Research Pieter Billen

Abstract

Polyurethane (PU) foams are all around us, from our walls to our beds and our cars. Only 20% of this PU is recycled, primarily into inferior products. Polyurethane is a heteropolymer of a polyol and a diisocyanate, mostly forming networks. It is well-understood that these monomers can be cleaved using various chemical recycling techniques, but only pilot plants using mattresses as feedstock are currently operational. To limit the complexity and avoid the difficulty of end-of-pipe purification, the foams should be sorted prior to recycling. Sorting based on isocyanate type can be done using near-infrared identification, due to limited isocyanates industrially used. However, the polyols used in PU are very diverse, limiting sorting possibilities. To enable sorting based on polyol, I propose to tag the polyols with a spectroscopically detectable tag. The tags proposed in this research are fluorophores. This research will provide a proof-of-concept that fluorescent tags can be attached to polyols and used to identify that polyol in PU foam. This will be done by synthesising functionalised tags, comparing different methods of attachment, followed by investigating the properties, stability and recyclability of foam with tagged polyols. This will provide applicable basic tag structures and an optimised screening method to find more tags that are suitable for PU foam. After implementation, this will lead to higher quality recycled polyols and an increased foam circularity.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Vande Velde Christophe
• Fellow: Cassimon Jonas

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Polyurethanes (PU) are widely used in mattresses, upholstery, furniture, automotive, construction, and insulation. They are mostly thermoset foams, made by reacting isocyanates (MDI, TDI, or HDI) with polyols. Their thermoset nature limits mechanical recycling, making chemical recycling crucial for circularity. The resulting aromatic molecules, ureas, amines and polyols from depolymerization have varied physicochemical characteristics, impacting separation during recycling. This doctorate aims to use thermodynamic modeling tools to predict the ease of separating depolymerized PU mixtures. Methods include activity coefficient based models (NRTL, UNIFAC, HANSEN) that are accompanied by computational chemistry methods to optimize the models and fill in unknown gaps. Modeling results will inform engineering software for process design, optimizing recycling for recyclers and informing circular design for PU formulators and recyclers. The focus is primarily on predicting interactions between different polyols used in PU, considering monomer composition, degree of branching, molecular weight distribution, and functionality, to facilitate efficient separations. Later, other constituents are covered in more detail as well. The goal is to provide recyclers and formulators with insights for process optimization and improved circularity of PU materials.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Cunha Ana
• Co-promoter: Nimmegeers Philippe
• Fellow: de Graaf Christophe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Nuclear Magnetic Resonance (NMR) is a spectroscopic technique that provides unique insight into the chemical structure and conformational dynamics of molecules. It is indispensable for medicinal and organic chemistry, for natural products research and for all related domains drawing on organic chemistry. For all publications in these fields, journals demand that research data are extensively supported by NMR-analysis: if NMR data are not or only partially delivered, research cannot be accepted for publication. This is because NMR spectroscopy is a sui generis methodology for which no generally applicable alternatives exist. There are currently only two operating NMRs left at UAntwerpen (both 400 MHz): one in the Medicinal Chemistry research group (UAMC) and one in the Organic Synthesis group (ORSY). In both groups, a large number of externally and internationally funded projects entirely rely on these very intensively used machines. Loss or temporary drop-out of a remaining instrument would have ruinous consequences on research. The available spectrometer at UAMC will be 15 years old in 2024 and at the end of its expected life-time. We therefore would like to replace the UAMC NMR. Spectrometers working at 400 MHz are the literature standard for most medicinal, organic and natural products applications and are expected to remain so for the next two decades. This application also fits in a long-term strategy to ensure that NMR-dependent research remains possible at UAntwerp.

Researcher(s)

• Promoter: Augustyns Koen
• Co-promoter: Billen Pieter
• Co-promoter: Elvas Filipe
• Co-promoter: Maes Bert
• Co-promoter: Prothiwa Michaela
• Co-promoter: Tuenter Emmy
• Co-promoter: Van Der Veken Pieter

Research team(s)

• Medicinal Chemistry (UAMC)

Project type(s)

