interests in the EU

01.12.2025 Liisa Rebane

On 1 December, a cooperation roundtable between the state and researchers took place, where 24 participants discussed key issues related to the circular economy, clean industry and material circulation, as well as Estonia’s role in shaping European Union policies.

Mihkel Krusberg, Head of Circularity and Financing at the Ministry of Climate, highlighted that the protection of human health is becoming an increasingly central driver in circular economy and environmental policies. The European Union’s ambition has grown — the Clean Industry Deal has been launched, and several important regulations are being prepared, including the Circular Economy Regulation and the “traffic-light” system for plastic products.

In Estonia, the waste reform has entered into force, and the national Circular Economy Plan 2029+ is nearing completion, focusing primarily on construction and demolition waste, plastics, and bio-based materials.

Researchers from TalTech presented challenges and solutions supporting companies and the state in the transition to a circular economy.
Professor Riina Aav, Head of the Circular Economy Centre of Excellence SOURCES, emphasised that meaningful change requires a systematic understanding of both technology and business models. She noted that the recycling rate of plastic packaging could rise from the current ~40% to more than 70%, but achieving this requires both technological innovation and political decisions.

Professor Tarmo Kalvet pointed out that Estonian companies are strongly influenced by international supply chains, making it crucial to understand how global restrictions — such as China’s export controls — affect Estonia’s security and industry. TalTech has developed databases and analytical tools to support the assessment of these impacts and assist policymakers.

Merle Küttim presented the business perspective on circular economy barriers. According to her, development is hindered by financial and knowledge-related obstacles, weak information exchange within supply chains, and an unstable geopolitical environment. Small enterprises particularly need more practical guidance and support from the state to keep pace with the transition.

During the discussions, participants stressed the need to make Estonia’s positions more visible within the EU.
Mihkel Krusberg noted that Estonia’s input often reaches the European Commission too late: “We need to be at the table early in the process for our ideas to be heard at all.” Participants also highlighted the importance of strengthening cooperation with Nordic and Baltic countries.

When addressing the practical barriers to circular economy implementation, Professor Allan Niidu remarked that a perfectly “clean industry” is not realistic — “we need workable and applicable solutions.” He pointed to bottlenecks in the battery and plastics sectors, as well as the growing potential of valorising future oil shale ash, a field in which regulatory clarity is urgently needed.

The roundtable also examined issues related to construction and textile waste. The textile sector is active, but technology enabling true textile-to-textile recycling is still lacking. As a result, much of the collected textile waste is exported to third countries, where it often accumulates in landfills.

Additional Information

The roundtable included representatives from the Ministry of Climate, the Ministry of Economic Affairs and Communications, and TalTech.
The aim of the meeting was to strengthen cooperation between the state and the research community and to prepare for the implementation of new EU initiatives.

Further meetings are planned, focusing on practical and concrete solutions, with the goal of jointly overcoming circular economy bottlenecks and supporting the implementation of real, actionable changes.

Doctoral Students Showcase Innovative Approaches to Sustainable Resource Use at SOURCES Conference

On 30 October 2025, doctoral students gathered for the second SOURCES Centre of Excellence PhD Conference, where they presented their ongoing research on circular economy and sustainable resource use.

The conference offered a glimpse into the wide range of research currently underway, highlighting different approaches to reusing materials, reducing waste, and developing environmentally sound production methods.

The conference began with opening remarks from professor Riina Aav, Head of SOURCES Centre of Excellence, followed by presentations from doctoral students across the centre’s focus areas and finished with the guest presentation of professor Innar Liiv on how to enchance resource circulation with artificial intelengents tools.

In the area of strategic mineral resources, researchers studied how Estonia’s natural minerals and industrial residues could be utilised more effectively. Presentations included studies on using Estonian clays in cementitious materials (Ademola Michael Adegbile), mechanically activating glauconitic sandstone to produce potassium fertilizer (Richard Pihel), incorporating calcium-rich oil shale ashes into carbon-sequestering concrete (Adheena Thomas), and extracting rare earth elements from phosphate rock (Ruhany S. Azeez). Each project explored practical ways to transform local resources and by-products into useful materials while addressing environmental concerns.

Some of the projects focused on new circular technologies, including bio-based materials and green chemistry solutions. They explored innovative approaches for recycling, waste reduction, and water treatment. These included scaling toluene oxidation with pulsed corona discharge and photocatalysis (Daniel Teittinen), developing nonwoven composites from recycled textile fibres (Md Toufiqur Rahman), selective oxidation of pharmaceuticals in water and source-separated urine (Irina Petrotšenko), optimising nonwoven design from mechanically recycled textiles (Katre Worth), and recovering biobased acetic acid from wood treatment wastewater (Kati Muldma).

