Teaching activities

->KZ8021 Materials Chemistry for Environmental Applications, Examiner

I accept interns and project students  at bachelor and master levels. Please contact me by e-mail with an application if you are interested in contributing to our reasearch.

Research

Materials for environment

• Fully biobased membranes/ filters for water purification
• Surface chemistry and interactions, mechanical properties, viscoelastic properties, in situ SAXS
• Atomic force microscopy (understanding properties at nano scale, colloidal probe)

Materials for health

• Biobased materials for medical applications
• Tissue engineering, wound dressing, antifouling and antibacterial materials 

Synthesis and processing methods for sustainable materials

• Nanocellulose and nanochitin isolation and characterization
• Designing of recycling and circularity of materials 
• Data driven design of materials
• High through put processing and synthesis

Earlier fundings 

3D printing of biobased filters functionalised with nanocellulose for water purification 

Wallenberg Wood Science Centre Funding, Functional Materials Research at Stockholm University, 2019-2022 (www.wwsc.se)

The overall project aims to develop new routes to process and produce filters by melt-based 3D printing. The active part in the filters will be based on nanocomposites having nanocellulose as a component, to elucidate how the porosity and surface chemistry can be tailored to provide high water flux, high separation efficiency, and long-term stability in wet environment. 

Understanding nanocellulose hybrid membranes by means of advanced atomic force microscopy (AFM), Raman/NMR spectroscopy, X-ray scattering and computational chemistry methodologies

Swedish Research Council (2018-2021)

The project develops experimental procedures to probe biobased hybrids in liquid medium/ wet conditions using atomic force microscopy and spectroscopy and in situ X-ray scattering, combined with computational chemistry is envisioned in the project to evaluate and predict the self-assembling between nanocellulose and other nanoparticles and understand how the self-assembled morphologies drive the pore structure formation and adsorption in biobased membarnes and filters used for water purification.

Project Co-ordinator: FP7-NMP-2011-SMALL-5, Proposal reference number: 280519-2 2011, Budget: 4M €uros, Co-ordinator, 2012-2016

Principal Investigator:

• Wallenberg Wood Science Centre Funding, Functional Materials Research at Stockholm University, 2015-2019
• Stockholm University Faculty support, 2015- 2019 
• VR 2013, 2014-2017.; Swedish research links
• International collaborative research grants, South Africa, 2009-2011
• Swedish research links, International collaborative research grants, India; 2009-2011
• Nanomembran för rening av gaser och vätskor, Innovationsbron, (2009) 
• Biobased scaffolds, membranes and hydrogels for imporved wound healing and bone regeneration (Bioheal) 
• Swedish Research Links, International collaboration: 2017-2020

Partner: CEREAL (ERANET-SUSFOOD, 2014- 2017; n-POSSCOG, no: 2011-02071
 MNT-ERA.NET 

Transnational Call 2011; H2020, NanoTextsurf, 2017-2020. www.nanotextsurf.eu

A selection from Stockholm University publication database

• Citrated cellulose nanocrystals from post-consumer cotton textiles

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

  Article

  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.

  Read more about Citrated cellulose nanocrystals from post-consumer cotton textiles

• In-Situ Growth of Metal Oxide Nanoparticles on Cellulose Nanofibrils for Dye Removal and Antimicrobial Applications

  2020. Luis Valencia (et al.). ACS Applied Nano Materials 3 (7), 7172-7181

  Article

  Nanocellulose is known to act as a platform for the in-situ formation of metal oxide nanoparticles, where the multiple components of the resultant hybrids act synergistically toward specific applications. However, typical mineralization reactions require hydrothermal conditions or addition of further reducing agents. Herein, we demonstrate that carboxylated cellulose nanofibril-based films can spontaneously grow functional metal oxide nanoparticles during the adsorption of heavy metal ions from water, without the need of any further chemicals or temperature. Despite the apparent universality of this behavior with different metal ions, this work focuses on studying the in-situ formation of copper oxide nanoparticles on TOCNF films as well as the resultant hybrid films with improved functionality toward dye removal from water and antimicrobial activity. Using a combination of cutting-edge techniques (e.g., in-situ SAXS and QCMD) to systematically follow the nanoparticle formation on the nanocellulosic films in real time, we suggest a plausible mechanism of assembly. Our results confirm that carboxylated cellulose nanofibril films act as universal substrate for the formation of metal oxide nanoparticles, and thus hybrid nanomaterials, during metal ion adsorption processes. This phenomenon enables the upcycling of nanocellulosic materials through multistage applications, thus increasing its sustainability and efficiency in terms of an optimal use of resources.

