NMSU Student Awarded NM WRRI Water Research Grant to Study Degradation of Microplastics from Wastewaters to H2 Energy

By Marcus Gay, NM WRRI Student Program Coordinator

The term microplastics refers to any fragmented plastic material with sizes less than 5 mm. In a 2017 worldwide study by Orb Media, researchers found that over 80 percent of tap water samples tested positive for microplastics. The U.S. had the highest contamination rate of any nation with more than 94 percent of tap water samples containing plastic fibers. Microplastics are found in the effluent of water treatment plants, industrial wastewaters, rivers, lakes, and oceans. A recent report in Science indicates that approximately 0.48–1.27 million tons of plastic debris enter oceans annually. Microplastics have the potential to cause harmful effects on human health (endocrine disrupting chemicals and disease-causing microbes) and ecological environments (invasive species can use them to travel to new habitats). For these reasons, it is important to remove microplastics from water before consumption and before releasing water into the environment.

However, due to the intrinsic physical and chemical characteristics of microplastics, removal from water or wastewater is difficult. Studies suggest that treatment technologies such as membrane bioreactors, activated sludge, hydrocyclone, coagulation, and filtration are effective at removing microplastics with sizes larger than 1 mm, but large amounts of smaller microplastics still pass through the existing water and wastewater treatment processes. There are some processes that can be used to remove or degrade microplastics like membrane filtration, or thermal, chemical, and catalytic oxidation, but these technologies are expensive and often have high energy requirements. Therefore, NM WRRI has awarded a Student Water Research Grant to Thiloka Edirisooriya as she works to develop an efficient and sustainable method to degrade micro-and nano-plastics from water. Under the guidance of her faculty sponsors, Dr. Huiyao Wang and Dr. Pei Xu, the project entitled, Solar reforming of microplastics in water for H2 production and degradation using nanocomposite photocatalysts, will use photocatalysis while producing hydrogen (H2) under solar reforming.

The project aims to develop highly functional nanocomposite photocatalysts to clean water and convert microplastics from a waste to H2 energy. According to Edirisooriya, “This research will help to improve water quality, reduce acute and chronic toxicity to human and aquatic life, and will assist in guiding the potential application of photocatalysis for environmental remediation of microplastic pollution.” Edirisooriya presented this project, which also addresses the renewable energy demand issue, at the 65th Annual New Mexico Water Conference.

Edirisooriya, originally from Sri Lanka, has a BS in Civil Engineering where she worked on flow forecasting modeling and flood modeling. Edirisooriya plans to graduate with her MS in Civil Engineering from New Mexico State University in December. After graduation, Edirisooriya plans to continue in academics and hopes to enroll in a PhD program.