In this study, the novel magnetic composite beads of Fe3O4/alginate/Ag were synthesized and characterized for point-ofuse water disinfection. Magnetite nanoparticles were prepared from waste spent pickling liquors and then were encapsulated by natural alginate to form the spherical beads of the size about 1-2 mm. | Vietnam Journal of Science and Technology 56 (3B) (2018) 192-198 PREPARATION OF MAGNETIC ANTIBACTERIAL COMPOSITE BEADS Fe3O4/ALGINATE/Ag Le Thi Thu Ha1, 2, Vu Xuan Minh1, Le Thi My Hanh1, Le Trong Lu1, 2, Pham Thi Lan1, Nguyen Tuan Dung1, 2, * 1 Institute for Tropical technology, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi 2 Graduate University of Science and Technology, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi * Email: ndung@ Received: 17 July 2018; Accepted for publication: 9 September 2018 ABSTRACT In recent years, the synthesis of magnetic polymer beads has much attractive attention from many technological fields such as biomedical and environmental. In addition of stabilizing effect for magnetic particles core, the polymer shells can also be further functionalized, thus enlarging the spectrum of possible applications of magnetite nanoparticles. In this study, the novel magnetic composite beads of Fe3O4/alginate/Ag were synthesized and characterized for point-ofuse water disinfection. Magnetite nanoparticles were prepared from waste spent pickling liquors and then were encapsulated by natural alginate to form the spherical beads of the size about 1-2 mm. Silver nanoparticles were loaded on the beads with the large content ( wt.%). The asprepared beads have a high saturation magnetization value, Ms = 59 emu/g, and very good antibacterial activity against both gram (-) and gram (+) bacteria. With the concentration 35 μg mL-1 the magnetic beads can kill 100 % Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, whereas this value found 70 μg mL-1 for Lactobacillus fermentum, 105 μg mL-1 for Salmonella enterica, and 140 μg mL-1 for Bacillus subtilis. Keywords: magnetic antibacterial beads, sodium alginate, silver nanoparticles, water disinfection. 1. INTRODUCTION Magnetic nanoparticles have received recently a considerable amount of attention due to their wide applications in various fields, which ranges from biomedical to .