  Read more about In-Situ Growth of Metal Oxide Nanoparticles on Cellulose Nanofibrils for Dye Removal and Antimicrobial Applications

• Unlocking the potential of post-consumer garments as a source of nanocellulose

  2024. Maria-Ximena Ruiz-Caldas, Varvara Apostolopoulou Kalkavoura, Aji P. Mathew. Cell Reports Physical Science 5 (2)

  Article

  Discarded garments contribute to an environmental crisis worldwide, prompting the development of new strategies for recycling and upcycling. In this work, we present the extraction of nanocellulose from textiles as an underexplored route for upcycling textile garments made of cotton. We summarize the current state of textile waste management worldwide, discuss strategies for extracting nanocellulose from cotton -based textiles, and outline the associated challenges and outlooks in this field. We further aim to highlight the opportunities and advantages of using cotton as a nanocellulose source and stimulate further research in this area.

  Read more about Unlocking the potential of post-consumer garments as a source of nanocellulose

• Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands

  2022. Anneli Adler (et al.). Joule 6 (8), 1845-1858

  Article

  Here, we show that lignin-first biorefining of poplar can enable the production of dissolving cellulose pulp that can produce regenerated cellulose, which could substitute cotton. These results in turn indicate that agricultural land dedicated to cotton could be reclaimed for food production by extending poplar plantations to produce textile fibers. Based on climate-adapted poplar clones capable of growth on marginal lands in the Nordic region, we estimate an environmentally sustainable annual biomass production of ∼11 tonnes/ha. At scale, lignin-first biorefining of this poplar could annually generate 2.4 tonnes/ha of dissolving pulp for textiles and 1.1 m³ biofuels. Life cycle assessment indicates that, relative to cotton production, this approach could substantially reduce water consumption and identifies certain areas for further improvement. Overall, this work highlights a new value chain to reduce the environmental footprint of textiles, chemicals, and biofuels while enabling land reclamation and water savings from cotton back to food production.

  Read more about Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands

• 3D printed polylactic acid (PLA) filters reinforced with polysaccharide nanofibers for metal ions capture and microplastics separation from water

  2023. Natalia Fijoł (et al.). Chemical Engineering Journal 457

  Article

  The need for multifunctional, robust, reusable, and high-flux filters is a constant challenge for sustainable water treatment. In this work, fully biobased and biodegradable water purification filters were developed and processed by the means of three-dimensional (3D) printing, more specifically by fused deposition modelling (FDM).

  The polylactic acid (PLA) – based composites reinforced with homogenously dispersed TEMPO-oxidized cellulose nanofibers (TCNF) or chitin nanofibers (ChNF) were prepared within a four-step process; i. melt blending, ii. thermally induced phase separation (TIPS) pelletization method, iii. freeze drying and iv. single-screw extrusion to 3D printing filaments. The monolithic, biocomposite filters were 3D printed in cylindrical as well as hourglass geometries with varying, multiscale pore architectures. The filters were designed to control the contact time between filter’s active surfaces and contaminants, tailoring their permeance.

  All printed filters exhibited high print quality and high water throughput as well as enhanced mechanical properties, compared to pristine PLA filters. The improved toughness values of the biocomposite filters clearly indicate the reinforcing effect of the homogenously dispersed nanofibers (NFs). The homogenous dispersion is attributed to the TIPS method. The NFs effect is also reflected in the adsorption capacity of the filters towards copper ions, which was shown to be as high as 234 and 208 mg/gNF for TCNF and ChNF reinforced filters, respectively, compared to just 4 mg/g for the pure PLA filters. Moreover, the biocomposite-based filters showed higher potential for removal of microplastics from laundry effluent water when compared to pure PLA filters with maximum separation efficiency of 54 % and 35 % for TCNF/PLA and ChNF/PLA filters, respectively compared to 26 % for pure PLA filters, all that while maintaining their high permeance.

  The combination of environmentally friendly materials with a cost and time-effective technology such as FDM allows the development of customized water filtration systems, which can be easily adapted in the areas most affected by the inaccessibility of clean water.

  Read more about 3D printed polylactic acid (PLA) filters reinforced with polysaccharide nanofibers for metal ions capture and microplastics separation from water

Show all publications by Aji Mathew at Stockholm University