• Research Project

Abstract

Polyurethane (PU) foams are a key constituent in mattresses. To date, only 20% of this PU is (mechanically) recycled, primarily into inferior products. Polyurethane is a heteropolymer of a polyol and a diisocyanate, mostly forming networks. The polyols used are can be very diverse, even within a single mattress foam formulation. It is well-understood that these monomers can be cleaved using various chemical recycling techniques, but only pilot plants using mattresses as feedstock are currently operational. To limit the complexity and avoid the difficulty of end-of-pipe purification, the foams should be sorted prior to recycling. Sorting based on isocyanate type can be done using near-infrared identification, due to limited isocyanates industrially used. However, the polyols used in PU are very diverse, limiting sorting possibilities. To enable sorting based on polyol, we propose to tag the polyols with a spectroscopically detectable tag. The tags proposed in this research are fluorophores. This research will provide a proof-of-concept that fluorescent tags can be used to identify polyols in a PU foam. This will be done by mixing tags into polyols, analysing how functional the tag is in the polyol, followed by making a foam out with these tagged polyols and testing the detectability of the tags in a foam. Further, an in-dept investigation of the properties of the tagged foam and an evaluation of the recyclability of foam with tagged polyols is conducted. This will provide applicable basic tag structures and an optimised screening method to find more tags that are suitable for PU foam. After obtaining a working proof-of-concept, the technology will be patented and PU additive manufacturers will be approached for scale up and bringing it to market. After implementation, sorting of foams based on the polyol can become trivial. With this sorting capabilities, better recycling strategies can be implemented such as justified decisions which foam will be mechanical recycled and which chemical. This will lead to higher quality (virgin-grade) recycled polyols and an increased foam circularity.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Vande Velde Christophe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Circular economy strategies are gaining attention within companies to reduce their environmental impact and meet government targets. In this context, companies in different sectors are investigating and implementing different strategies to reuse, repair, refurbish, remanufacture, reuse, recycle and recover end-of-life products, components, parts or materials. Deciding which strategy to choose requires case-specific life cycle and techno-economic assessments, which typically require a lot of data, expertise and time. Furthermore, there is no single quantitative definition of circularity that can be directly used to assess, monitor and optimize the circularity of product designs or value chains. Therefore, there is a need for generic tools/methods that can be used to assess circularity based on generic information that is commonly available. To address this knowledge gap, we present three central hypotheses, in which we argue that energy consumption provides an adequate projection of circularity and that entropy is a valid parameter to move from process-specific assessment methods to more generic state-based assessment methods: Hypothesis 1: The relationship between the embodied energy of materials and products and their carbon footprint is linear. This has already been demonstrated in several studies, Hypothesis 2: The relationship between the embodied energy of materials and their economic value (as raw materials) is linear. This has already been demonstrated by the work of Tim Gutowski and others. Hypothesis 3: The relationship between resource dilution (reciprocal concentration in deposits) and embodied energy of materials is linear. Dilution here can be interpreted directly as entropy, cf. the description above. This has already been demonstrated for metals, while we have calculated a similar relationship for post-consumer packaging waste in preliminary work. Evidence supporting these three hypothesis would for the first time establish a direct and quantitative link between materials circularity and climate change. That way entropy can be used as a proxy for energy expenditure over the life cycle of a material, and in turn for the carbon footprint. We would further provide basic evidence, that can convince companies and policy makers using simple case studies. In this project, we will further demonstrate hypotheses 2 and 3, by focusing on the value versus entropy of waste materials, and by looking at bioresources. As a result, using this framework, waste sorting and (bio-)refining processes can be judged on the performance of individual unit operations rather than only on the end results of a complete plant configuration. The scope for this project will be restricted to different fossil-based polymers and bio-based polymers, to ensure feasibility and complementarity with the group's expertise. The anticipated results will accelerate the deployment and valorization of the novel circularity assessment methodology and make it more accessible to the main target audience, i.e. product and process designers. In this way, the foundations will be laid for a circularity quantification and optimization tool based on generic thermodynamic principles.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Nimmegeers Philippe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

3D printing, and additive manufacturing in particular, has in the last couple of years transformed from a prototyping to a more mature manufacturing technology. The driving force for this transformation was the need for custom built, lightweight parts and a more efficient use of raw materials in order to reduce waste. The current trend is towards increasingly complex parts, consisting of multiple materials to enhance their physical and/or mechanical properties. The complexity of the parts brings with it a need for specialized inspection and quality control methods. In this project, the complementarity between different imaging technologies such as 3D x-ray imaging, thermal imaging and terahertz imaging will be explored within the application field of 3D inspection and metrology of 3D printed parts.

Researcher(s)

• Promoter: De Beenhouwer Jan
• Co-promoter: Billen Pieter
• Co-promoter: Sijbers Jan
• Co-promoter: Vanlanduit Steve
• Co-promoter: Van Passel Steven

Research team(s)

• Vision lab

Project type(s)

• Research Project

Abstract

Develop a novel chemical recycling approach to process rigid polyurethane (PU) and polyisocyanurate (PIR) end-of-life materials. By using selective depolymerization, we will transform these wastes into valuable building blocks to produce more sustainable materials, guaranteeing in this way a high carbon circularity. To secure the sustainability of the new technological route, CHRONICLE will also have a strong value chain management supported by techno-economic and life cycle assessment. CHRONICLE will link waste providers and recyclers, with downstream chemical companies and PU producers, resulting in an optimized value chain with enhanced circularity, new economic opportunities and new synergetic partnerships. CHRONICE is a part of the Moonshot program, where VITO, KUL and UA join forces. (2023-2027).

