Synthesis,characterization and application of magnetic mesoporous multifunctional nanocomposite

Removal of water-soluble and/or insoluble pollutants is very important since water pollution resulted from industrial organic waste water drains and oil spills seriously harms human health and animal habitats. Multifunctional magnetic mesoporous nanocomposites are promising materials for the removal of water-soluble and/or insoluble pollutants due to the remarkable properties such as changeable surface properties, multiple binding sites, high surface area and magnetic separation. In this study, for that purpose, multifunctional magnetic nanocomposites Fe3O4@PDA@SBA-15@VTES and SBA-15-Fe3O4-PDA-ODA were designed by using mesoporous silica SBA-15 as matrix, magnetite (Fe3O4) providing magnetic separation as reinforcement, polydopamine (PDA) providing multiple bonding sites as functionalization element, and vinyltriethoxysilane (VTES) and octadecylamine (ODA) providing hydrophobicity as a modifier. The adsorption capacity of SBA-15-Fe3O4-PDA nanocomposite was determined as 138.08 mg g-1, while the adsorption capacity of Fe3O4@PDA@SBA-15 nanocomposite was determined as 71.92 mg g-1 for the removal of water-soluble cationic dye Malachite Green (MG) before surface modification. After VTES and ODA modification, for removal of oil which is a water-insoluble pollutant, the capacity of SBA-15-Fe3O4-PDA-ODA nanocomposite was determined 40.28 times of its own weight, while the capacity of Fe3O4@PDA@SBA-15@VTES nanocomposite was determined 8.83 times of its own weight. The magnetic nanocomposites could be easily separated from the water with an external magnet after the adsorption process and reused 3 times with simple regeneration processes, and no significant decrease was observed in their removal capacities. Moreover, SBA-15-Fe3O4-PDA-ODA from nanocomposites characterized by structural, magnetic and surface properties also exhibited successful adsorption properties in removal of water-soluble MG and water-insoluble oil pollutants in the same process. The prepared multifunctional magnetic mesoporous nanocomposites increase the functionality of the environmental cleaning process for water-soluble and insoluble pollutants, due to an easy and low cost production, selectively controllable removal ability of cationic dye and oil.