Novel sustainable alternatives for the fashion industry: A method of chemically recycling waste textiles via acid hydrolysis

Recycling of Nanocellulose from Polyester-Cotton Textile Waste for Modification of Film Composites

Textile waste has emerged as a critical global challenge, with improper disposal practices leading to adverse environmental consequences. In response to this pressing issue, there is growing interest in recycling textile waste containing cellulose as an alternative approach to reducing the impact of industrial waste on the environment. The objective of this research is to investigate the extraction and characterization of nanocellulose from polyester-cotton textile waste as a potential solution to address the growing concerns of waste management in the textile industry. To obtain nanocellulose, a comprehensive process involving alkaline sodium hydroxide (NaOH) treatment of the polyester-cotton textile (35% PET and 65% cotton) was employed, resulting in average yield percentages ranging from 62.14% to 71.21%. To achieve the complete hydrolysis of PET polyester in the blends, second hydrolysis was employed, and the optimized condition yield cotton fiber was 65.06 wt%, relatively close to the theoretical yield. Subsequently, the obtained cellulosic material underwent an acid hydrolysis process using 70 percent (v/v) sulfuric acid (H2SO4) solution at 45 °C for 90 min, resulting in nanocellulose. Centrifugation at 15,000 rpm for 15 min facilitated the separation of nanocellulose from the acid solution and yielded 56.26 wt% at optimized conditions. The characterization of the nanocellulose was carried out utilizing a comprehensive array of techniques, including absorption, transmission, and reflection spectra, and Fourier transform infrared. The characterization results provide valuable insights into the unique properties of nanocellulose extracted from textile waste. In this research, the obtained nanocellulose was mixed with PVA and silver nanoparticle to form biodegradable film composites as the reinforcement. In comparison, biodegradable film of PVA:nanocellulose 9.5:0.5 with silver nanoparticle 0.3 wt% and glycerol as a plasticizer exhibits better tensile strength (2.37 MPa) and elongation (214.26%) than the PVA film with normal cellulose. The prepared biodegradable film was homogeneous and had a smooth surface without the internal defect confirmed by the CT scan. This result opens avenues for enhancing the quantities of eco-friendly film composites, potentially replacing conventional plastic films in the future.

Consumer perceptions and actions related to circular fashion items: Perspectives of young Brazilians on circular economy

The fashion industry is one of the most important industries for the world economy, but is also one of the most polluting. Some fashion companies have been adopting circular economy initiatives to combat this. Circular fashion (CF) results in cleaner production and reduces textile waste, but depends on consumer collaboration. Several studies analysing consumer CF issues worldwide have been recently published, but these studies are not common in emerging countries. This paper seeks to investigate the relationships between Brazilian consumers and CF. The methodology comprised a systematic literature review and survey. The main results show that, although young consumers are willing to change their clothing consumption habits and believe that fashion companies should be more sustainable, most of them never get involved in circular actions in the fashion chain. This paper seeks to fill a research gap on Brazilian CF, and contribute to both literature and the fashion industry in developing countries.

Valorization of Cheese Whey as a Feedstock for Production of Cyclosporin A by Tolypocladium inflatum

Food waste-based biorefineries are considered an essential concept for the implementation of a sustainable circular economy. In this study, cheese whey powder (CWP), a dairy industry waste, was utilized to produce cyclosporin A (CsA). As it is difficult to valorize CWP because its components vary depending on the origin, a process for sugar conversion via acid hydrolysis was designed to obtain reproducible results using refined whey powder (WP) of a consistent quality. Acid hydrolysis was carried out using 2% (w/w) HCl and biomass loading of 50 g/L at 121 °C for 20 min. CWP hydrolysates were utilized to ferment Tolypocladium inflatum ATCC 34921. CsA production was found to be 51.3 mg/L at 12 days, a 1.4-fold increase compared to the control (commercial glucose, 36.3 mg/L). Our results showed that 100 g CWP can be converted to 81.8 mg of CsA. This finding demonstrated that CWP can be used as a sustainable feedstock for biorefineries.

Recycling of textile wastes, by acid hydrolysis, into new cellulosic raw materials

Chemical recycling can be used to separate fibers that are constituents of different types of fabrics. This type of process can be considered one of the most effective forms of recycling, given that a large part of fabrics is made up of fiber mixtures. As part of an innovative circular strategy, the main goal of this work was to study the conditions for extracting cellulose from mixed textile wastes by acid hydrolysis and further transform it into cellulose derivatives, thus contributing to reduce such wastes and expanding the possible sources of cellulose. Our work covers a wide range of textile wastes and addresses the main technical challenges of this recycling methodology. The percentage of recovered cellulose powder varies between 65 and 88%. To evaluate the feasibility of using the extracted cellulose as raw material to produce cellulose derivatives, two strategies were applied: etherification to obtain sodium carboxymethylcellulose (with degree of substituion between 0.27 and 0.61) and esterification, to obtain cellulose acetate (with degree of substituion of 2.59). The cellulose derivatives obtained are very useful as additives in the textile industry, and hence the concept and practice of a circular economy are promoted.

