I urval från Stockholms universitets publikationsdatabas

• Citrated cellulose nanocrystals from post-consumer cotton textiles

  2023. Maria-Ximena Ruiz-Caldas (et al.). Journal of Materials Chemistry A

  Artikel

  We propose a new method for the extraction of cellulose nanocrystals (CNCs) from post-consumer cotton textiles through surface functionalization followed by mechanical treatment. Cotton-based textiles were esterified using an 85 wt% solution of citric acid at 100 degrees C, then further fibrillated in a microfluidizer. The final product, citrated cellulose nanocrystals (CitCNCs), was a dispersion of needle-like nanoparticles with high crystallinity. Up to 78 wt% of the cotton fabric was converted to CitCNCs that exhibited higher yields and a higher surface group content than CNCs extracted through H2SO4 hydrolysis, although CitCNCs showed a broader size distribution and decreased thermal stability. Experimental data supported by DFT calculations showed that the carboxyl groups on the CitCNC surface are bonded to cellulose by mono or diester linkages. An early-stage life cycle assessment (LCA) was performed to evaluate the environmental impact of using discarded textiles as a source of cellulose and analyze the environmental performance of the production of CitCNCs. Our work showed a significant reduction in the environmental burden of CNC extraction using post-consumer cotton instead of wood pulp, making clothing a good feedstock. The environmental impact of CitCNC production was mainly dominated by citric acid. As a proof of concept, around 58 wt% of the citric acid was recovered through evaporation and subsequent crystallization, which could reduce climate impact by 40%. With this work, we introduce a catalyst-free route to valorize textiles with the extraction of CitCNCs and how conducting LCA in laboratory-scale processes might guide future development and optimization.

  Läs mer om Citrated cellulose nanocrystals from post-consumer cotton textiles

• Cellulose Nanocrystals from Postconsumer Cotton and Blended Fabrics: A Study on Their Properties, Chemical Composition, and Process Efficiency

  2022. Maria-Ximena Ruiz-Caldas (et al.). ACS Sustainable Chemistry and Engineering 10 (11), 3787-3798

  Artikel

  From manufacturing to disposal, the textile industry faces multiple challenges to achieve sustainability and reduce its environmental impact. This work investigates the properties and composition of cellulose nanocrystals (CNCs) extracted from clothing waste made of cotton fibers. We isolated CNCs from cotton, polyester/cotton, and acrylic/cotton waste fabrics through acid hydrolysis with sulfuric acid. A yield of 51-62 wt S4, ( co tt on basis) was obtained, and nearly all the polyester and acrylic libers contained in the initial fabrics were recovered in a convenient shape that could allow easier recycling. CNCs extracted from the selected fabrics showed high purity, similar structural, physical, and chemical characteristics, and their properties were comparable to those extracted from virgin sources, although their surface chemistry and elemental composition slightly differed. The chemical components in the waste fabrics and the extracted CNCs were evaluated through a nontarget chromatographic-mass spectrometric screening strategy. Both the recycled textiles and the CNCs contained hundreds of compounds common in postconsumer textiles, including some with health and environmental concerns. However, our initial findings show that their concentrations in the CNCs are negligible. Our results provide insights into the challenges associated with the use of cotton waste textiles for the extraction of cellulose nanoparticles, and into the potential applications of the extracted nanomaterials.

  Läs mer om Cellulose Nanocrystals from Postconsumer Cotton and Blended Fabrics

• Water Filtration Membranes Based on Non-Woven Cellulose Fabrics: Effect of Nanopolysaccharide Coatings on Selective Particle Rejection, Antifouling, and Antibacterial Properties

  2021. Blanca Jalvo (et al.). Nanomaterials 11 (7)

  Artikel

  This article presents a comparative study of the surface characteristics and water purification performance of commercially available cellulose nonwoven fabrics modified, via cast coating, with different nano-dimensioned bio-based carbohydrate polymers, viz. cellulose nanocrystals (CNC), TEMPO-oxidized cellulose nanofibers (T-CNF), and chitin nanocrystals (ChNC). The surface-modified nonwoven fabrics showed an improvement in wettability, surface charge modification, and a slight decrease of maximum pore size. The modification improved the water permeance in most of the cases, enhanced the particle separation performance in a wide range of sizes, upgraded the mechanical properties in dry conditions, and showed abiotic antifouling capability against proteins. In addition, T-CNF and ChNC coatings proved to be harmful to the bacteria colonizing on the membranes. This simple surface impregnation approach based on green nanotechnology resulted in highly efficient and fully bio-based high-flux water filtration membranes based on commercially available nonwoven fabrics, with distinct performance for particle rejection, antifouling and antibacterial properties.

  Läs mer om Water Filtration Membranes Based on Non-Woven Cellulose Fabrics

Visa alla publikationer av Maria Ximena Ruiz Caldas vid Stockholms universitet