Applications and environmental impact of biodegradable polymers in textile industry: A review.

With the increasing global population, the disposal of waste has risen, especially over the last century. The Environmental Protection Agency (EPA) reported that 11 million tons of textile-related waste were landfilled in the USA in 2018, and this amount is projected to increase to 4.5 billion tons by 2040. Bio-based polymers have gained attention due to their remarkable properties. The most important biodegradable polymers include PLA, PHA, PHB, PCL, PBS, bamboo fibers, and banana fibers. Global biopolymer production capacity is expected to rise significantly, from around 2.18 million tons in 2023 to approximately 7.43 million tons by 2028. In the textile industry, the linear waste model presents numerous challenges, such as environmental damage and resource shortages. Shifting from a linear to a circular economy is essential to address these issues. Reducing, reusing, and recycling are the three key actions and strategies that form the foundation of the circular economy. This paper presents the current state of knowledge and technological advancements in biodegradable polymers in the textile industry, along with their products and applications. The study explores the cost-effectiveness, limitations, opportunities, and advancements in their manufacturing technologies. Biodegradable polymers in the textile sector are regarded as green alternatives to non-biodegradable polymers.

TG-FTIR-Py-GCMS analysis and catalytic pyrolysis mechanism of textile waste by red mud catalyst for liquid fuel production.

The substantial generation of textile waste (TW) and red mud (RM) has resulted in significant resource wastage and environmental challenges. Co-utilization technology of solid waste is an effective approach to improve waste utilization efficiency. In this study, RM catalytic pyrolysis experiments of TW were conducted using TG-FTIR and Py-GC-MS for liquid fuel production, and TW and RM were recycled simultaneously. At the optimal experimental conditions (temperature of 600 °C and feed catalyst ratio of 2:1), the tar yield and higher heating value (HHV) of TW pyrolysis catalyzed by RM were 73.43 wt% and 32.34 kJ/g, respectively. Additionally, experiments on the pyrolysis of various TW types revealed that LDPE and PP are suitable for tar production, while cotton, nylon, and PET are more suitable as feedstock for syngas production. The RM catalytic pyrolysis mechanism of textile waste is that Fe2O3 in RM exhibits significant catalytic activity in enhancing tar and syngas yields. However, during the catalytic process, Fe2O3 undergoes reduction to Fe3O4, resulting in diminished catalytic performance of the RM. After five cycles of use, the RM essentially lost its catalytic activity due to the accumulation of char and tar. All experimental findings of this study could offer an effective guideline for TW recycle and promoting RM utilization toward the waste-to-energy circular economy.

A review on textile solid waste management: Disposal and recycling.

Due to global population growth and living standards improvements, textile production and consumption are increased. Textile solid waste has become challenging issue for waste management authority. It is reported that textile materials are discarded daily, representing approximately 1.5% of the generated waste around the world. Over the past few decades, special attention has been given to the used clothes in all regions globally, which can reduce energy costs by 80% and also represent a source of raw materials economically profitable and environmentally responsible. This review article attempted to address different topics including: source of solid textile waste, environmental impact of textile waste as a result of massive consumption of clothing, textile waste management processes such as recycling, reuse of textile waste, landfill and incineration and energy recovery from textile waste. Narrative review with collection of recent quantitative information was carried to reflect the status of textile solid waste. In this article, the possibilities of bio-ethanol production from textile waste as valuable cellulosic raw material are investigated and presented. Results show that developing countries lack of systematic waste management. On another side of the globe, some countries are trying to recover energy these days by incineration. The heat and power that recovered from this process can be used instead of other energy sources. Throughout the incineration process, flue gases (CO2, H2O, O2, N2) are generated so it should be properly designed to avoid pollution. During energy recovery, different pre-treatment methods and different enzymatic hydrolysis parameters are recommended to be implied for better results.

Development of Eco-Efficient Composite from Textile Waste with Polyamide Matrix.

