Improvement of a microfiber filter for domestic washing machines

Global microplastic fiber pollution from domestic laundry

The rapid expansion of fast fashion has significantly increased microplastic fiber (MPF) release during laundry practices, accounting for approximately one-third of primary microplastics entering the ocean. Currently, a significant gap exists in global-scale research on the release of MPFs from washing textiles. This study introduces an innovative empirical model to assess the spatial distribution of MPF emissions. The model estimates an annual global emission of 5.69 million tons of MPFs from laundry. Of this total, machine washing accounts for the majority (93.7 %), with hand washing contributing the remaining 6.3 %. As the primary source of MPF pollution, Asia's emissions reach 3.71 million tons, far exceeding those of North America (1.18 million tons) and Europe (0.45 million tons). The primary issue is that wastewater management efficiency varies significantly worldwide. In Asia, there is persistently high discharge of MPFs into natural waters, and the removal efficiency of wastewater treatment plants is still comparatively low. In contrast, the United States and many European countries exhibit better MPF retention. The global nature of this challenge mandates international collaboration for comprehensive environmental conservation. Our study provides the first high-resolution global distribution map of MPF emissions and discharge into natural waters, establishing a data foundation for global and regional management of microplastics originating from household laundry sources.

Innovative tarantula hair-inspired washing machine filters for enhanced microfiber capture

Aquatic environments are being polluted by microplastics primarily originating from the washing of synthetic textiles. Microfibers (MF), which are microplastics in synthetic fibers, are consistently introduced into the environment with each domestic laundry cycle. To address this issue, we developed a specialized MF capture "barbed filter" (BF) by transforming PET monofilaments of different diameters (0.4, 0.6, and 0.8 mm) into structures that closely resemble the characteristics of tarantula urticating hairs. BFs feature sharp barbs that effectively capture and retain microfibers of diverse lengths, surpassing the performance of conventional control filters. The BFs had a retention efficiency of 88-91 %, while the CFs had an efficiency of 79-86 %. Our findings revealed that the barbed filter significantly outperformed the conventional control filter in capturing microfibers due to its smaller pore size, shorter pore distance, and unique filter shape. This design not only enhances the surface area and friction, facilitating microfibril strong entrapment but also minimizes the probability of microfibril passage through the filter. This research offers a promising solution for reducing microfibril release from laundry and textile industrial wastewater. The implementation of BFs in real life has the potential to significantly reduce microplastic pollution and promote a cleaner and more sustainable environment.

Impact of vented and condenser tumble dryers on waterborne and airborne microfiber pollution

Laundering of textiles is a significant source of waterborne microfiber pollution, and solutions are now being sought to mitigate this issue including improvements in clothing technology and integration of filtration systems into washing machines. Vented tumble dryers are a potential source of airborne microfiber pollution, as their built-in lint filtration systems have been found to be inefficient with significant quantities of textile microfibers being released to the external environment through their exhaust air ducts. The present study is the first to evaluate the impact of condenser dryers, finding that they are significant contributors to waterborne microfiber pollution from the lint filter (if users clean this with water), the condenser and the condensed water. Microfiber release from drying of real consumer loads in condenser and vented tumble dryers was compared, finding that real loads release surprisingly high levels of microfibers (total 341.5 ± 126.0 ppm for those dried in a condenser dryer and 256.0 ± 74.2 ppm for those dried in a vented dryer), similar in quantity to microfibers produced during the first highly-shedding drying cycle of a new T-shirt load (total 321.4 ± 11.2 ppm) in a condenser dryer. Vented dryers were found to be significant contributors to waterborne microfiber pollution if consumers clean the lint filter with water in accordance with some published appliance usage instructions, as most (86.1 ± 5.5% for the real consumer loads tested) of the microfibers generated during vented tumble drying were collected on the lint filter. Therefore, tumble dryers are a significant source of waterborne and (for vented dryers) airborne microfiber pollution. While reducing the pore size of tumble dryer lint filters and instructing consumers to dispose of fibers collected on lint filters as municipal solid waste could help reduce the issue, more sophisticated engineering solutions will likely be required to achieve a more comprehensive solution.