Che H., Gwee S., Ahmad A., Lim J., 2015, Guided Assembly of Magnetic Nanocomposite with Open Shell Structure for Water Remediation, Chemical Engineering Transactions, 45, 1489-1494.
Colloidally stable magnetic nanocomposite with magnetic and catalytic bifunctionalities was constructed by using silica colloids as a building template. The fabrication of the open shell structure of the magnetic nanocomposite was achieved by employing polyelectrolyte as the bridging agent between silica and iron oxide nanoparticles (IONPs). The dimension and composition of the nanocomposite was fine-tuned by altering the number of polyelectrolyte interlayer, constructed by poly-diallydimethylammonium chloride (PDDA) and/or poly-styrenesulfonate (PSS), from one PDDA layer to three PDDA/PSS/PDDA layers through layer-by-layer assembly. The successful development of nanocomposite from its building blocks was confirmed by dynamic light scattering and zeta potential measurements. With the evidence of surface morphology of nanocomposite examined by transmission electron microscopy (TEM), IONPs were found to be more evenly distributed on the silica colloid surface by single layer of polyelectrolyte and forming ramified structure as the polyelectrolyte layers increased. Additionally, the structure of the assembled films was evaluated by quartz crystal microbalance with dissipation (QCM-D). Experiments showed nanocomposite constructed by single polyelectrolyte was more flexible and promoted better pollutant removal capability than that of three polyelectrolyte layers by taking Methylene Blue and Methyl Orange dyes as the model system. The nanocomposite can be used for water treatment purpose for multiple cycles by magnetic collection at the end of each treatment cycle.
