Pictured above: Matthew Scarfo, Ryan Ellis, Alex Matos and Helen Engelhardt

The members of Capstone Project Team 6 are very passionate about sustainability. Their project aim was to discover solutions to problems that harm the environment. The group chose to concentrate on the critical problem of microplastics in wastewater. Microplastics are not only harmful to delicate ecosystems but also pose a threat to human health, as well as land and marine life.

The project was called MicroSeize. Team members are Ryan Ellis, Helen Engelhardt, Alex Matos, and Matthew Scarfo. Through their project research, they discovered that microplastics smaller than 20 microns bypass existing standard filtration mechanisms.  They targeted wastewater and aimed to remove particles in the range of 10 to 20 microns. In other wastewater treatment methods, those particles are not currently removed.

They developed a scalable methodology for capturing common plastics that other methods cannot retrieve, such as polystyrene and PET microplastics, from wastewater. Most of their testing was conducted on polystyrene because it creates the smallest microplastics.

Team 6 brought the broad skills derived from their undergraduate degree to the forefront to complete this challenging project.

“I'd like to highlight that our project was really interdisciplinary. We all have interests in separate domains, during our undergraduate degrees we all branched out and specialized in different areas, but we came together and used a lot of shared understanding of core concepts, navigated complex ideas from many different aspects, from chemistry, to mechanical, to electrical and we brought it all together to successfully complete our Fourth-Year Design Project,” says Ellis.

Mesh and trapped microplastics

a hand holding a mesh strip with microplastics stuck to it

The team developed a removal method that involves functionalized iron oxide (rust) nanoparticles. These nanoparticles adsorb onto microplastics when mixed together allowing microplastics to be captured magnetically from the wastewater stream. The synthesized iron oxide nanoparticles and the microplastics are both hydrophobic and are more stable when adsorbed to each other. When mixed in a reactor, the microplastics are magnetized and can be removed with a magnet.

The team designed a mechanical system for this process using a magnet that removes microplastics in a scalable way. The process has four phases: mixing, draining, separation and finally, flushing.

This proof-of-concept reactor for scalability consists of a mixing chamber with an axial flow impeller to facilitate the efficient mixing and adsorption of microplastics to iron oxide NPs, after which the mixture flows through a valve into the separation chamber consisting of a pipe lined with ferrous stainless steel mesh, which is magnetized via an external magnet. The presence of the large surface area of magnetized material attracts and traps the microplastics adsorbed to the iron oxide in the effluent, releasing clean water. After the capture is complete, the external magnet can be removed and the device flushed by a lesser quantity of water, freeing the occupied mesh area to process more untreated water.

The team credits their professors and instructors for the success of MicroSeize.

“We’d like to thank our supervisor Dr. Juewen Liu for his help and for giving us lab space to work. Professor Ahmad Ghavami was also incredibly helpful. We could only do the work that we did because we were given supplies, time, energy and thought from others who had a lot more experience than us,” says Engelhardt.

The team has applied for a patent for their prototype and that will allow them a couple of years to decide if they want to pursue a start-up. As for future plans, Ellis will be doing a Masters degree in Electrical and Computer Engineering. Scarfo plans to pursue a Masters in Chemical Engineering. Engelhardt has been given a Clarendon Scholarship to undertake PhD research in Materials at Oxford University. Matos aims to work in the field of carbon capture to take a break from studies and will decide if graduate school is in their future.

Congratulations to Team 6!