Asian Scientist Magazine (Sep. 07, 2022) — Microplastics in our oceans not only bleach corals and endanger marine life, but they also eventually find their way into our dinner plates. This makes the task of reducing microplastic pollution both an environmental initiative and a public health measure—but it is easier said than done.
Part of the problem is their size. Microplastics are so small, it’s difficult to filter them out from seawater. Some nano-particles end up clogging the filters themselves, and many solutions currently being developed across the world use up a lot of energy and resources.
This is why two teams, led by Dr. Lee Ju-hyuck of the Daegu Gyeongbuk Institute Of Science And Technology (DGIST) and Dr. Cho Han-cheol of the Korea Institute of Industrial Technology (KITECH), sought to design an eco-friendly technique for removing micro-to-nano-sized microplastics from water using a triboelectric nanogenerator (TENG).
The technology uses a three-dimensional porous pyramid polydimethylsiloxane (PMDS). This has been designed to efficiently filter out microplastic particles as compared to previous TENG models, which used flat PDMS. The key to improve efficiency is to increase the surface area of the filter, Lee pointed out in an interview with Asian Scientist Magazine.
“The larger the surface area, the larger the contact area, which in turn increases the charge density by contact electrification,” he explained. In other words, the porous pyramidal PDMS provides a bigger surface area than a flat PDMS, which improves the output of the TENG.
The challenge for Lee and the teams at DGIST and KITECH was to make the porous pyramid uniform over a large area. Over the course of their research, he shared that they spent a lot of time “trying different pyramid sizes, and porosity densities and sizes to find the optimal conditions.”
The study, published in the journal of Nano Energy, revealed positive results. The porous pyramid PDMS-based TENGs were able to generate four times more energy than the flat PDMS-based generators, while removing 5.6 times more toxic particles. Moreover, the technology can work in a wider variety of locations.
The study was conducted with the support of South Korea’s National Research Foundation and the Ministry of Science and ICT. Overall, the porous pyramid PDMS-based TENGs were able to filter nanoparticles of polystyrene, cadmium selenides, zinc oxides and silicon dioxides, as well as heavy metal composites. These results are promising, as the joint study presents a more eco-friendly and adaptable method for removing microplastics in our rivers and oceans.
Lee, an expert in the field of triboelectric nanogenerators, plans to continue working together with KITECH’s Cho, whom he cites as a “great scientist” in the field of electrophoresis. “Collaborating with experts in different fields is a great opportunity to learn new knowledge,” he said, “and through this, we have been able to obtain excellent research results.”
Together, they hope to continue developing their TENG for removing microplastic pollution from larger amounts of water, in the hopes of developing a full, commercialized system to clean our oceans and improve human health.
Source: Daegu Gyeongbuk Institute Of Science And Technology ; Image: Pexels
The article can be found at: Toxic micro/nano particles removal in water via triboelectric nanogenerator