Researcher(s)

• Promoter: Billen Pieter

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Rubbers, although widely used in society, are traditionally difficult to recycle. Most commercial recycling techniques are restricted to granulation, although the products of this process have low value and are under environmental scrutiny. State-of-the-art devulcanisation and/or pyrolysis of rubbers are associated with very high costs, and lead to an ill-defined array of products. However, for a long time tyre, degradation studies have unknowingly shown us a different way of depolymerisation, that is ozonolysis. For the first time, its potential as a recycling technique has been identified instead of being a nuisance to be avoided. Ozonolysis will be used as a novel, sustainable approach to potentially derive telechelic resins from rubber waste. In this project the various challenges regarding mass transfer, characterisation, work-up and scale-up will be overcome in order to provide recycled resin samples and recovered carbon black to industrial stakeholders, while establishing a functional lab scale reactor setup to attain this goal. Furthermore, the obtained resins will be characterised and employed in final demo-applications of new polycondensates as well as adhesives. Starting from recalcitrant (sometimes bio-based) waste, this green and relatively cheap oxidation method can therefore yield products with interesting, new properties, and at the same time off-set fossil-based source materials.

Researcher(s)

• Promoter: Vande Velde Christophe
• Co-promoter: Billen Pieter
• Fellow: Fishel Yanou

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Most chemical reactions in the cell have high activation energies, and without enzymes, they would not occur with the required speed for biological processes. Hydrogen bond donors (HBD) as Lewis-acid-catalysts play a key role in many enzymatic reactions, both in orienting the substrate molecules and lowering barriers to reaction. Their tendency to undergo self-quenching however, decreases both solubility and reactivity. Supramolecular chemistry under the form of MOFs offers a promising biomimetic platform for immobilizing these catalytically active sites, and features defined structure and high porosity. Previous attempts have been less than successful due to limited substrate scope and small pore size, instability and complex synthesis. Here, we propose a new method with three goals: 1) pre-design large pore MOFs to lock in the desired porosity and stability, 2) extend linker size to achieve large pores by using direct arylation reactions to decrease synthetic complexity, and 3) propose several alternatives to add (combinations of, as well as chiral) HBD catalysts to the MOF framework. These materials can be used as templates for metal/carbon hybrids with unprecedented porosity. Finally, all materials will be tested for catalytic activity. This modular and concerted synthetic approach towards heterogeneous (organo)catalysts will re-start a direction of research in which the spectacular advantages offered by addressing the main issue with existing HBD catalysts are obvious.

Researcher(s)

• Promoter: Vande Velde Christophe
• Co-promoter: Billen Pieter
• Fellow: Esrafili Dizaji Leili

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

The continuously rising demand for resources is pushing us to exceed the planetary boundaries. At present, methods as life cycle assessment and techno-economic assessment have been proposed to develop sustainable systems and processes. However, these traditional methods do not allow us to predict the sustainability of disruptive technologies starting from a blank canvas, as these rely on very specific information that only becomes available at higher technology readiness levels (TRL) and a background system. Hence, methods are needed that solely rely on generic information available at any TRL. This is exactly what I aim to achieve in this research project: I will create an innovative design-for-sustainability paradigm that can deliver forecasts and can optimize the development of novel processes and systems in view of economic and environmental sustainability at any TRL. To this end, I will connect statistical entropy to generic energy calculations and generic capital cost estimates and I will define multi-objective optimization problem formulations and solution strategies. As validation, three applications will be studied: (i) the design of lignocellulosic biorefineries, (ii) polyolefin plastic waste management and (iii) phosphorous management. The proposed groundbreaking research will open avenues towards my future career as an independent academic principal investigator working on process-based modeling, control and optimization for the development of sustainable systems.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Van Passel Steven
• Fellow: Nimmegeers Philippe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

This Baekeland project will lead to a novel method of recycling rigid polyurethane foams in a close collaboration between SurePUre (Triple Helix BV) and the University of Antwerp, in the form of a shared doctoral trajectory. Current processes recover only a single-phase mixture, which are low-grade polyols with limited utility. There is, however, a strong need to replace today's petrochemical PU feedstock. This project aims at recycling the main PU constituents separately, and therefore creating more value to a circular economy.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Vande Velde Christophe
• Fellow: Porters Matthew

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Plastics are an integral part of our daily lives, however, they are difficult to recycle. Nevertheless, the diversity of polymeric materials is still increasing, despite societal and legislative pressure to reduce their complexity. Unfortunately life cycle assessment and techno-economic assessment always start from enthalpic considerations, i.e. material and energy balances, rather than entropic considerations, i.e. product complexity and structure. This leads to the paradoxical situation that we do not know which waste material is of enough high value to recycle taking into account any (future) market conditions, and that we do not exactly know how to produce plastics to optimize the value of post-consumer recyclate. Moreover, the (macro)molecular level, which determines macroscopic properties, is never addressed, although it is well-recognized that industrial polymer synthesis is characterized by significant inter-and intramolecular variations. A linking of polymer reaction eng (PRE; Ghent University expertise) and generic sustainability assessment (SA) methods (University of Antwerp) is thus almost absent but highly recommendable, justifying the scope. We aim at a generic method for the prediction and optimization of the recyclability of economic goods starting at the molecular level. In the long run the method can predict on the fly whether chemical modifications are not only worthwhile application wise but also in view of recyclability.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Nimmegeers Philippe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

The project concerns chemical recycling of vulcanized latex foams (i.e. foam rubbers) through a novel method to generate smaller telechelic oligomers, making a start on elaborating possible reaction conditions and the characterization of the products.

