We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Enhancing microplastic removal from natural water using coagulant aids
Summary
Researchers tested different chemical treatments for removing microplastic beads from natural water and found that polyaluminium chloride combined with polyacrylamide achieved over 95% removal across six common plastic types. The treatment worked on particles ranging from 10 to 1,000 micrometers, and natural organic matter in the water actually improved performance. The findings suggest that optimizing standard water treatment processes could be a practical way to reduce microplastic contamination in drinking water sources.
Microplastic (MP) pollution poses a significant environmental challenge, underscoring the need for improved water treatment methods. This study investigates the effectiveness of coagulation, flocculation, and sedimentation processes for removing microbeads, focusing on key factors that influence removal efficiency. Among the coagulants tested, polyaluminium chloride (PAC) demonstrated superior performance by enhancing the aggregation of microplastics with flocs. Optimal treatment conditions were determined to be 0.4 mmol/L PAC and 3 mg/L polyacrylamide (PAM) at pH 8 (before adding PAC), with rapid stirring at 240 rpm for 1 min, followed by slow stirring at 35 rpm for 13 min, and a sedimentation period of 25 min. Under these conditions, removal efficiencies exceeded 95 % for a range of microbeads (10-1000 μm: Polystyrene (PS), Polypropylene (PP), Polyvinyl chloride (PVC), Polyamide (PA), Polyethylene (PE), and Polyurethane (PU)) from natural water samples. Without PAM, PAC alone achieved a 97 % removal rate for PS microbeads. The addition of PAM maintained high removal efficiency, while aluminium sulphate and ferric chloride were less effective, with removal rates of 67 % and 48 % for PS microbeads, respectively. PAM enhanced MP removal across various coagulants and microbead types, with maximum efficiency observed at PAM concentrations of ≥3 mg/L. The treatment also demonstrated that organic matter in Regent's Park pond water could further improve MP removal. Size significantly impacts removal efficiency: larger microbeads (1 mm to >250 μm) were removed more effectively (95 %) compared to smaller ones (10 to <250 μm), which had a lower removal rate of 49 %. Denser microbeads like PVC (density 1.38 g/cm³) settled more efficiently than lighter microbeads such as PE (density 0.97 g/cm³). These findings suggest a need for advanced technologies to better remove lighter, smaller MPs from water.