The main aim of the present work is to evaluate and characterize the mechanical, morphological and thermal properties of wastes coming from the textile industry, mainly composed of cotton and polyester. These wastes will be thereafter implemented in commodity plastic such as polyamide, in order to develop new formulations of environmentally friendly materials. The composites were produced by extrusion and injection-molded processes in amounts between 15 wt.% and 60 wt.% of textile waste. With the objective of improving the properties of the materials, silanes were used as a compatibilizer between the textile fibers and the polymeric matrix. The effect of the compatibilizer in the composites was studied together with the effect of the amount of textile fiber added to the composites. Mechanical, thermal, morphological and wettability properties were analyzed for each composite. The results show that the use of silanes improves the interaction especially in those composites with a higher amount of textile waste, offering a balanced mechanical behavior with significantly high quantities. On the other hand, the melting temperature does not vary significantly with the introduction of silanes and textile waste content, although the incorporation of textile waste slightly reduces up to 23% the degradation temperature of the resulting composites. The wettability of the composites is also increased up to 16% with the incorporation of textile waste. Finally, the appearance of the composites with textile waste is strongly influenced by the incorporation of the reinforcement, offering shades close to dark brown in the whole range of compositions.

Physicochemical Properties of Cellulose Nanocrystals Extracted from Postconsumer Polyester/Cotton-Blended Fabrics and Their Effects on PVA Composite Films.

The utilisation of cotton waste as precursors in the synthesis of nanocrystalline cellulose has gained significant attention. This approach suggests a sustainable solution to address the growing concern of textile waste accumulation while simultaneously producing a valuable material. The main aim of this study is to examine the properties of cellulose nanocrystals (CNCs) obtained from postconsumer polyester-cotton waste and assess the effect of different fabric structures on the extraction and these properties. To acquire nanocellulose, a thorough decolourisation pretreatment process was utilised, which involved the treatment of polyester-cotton waste with sodium dithionite and hydrogen peroxide. Consequently, the postconsumer material was then treated with an acid hydrolysis method employing a 64% (v/v) sulphuric acid solution at 50 °C for 75 min, resulting in the formation of CNCs with average yield percentages ranging from 38.1% to 69.9%. Separation of the acid from the CNC was facilitated by a centrifugation process followed by dialysis against deionised water. Uniform dispersion was then achieved using ultrasonication. A variety of analytical techniques were employed to investigate the morphological, chemical, thermal, and physical properties of the isolated CNCs. Among these techniques, attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR), energy-filtered transmission electron microscopy (EF-TEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) were utilised to analyse the CNCs. The findings indicated that the separated CNCs exhibited a rod-shaped morphology, measuring between 78 and 358 nm in length and 5 and 16 nm in diameter, and also exhibited high crystallinity (75-89%) and good thermal stability. The extracted CNCs were mixed with polyvinyl alcohol (PVA) and glycerol to assess their reinforcing effect on plastic films. The prepared composite film exhibited improved mechanical properties and thermal stability. Incorporating CNCs led to a 31.9% increase in the tensile strength and a 42.33% rise in the modulus of elasticity. The results from this research proved that CNCs can be extracted from postconsumer mixed fabrics as a potential solution to effectively address the mounting concerns surrounding waste management in the textile industry and also provide avenues for enhancing the qualities of eco-friendly composite films.

Chromogenic fusion proteins as alternative textiles dyes.

The widespread adoption of fast fashion has led to a significant waste problem associated with discarded textiles. Using proteins to color textiles can serve as a sustainable alternative to chemical dyes as well as reduce the demand for new raw materials. Here, we explore the use of chromogenic fusion proteins, consisting of a chromoprotein and a carbohydrate-binding module (CBM), as coloring agents for cellulose-based textiles such as cotton. We examined the color properties of chromoproteins AeBlue, SpisPink and Ultramarine alone and fused to CBM under various conditions. AeBlue, SpisPink and Ultramarine exhibited visible color between pH 4-9 and temperatures ranging from 4 to 45℃. Fusing CBM Clos from Clostridium thermocellum and CBM Ch2 from Trichoderma reesei to the chromoproteins had no effect on the chromoprotein color properties. Furthermore, binding assays showed that chromoprotein fusions did not affect binding of CBMs to cellulosic materials. Cotton samples bound with Ultramarine-Clos exhibited visible purple color that faded progressively over time as the samples dried. Applying 10% 8000 polyethylene glycol to cotton samples markedly preserved the color over extended periods. Overall, this work highlights the potential of chromoprotein-CBM fusions for textile dying which could be applied as a color maintenance technology or for reversible coloring of textiles for events or work wear, contributing to sustainable practices and introducing new creative opportunities for the industry.