Researcher(s)

• Promoter: Vande Velde Christophe
• Co-promoter: Billen Pieter
• Fellow: Fishel Yanou

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Polyurethane (PUR) as a thermohardening polymer is difficult to recycle - two current techniques are mechanical recycling (cutting and rebonding) and up to a certain limit also chemical recycling, in which the polyol component is recovered through hydrolysis, alcoholysis or glycolysis. The isocyanate component, however, reacts to amines, for which the current state of the art is to incinerate them. In this project, an alternative route is researched to generate isocyanates from this remaining fraction, without use of toxic or environmentally unfriendly reagents, to close the material loop regarding the use of polyurethanes in a sustainable manner.

Researcher(s)

• Promoter: Vande Velde Christophe
• Co-promoter: Billen Pieter
• Fellow: Nees Marthe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

This IOF consortium connects chemists, engineers, economic and environmental oriented researchers in an integrated team to maximize impact in key enabling sustainable chemical technologies, materials and reactors that are able to play a crucial role in a sustainable chemistry and economic transition to a circular, resource efficient and carbon neutral economy (part of the 2030 and 2050 goals in which Europe aims to lead). Innovative materials, renewable chemical feedstocks, new/alternative reactors, technologies and production methods are essential and central elements to achieve this goal. Due to their mutual interplay, a multidisciplinary, concerted effort is crucial to be successful. Furthermore, early on prediction and identification of strengths, opportunities, weaknesses and threats in life cycles, techno-economics and sustainability are key to allow sustainability by design and create effective knowledge-based decision-making and focus. The consortium focuses on sustainable chemical production through efficient and alternative energy use connected to circularity, new chemical pathways, technologies, reactors and materials, that allow the use of alternative feedstock and energy supply. These core technical aspects are supported by expertise in simulation, techno-economic and environmental impact assessment and uncertainty identification to accelerate technological development via knowledge-based design and early stage identified key research, needed for accelerated growth and maximum impact on sustainability. To achieve these goals, the consortium members are grouped in 4 interconnected valorisation programs focusing on key performance elements that thrive the chemical industry and technology: 1) renewable building blocks; 2) sustainable materials and materials for sustainable processes; 3) sustainable processes, efficiently using alternative renewable energy sources and/or circular chemical building blocks; 4) innovative reactors for sustainable processes. In addition, cross-cutting integrated enablers are present, providing expertise and essential support to the 4 valorisation programs through simulation, techno-economic and environmental impact assessment and uncertainty analysis.

Researcher(s)

• Promoter: Meynen Vera
• Co-promoter: Billen Pieter
• Co-promoter: Bogaerts Annemie
• Co-promoter: Breugelmans Tom
• Co-promoter: Compernolle Tine
• Co-promoter: Cool Pegie
• Co-promoter: Das Shoubhik
• Co-promoter: Lenaerts Silvia
• Co-promoter: Maes Bert
• Co-promoter: Neyts Erik
• Co-promoter: Perreault Patrice
• Co-promoter: Vande Velde Christophe
• Co-promoter: Vande Velde Christophe
• Co-promoter: Van Passel Steven
• Co-promoter: Verbruggen Sammy
• Fellow: Meyer Nathalie

Research team(s)

• Laboratory of adsorption and catalysis (LADCA)

Project type(s)

• Research Project

Abstract

The ADV_BIO project aims to develop, through innovative and competitive approaches, advanced (bio)fuels from renewable non-food resources that do not generate waste. This project focuses on the development of innovative and competitive technological production schemes in order to position Belgium as a strategic and differentiated partner and actor for the eco-efficient production of second and third generation alternative advanced (bio)fuels. Biofuels from renewable resources for non-food use that do not cause indirect land use changes are envisioned as established by the Renewable Energy Directive Directive 2018/2001 adopted in December 2018 by the European Parliament and the Council of Ministers of the European Union. The ADV_BIO project therefore aims to study the removal of technological barriers related to these alternative fuels by offering a decision-making grid through innovative research actions, differentiated, adapted to the requirements of the national territory. The new products, whether they are adapted to road or air transport, will have a chemical composition that will enable them to meet the specifications of the fuel industry. The project focuses on biomass as a feedstock for the production of alternative fuels (biofuels and synthetic fuels) as defined in Directive 2014/94/EU of the European Parliament and of the Council of 22/10/2014 on the deployment of an infrastructure for alternative fuels, paragraphs 4 and 6, and on the Commission Communication of 24/01/2013 "Clean energy and transport: the European strategy for strategy for alternative fuels". To carry out this ADV_BIO project, the project will focus on non-food biomasses, namely microalgae and lignocellulosic materials, which have a risk of have a low risk of Indirect Land Use Change as foreseen in the Directive (EU) 2018/2001 of the European Parliament and of the Council of 11 December 2018 on the promotion the use of energy from renewable sources and its recast of 13 March 2019 describing the specification of sustainability criteria for biofuels. To carry out this research, four universities are involved: the University of Liège (ULiege), the Catholic University of Leuven (UCLouvain), Ghent University (UGent) and the University of Antwerp (UAntwerp) through 6 distinct research groups covering aspects of physiology, genetical modification, chemical engineering, energy and environmental economics and quantitative sustainability assessments.

