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

Abstract

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.

Biological Conversion of Agricultural Wastes into Indole-3-acetic Acid by Streptomyces lavenduligriseus BS50-1 Using a Response Surface Methodology (RSM)

“…Each raw material (5% w/v) was autoclaved at 121 °C for 15 min and enzymatically saccharified using a Cellic CTec 2 system (185 FPU/mL, Novozyme A/S, Basgsværd, Denmark) in a citrate buffer (50 mM, pH 4.8) 47 at 50 °C and 150 rpm. The enzyme loading was 15, 25, or 35 FPU/g cellulose.…”

From trash to cash: current strategies for bio-upcycling of recaptured monomeric building blocks from poly(ethylene terephthalate) (PET) waste

“…91–95 Consequently, many pretreatments have been considered to decrease PET crystallinity degree, leading to an easier enzymatic depolymerization. Pretreatments involving hydrophobins, 96 alkali 97,98 and microwave radiation 99 have been shown to present a positive effect in the depolymerization. For example, the first treatment 100 almost doubles PET weight loss (18% to 34%) in the studied conditions.…”

A Systematic Review of Recycled Cotton Fibre Blending Practices, Challenges and Recommendations

“…Other authors analyzed the proportion of fabric quality based on recycled fibre yarns; for this, the following prototypes were created in 100% FAR, 100% VCF, 35% polyester -65% RCF, 35% polyester -65% VCF, 50% VCF -50% polyester and 50% RCF -50% polyester, the adequate proportion was 50% RCF -50% polyester, which presented 79 defects [34], the lower the defect present in the fabric, the higher it's quality according to the Graniteville 78 system, which evaluates the defects and quality of https://doi.org/10.31881/TLR.2023.184 the fabric, which rated the proportion 50% RCF -50% polyester as acceptable. Other more recent studies used hydrolysis to be able to mix other types of fibres other than 35% polyester with 65% cotton with PET to improve the properties of the fibres [35] and 60% cotton with 40% PET [36].In addition, it is essential to mix recycled fibres with virgin fibres in a particular proportion so that the properties of the yarn are better and the fabric presents fewer defects; from the sample of 54 fabrics produced, ten were evaluated, and the author suggests the mixture of 50% VCF and 50% RCF as the adequate [37], for this it is required to separate the textures and fibre type of the materials, to achieve a quality as if new raw materials were used. Moreover, the yarn behaviour in elongation and strength criteria are adequate [38].…”