Sorption of Ni(II) by Sol-Gel Silica Functionalized with DMG and Other Chelating Agents

In this study, a comprehensive investigation of doping of sol-gel silica with DMG and other chelating agents is provided at room temperature using infrared spectroscopy, elemental analysis, SEM, EDS and powder XRD. Sol-gel silica was doped with dimethyl glyoxime (DMG), ethylenediamine (EDA), 1,10-Phenanthroline (Phen), dithizone (DZ), and sulfanilamide (SB) to investigate the sorption of Ni(II) from aqueous media. It is observed that the chelating agents are encapsulated by the pores of the xerogel from where they interact with the metal ions by ion exchange and chelation mechanism. Nickel complexes of the chelating agents were also synthesized. Sol-gel silica was doped with metal complexes for comparison with sol-gel silica with sorbed metal ions. Ni(II) in metal complex was compared with that in functionalized silica from EDS of both samples. The batch adsorption experiments were performed at room temperature and neutral pH. The developed method can be applied on large scale removal of Ni(II) using silica and chelating agents from cheap natural sources. The sorption process was completed within 5 minutes and 0.1 N HNO3 resulted in complete desorption of metal ions. The regenerated sorbent can be reused six times with negligible loss of sorption capacity.