The global production of textiles involves large amounts of health-hazardous chemicals, constituting possible health risks since residues usually remain in the finished garments. An analytical method based on automated thermal desorption (ATD) coupled online to GC/MS for screening of several classes of toxic chemicals in synthetic garments was recently published by us. In the present study, the ATD-GC/MS methodology is further extended to cotton and cotton blend materials. 

Different textile materials with a high content of cotton were found to exhibit large variations in adsorption strength for many chemicals frequently detected in textiles. This was shown to influence the thermal desorption efficiency strongly in ATD-GC/MS. By using absolute response factors from appropriate internal standards spiked directly onto the textile samples, the effects of these differences could be minimized. In this way, accurate quantification was made possible regardless of textile composition, and quantification of native textile chemicals in garments made with the ATD-GC/MS method agreed well with an offline method based on solvent extraction and GC/MS analysis.

The ATD-GC/MS method has now been shown to be applicable for quantitative screening of around 75% of [UN1] [TÅ2] all the textiles on the retail market. The simplified quantification method makes it suitable for screening many samples. For all textile chemicals and fibre materials investigated, the method limits of detection, using only 20 mg of textile, is at least 100 times lower than the current EU regulation for quinoline and several toxic arylamines.

Cellulose nanocrystals (CNCs) are widely used in advanced materials due to their unique mechanical and physicochemical properties. However, their interactions with water, particularly in the context of drying, remain poorly understood. The presence of bound water in CNC poses challenges for processing, storage, and applications sensitive to moisture. In this study, we combine molecular simulations and experimental drying investigations to assess the extent of water retention in both native and TEMPO-CNC under different thermodynamic conditions. Our results demonstrate that while native CNCs can be fully dried under low pressure (≤1 mbar) and elevated temperature (110 °C), TEMPO-CNC retain a significant amount of water (1–7 wt%) due to electrostatic interactions between water molecules and the charged surface carboxylic groups and the sodium counter-ions. These findings provide fundamental insights into the drying behavior of functionalized nanocellulose and highlight the importance of considering residual bound water in applications requiring moisture-sensitive performance.

We have produced foams from cellulose nanofibrils from upcycled cotton (upCNF) and wood (wCNF) through unidirectional (UIT) and multidirectional ice-templating (MIT) and investigated the structural humidity response through in-situ WAXS, SAXS, and micro tomography (μCT) between 10 and 95 % relative humidity (RH). The upCNF and wCNF WAXS patterns displayed a shape- and position shift as the RH was increased, with a compression in the (200) direction and an elongation in the (004) direction. The average separation distance extracted from the 1D SAXS patterns revealed no significant change for the upCNF foams regardless of RH and processing route, while a significant increase was observed for the wCNF foams. The μCT measurements of the upCNF foams showed a slight shift in macropore distribution towards larger pores between 50 and 80 % RH which can be attributed to the weakening and partial disintegration of the pore wall as more moisture is introduced. The humidity-induced structural alterations of the upCNF foam were significantly lower compared to the wCNF foams, confirming our claim of upCNF being more moisture resistant than wCNF foams.

Extracting high-performance nanomaterials from waste presents a promising avenue for valorization. This study presents two methods for extracting cellulose nanofibrils (CNFs) from discarded textiles. Post-consumer cotton fabrics are chemically treated through either cationization with (2,3-epoxypropyl)trimethylammonium chloride or TEMPO/NaBr-catalyzed oxidation, followed by fibrillation to produce Cat-CNFs and TO-CNFs, respectively. Molecular models indicate variations in the effective volume of each grafted group, influencing the true densities of the functionalized fibers. Significant differences in the morphology of the CNFs arise from each functionalization route. Both CNF types exhibit high surface charge (>0.9 mmol g⁻¹), small cross-sections (<10 nm), and high aspect ratios (>35). TO-CNFs have a higher surface charge, whereas Cat-CNFs exhibit a higher aspect ratio and greater colloidal stability across a broader pH range. Cat-CNFs exhibit cross-sections at the elementary fibril level, highlighting the steric impact of the grafted surface groups on fibrillation efficiency. Nanopapers from these CNFs demonstrate high optical transmittance and haze, whereas anisotropic foams show mechanical properties comparable to foams made from wood-based CNFs. This work highlights the potential of post-consumer cotton textiles as a CNF source and the impact of chemical treatment on the properties of the fibers, CNFs, and resulting lightweight materials.

