Abstract
The removal of engineered nanoparticles (NPs) in drinking water treatment has posed a longstanding challenge due to their small sizes and widespread presence. This study aimed to assess the effectiveness of different methods, namely natural sedimentation, coagulation-sedimentation, and polyvinyl chloride (PVC) membrane ultrafiltration (UF), in removing silver NPs coated with carboxyl-terminated polymer with a primary diameter of 4.7 nm, hematite NPs of three diameters (53, 98, and 205 nm), and SiO2 NPs (740 nm). The results revealed that after 24 h of natural sedimentation, only approximately 28 %, 10 %, and 3 % of SiO2, hematite, and silver NPs, respectively, were removed. However, when coagulation with aluminum sulphate at an Al3+ dosage of 60 mg/L was implemented, followed by 4 h of sedimentation, the removal efficiencies of the three types of NPs increased to 90–95 %. Furthermore, membrane ultrafiltration achieved removal rates of 99.95 % for hematite, 99.6 % for silver, and 99.70 % for SiO2, unaffected by variations in solution pH (ranging from 5.0 to 10.0) and the initial concentrations (approximately 10 and 100 mg/L). Analyses based on the blocking filtration model indicated that the primary removal mechanism involved straining for 53 nm-hematite NPs, and a combination of straining and inside pore attachment for silver NPs.
Published Version
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