Qualitative classification of waste garments for textile recycling based on machine vision and attention mechanisms.

The increasing volume of garment waste underscores the need for advanced sorting and recycling strategies. As a critical procedure in the secondary usage of waste clothes, qualitative classification of garments categorizes post-consumer clothes based on types and styles. However, this process currently relies on manual labor, which is inefficient, labor-intensive, and poses risks to workers. Despite efforts to implement automatic clothes classification systems, challenges persist due to visual complexities such as similar colors, deformations, and occlusions. In response to these challenges, this study introduces an enhanced intelligent machine vision system with attention mechanisms designed to automate the laborious and skill-demanding task of garment classification. Initially, a waste garment dataset comprising approximately 27,000 garments was curated using a self-developed automatic classification platform. Subsequently, the proposed attention method parameters were selected, and a series of benchmarks were conducted against state-of-the-art methods. Finally, the proposed system underwent a two-week online deployment to evaluate its running stability and sensitivity to similar colors, deformation, and occlusion in industrial production settings. The benchmarks indicate that the proposed method significantly improves classification accuracy across various models. The visualization interpretation of Grad-CAM reveals that the proposed method effectively handles complex environments by directing its focus toward garment-related pixels. Notably, the proposed system elevates classification accuracy from 68.28 % to human-level performance (>90 %) while ensuring greater running stability. This advancement holds promise for automating the classification process and potentially alleviating workers from labor-intensive and hazardous tasks associated with clothes recycling.

Assessment of Potential Use of a Composite Based on Polyester Textile Waste as Packing Elements of a Trickle Bed Bioreactor.

Biological wastewater treatment using trickle bed reactors is a commonly known and used solution. One of the key elements of the proper operation of the trickle bed bioreactor is the appropriate selection of biofilm support elements. The respective properties of the bioreactor packing media used can influence, among other things, the efficiency of the treatment process. In this study, the possibility of polyester waste material usage for the preparation of the biofilm support elements was tested. The following properties were checked: adsorption capacity, swelling, surface morphology, microbicidal properties, as well as the possibility of their use in biological wastewater treatment. The tested elements did not adsorb copper nor showed microbicidal properties for bacterial strains Escherichia coli and Staphylococcus aureus as well as fungal strains Aspergillus niger and Chaetomium globosum. The hydrophilic and rough nature of the element surface was found to provide a friendly support for biofilm formation. The durability of the elements before and after their application in the biological treatment process was confirmed by performing tests such as compressive strength, FTIR analysis, hardness analysis and specific surface area measurement. The research confirmed the applicability of the packing elements based on polyester textile waste to the treatment of textile wastewater. The treatment efficiency of the model wastewater stream was above 90%, while in the case of a stream containing 60% actual industrial wastewater it was above 80%. The proposed solution enables the simultaneous management of textile waste and wastewater treatment, which is consistent with the principles of a circular economy. The selected waste raw material is a cheap and easily available material, and the use of the developed packing elements will reduce the amount of polyester materials ending up in landfills.

Transparent Cellulose/Multi-Walled Carbon Nanotube Hybrids with Improved Ultraviolet-Shielding Properties Prepared from Cotton Textile Waste.

Plastics offer many advantages and are widely used in various fields. Nevertheless, most plastics derived from petroleum are slow to degrade due to their stable polymer structure, posing serious threats to organisms and ecosystems. Thus, developing environmentally friendly and biodegradable plastics is imperative. In this study, biodegradable cellulose/multi-walled carbon nanotube (MCNT) hybrid gels and films with improved ultraviolet-shielding properties were successfully prepared using cotton textile waste as a resource. It was proven that MCNTs can be dispersed evenly in cellulose without any chemical or physical pretreatment. It was found that the contents of MCNTs had obvious effects on the structures and properties of hybrid films. Particularly, the averaged transmittance of cellulose/MCNT composite films in the range of 320-400 nm (T320-400) and 290-320 nm (T290-320) can be as low as 19.91% and 16.09%, when the content of MCNTs was 4.0%, much lower than those of pure cellulose films (T320-400: 84.12% and T290-320: 80.03%). Meanwhile, the water contact angles of the cellulose/MCNT films were increased by increasing the content of MCNTs. Most importantly, the mechanical performance of cellulose/MCNT films could be controlled by the additives of glycerol and MCNTs. The tensile strength of the cellulose/MCNT films was able to reach as high as 20.58 MPa, while the elongation at break was about 31.35%. To summarize, transparent cellulose/MCNT composites with enhanced ultraviolet-shielding properties can be manufactured successfully from low-cost cotton textile waste, which is beneficial not only in terms of environmental protection, but also the utilization of natural resources.

