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Foram feitas algumas alterações no investimento (em ambos os cenários, considerámos um investimento inicial em terrenos e um investimento para projetos de I&D mais à frente no projeto e eliminámos o investimento em terrenos no último ano do projeto) e financiamento (diminuímos o capital para 50 000€ e o empréstimo bancário para 100 000€) do projeto, tidas em conta na elaboração do pitch final.

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A indústria têxtil enfrenta desafios significativos relacionados com a uniformidade de materiais, especialmente quando se trata de fibras celulósicas naturais. Estas fibras são naturalmente hidrofóbicas no seu estado bruto, devido à presença de impurezas que criam uma barreira à absorção uniforme de líquidos durante os processos de impregnação. Como resultado, a qualidade dos produtos finais varia consideravelmente. Para superar esses problemas e elevar a qualidade dos produtos têxteis, a nossa solução faz uso da tecnologia de CO2 supercrítico. Esta abordagem permite a modificação controlada das fibras celulósicas naturais, em especial de origem animal como a lã, tornando-as mais hidrofílicas e, assim, capacitadas para uma absorção uniforme de soluções aquosas. Com isso, resolvemos os problemas de uniformidade na indústria têxtil, proporcionando produtos finais de alta qualidade. Além disso, a nossa solução promove práticas sustentáveis, uma vez que se trata de uma tecnologia waterless que não requer o uso de produtos químicos tóxicos e não produz efluentes tóxicos.

https://www.sciencedirect.com/science/article/pii/S0959652620348630

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Abstract

Raw sheep wool contains various impurities such as wax, suint, dirt, and . Water-based cleaning process of sheep wool requires toxic volatile organic compounds that generate a significant portion of toxic effluents. ) is a waterless microorganisms Supercritical CO ₂ (scCO technology that has been utilized for sterilization, extraction, cleaning, and drying in various manufacturing sectors. The application of the scCO ₂ ₂ technology in sheep wool processing is cleaner, as it avoids the generation of toxic effluents. scCO ₂ is a promising technology that can be simultaneously utilized in sheep wool processing for sterilization, extraction of lanolin, and cleaning and drying. Therefore, the present study was conducted to evaluate the potential and limitations of the use of the scCO ₂ technology for sheep wool processing. Moreover, the properties of sheep wool, the impurities associated with sheep wool fiber, and treatment technology are discussed.

Introduction

Wool, an excellent natural protein fiber derived from animals, e.g. sheep, has been widely utilized in the production of clothing materials and technical textiles in the medical, aerospace, automotive, and decoration fields. It is a major raw material in the fabric industry. The demand for wool fabric materials is increasing due to their high quality and excellent mechanical properties, such as good flexibility, high heat retention, high hygroscopicity, high stain and static resistances, tender luster, high igniting temperature, and soft handling (Niu et al., 2012; Patnaik et al., 2015). Sheep wool is a keratin fiber. The chemical characteristics of sheep wool are associated with its semi-crystallized protein polymer structure, which consists of various types of amino acids linked through peptide bonds. However, raw sheep wool is a dirty natural fiber because it contains high levels of impurities, including wax, grease, suint, mineral soil, dead skin, dust, vegetable matter (VM), and dags (Bertini et al., 2013). The impurities on the surface of raw wool fiber need to be removed through cleaning processes prior to its use as a textile material. In the textile industry, wool fibers are subjected to a series of water-based treatment processes such as scouring, washing, bleaching, fulling, carbonization, and functional finishing (Abecia et al., 2005; Patnaik et al., 2015). These processes involve the use of large volumes of water and chemicals, which consequently generate huge volumes of toxic effluents from wet-chemical treatment processes.

The high dependence on water-based treatment is a major environmental concern in the textile industry due to the associated generation of significant amounts of wastewater with pollutants (Holkar et al., 2016). The wastewater generated during sheep wool processing poses serious environmental and economic concerns, as effective treatment is required to remove impurities prior to the discharge or recycling of water (Holkar et al., 2016; Poole and Cord-Ruwisch, 2004). Due to the detrimental impact of existing sheep wool processing techniques, the annual production of wool in the textile industry has reduced to 75% in European sheep farms (Sabatini et al., 2019). Therefore, scientists and environmentalists are seeking alternatives for conventional water-based treatment technologies in sheep wool processing. Over the years, numerous technologies have been implemented for processing sheep wool to minimize the environmental and economic impacts (Pavlikova, 2020; Poole and Cord-Ruwisch, 2004).

