Fabrication of zonal thiol-functionalized silica nanofibers for removal of heavy metal ions from wastewater

Novel zonal thiol-functionalized silica nanofibers were fabricated for the removal of heavy metal ions from waste water by the sol–gel polymerization of 3-mercaptopropyl trimethoxysilane on the electrospun polyacrylonitrile (PAN) nanofibers, followed by removal of PAN nanofibers using dimethylformamide dissolution. The removal of PAN templates resulted in higher surface areas. As self-supporting adsorbents, these zonal silica nanofibers are efficient in removing mercury from aqueous waste streams with a maximum adsorptive capacity of 57.49 mg/g due to the introduction of thiol groups onto the surface of nanofibers and the increased surface areas of nanofibers. The adsorption equilibrium was obtained for only about 30 min, suggesting that the –SH groups were readily available and easily accessible because the uniform porous channels between nanofibers facilitated the Hg2+ transportation in the adsorption process.