Organosilane-functionalized Fe3O4 composite particles as effective magnetic assisted adsorbents

Organosilane-functionalized Fe3O4 composite particles are prepared by reacting organosilane precursor, bis[(3-trimethoxysilyl)propyl]-ethylenediamine (TSPED) on Fe3O4 magnetic particles. To examine the adsorption and desorption properties of the composites, brilliant blue FCF (BBF) is used as a model adsorbate. The effects of solution pH, ionic strength, temperature and initial BBF concentration on adsorption are investigated. The experimental results show that most of the dye is adsorbed and desorbed within 15 min. The equilibrium adsorption amount increases with the increase in initial BBF concentration, but decreases with the increase in ionic strength. The adsorption amount exhibits a maximum at the pH ∼6.5, and temperature does not have a significant effect on the adsorption below 50 °C. NaOH solution appears to be a more efficient desorption medium than NaCl solution. Hydrogen bonding, electrostatic and hydrophobic attractions are found to be the driving forces for the adsorption of BBF.