Case studies

In this case study, cotton-based textiles are converted into cellulose nanocrystals (CNC) using acid hydrolysis in a water-based system. The development of a new milder processing route was investigated, where citric acid was used for acid hydrolysis. The aim is to develop safer process routes and reagent recycling for improved environmental performance compared to other textile recycling routes. By use of analytical non-target screening tools based on mass spectrometry, the content of potentially hazardous chemicals in both recycled material and waste streams can be assessed, enabling evaluation of the environmental performance.

Contact person: Aji Mathew, Stockholm University

References:

• Ruiz-Caldas, M.-X., et al. (2022). "Cellulose Nanocrystals from Postconsumer Cotton and Blended Fabrics: A Study on Their Properties, Chemical Composition, and Process Efficiency." ACS Sustainable Chemistry & Engineering 10(11): 3787-3798.
• Ruiz-Caldas, M.-X., et al. (2023). "Citrated cellulose nanocrystals from post-consumer cotton textiles." Journal of Materials Chemistry A . 11 (13), 6854-6868.

In this case study a Ni-catalyzed electrochemical reduction of alkynes to Z-alkenes, and alkenes to alkanes, in a water-based reaction medium, is developed. Scarce metals are replaced by more abundant metals as the Pd catalyst is replaced by Ni. Hydrogen gas from fossil resources is replaced by hydrogen produced electrochemically from water. The case study includes an assessment of further optimization possibilities by application of non-target screening combined with hazard assessment and life cycle assessment (LCA).

Contact person: Belén Martin-Matute, Stockholm University

References:

• Valiente, A., et al. (2022). "Electrochemical Proton Reduction over Nickel Foam for Z-Stereoselective Semihydrogenation/deuteration of Functionalized Alkynes." ChemSusChem 15(1): e202102221.
• Appiah-Twum, H. (2022). Prospective Life Cycle Assessment of an Electrochemical Hydrogenation Process Over a Nickel Foam Cathode. Master Thesis Uppsala University.
• Valiente Sánchez, A. (2021) Catalytic and Electrocatalytic Transformations with Palladium and Nickel: Scope and mechanistic investigations. (Department of Organic Chemistry, Stockholm University).

In this case study, a biocatalytic pipeline for sustainable and safe discovery chemistry is developed and validated. This comprises filtering of available starting material according to initial in silico hazard-based prioritization to generate safe building blocks. Then all possible products from these building blocks are assembled in silico and assessed from a safety perspective, reducing the vast amount of possible components further. Next, the identification of suitable biocatalysts that can convert filtered starting material into desired products is identified, followed by engineering and high-throughput screening. The process is scaled up by flow chemistry, followed by an exploration if the products are safe and more sustainable by combining life cycle assessment (LCA) and safety approaches.

Contact person: Per-Olof Syrén, KTH

References:

• Syrén et al. Engineering of Ancestors as a Tool To Elucidate Structure, Mechanism and Specificity of Extant Terpene Cyclase. J. Am. Chem. Soc. 2021, 143, 3794–3807.

A car cabin is a microenvironment that the human population is exposed to and that is affected both by ventilation and emissions from interior materials. The focus of this case study is on the evaluation of exposure to certain chemicals as well as the identification of strategies to decrease or substitute these substances with better alternatives from a health and environmental perspective. The aim is to achieve a substitution with a systems perspective, assuring not only increased safety but also improved environmental performance of the alternatives.

Contact person: Damien Bolinius, IVL Swedish Environmental Research Institute

References: External reports in preparation.

In this case study the environmental effects of silicones are studied and when necessary, suitable substitutes or alternative processes are identified or developed. This entails hazard and risk-based prioritization followed by alternatives assessment for substitution to minimize risks to humans and the environment from siloxanes or other chemicals providing similar function in cosmetics. The aim is to achieve a substitution with a systems perspective assuring not only increased safety but also improved environmental performance of the alternatives.

Contact person: Lisa Skedung, RISE

References: External reports in preparation.

In this case study methods for the inclusion of green chemistry and environmental assessment in the production scale-up of a specialty chemical are developed and tested. This is done on a new chemical, going from the R&D phase to the production phase. Actions include production optimization from an environmental point of view, assessment of degradation products (by in silico approaches and analytical tools) and their potential ecotoxicity (by in silico screening).

Contact person: Richard Lihammar, IVL Swedish Environmental Research Institute

References: Internal reporting. External report expected in end of 2023.

Use of consequential LCA to evaluate environmental sustainability benefits by using kraft lignin in different applications, such as valorization of forest residues.

Contact person: Joseph Samec, Stockholm University

References:
Consequential life cycle assessment of kraft lignin recovery with chemical recyclingExternal link, opens in new window. External link.
Kraft Lignin: A Valuable, Sustainable Resource, Opportunities and ChallengesExternal link, opens in new window. External link.
Valorization of Tops and Branches to Textile Fibers and Biofuel: Value Chain Explored Experimentally; Environmental Sustainability Evaluated by Life Cycle Assessment External link.