Researcher(s)

• Promoter: Van Passel Steven
• Co-promoter: Billen Pieter

Research team(s)

• Engineering Management

Project type(s)

• Research Project

Abstract

This project aims to recycle post-industrial polyurethane (PU) waste, i.e., production waste, scrap and/or poor-quality PU containing more than one polyol as a three-phase system, which we have recently observed for the first time in our laboratory. Using this technology, different polyols can be recovered separately with higher purity than the current state of the art chemical recycling. Currently, this post-industrial waste is either incinerated or, at best, mechanically recycled into low-value products. With our strategy, all polyols will be fully recovered and reused in foam production. In the medium term, this should lead to small modular polyol recovery units. In addition, the project will produce amines in a one-step recycling process and separate them in a less energy-intensive process. An important operational objective is to apply this concept to different types of PU waste containing more than one polyol from different production units.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Vande Velde Christophe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

ChemReRub is a project that aims to recycle natural and synthetic rubber, a recalcitrant waste material of partly natural origin, into high-value chemical feedstock for use in various applications, in order to get away from the classical strategy of energy recuperation.

Researcher(s)

• Promoter: Vande Velde Christophe
• Co-promoter: Billen Pieter

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

This project aims at the complete recycling of polyurethane waste, by a two stage procedure in which both polyols and isocyanates are recovered. With respect to state-of-the-art technologies and concurrent research initiatives, this project targets production of isocyanate fractions from waste via a shorter route, without prior production of amines. An important operational goal is the development of a new lab scale custom reactor setup, next to the testing on actual polyurethane waste samples.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Vande Velde Christophe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

This project is being carried out by the University of Antwerp and VITO, and supported by the Belgian Road Research Centre (BRRC). Two possible solutions are being investigated to prevent the release of zinc from rubber granules; on the one hand by coating the rubber granules (UAntwerp) and on the other hand by trapping the released harmful components in a sorbent before they are released into the environment (VITO). Possible solutions can, be developed further at a later stage (phase II) and can be used for many applications of rubber granulates where environmental problems play a role. In the follow-up research, attention will also be paid to the recyclability and durability of both solutions (influence of ageing and/or exceptional weather conditions).

Researcher(s)

• Promoter: Vuye Cedric
• Co-promoter: Billen Pieter
• Co-promoter: Blom Johan
• Co-promoter: Blust Ronny
• Co-promoter: Dardenne Freddy
• Co-promoter: Vande Velde Christophe
• Co-promoter: Verbruggen Sammy

Research team(s)

• Sustainable Pavements and Asphalt Research (SuPAR)

Project type(s)

• Research Project

Abstract

The series of lectures is structured around three important production and consumption chains that largely determine the footprint of the modern consumer: energy, materials and food. For each of these three chains, the international context and evolution is outlined. Critical elements in the chains are examined with a closer look at production, consumption and disposal. The lectures are illustrated with cases from own research.

Researcher(s)

• Promoter: Billen Pieter

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

This project provides an innovative, new and different way of recycling post-consumer rubber, not as granulates, but as valuable feedstock for the production of recyclable polymers. Two important contributors in Flanders are recycled tires and latex mattresses. The purpose of this project is to bring the recycling technology from initial concept stage to a laboratory demonstrated process with poly-diene rubbers being recycled into starting materials for recyclable condensation polymers, preferably with ground rubber tire material as feedstock.

Researcher(s)

• Promoter: Vande Velde Christophe
• Co-promoter: Billen Pieter

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Natural rubber is a biopolymer with many applications, but its recycling and reuse are an especially challenging problem. Until now, the most prevalent waste treatment method for rubber is either burning or landfills. Devulcanization of the rubber, necessary for for its reuse as an elastomer, is extremely difficult. Use of rubber as a green feedstock, after a useful life as an elastomer, has hardly been explored. Ozonolysis is a polyvalent technique that finds application in cutting C=C double bonds in a polymer and creating terminal functionalities where the chain has been cut. In this way, it must be possible to depolymerize natural rubber to use as feedstock for other condensation polymers that are easier to recycle than rubber itself. This, then, is the threefold goal of this project: 1. Depolymerization of rubber – latex foam and ground rubber tire- into oligomeric materials with terminal functionalization, and researching the influence of the process parameters of ozonolysis on the properties and chain lengths of these materials. 2. Researching the fate during this process of the cross-links that are created in natural latex during vulcanization. 3. Using the example of rubber as a case in the development of LCA and TEA tools, and provide real-time feedback from these studies to this project with regard to the use of certain chemicals, solvents and the general technical-economic feasibility of the process during its development.