Open-loop recycling of end-of-life textiles as geopolymer fibre reinforcement.

The treatment and management of textile waste is an ever-growing issue worldwide, due to the continuously changing trends and the popularity of fast-fashion brands. There are numerous waste management methods besides simple landfilling, including reuse, open-loop or closed-loop recycling options. The described research explores the applicability of an open-loop recycling method, the processing of end-of-life textiles to produce fibres for fibre-reinforced geopolymers, to combine various waste streams for the production of an environmentally friendly binder system. By the examination of different textile waste processing methods, the most valuable fibrous material was produced with the application of a rotary shear and a vertical cutting mill, eliminating the necessity of manual cutting. As the most common base material of the textiles was found to be polyester and cotton, these were deemed useful for fibre reinforcement. The flexural strength showed a significant increase with the addition of 5 wt.% fibres, indicating the possibility of more than doubling the flexural strength of geopolymer specimens. Based on the microstructural analysis, however, even though there was good adhesion between the fibre and the geopolymer matrix, the latter showed inhomogeneities with higher fibre addition, indicating the need to further optimise the production steps, such as mixing time, vibration time, etc.

Valorisation of cotton post-industrial textile waste into lactic acid: chemo-mechanical pretreatment, separate hydrolysis and fermentation using engineered yeast.

BACKGROUND: The textile industry has several negative impacts, mainly because it is based on a linear business model that depletes natural resources and produces excessive amounts of waste. Globally, about 75% of textile waste is disposed of in landfills and only 25% is reused or recycled, while less than 1% is recycled back into new garments. In this study, we explored the valorisation of cotton fabric waste from an apparel textile manufacturing company as valuable biomass to produce lactic acid, a versatile chemical building block. RESULTS: Post-industrial cotton patches were pre-treated with the aim of developing a methodology applicable to the industrial site involved. First, a mechanical shredding machine reduced the fabric into individual fibres of maximum 35 mm in length. Afterwards, an alkaline treatment was performed, using NaOH at different concentrations, including a 16% (w/v) NaOH enriched waste stream from the mercerisation of cotton fabrics. The combination of chemo-mechanical pre-treatment and enzymatic hydrolysis led to the maximum recovery yield of 90.46 ± 3.46%, corresponding to 74.96 ± 2.76 g/L of glucose released, which represents a novel valorisation of two different side products (NaOH enriched wastewater and cotton textile waste) of the textile industry. The Saccharomyces cerevisiae strain CEN.PK m850, engineered for redirecting the natural alcoholic fermentation towards a homolactic fermentation, was then used to valorise the glucose-enriched hydrolysate into lactic acid. Overall, the process produced 53.04 g/L ± 0.34 of L-lactic acid, with a yield of 82.7%, being the first example of second-generation biomass valorised with this yeast strain, to the best of our knowledge. Remarkably, the fermentation performances were comparable with the ones obtained in the control medium. CONCLUSION: This study validates the exploitation of cotton post-industrial waste as a possible feedstock for the production of commodity chemicals in microbial cell-based biorefineries. The presented strategy demonstrates the possibility of implementing a circular bioeconomy approach in manufacturing textile industries.

A review on existing and emerging approaches for textile wastewater treatments: challenges and future perspectives.

