Amidoxime Functionalized SBA-15 for Selective Adsorption of Li+ ions

Amidoxime functionalized SBA-15 was prepared by post modification onto the mesoporous silica SBA-15 surface using chemically synthesized functional group 1,1'-dinitrilopropyltriethoxysilane (DNPTES), followed by further chemical conversion of nitrile part of the functional groups into amidoxime by post chemical transformation procedure using hydroxylamine hydrochloride reagent. The resulted materials have enriched amount of functional ligands onto the SBA-15 surfaces. The synthesized Amidoxime-SBA-15 materials were characterized by small-angle X-ray scattering (SAXS), Fourier-transform infrared (FT-IR) spectroscopy, N-2 adsorption-desorption isotherms, Si-29 MAS, C-13 CP MAS NMR spectroscopic analyses and transmission electron microscopy (TEM) analysis and elemental analysis. The prepared Amidoxime-SBA-15 materials were tested for the selective adsorption of Li+ ions from the aqueous waste solution containing Li+, Cd2+, and Ni2+. Amidoxime-SBA-15 exhibited a high selectivity (similar to 90%) of Li+ ion with high amount of adsorption capacity (0.9 mmol g(-1)) under acidic medium (pH 5). Moreover, Amidoxime modified SBA-15 would be a desirable sorbent material for selective adsorption of Li+ ions in aqueous waste discharged from lithium battery and lithium ion fuel industries.