Researcher(s)

• Promoter: Vande Velde Christophe
• Co-promoter: Billen Pieter
• Co-promoter: Pazdur Lukasz

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

The proposal concerns versatile instrumentation for determining crystallinity, unit cell size and structure of organic, metal-organic and inorganic materials. Several groups at UAntwerp have a pressing need for fast, reliable, X-ray diffraction data, at low angles to determine large unit cells, and preferably in 2D to determine sample homogeneity. The envisaged machine has a Cu K alpha source, horizontal sample platform (Bragg-Brentano geometry), capability for measuring down to low angles (theta = 0.5°), and a fast and sensitive 2D solid state area detector. It will be used for materials research and characterization in inorganic porous materials (zeolites, templated silicas and titanias), metal organic materials (crystalline metal-organic frameworks), organic materials (fatty acids, PUR building blocks) and identification and characterisation of pigments for study and conservation of old masters' paintings. In addition, through the use of the PDF (probability density punction), the machine can generate experimental information through x-ray scatterineg on average short-range order in non-crystalline materials such as glasses and amorphous powders.

Researcher(s)

• Promoter: Vande Velde Christophe
• Co-promoter: Billen Pieter
• Co-promoter: Cool Pegie
• Co-promoter: Kiekens Filip

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Based on the recently developed "physico chemical separation methods", a process will be developed that allows to reduce the level of oxygenates and nitrogenates in pyrolysis oil and increasing it valorization potential. The process can be a substitute for hydrotreatment.

Researcher(s)

• Promoter: Billen Pieter
• Promoter: Tavernier Serge
• Co-promoter: Billen Pieter
• Co-promoter: Perreault Patrice

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Natural deep eutectic solvents (NADES) show great promise as media for enzymatic reactions in sectors where (bio)compatibility with natural or medical products is a must. Whereas in theory they can be tailored to the envisioned reaction, ensuring optimized yields, to date the knowledge is predominantly empirical, with some mechanistic reports giving a fragmented view at best. Therefore, even merely explaining experimental observations is not straightforward, let alone making predictions. This doctoral study aims at building a structured, holistic understanding of the effect of NADES media on enzymatic reactions, whereby effects on solubility, solvation, viscosity, inhibition and denaturation will be distinguished. The solubility, solvation energy and viscosity will be predicted by first principles and molecular dynamics calculations, serving as input for a group contribution model using machine learning. Experiments will train and validate the model, and learnings from observed reaction kinetics will be further benchmarked against molecular dynamics calculations of enzyme structures and interactions in NADES. Structural changes of the enzyme will be demonstrated using Raman optical activity spectroscopy. The combination of these methods ensures fundamental knowledge acquisition, while the group contribution model is part of a structured methodology. The findings of this project are transferable to other uses of NADES.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Cornet Iris
• Co-promoter: Neyts Erik
• Fellow: Kovács Attila

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

Polyurethanes (PU) are versatile group of polymers, being used increasingly in diverse applications; for instance in mattresses, building foams, automotive and adhesives. PU is a cross-linked polycondensation polymer, in which polyols (polyhydroxyl alcohols) react with highly reactive diisocyanates. As a thermoset (they do not have a melting point), PU is difficult to recycle, and the current state-of-the-art mechanical recycling results in low-value materials. Nonetheless, chemolysis (chemical depolymerization) has been explored since decades as an alternative, yet was only commercially developed for polyol recovery. The absence of a working technology for recovery of diisocyanate derivatives is largely due to the complexity of these molecules, and a lack of knowledge regarding their chemical fate in a chemolysis process. The proposed STIMPRO aims at understanding how various isocyanate derivatives are formed, and how they react upon alcoholysis, by experiments using model monomers. This knowledge, together with experimental and computational insights in mixing/solubility, will be exploited to create a bottom-up chemolysis process for model polyurethanes. The outcome of the proposed study will be used in subsequent chemolysis of realistic waste polyurethanes, with recovery of both monomers as significant technological novelty. Additionally, the resulting knowledge may be transferred in the future formulation of new polyurethanes with biobased alternative monomers

Researcher(s)

• Promoter: Pazdur Lukasz
• Co-promoter: Billen Pieter
• Co-promoter: Vande Velde Christophe

Research team(s)

• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)
• Biochemical Wastewater Valorization & Engineering (BioWaVE)

Project type(s)

• Research Project

Abstract

The P2PC project aspires to cope with the urgent issue of plastics waste management. The project targets the challenge of increasing plastic waste volumes and diversity on the one hand, as well as the establishment of circular material schemes instead of value destruction. The most important premise of P2PC is that by pyrolysis, plastic waste that is currently being burned or landfilled can be a source of diverse chemical building blocks, the so-called "precious chemicals". Its target, in other words, is to turn plastic waste into value. This way, P2PC can be considered as the next step in Flanders' efforts to lead the global effort in tackling the challenge of waste plastics.

