Utilizing Hydrophobic Surfaces for Microplastics Quantification and Detection in Water Reservoirs

Microplastic pollution is one of the most prevalent environmental issues facing society today. To combat this emerging issue, research continues to develop to detect these plastics, but current methods are time-consuming and often involve costly technology. By developing a more cost-effective and efficient method to quantify and detect microplastics, future pollution can be mitigated, which is the focus of this report. Multiple methodologies were considered: density separation, plankton nets, photoluminescence spectroscopy, and passive microplastics collection devices. After careful consideration of laboratory testing results, the requirement for portability, and the constraint of a 30-minute time limit, the chosen approach employs a hydrophobic surface in conjunction with a vortex chamber to accurately quantify and detect microplastics in water reservoirs. The vortex chamber used in laboratory testing was built with two galvanized steel basins of differing sizes. The smaller basin contains a plexiglass slide coated in the selected hydrophobic surface in conjunction with small mesh netting on the top of the basin allowing water to flow into the larger basin while detaining the microplastics inside the smaller basin. A sample of microplastics suspended in water was added to the system and a small submersible pump generated a vortex in the smaller basin to circulate the microplastics onto the slide. Experiments were first performed with Museum Wax as the chosen hydrophobic surface, but recovery rates were low, with an average of 25% of the microspheres. To improve recovery rates, a larger plexiglass slide was chosen with Ultra Clear sealant as the selected hydrophobic surface, increasing recovery rates to 60% for microspheres and 88% microfibers for a 10-minute trial. The chosen design has the capability to utilize rechargeable battery power on a research vessel as evidenced by laboratory testing conducted on Bayou Lafourche. Additionally, the chosen design facilitates the preservation of microplastics for further processing and research, while also enabling seamless imaging through the utilization of a transparent hydrophobic surface.