Design of novel nano-sorbents based on nano-magnetic iron oxide-bound-nano-silicon oxide-immobilized-triethylenetetramine for implementation in water treatment of heavy metals

摘要

Novel nano-sorbents were synthesized from the direct surface impregnation of magnetic nano-iron oxide (Nano-Fe3O4) with nano-silicon oxide (Nano-SiO2) for the formation of (Nano-Fe3O4-SiO2) sorbent. The product material was further functionalized with target nitrogen donor atoms via covalent surface binding and immobilization of triethylenetetramine (TETA) for the formation of (Nano-Fe3O4-SiO2-TETA) sorbent. Functionalized magnetic nano-sorbents were collected by facile separation under the influence of an external magnetic field. The magnetic nano-sorbents were identified by using FT-IR, SEM technique and TGA. The average particle size was found in the range of 14-40 nm based on the SEM analysis. All synthesized nano-sorbents were examined to evaluate their selectivity and efficiency in removal of some heavy metal ions such as Cu(Il) and Pb(II) from water samples by the batch equilibrium and micro-column techniques. (Nano-Fe3O4-SiO2-TETA) sorbent was identified by a high Cu(II) sorption capacity (480 μmol g~(-1)) in pH 7.0, while (Nano-Fe3O4) and (Nano-Fe3O4-SiO2) sorbents were characterized by high affinity to Pb(II). The contributions of various controlling factors such as solution pH, contact time and sorbent dosage on the extraction and sorption processes of metal ions were also studied and optimized.