Researcher(s)

• Promoter: Billen Pieter
• Promoter: Tavernier Serge
• Co-promoter: Billen Pieter
• Co-promoter: Van Passel Steven

Research team(s)

• Biochemical Wastewater Valorization & Engineering (BioWaVE)
• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project website

Project type(s)

• Research Project

Abstract

The poor air quality in our cities is currently at the centre of public debates on health living conditions and at the pinnacle of innovative urban planning and mobility policies. Especially, so-called 'street canyons' represent the most problematic arteries of our cities: these are narrow inner-city roads that are flanked on both sides by a continuous row of (high) buildings. In these street canyons, the air quality is often below the European standards and those of the World Health Organization. Both urban design and technological solutions, such as photocatalyst, have proven to be a powerful tools for improving the air quality and overall health. However, this research is often restricted to a single domain, sector or discipline (either bioengineering or urban design) and is often limited to the analysis of the impact of a single parameter on air quality. Secondly, the most well-known measures focus on the reduction of emissions of pollutants and are situated on a larger scale planning and policy level. At the local scale level of traffic intensive locations and the so-called street canyons, systematic research on the possible contribution of urban design and technological interventions to improve the air quality is lacking. Moreover, a group of pollutants under less public scrutiny, volatile organic carbon (VOC), are less susceptible to traffic regulations. The treatment of paving, walls and facades with a photocatalyst have proven to contribute to improve the air quality. However, in street canyons the airflow rates are often low for an optimal performance of these photocatalysts. Alterations of the urban design (that improve the air circulation and the integration of UV lightning) can seek VOC abatement in urban street canyons with minimized environmental burden. In conclusion, in terms of air quality on the level of street canyons, there exists a fundamental disciplinary schism between environmental and urban design sciences. Dealing with the spatial distribution of air pollution and high threshold to bridge technological innovation with urban planning, this research project aims to combine environmental and design sciences. Therefore, the Research group for Urban Development (Design Sciences), DuEL and BioGEM (Engineering Sciences) decided to team up to tackle together this pregnant challenge. The scientific challenge grasped in this project is threefold: (1) Understand the spatial and molecular distribution of VOC in urban environment, with focus on street canyons, (2) Maximize the effect of urban design changes to improve the health effects of street canyons by incorporating photocatalytic abatement technologies; (3) Formulate design guidelines for improvement of air quality in street canyons based on LCA metrics, and extrapolate the methodology to future technological improvements. Together these challenges constitute an opportunity to significantly lower the threshold for future developments to improve the health conditions in street canyons. Divided over four Work Packages and four years, this multidisciplinary approach of this challenge calls for a combination of methodologies, ranging from literature review, to research by design, over modelling and case study research. The Turnhoutsebaan in Antwerp is selected as case study, being representative for typical Flemish street canyons in terms of structural characteristics (length, height over width ratio), traffic density, demonstrated high air pollution levels and the availability (or lack) of green infrastructure.

Researcher(s)

• Promoter: Van Acker Maarten
• Co-promoter: Billen Pieter
• Co-promoter: Tytgat Tom
• Fellow: Voordeckers Dimitri

Research team(s)

• Research Group for Urban Development

Project website

Project type(s)

• Research Project

Abstract

This proposal aims at demonstrating the suitability and elucidating the effect of new green solvent media, natural deep eutectic solvents (NADES), on enzymatic reactions. NADES are eutectic mixtures of two or more biological primary metabolites (saccharides, amino and other organic acids, polyols, urea, choline) that are liquid at or slightly above room temperature, due to networking hydrogen bond interactions. Although they have been investigated earlier as green extraction media, reports on their use for enzymatic reactions are limited. For the first time, we will investigate their influence on enzymatic reactions by disaggregating the following effects: solvation energy, mass transfer in bulk and enzyme-substrate-intermediates stability. A well-known enzymatic conversion, i.e. deacetylation of a crude mannosylerythritol lipid (MEL) mixture aided by Novozym 435 (a commercial lipase), will be performed in selected NADES as a case example. Although no multi-parametric regression modeling will be done, qualitative (and semi-quantitative) insights will be gathered through coupling parametric solubility modeling (Hansen model, with experimental validation and input) with physicochemical characterization (viscosity, surface tension) of NADES systems, and concentration (substrate, enzyme) and temperature dependent kinetic experiments and modeling. The anticipated outcome of the project is a clear indication of enzymatic performance in fit for purpose NADES, and a breakdown of marginal efficiency change into solvation, activity and mass transfer differences with respect to traditional organic solvent systems.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Cornet Iris

Research team(s)

• Biochemical Wastewater Valorization & Engineering (BioWaVE)
• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

The MATTER-project, a two-year Catalisti-ICON project (2018-2019), wants to evaluate the recycling of mixed (post-consumer) plastic waste streams and to use the generated data to develop a decision supporting framework. Within the MATTER-project, technical and market-based criteria will be developed to support an optimal plastic waste management system. More specifically, the project will focus on the P+ fraction (all plastics packaging waste) of the extended P+MD collection and recycling scheme. Partners from across the whole value chain are included in the project consortium: separation and pretreatment (Indaver and Bulk.ID), mechanical recycling (Borealis and ECO-oh!) and thermochemical recycling (Indaver and Borealis). Sustainability analyses will enable the development of a decision-supporting framework.