Methods for Natural and Synthetic Polymers Recovery from Textile Waste

Trends in the textile industry show a continuous increase in the production and sale of textile materials, which in turn generates a huge amount of discarded clothing every year. This has a negative impact on the environment, on one side, by consuming resources—some of them non-renewables (to produce synthetic polymers)—and on the other side, by polluting the environment through the emission of GHGs (greenhouse gases), the generation of microplastics, and the release of toxic chemicals in the environment (dyes, chemical reagents, etc.). When natural polymers (e.g., cellulose, protein fibers) are used for the manufacturing of clothes, the negative impact is transferred to soil pollution (e.g., by using pesticides, fertilizers). In addition, for the manufacture of clothes from natural fibers, large amounts of water are consumed for irrigation. According to the European Environment Agency (EEA), the consumption of clothing is expected to increase by 63%, from 62 million tonnes in 2019 to 102 million tonnes in 2030. The current article aims to review the latest technologies that are suitable for better disposal of large quantities of textile waste.

Recycling different textile wastes for methane production: Morphological and microstructural changes and microbial community dynamics

The dramatic increase of textile wastes has become a major global concern, which calls for alternative practices to alleviate severe environmental pollution and waste of resources due to their improper disposal and management. Anaerobic digestion (AD) is a cost-effective and eco-friendly technology that allows the bioconversion of organic wastes into clean energy (methane), which might be potentially useful for recycling textile wastes. In this study, AD was applied to 11 commonly available textile wastes in daily life to explore their feasibility, along with the methane production efficiency, biodegradability (B_D), degradation mechanism, and microbial community dynamics during AD. The results showed that all textile wastes presented an obvious decomposition from an integrated shape to fragmented pieces within 18 days except blue denim. The highest experimental methane production (EMP) of 356.0 mL/g volatile solids (VS) and B_D of 78.0 % were obtained with flax. The degradation mechanism could be concluded that predominant bacteria, especially Clostridium sensu stricto, first attached to the surface of textile waste and converted its main compositions cellulose and hemicellulose into acetate as the core intermediate. Then, acetate was utilized by the major methanogen, Methanothrix, through the acetoclastic methanogenesis pathway to produce methane. This study not only enriches the understanding of textile wastes degradation mechanisms during AD and provides very useful data on methane production from commonly available textile wastes but also proposes a promising method for efficiently recycling and utilizing the diverse range of textile wastes to reduce waste pollution and generate clean energy simultaneously.

Chemical Recycling of a Textile Blend from Polyester and Viscose, Part I: Process Description, Characterization, and Utilization of the Recycled Cellulose

Material recycling requires solutions that are technically, as well as economically and ecologically, viable. In this work, the technical feasibility to separate textile blends of viscose and polyester using alkaline hydrolysis is demonstrated. Polyester is depolymerized into the monomer terephthalic acid at high yields, while viscose is recovered in a polymeric form. After the alkaline treatment, the intrinsic viscosity of cellulose is decreased by up to 35%, which means it may not be suitable for conventional fiber-to-fiber recycling; however, it might be attractive in other technologies, such as emerging fiber processes, or as raw material for sugar platforms. Further, we present an upscaled industrial process layout, which is used to pinpoint the areas of the proposed process that require further optimization. The NaOH economy is identified as the key to an economically viable process, and several recommendations are given to decrease the consumption of NaOH. To further enhance the ecological end economic feasibility of the process, an increased hydrolysis rate and integration with a pulp mill are suggested.

