Bromopropyl functionalized silica nanofibers for effective removal of trace level dieldrin from water

Novel bromopropyl functionalized silica nanofiber films were successfully fabricated by electrospinning the mixture of tetraethylorthosilicate (TEOS) and polyvinyl alcohol (PVA), followed by calcination and subsequent surface modification with 3-bromopropyl trichlorosilane (BPTCS). A polychlorinated chemical of dieldrin detected from the surface water frequently was selected as a model pollutant to test the removal efficiency of persistent organic pollutants (POPs) by bromopropyl modified silica nanofiber films. Because of larger specific surface area and large amount of pores, the bromopropyl modified silica nanofibers were found to be highly effective for the removal of hydrophobic POPs from micro-polluted water, especially at low concentrations. Its removal rate was evaluated to be 91.02%, much higher than that of the unmodified silica nanofibers (20.93%) and the commercially used granular activated carbon (38.65%). The higher adsorption efficiency of the bromopropyl silica nanofibers was assumed to be the accumulating effect of the bromopropyl groups on hydrophobic dieldrin due to strong hydrophobic interaction between dieldrin and bromopropyl groups on the surface of the fibers based on the principle of “like prefers like”.