Researcher(s)

• Promoter: Billen Pieter
• Co-promoter: Van Passel Steven

Research team(s)

• Biochemical Wastewater Valorization & Engineering (BioWaVE)
• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

This proposal aims at confirming/contradicting recently discovered (Bombelli et al., Current Biology 2017) accelerated biochemical conversion of low density polyethylene (LDPE) by larvae of the greater wax moth Galleria mellonella, and investigate the nature and yield of metabolites. Strong concerns about the validity of these findings were published immediately thereafter (Weber et al., Current Biology 2017). The proposed research will employ an improved analytical setup, using blank and sterile samples, while analyzing composite homogenate/LDPE samples, and additionally will focus on a mechanistic understanding of the conversion process. In case of a positive result, this research will initiate further efforts to establish new biochemical recycling processes for polyolefins, in a time at which mechanical recycling is faced with its limitations. Yet, in case of disproval of state-of-the-art literature, the proposed research allows to join a running scientific discussion, and will generate knowledge and expertise on biochemical polyolefin degradation, or alkane functionalization in a broader perspective.

Researcher(s)

• Promoter: Billen Pieter

Research team(s)

• Biochemical Wastewater Valorization & Engineering (BioWaVE)

Project type(s)

• Research Project

Abstract

The ImPrOVE (Innovative (pre)POmace Valorization procEss) project addresses a major European wide agro-related problem: pomace resulting from pressing fruit. This high amount of pomace is considered waste, but contains natural and highly functional compounds. Skin and core of fruit contain protecting and functional molecules: antioxidants, stabilizers, colorants, aromas, fibers with potential in high value applications in cosmetics, diets and, as bio-additives in food and beverages. ImPrOVE aims to fully valorize pomace by using a combination of existing and innovative processes. These should be easy without high energy/cost demands, resulting in access for S(M)E's (economic strategic European targets) with profit redistributed over the whole chain, strengthening Europe's agro and food activities. ImPrOVE will design a generic process flow applicable to most pomace types. Two cases will be studied: Southern European olive pomace and Mid/Northern European apple/pear/cherry/cucumber pomace. Total valorization is achieved in three process clusters: (1) pretreatment of the pomace giving raise to aromas and oil from separated seeds; (2) extraction of high value materials from the pretreated pomace and (3) valorization of the resulting fibrous mass, either directly (functionally designed fibers) or by splitting cellulose-lignin and valorizing both materials physically, enzymatically and/or chemically. An ambitious concept is to use bio-based ionic liquids (BIOILs) or natural deep eutectic solvents (NADES) as extraction liquids advanced green solvents. More ambitious, highly appealing, is to study whether the extraction solution itself can be utilized instead of the isolated and purified ingredients, avoiding some downstream processing. Dermatological and metabolomic tests, (eco)toxicity, biodegradation, LCA, industrial relevance, scalability and economic viability will be sustainably addressed by the European multidisciplinary partner cluster, with academic and industrial members.

Researcher(s)

• Promoter: Billen Pieter
• Promoter: Tavernier Serge

Research team(s)

• Biochemical Wastewater Valorization & Engineering (BioWaVE)
• Intelligence in PRocesses, Advanced Catalysts and Solvents (iPRACS)

Project type(s)

• Research Project

Abstract

The proposed research aims at developing (new) affordable, valuable long chain α,ω bifunctional monomers for condensation reactions, sustainably produced, and provide demonstration samples, in view of filing a patent application with parallel industrial valorization. The envisioned monomers will yield new materials, polymers in particular, with unprecedented physicochemical, thermal and mechanical properties compared to existing short (max. C10 chains) α,ω bifunctional condensation monomers. Moreover, the newly developed materials are expected to be biodegradable, and offer opportunities for chemical recycling. To date, monomers comparable to our envisioned monomers can only be produced at low carbon efficiencies and high economic and environmental cost. In contrast, we propose a new synthesis route, complying to green chemistry principles, yielding long (C18+) α,ω bifunctional monomers, as well as their asymmetric versions, and a synthesis route for chain length extension and even doubling. The latter two processes were thus far (industrially) neither known nor feasible. Monomers with such long or doubled chain length were unprecedented to date. The feasibility of our proposed synthesis route has already been demonstrated by preliminary experiments. The performance of such new C18 polyester structures will be benchmarked against that of traditional (short chain) alternatives. A second phase focuses on longer (C18+) chains. In the latter case an ether molecule from two fatty chains, terminated on both sides, will be obtained. The total length of the chain between two functional groups is intended to be long, meaning at least 18 atoms. We hypothesize that the presence of the ether-oxygen internally does not fundamentally alter the chain structure, resulting in similar properties as an equivalent homogeneous carbon chain. The properties of the associated newly obtained oligomers and polymers will be assessed, and the data obtained will serve as examples for a patent application. In a third phase the production process will be optimized (e.g. with respect to cost structure) for a selection of monomers, i.e. those with the highest industrial demand. These monomers will be produced and supplied in larger quantities as demonstration samples, in light of prompting industrial valorization. First cost estimates will be made.

Researcher(s)

• Promoter: Tavernier Serge
• Co-promoter: Billen Pieter

Research team(s)

• Biochemical Wastewater Valorization & Engineering (BioWaVE)

Project type(s)

• Research Project