Polyester fabrics contributing to the microplastic problem
In a review recently published in the open access journal Materialsresearchers presented the role of washing polyester fabrics in increasing microplastics in wastewater.
Study: Microplastics in wastewater by washing polyester fabrics. Image Credit: chayanuphol/Shutterstock.com
Microplastics have become one of the most serious environmental threats today, raising fears that levels will continue to climb in the near future. When plastic breaks down into microscopic fragments due to mechanical or photochemical processes, micro/nanoparticles are formed. Microplastics are ubiquitous and have a strong tendency to interact with the ecosystem, posing a threat to biogenic flora and fauna.
Therefore, even before research studies on the dangers and long-term impacts are accessible, the slow release and utilization of microplastics, which occur directly in the fiber production process, must be significantly reduced and be part of a global campaign.
Microfibers detected in laundry effluent, sewage and seawater. Image credit: Šaravanja, A et al., Materials
About the study
In this study, the authors discussed the most common causes of microplastic pollution in the environment and provided an overview of washable polyester materials. The impact of microplastics on the environment and human health was also discussed.
The researchers presented a detailed analysis of polyester (PET) and polyamide (PA) as two of the most widely used synthetic fibers, as they account for more than 60% of total global fiber production. The need for synthetic textiles for clothing, carpets and a range of other products was also discussed. The potential of synthetic fabrics to release microplastics into the environment during the production or washing process was illustrated.
The team assessed the need to create as many programs as possible to monitor microplastics and their role in preventing and managing microplastic pollution.
Comamonas Testosteroni, a type of biocatalyst cell, could break down EPS and thereby minimize microplastic discharge. The diameter of the PES was 7.30 µm at the start of the process and after treatment in an alkaline medium, the diameter reduced to 1.58 µm, which favored the rapid degradation of the PES by the bacteria under alkaline degradation conditions, as well as than biosorption, which facilitated the fixation of the adsorbate and the adsorbent surface.
Accumulated microfibers can be easily removed by hand. Numerous studies have shown that the ball absorbs approximately 35% of the total amount of fibers with each wash. Test results of washed treated materials revealed a dramatic reduction in microfibers of up to 90% compared to untreated fabrics, as well as promising wash fastness.
Washing factors according to the Sinner cycle: t-time, T-temperature, M-mechanics, C-chemistry. Image credit: Šaravanja, A et al., Materials
According to several studies, a human could swallow between 39,000 and 520,000 microplastics per year via food and drink, with levels that naturally varied according to age and gender. With an efficiency of 95%, microplastic particles with a diameter of up to 10 µm could be removed. Finland’s annual microfiber emissions were estimated at 154,000 kg (PES) and 411,000 kg (PES) (cotton). The average fiber diameter released during washing was 11.9-17.7 µm and the length was 5.0-7.8 mm.
The results revealed that materials aged for 12 and 35 minutes at temperatures below 160°C showed no difference compared to untreated yarns. Materials treated at temperatures above 160°C but below 200°C lost strength below 1.11 cN/tex.
When polyester samples were aged at temperatures of 140°C and 160°C for 12 minutes and 35 minutes, there was essentially no difference in strength between treated and untreated samples. However, as the temperature increased, the strength and hardness of the material decreased by about 5% at 200°C and 19% at 220°C, respectively. The strength of a sample aged at 220°C for 35 minutes was nearly 31% lower than that of the untreated polyester.
The microfiber shedding mode. Image credit: Šaravanja, A et al., Materials
In conclusion, this study showed that many countries have yet to develop a comprehensive strategy for the biggest sources of microplastics in water, as well as ways to clean them up effectively. Several research initiatives have looked into the impact of microplastics on ultimate waste and the disposal of microplastics in sewage treatment plants at each stage of the process. The authors stressed that it is essential that the machines are energy efficient, cost-effective and environmentally friendly in order to limit microplastic emissions as much as possible.
They mentioned that in terms of polyester and microplastics, the main goal is to make polyester with the best structural properties and move to as many recycled products as possible. They determined that it was essential to use the best agents to protect the structure of the polymer and prevent the release of microplastics during washing. According to the results, the washing and drying procedures of synthetic materials should also be optimized, as they are market-relevant and unique. The authors believe this interdisciplinary topic will remain important in the future, with plenty of room for further research.
Šaravanja, A., Puši´c, T., Dekani´c, T., Microplastics in wastewater by washing polyester fabrics. Papers 15(7) 2683 (2022). https://www.mdpi.com/1996-1944/15/7/2683