Efficacy of DCN Filters in Removing Micro/Nanoplastics from Water

• Kadisha Mitchell, Environmental Science, Howard University

• Changqing Wu, Animal and Food Science, University of Delaware
• Jinglin Zhang, Animal and Food Science, University of Delaware

Microplastic contamination in drinking water has emerged as a significant global concern due to its potential adverse impact on human health and the environment. Consequently, there is an increasing demand for efficient and economically viable water treatment technologies. This study aims to assess the efficacy of a novel Densified Carbon Nanotube (DCN) filter in removing micro/nanoplastics from drinking water. Originally designed for electronic device applications, the DCN filter is composed of extremely thin and dense carbon nanotube films that provide a substantial surface area. This unique structure enables the filter to efficiently adsorb and trap small particles, including micro and nano plastics. To evaluate its performance, synthetic micro/nanoplastic particles with sizes ranging from 0.02 μm to 2 μm, representative of some typical micro/nanoplastics found in drinking water sources, were labeled with fluorescence markers. Solutions with microplastic concentrations of 5 µg/ml were created and subjected to vacuum filtration with the DCN filter. The fluorescence intensity of the solutions before and after filtration was monitored by a fluorometer, and test samples were compared with different concentrations of standard polystyrene microplastic solutions. Additionally, dry samples of the solutions, both before and after filtration, were prepared and examined under a hybrid echo microscope with fluorescence capabilities. Images of the samples were analyzed using the Microplastics Visual Analysis Tool (MP-VAT) in ImageJ. The MP-VAT automatically quantifies and characterizes the shape (fiber, fragment, particle) and size of fluorescent microplastics. Throughout the experiments, rigorous cleaning procedures were meticulously applied to prevent any potential contamination. The results showcased the remarkable efficiency of the DCN filter in removing microplastics, with an average removal rate of approximately 98%. As microplastic contamination continues to be a pressing global issue, the utilization of advanced filtration technologies, such as the DCN filter, holds the potential to safeguard public health.