Research in carbon-based resources area addressed cleaner methods for chemical production. The presented projects included mechanochemical generation of lithium amide bases (Suman Sahoo) and electrochemical Ferrier rearrangement in continuous flow (Mihhail Fokin), offering approaches that reduce reliance on traditional fossil-based processes.

The conference concluded with a guest lecture by Professor Innar Liiv from TalTech Department of Software Science, who discussed “AI as the Missing Link: From Frictionless Arbitrage to Circular Interoperability”, demonstrating how innovative digital tools can support circular systems.

SOURCES Doctoral Conference Brings Together Young Researchers and Circular Economy Experts on October 30

On October 30 at 10:00, the SOURCES Doctoral Autumn Conference will take place at the Venus Auditorium in Tehnopol (Akadeemia tee 21, Tallinn). Young researchers will present their latest findings in the fields of circular economy and sustainable material use.

The conference focuses on the valorisation of strategic mineral and carbon-based resources, bio-based materials, green chemistry solutions, and circular business practices.

The event is organised within the framework of the Centre of Excellence for the Circular Economy of Strategic Mineral and Carbon-Based Resources (SOURCES), which brings together Estonian researchers and companies to enhance resource efficiency, promote reuse and recycling, and reduce dependency on new natural resources. Over its first 18 months of activity, the centre has published more than 20 scientific papers and attracted over €9.5 million in additional funding for advancing circular economy research and innovation.

The published studies cover topics such as new methods for lithium battery recycling, production of lignin-based biopolymers, synthesis of receptor molecules for pollutant capture, electrically assisted water purification, and analyses of circular business practices, among others.

The SOURCES Doctoral Conference offers an opportunity to see how science contributes to building a more sustainable future and promotes the principles of the circular economy in Estonia and through international collaboration.

Danish Professor Maj Munch Andersen: The Circular Economy Must Become Mainstream, Not a Niche Topic

At the SOURCES Centre of Excellence conference, Danish Professor Maj Munch Andersen emphasized that the circular economy is no longer just about the environment – it’s crucial for security, the economy, and societal resilience.

She praised CoE SOURCES team, led by Prof. Riina Aav, for its progress and engagement, and highlighted the need for stronger collaboration between science and industry. Researchers should actively approach companies with real-world solutions and better understand industrial needs.

Andersen pointed to innovative areas like rare materials reuse, algae in food, and mushroom-based building materials as key to future trends. She stressed the importance of designing sustainability into products from the start.

She welcomed the EU’s new circular economy plan focused on durability and reuse, but warned against blindly embracing alternatives like bioplastics without proper evaluation.

On the cultural level, she noted growing public awareness, praising Estonia’s deposit system, and called for inclusive systems that value dignity, especially in developing regions.

Globally, Andersen noted China’s long-term policies and India’s rising innovation as key trends. Despite challenges, she concluded that circular thinking is becoming mainstream – and is essential for a sustainable and resilient future.

Read the full article 

SOURCES Spring Conference 2025: The Future of Circular Economy

The Centre of Excellence for the Circular Economy of Strategic Mineral and Carbon-Based Resources (SOURCES), led by TalTech, held its spring conference focused on advancing circular economy through research, technology, and policy. Nearly 60 experts from Estonia and abroad discussed innovations in resource efficiency, waste reduction, and sustainability.

• Professor Riina Aav emphasized the Centre's mission to bridge scientific research with practical applications, covering both mineral and organic resources. Topics included plastic and textile waste recycling, water purification, and greener chemical processes. The Centre has launched 14 new projects worth over €9 million and published 19 scientific articles in its first year.
• Professor Tarmo Kalvet discussed the geopolitical dimension of circular economy, particularly Europe’s dependency on Chinese raw materials (e.g., graphite, magnets) for electric vehicle production. He stressed the need for strategic autonomy and better supply chain analysis.
• Dr. Kristiina Kaldas introduced chemical technologies to convert oil shale waste into valuable products like dicarboxylic acids and plant growth stimulants. She also explored the potential of biobased de-icing agents.
• Professor Allan Niidu presented research on rare earth elements, CO₂ conversion into chemicals, and hydrogen production via methane pyrolysis. He highlighted the need for advanced materials and interdisciplinary collaboration.
• Professor Sergei Preis showcased electrochemical methods for removing pharmaceutical residues from urine while preserving nutrients for reuse in agriculture.
• Professor Tiia Plamus focused on textile waste recycling and valorization of underused Estonian bioresources like sheep wool and flax. Her group develops both mechanical and thermochemical recycling methods.
• Dr. Can Rüstü Yörük (The Centre of Excellence SOURCES Advisory Board member) discussed the use of secondary raw materials (like oil shale ash and clays) in eco-friendly construction materials. His team works on mineral carbonation and CO₂-binding construction composites.

