Enhanced Adsorption of Ni (II) ions by Amino-Carboxyl Functionalized Illite/Smectite Clay Nanoflakes Prepared Via Mechanochemical Route

A ternary nanocomposite integrating disodium ethylenediaminetetraacetate (EDTA), cetyltrimethylammonium bromide (CTAB) and illite/smectite (I/S) clay nanoflakes (denoted as C-I/S-E) was prepared by a mechanochemical route in a high energy–density stirred bead mill. The characterizations confirm the exfoliation of clay into nanoflakes and effective EDTA functionalization. The adsorption behavior of Ni (II) ions in aqueous solution was evaluated with respect to the effects of adsorbent dosage, contact time, and initial Ni (II) concentration. Meanwhile, the adsorption mechanism in an atomic scale was analyzed via the first-principles density functional theory (DFT) calculations. The integrated experimental and simulation findings indicate that the enhanced adsorption performance of the EDTA-modified I/S clay nanoflakes is attributed to a synergistic interplay of physical adsorption by the clay substrate and chemical chelation by the EDTA functional groups. The nanocomposite C-I/S-E shows a promising potential as an efficient adsorbent for removal of heavy metal ions from wastewater.