The handling and processing of raw sheep wool may pose potential hazards to personnel handling sheep wool. This is because sheep wool fiber is highly susceptible to microbial contamination, starting from its time on the sheep body to the various stages of its processing. The potential development of pathological diseases due to microorganisms has been identified in sheep (Giannitti et al., 2018). However, certain microorganisms may not be pathological to sheep, but they can rapidly multiply and stain wool fibers with mildew under favorable conditions. This results in loss of strength and leads to deterioration. The activity of various microbes can inhibit the utilization of wool. Hence, wool must often be sterilized against pathogenic organisms and other microbes that can easily damage it. Bacteriological studies are required to ensure the sterilization of these fibers, to mitigate the effect of these microorganisms. However, most of these organisms exist as spores and are highly resistant to conventional water-based treatment methods.

Supercritical carbon dioxide (scCO ₂) technology has been extensively utilized in various industrial fields for the extraction and separation of bioactive compounds (Hossain et al., 2016a; Vardanega et al., 2019), the sterilization of biomaterials to remove biological hazards (Hossain et al., 2016b; Soares et al., 2019), and the cleaning of the surfaces of fabric materials to remove dirt and other impurities (Aslanidou et al., 2016). In the scCO ₂ technology, fluid CO ₂, which is a gas at ambient temperature, is used as the solvent. Therefore, the scCO ₂ technology does not produce any residue after treatment. It offers numerous advantages as a cleaner sterilization technology, such as easy separation, shorter processing time, environment-friendliness, waterless nature, high solubility, and treatment of heat-sensitive materials without causing damage (Hossain et al., 2016b). The implementation of the scCO ₂ technology in the textile industry for treating wool and fabric materials has been studied (Long et al., 2013; Zheng et al., 2016). Thus, the scCO ₂ technology could be utilized as an effective alternative technology for conventional steam-based treatment. Therefore, the present study was conducted to summarize the existing methods of sheep wool processing and their impact on sheep wool properties and structure. Subsequently, the implementation of the scCO ₂ technology as a waterless alternative for conventional steam-based technology was assessed. Finally, the potential and limitations of the use of the scCO ₂ technology for sheep wool processing were also discussed.

Section snippets

Production, properties, and structure

Wool is a natural fiber whose specifications are determined by several production variables. According to the statistics reported by the International Sheep Wool Organization, the worldwide production of clean sheep wool was estimated to be approximately 1.155 million kg in 2018 (IWTO, 2019). Generally, sheep wool is collected by trimming wool from sheep once a year during summer or spring. Australia produced the highest amount of clean sheep wool, i.e., 23.4% of the total worldwide production

Sheep wool fiber processing

During the production of fabric, sheep wool undergoes several processing steps, such as shearing, classing, scouring, carding, combining, and spinning into a yarn (Millington and Rippon, 2017). Fig. 3 shows the process of sheep wool processing for producing clean fabrics. Sheep are generally sheared once a year. After shearing, the fleece is separated manually from shorter wool, leaves, twigs, and undesirable parts of the fleece. The folded and rolled fleece is classified according to the

Supercritical carbon dioxide technology

The scCO ₂ technology has been viewed as an effective method for the extraction and separation of lipids, sterilization of heat-sensitive materials, and cleaning and drying of textiles and fabric materials. Due to the rising environmental concerns associated with the discharge of toxic pollutants to the environment and greenhouse gas emissions, the scCO ₂ technology has been increasingly implemented. Supercritical carbon dioxide refers to the physical condition of fluid carbon dioxide in the

Conclusions

The present review was conducted to determine the potential and challenges of the use of scCO ₂ technology in sheep wool processing. Increasing environmental awareness, legislation, and worldwide concerns related to the generation of toxic effluents from the sheep wool manufacturing industry, there is an urgent need for a waterless technology for cleaner sheep wool production. Currently, steam-based technology in sheep wool processing requires a series of water-based treatment processes and

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgement

Authors would like to acknowledge to Ministry of Education MoE, Malaysia for providing Fundamental Research Grant Scheme FRGS, Grant N)-203/PTEKIND/6711817, as a financial support.

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Waterless processing of sheep wool fiber in textile industry with supercritical CO2: Potential and challenges

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Raw sheep wool contains various impurities such as wax, suint, dirt, and microorganisms. Water-based cleaning process of sheep wool requires toxic vol...

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Link do questionário: https://forms.gle/FXDT8bjRzsrnhBKP8

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Beatriz Matos, pg50255
Catarina Pereira, pg50291
Isabel Silva, pg50443
Mariana Gonçalves, pg50626

Engenharia Clínica

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