This comprehensive review explores the complex environment of textile wastewater treatment technologies, highlighting both well-established and emerging techniques. Textile wastewater poses a significant environmental challenge, containing diverse contaminants and chemicals. The review presents a detailed examination of conventional treatments such as coagulation, flocculation, and biological processes, highlighting their effectiveness and limitations. In textile industry, various textile operations such as sizing, de-sizing, dyeing, bleaching, and mercerization consume large quantities of water generating effluent high in color, chemical oxygen demand, and solids. The dyes, mordants, and variety of other chemicals used in textile processing lead to effluent variable in characteristics. Furthermore, it explores innovative and emerging techniques, including advanced oxidation processes, membrane filtration, and nanotechnology-based solutions. Future perspectives in textile wastewater treatment are discussed in-depth, emphasizing the importance of interdisciplinary research, technological advancements, and the integration of circular economy principles. Numerous dyes used in the textile industry have been shown to have mutagenic, cytotoxic, and ecotoxic potential in studies. Therefore, it is necessary to assess the methods used to remediate textile waste water. Major topics including the chemical composition of textile waste water, the chemistry of the dye molecules, the selection of a treatment technique, the benefits and drawbacks of the various treatment options, and the cost of operation are also addressed. Overall, this review offers a valuable resource for researchers and industry professionals working in the textile industry, pointing towards a more sustainable and environmentally responsible future.

Assessment of Properties and Microstructure of Concrete with Cotton Textile Waste and Crushed Bricks.

Cotton textile waste (CW) and crushed bricks (CB) are wastes generated by the textile and construction industries that cause adverse effects on the environment. This paper explores the effect of adding 1, 2, 5, and 10 wt.% of CW and CB, instead of natural sand under 1 mm (50 to 100 vol.%), on the properties of concrete. The study included the analysis of workability, density, water absorption, thermal conductivity, mechanical strengths, and electron microscopy. The results show that the presence of CW and CB increased the water required to obtain the same slump value as reference, R. Concretes with CW provided better performance in terms of density, water absorption (for 1 wt.%), and splitting strength (for 1 to 2 wt.%). The 28 days of compressive strength decreased with increasing CW (33.3 MPa for R and 26.9 MPa for 2 wt.% of CW). The partial substitution of sand decreased the workability and density and increased the mechanical strength of concrete. The presence of both CW and CB decreased workability, density, and mechanical strengths. Regarding the ability of concrete to transfer heat, the addition of CW and CB decreased the thermal conductivity value (e.g., 0.32 W/(m·K) for 1 wt.% of CW compared to 0.37 W/(m·K) for reference).

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.

Implications of circular textile policies for the future regulation of hazardous substances in textiles in the European Union.

The textile industry's business model is currently unsustainable and systemic changes must be made. The transition to a circular textile economy can be a major lever for this. However, it faces multiple issues, including the (in)ability of current legislations to provide sufficient protection regarding hazardous chemicals in recirculating materials. It is therefore crucial to identify legislative gaps that prevent the implementation of a safe circular textile economy, and to identify which chemicals could jeopardize this process. With this study, we aim to identify hazardous substances that could be found in recirculated textiles, to identify and discuss gaps in current regulations covering chemicals in textiles, and to suggest solutions to ensure better safety of circular textiles. We compile and analyze data on 715 chemicals and their associated functions, textile production stage, and hazard data. We also present how chemicals have been regulated over time and discuss regulations' strengths and weaknesses in the perspective of circular economy. We finally discuss the recently proposed Ecodesign regulation, and which key point should be included in the future delegated acts. We found that most of the compiled chemicals present at least one recognized or suspected hazard. Among them, there were 228 CMR (carcinogenic, mutagenic, reprotoxic substances), 25 endocrine disruptors, 322 skin allergens or sensitizers, and 51 respiratory allergens or sensitizers. 30 chemicals completely or partially lack hazard data. 41 chemicals were found to present a risk for consumers, among which 15 recognized or suspected CMR and 36 recognized or suspected allergens/sensitizers. Following the analysis of regulations, we argue that an improved risk assessment of chemicals should consider chemicals specific hazardous properties and product's multiple life cycles, instead of being limited to the product's end-of-life stage. We especially argue that implementing a safe circular textile economy requires that chemicals of concern are eliminated from the market.

Optimization of Textile Waste Blends of Cotton and PET by Enzymatic Hydrolysis with Reusable Chemical Pretreatment.

Textile waste usually ends up in landfills and causes environmental pollution. In this study, pretreatment methods for textile recycling, including autoclaving, freezing alkali/urea soaking, and alkaline pretreatment, were applied to textile waste with various cotton/polyester blending ratios. The best condition for enzymatic hydrolysis was a 60/40 textile waste blend of cotton/polyethylene terephthalate (PET) with a reusable chemical pretreatment (15% NaOH) at 121 °C for 15 min. The hydrolysis of pretreated textile waste by cellulase was optimized using response surface methodology (RSM) based on central composite design (CCD). The optimized conditions were 30 FPU/g of enzyme loading and 7% of substrate loading, which resulted in a maximum observed value of hydrolysis yield at 89.7%, corresponding to the predicted value of 87.8% after 96 h of incubation. The findings of this study suggest an optimistic solution for textile waste recycling.