PhD students from TalTech and University of Tartu shared brief overviews of their research on green chemistry, nutrient recycling, decision-making in sustainable innovation, and environmental safety of amines.

The conference highlighted Centre of Ecellence SOURCES’ role as a driver of interdisciplinary and international collaboration to develop sustainable technologies and address geopolitical risks tied to resource dependency.

Full article in Estonian

Scientific Achievements in the Field of Circular Economy in 2024

As part of the activities of the Centre of Excellence for Circular Economy of Strategic Mineral and Carbon-Based Resources, 19 peer-reviewed scientific articles were published in 2024. Additionally, over €9.5 million in extra funding was secured to promote research and innovation activities.

Under the SOURCES Centre of Excellence, 19 publications were released, covering topics such as mineral raw materials, including Estonia's natural resources, as well as technologies for processing carbon-based raw materials. The research focused on secondary raw material valorization technologies, improving resource use efficiency, and developing new bio-based polymers.

Furthermore, studies analyzed processes using green chemistry metrics, examined pollutant neutralization, and assessed the toxicity and life cycle of lignin-based polymers. Circular economy entrepreneurship was also explored.

Among these publications:

• 11 articles were published in collaboration with international research partners, strengthening global scientific cooperation.
• 5 articles resulted from joint research between multiple institutions, including TalTech, the University of Tartu, and NICPB.
• 2 articles were published in cooperation with public and private sector partners, emphasizing the importance of cross-sector collaboration in advancing circular economy solutions.

In 2024, the Centre of Excellence secured an additional €9,576,426 in funding, considering the financial volume of projects until their completion.

These achievements reflect the Centre's commitment to high-level research, interdisciplinary collaboration, and the development of sustainable resource management strategies. The Centre looks forward to further discussions and the establishment of new partnerships at the upcoming SOURCES Consortium Conference in Tartu 13.-14.03.2025.

Sustainable Methods for Decomposing Ionic Liquids in Wastewater

Industrial processes generate toxic chemical waste that does not naturally degrade and therefore poses an environmental risk. Among these are widely used ionic liquids, also known as liquid salts or electrolytes. Conventional wastewater treatment methods are not effective in breaking them down.

One of the goals of the Circular Economy Centre of Excellence is to develop sustainable (waste)water treatment technologies that help reduce chemical waste and its environmental impact.

The Environmental Technology Laboratory at the Department of Materials and Environmental Technology of Tallinn University of Technology explored alternative and energy-efficient solutions for treating wastewater contaminated with ionic liquids.

Three different methods for decomposing ionic liquids through advanced oxidation were tested:

• Pulsed Corona Discharge (PCD) – Electrical pulses generate strong oxidizing particles, such as hydroxyl radicals, which attack and break down pollutant molecules.
• PCD oxidation combined with peroxymonosulfate (PCD/PMS) and peroxydisulfate (PCD/PDS) – The discharge potentially activates persulfates, which decompose into sulfate radicals and additional hydroxyl radicals.
• UV photolysis with persulfates (UV/PDS and UV/PMS) – Ultraviolet radiation activates persulfates, which break down into sulfate radicals. These radicals have a strong oxidation capability and effectively decompose ionic liquids.

PCD oxidation has been primarily studied for the degradation of micropollutants, but its application in decomposing ionic liquids is novel. The study examined the breakdown of three different ionic liquids using various advanced oxidation processes. The combined UV/PDS method proved to be the most effective for decomposing ionic liquids. In terms of energy efficiency, PCD was comparable to the UV/PDS combination. Additionally, it was found that the degradation rate is influenced by the chemical structure of the ionic liquid.

This research contributes to the development of sustainable wastewater treatment technologies, the minimization of chemical waste, and the more efficient use of resources. Further research is needed to evaluate the scalability of these methods for industrial applications.

The findings can be applied in industrial wastewater treatment plants, particularly in sectors related to battery production, chemical synthesis, and carbon capture.

Source: Nikitin, D.; Preis, S.; Dulova, N. (2024). Degradation of imidazolium-based ionic liquids by UV photolysis and pulsed corona discharge: The effect of persulfates addition. Separation and Purification Technology, 344, #127235. DOI: 10.1016/j.seppur.2024.127235.

Kerli Liivand is researching battery recycling for reuse

Approximately 8,000 electric cars are currently on Estonian roads, and the Ministry of Climate predicts that in five years, this number will rise to 30,000. However, at the end of their lifespan, a significant portion of their batteries currently ends up in landfills, so to speak. Estonian scientists have now taken a step closer to fully recycling the materials found in batteries.