The upcycling of discarded garments can help to mitigate the environmental impact of the textile industry. Here, we fabricated hybrid anisotropic foams having cellulose nanocrystals (CNCs), which were isolated from discarded cotton textiles and had varied surface chemistries as structural components, in combination with xanthan gum (XG) as a physical crosslinker of the dispersion used for foam preparation. All CNCs had crystallinity indices above 85 %, zeta potential values below -40 mV at 1 mM NaCl, and true densities ranging from 1.61 to 1.67 g center dot cm(-3). Quartz crystal microbalance with dissipation (QCM-D) measurements indicated weak interactions between CNC and XG, while rheology measurements showed that highly charged CNCs caused the XG chains to change from an extended to a helicoidal conformation, resulting in changes the in viscoelastic properties of the dispersions. The inclusion of XG significantly enhanced the compression mechanical properties of the freeze-casted foams without compromising their thermal properties, anisotropy, or degree of alignment. CNC-XG foams maintained structural integrity even after exposure to high humidity (91 %) and temperatures (100 degrees C) and displayed very low radial thermal conductivities. This research provides a viable avenue for upcycling cotton-based clothing waste into high-performance materials.

The linear lifecycle of the textile industry contributes to the enormous waste generation of post-consumer garments. Recycling or repurposing of post-consumer garments typically requires separation of the individual components. This study describes a novel and facile chemo-thermo-mechanical method for producing extrudable pellets, involving one-pot, 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation of post-consumer polycotton textiles, followed by mild mechanical treatment, all without isolating the constituents of the polycotton blend. The oxidized blend with high cellulose and carboxylate content of 1221 ± 82 mmol COO− per kg of cotton, is pelletised into a masterbatch and further in situ extruded into nanocomposite filaments for 3D printing. The carboxyl groups introduced on the polycotton-based filters enable cotton fibrillation into nanoscaled fibers during mechanical treatment and extrusion resulting to a variety of functional and high surface-finish quality models, including filters and fashion accessories. The electrostatic interactions with positively charged species, such as methylene blue (MB), facilitate their adsorption from water while exhibiting promising adsorption capacities. The adsorption of MB follows the Freundlich model and depends on the printed porosity of the filter. A “trash to treasure” concept for textile waste is further corroborated through the use of the developed 3D printing filament into commodity products.

The environmental impact is a strong incentive for the development of upcycling processes for textile waste. However, toxic chemicals may occur in both brand-new textiles and post-consumer garments, and the chemical transfer in such routes is important to investigate. The present study applied non-target screening and quantification with liquid chromatography/mass spectrometry to follow the fate of hazardous chemicals from post-consumer polycotton garments to a new material, cellulose nanocrystals, in a chemical upcycling utilizing strongly acidic conditions. The majority of hazardous chemicals detected within the process were found to be transferred to a residual of polyester material and not to the enriched cellulose. However, phthalates were found to be mainly attached to the cellulose nanocrystals. The detected total concentration, in this case, was below 5 μg/g, at least 200 times lower than the limit set by the European Union. This indicates the importance of monitoring and controlling the phthalate content in the starting material of the process, i.e., the post-consumer garments. The chemical release into the process waste effluent could be estimated based on water solubility data for chemicals under the applied conditions. Three compounds, the water-repellent substance perfluorooctanesulfonic acid and the dyes Crystal Violet and Victoria Pure Blue, were almost entirely transferred into the process waste effluent. Although the levels detected were very low in the present pilot process, their presence eventually indicates the need for wastewater purification at further upscaling, depending on the exposure and dose in relation to toxicological relevant thresholds.

Biopolymer-based functional materials are essential for reducing the carbon footprint and providing high-quality lightweight materials suitable for packaging and thermal insulation. Here, cellulose nanocrystals (CNCs) were efficiently upcycled from post-consumer cotton clothing by TEMPO-mediated oxidation and HCl hydrolysis with a yield of 62% and combined with wood cellulose nanofibrils (CNFs) to produce anisotropic foams by unidirectional freeze-casting followed by freeze drying (FD) or supercritical-drying (SCD). Unidirectional freeze-casting resulted in foams with aligned macropores irrespective of the drying method, but the particle packing in the foam wall was significantly affected by how the ice was removed. The FD foams showed tightly packed and aligned CNC and CNF particles while the SCD foams displayed a more network-like structure in the foam walls. The SCD compared to FD foams had more pores smaller than 300 nm and higher specific surface area but they were more susceptible to moisture-induced shrinkage, especially at relative humidities (RH) > 50%. The FD and SCD foams displayed low radial thermal conductivity, and the FD foams displayed a higher mechanical strength and stiffness in compression in the direction of the aligned particles. Better understanding how drying influences the structural, thermal, mechanical and moisture-related properties of foams based on repurposed cotton is important for the development of sustainable nanostructured materials for various applications.

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.

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.