Textile waste water treatment: analysis of mapping knowledge domains.

Textile waste water contains dyes and chemicals that produce harmful vapors and exhaust gases, which is hazardous to the environment and public health. Therefore, it must be carefully treated before discharged. To understand the research evolution in the research area of textile waste water treatment, based on bibliometrics, an in-depth analysis of the publications and hotspots in this area was presented in this paper. For the analysis, totally 6774 papers related to the research area that are published between the year 1964 and 2023 were collected from the Web of Science Core Collection. Using CiteSpace and VOSviewer as bibliometric analysis tools, the collaboration of countries, regions, and organizations was investigated. Besides, an analysis for citation and co-citation of journals, authors, references, and co-occurrence of keywords was performed. The evolution of research hotspots in the three major research directions related to degradation, oxidation, and adsorption is also analyzed in this paper. The analysis results show that researches related to oxidation and adsorption are active in recent years, while nanocomposite adsorbents and graphene oxide are the current research hotspots.

Smart textile waste collection system - Dynamic route optimization with IoT.

Increasing textile production is associated with an environmental burden which can be decreased with an improved recycling system by digitalization. The collection of textiles is done with so-called curbside bins. Sensor technologies support dynamic-informed decisions during route planning, helping predict waste accumulation in bins, which is often irregular and difficult to predict. Therefore, dynamic route-optimization decreases the costs of textile collection and its environmental load. The existing research on the optimization of waste collection is not based on real-world data and is not carried out in the context of textile waste. The lack of real-world data can be attributed to the limited availability of tools for long-term data collection. Consequently, a system for data collection with flexible, low-cost, and open-source tools is developed. The viability and reliability of such tools are tested in practice to collect real-world data. This research demonstrates how smart bins solution for textile waste collection can be linked to a dynamic route-optimization system to improve overall system performance. The developed Arduino-based low-cost sensors collected actual data in Finnish outdoor conditions for over twelve months. The viability of the smart waste collection system was complemented with a case study evaluating the collection cost of the conventional and dynamic scheme of discarded textiles. The results of this study show how a sensor-enhanced dynamic collection system reduced the cost 7.4% compared with the conventional one. We demonstrate a time efficiency of -7.3% and that a reduction of 10.2% in CO2 emissions is achievable only considering the presented case study.

Converting textile waste into value-added chemicals: An integrated bio-refinery process.

The rate of textile waste generation worldwide has increased dramatically due to a rise in clothing consumption and production. Here, conversion of cotton-based, colored cotton-based, and blended cotton-polyethylene terephthalate (PET) textile waste materials into value-added chemicals (bioethanol, sorbitol, lactic acid, terephthalic acid (TPA), and ethylene glycol (EG)) via enzymatic hydrolysis and fermentation was investigated. In order to enhance the efficiency of enzymatic saccharification, effective pretreatment methods for each type of textile waste were developed, respectively. A high glucose yield of 99.1% was obtained from white cotton-based textile waste after NaOH pretreatment. Furthermore, the digestibility of the cellulose in colored cotton-based textile wastes was increased 1.38-1.75 times because of the removal of dye materials by HPAC-NaOH pretreatment. The blended cotton-PET samples showed good hydrolysis efficiency following PET removal via NaOH-ethanol pretreatment, with a glucose yield of 92.49%. The sugar content produced via enzymatic hydrolysis was then converted into key platform chemicals (bioethanol, sorbitol, and lactic acid) via fermentation or hydrogenation. The maximum ethanol yield was achieved with the white T-shirt sample (537 mL/kg substrate), which was 3.2, 2.1, and 2.6 times higher than those obtained with rice straw, pine wood, and oak wood, respectively. Glucose was selectively converted into sorbitol and LA at a yield of 70% and 83.67%, respectively. TPA and EG were produced from blended cotton-PET via NaOH-ethanol pretreatment. The integrated biorefinery process proposed here demonstrates significant potential for valorization of textile waste.