Read more and watch the news segment in the Aktuaalne Kaamera news program (in Estonian)

Center of Excellence in Circular Economy First Year of Action is Summarised in Autumn Symposium

Tallinn, 29.11.2024 – This Friday, researchers from the Circular Economy Center of Excellence will gather to share insights and results from the first year of action on advancing sustainability and circular economy technologies. The event brings together interdisciplinary workgroups to present research and explore innovative solutions for a greener future.

The workshop will be opened by introduction from CoE leader Riina Aav, on the critical role of collaboration in tackling global resource challenges.

Morning session will showcase developments in the extraction, utilization, and recovery of critical resources from progress in Strategic Mineral Resources  and innovative synthesis and application of materials in Carbon-Based Resources Workgroups.    

Presentations on research at TalTech will include advancements in inorganic technologies for 2024, sustainable mineral foam block development with CO₂ curing, and critical element recovery from Estonian phosphate rock. Topics will also cover metallic extraction from black shale using thermal treatment, hydrogen decrepitation techniques for Nd₂Fe₁₄B magnets, and advances in asymmetric organocatalytic electrosynthesis, as well as mechanochemical method for synthesis of receptor molecules. Researchers from University of Tartu will present development of lignin-based high-performance polymers.

In the afternoon session TalTech and KBFI researchers from Circular Technologies Upscaling Workgroup presentations will highlight novel approaches to recycling and upcycling various materials, including nutrient recycling from source-separated urine, lithium battery recycling, and textile fiber valorization methods. Additional topics will cover structural research of kerogen, phenolic waste valorization, innovative uses for oil shale byproducts in snow and ice melting agents, and rapid synthesis techniques for MOFs.

Final session of the day on results of Circular Business Ecosystem and Modeling Workgroup will address future research by analyzing geopolitical aspects of resource value chains, explore circular economy concepts and sustainability motivations, and investigate potential scenarios and attention patterns in the circular economy.

SOURCES Center of Excellence activity will help to step toward a sustainable future by uniting experts across fields in action to address critical challenges in resource management, recycling, and circular business ecosystems.

Event agenda

Kalle Kirsimäe: Natural Resources Are Wealth, but Not a Thing of Beauty

Natural resources are wealth, but not a thing of beauty. As a nation, we need to know, based on scientific research, what we have here, in what quantities, with what quality, as well as the potential damages, benefits, and economic impacts, writes academician Kalle Kirsimäe.

Read the full article on ERR's portal

Establishment of the Baltic Circular Hotspot

Helsinki, 19.11.2024 - Baltic Circular Hotspot is a collaborative initiative designed to drive the transition from linear to circular economies across the Baltic States and Nordic countries. This effort is formalized through a newly signed Memorandum of Understanding (MOU) that brings together key stakeholders committed to sustainability and innovation. MOU was signed during the Nordic Circular Summit 2024 in Helsinki.

Signing of the memorandum (LinkedIn)

Read more about the event here

Riina Aav: The Circular Economy Helps Mitigate the Shortage of Strategic Raw Materials

At a time when much of the strategic raw materials come from China and Russia, and increasingly strict export restrictions are imposed on their supply, it has become critically important for Europe to find alternative solutions. Even in our own "backyard," there are numerous resources that could be utilized sustainably, writes Riina Aav, head of the Center of Excellence for Circular Economy of Carbon-Based Resources at Tallinn University of Technology.

Read the full article on the Novaator portal

The First Conference of the Circular Economy Center of Excellence Took Place

On April 12, 2024, the first conference of the Strategic Mineral and Carbon-Based Resource Circular Economy Center of Excellence consortium was held at Kultuurikatel.

The Center of Excellence, launched in 2024 under the leadership of Professor Riina Aav, is dedicated to the circular economy of raw materials. Researchers are working to address technological challenges related to the (re)use of mineral and carbon-based resources.

The research groups within the center analyze the availability of strategic raw materials, develop more environmentally friendly chemical technologies, and evaluate circular economy business models. Funded for seven years, the center also focuses on issues related to plastics, textiles, and water purification, as well as assessing the sustainability of technologies from both environmental and supply chain security perspectives.

The conference, attended by over 50 participants, featured presentations by the heads of the center's working groups, including Academician Prof. Kalle Kirsimäe, Andres Trikkel, Sergei Preis, Kristiina Kaldas, Riina Aav, Lauri Vares, Tarmo Kalvet, Wolfgang Dieter Gerstlberger, and many other scientists. Members of the advisory board also participated, and Mihkel Krusberg, an expert on European Union policies, delivered a keynote presentation.

At the consortium conference, interdisciplinary research groups shared ideas to address a complex challenge: how to transition an economy primarily reliant on natural resources to one that increasingly reuses anthropogenic resources.

Event agenda