Flow cytometry analysis of nanoplastics during enhanced coagulation

Nanoplastics (NPs) are a growing environmental concern, posing risks to human health and aquatic ecosystems. Due to their varying physicochemical properties, such as size, surface charge, shape, and chemical compositions, the removal of nanoplastics from water, their accurate detection and quantification remains a challenge. This is especially pronounced in water treatment facilities that depend on conventional coagulation, flocculation, sedimentation, and filtration processes. In this study, we explored enhanced coagulation-flocculation techniques for efficient removal of nanoplastics from water. Nanoplastics removal was investigated by studying fluorescent PS-SO4 NPs of varying sizes (293 nm, 507 nm, and 810 nm) in a simple experimental matrix while varying coagulant dosage (0.2 – 50 mg/L) and mixing speeds (100, 50, 25 rpms). In our approach, we utilized flow cytometry (FCM) as a quantification technique to assess the removal efficiency of the fluorescently labeled PS-SO4 NPs during coagulation and flocculation. We then compared the efficacy of FCM to quantify NPs with the commonly used turbidity measurements. We highlight that FCM is a more reliable technique to quantify NPs removal during coagulation and flocculation. Additionally, we show that particle size influenced the removal efficiency, with the smallest particle showing the lowest removal efficiency at all coagulant dosages. Also see: https://micro2024.sciencesconf.org/552420/document