A novel ion-imprinted polymer based on graphene oxide-mesoporous silica nanosheet for fast and efficient removal of chromium (VI) from aqueous solution.

A novel chromium (VI) ion-imprinted polymer (Cr(VI)-IIP) was prepared using surface ion imprinting technique on graphene oxide-mesoporous silica (GO-MS) nanosheets with 3-(2-amino ethyl amino) propyl trimethoxysilane as the functional monomer. The prepared Cr(VI)-IIP was characterized by Fourier transform infrared spectroscopy, scanning electronic microscopy, X-ray diffraction and thermogravimetric analysis. The prepared Cr(VI)-IIP was then applied to remove Cr(VI) ions from aqueous solution. The influences of functional monomer amount, contact time, initial Cr(VI) concentration, solution pH and temperature, on the adsorption performance of Cr(VI)-IIP were investigated. Adsorption experiments revealed that the sorption equilibrium was achieved within 5 min with a high adsorption capacity up to 438.1 mg g-1, and the adsorption process followed pseudo-second-order kinetic model and Freundlich adsorption isotherm model. The Cr(VI)-IIP exhibited superior selectivity for Cr(VI) with respected to Cr(III), Mo(VI), PO43-, SO42- and NO3-. Moreover, Cr(VI)-IIP showed good reusability in five adsorption/desorption cycles. Results indicated that the synthesized Cr(VI)-IIP possessed excellent potential applications for the treatment of wastewaters containing Cr(VI).