Concept for the Use of Cotton Waste Hydrolysates in Fermentation Media for Biofuel Production

Currently, most cotton textile waste is sent to landfill. However, due to the use of synthetic additives and the chemical treatment of cotton fibers, cotton textile waste is difficult to biodegrade. Cotton textile waste can also be subjected to material recycling, or to incineration/gasification to produce energy. Here, we present the optimization of acid hydrolysis of cotton yarn fibers for glucose efficiency. The cotton yarn hydrolysates showed great potential for replacing simple sugar solutions in fermentation media. The highest glucose concentration was obtained in the hydrolysates of cotton yarn hydrolyzed in a 2% solution of sulfuric acid or phosphoric acid at 140–160 °C for 2 h. After 2 h of hydrolysis at 140 °C with 2% H3PO4, the concentration of glucose in the cotton yarn hydrolysate (13.19 g/L) increased fivefold compared with cotton yarn treated under the same conditions with H2SO4 (2.65 g/L). The structural modifications in the solid residues after acid hydrolysis were analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), attenuated total reflectance Fourier-transform infrared spectroscopy (FTIR-ATR), and Raman spectroscopy. The SEM images, IR spectra, and Raman spectra revealed that the most significant changes in the morphology of the fibers occurred when the process was carried out at high temperatures (≥140 °C). Better growth of the yeast strains Saccharomyces cerevisiae Ethanol Red and Saccharomyces cerevisiae Tokay ŁOCK0204 was observed in the medium containing phosphoric acid hydrolysate. The maximum methane yield of 278 dm3/kgVS and the maximum hydrogen yield of 42 dm/kgVS were reported for cotton yarn waste after pretreatment with H3PO4. This might have been linked to the beneficial effect of phosphorus, which is a key nutrient for anaerobic digestion. The proposed hydrolysis method does not generate fermentation inhibitors.

The Environmental Impacts of Fast Fashion on Water Quality: A Systematic Review

The fashion industry is the second most polluting industry, contributing 8% of all carbon emissions and 20% of all global wastewater, with an anticipated 50% increase in greenhouse gas emissions by 2030. To gain a better understanding of the state of the academic literature on the environmental impacts of the fast fashion industry, we systematically identified 65 publications from 1996 to November 2021 that were subjected to (i) bibliometric, (ii) text, and (iii) content analysis. We found that there is a growing research interest surrounding fast fashion and water quality, with 74% of the articles published in the last 5 years, and the majority of publications and citations are from China and European countries. We summarise the evaluation of production processes, such as carbon and water footprints, along with recycling practices aimed to increase the sustainability of the fashion industry. Circular economy, social environmental responsibility, and sustainability governance are key areas for future research in this growing field.

Possibility Routes for Textile Recycling Technology

The fashion industry contributes to a significant environmental issue due to the increasing production and needs of the industry. The proactive efforts toward developing a more sustainable process via textile recycling has become the preferable solution. This urgent and important need to develop cheap and efficient recycling methods for textile waste has led to the research community's development of various recycling methods. The textile waste recycling process can be categorized into chemical and mechanical recycling methods. This paper provides an overview of the state of the art regarding different types of textile recycling technologies along with their current challenges and limitations. The critical parameters determining recycling performance are summarized and discussed and focus on the current challenges in mechanical and chemical recycling (pyrolysis, enzymatic hydrolysis, hydrothermal, ammonolysis, and glycolysis). Textile waste has been demonstrated to be re-spun into yarn (re-woven or knitted) by spinning carded yarn and mixed shoddy through mechanical recycling. On the other hand, it is difficult to recycle some textiles by means of enzymatic hydrolysis; high product yield has been shown under mild temperatures. Furthermore, the emergence of existing technology such as the internet of things (IoT) being implemented to enable efficient textile waste sorting and identification is also discussed. Moreover, we provide an outlook as to upcoming technological developments that will contribute to facilitating the circular economy, allowing for a more sustainable textile recycling process.

Can Fashion Be Circular? A Literature Review on Circular Economy Barriers, Drivers, and Practices in the Fashion Industry’s Productive Chain

Circular economy (CE) principles have gained prominence in the fashion industry since it is a highly polluting industry and requires sustainable changes. Even though there are several CE initiatives already in place within the fashion production chain, changes towards CE are still slow. This study seeks to identify the drivers, barriers, and practices that influence implementing circular economy concepts in the fashion industry production chain using a systematic literature review. The results show that some more barriers and criteria keep consumers away from circular fashion concepts than drivers. These barriers include fast fashion consumer culture, even though more consumers are environmentally conscious. This is because awareness has not reached large-scale populations, despite the world being more aware of social and environmental issues. Consumers still do not see ethical and ecological problems associated with the fashion industry and continue to be targeted for large fast fashion retailers that sell a misguided version of consumerism. This study contributes to both academia and new fashion business models that seek to become more sustainable since it presents opportunities for investments and the obstacles that must be overcome for reaching CE within this sector.

Synthesis and melt-spinning of partly bio-based thermoplastic poly(cycloacetal-urethane)s toward sustainable textiles

Partly bio-based thermoplastic poly(cycloacetal-urethane)s synthesized and melt-spun into textile fibres that can be potentially chemically recycled.