Adsorption of Cu Ions onto a 1.10 Phenanthroline-Grafted Brazilian Bentonite

Abstract

The grafting, by chemical adsorption, of molecular 1.10-phenanthroline (OP) onto some Brazilian bentonite (montmorillonites) was studied to improve their adsorptive capacities to remove Cu ions from synthetic wastewater. The quantity of OP adsorbed was 112 mg g−1 of bentonite at pH 8.5 and no significant desorption was detectable in acidic or basic solutions. X-ray diffraction (XRD) spectra show that a complex type-β is formed in which the OP molecules lay inclined in the clay interlayer. After the intercalation of OP, the adsorptive capacities of the natural bentonites increased by a factor of ten. Thus, adsorption of Cu ions, at optimal pH of 8.0±0.5, showed saturation values, which, calculated by the Langmuir model, yielded 110 mg of Cu ions g−1 of bentonite (3.5 meq g−1). The mechanisms of Cu uptake are ion-exchange adsorption onto untreated bentonite and ion exchange plus Cu2+ phenanthroline complexation (chemisorption) on the modified pillared clay. The desorption of Cu ions from OP clay revealed high uptake irreversibility and physical stability (of the adsorbent) either in strongly acidic or basic solutions. Thus, after acid treatment ∼90% of the adsorbed Cu ions continued to be bound onto the OP-modified bentonite surface.

Immobilization of Pb(II), Cd(II) and Ni(II) ions on kaolinite and montmorillonite surfaces from aqueous medium

“…Various forms of modified clays have also been used: Na-exchanged bentonites for Cr(III), Ni(II), Zn(II), Cu(II) and Cd(II) (Alvarez-Ayuso and Garcia-Sanchez, 2003), surfactant modified montmorillonite for Cu(II) and Zn(II) (Lin and Juang, 2002), 1:10 phenanthroline-grafted Brazilian bentonite for Cu(II) (De Leon et al, 2003).…”

Adsorption of Fe(III) from water by natural and acid activated clays: Studies on equilibrium isotherm, kinetics and thermodynamics of interactions

“…Uses of bentonite for adsorptive removal of Zn(II) (Mellah and Chegrouche, 1997) and Sr(II) (Khan et al, 1995), natural and Na-exchanged-bentonite for removal of Cr(III), Ni(II), Zn(II), Cu(II) and Cd(II) from water (Alvarez-Ayuso and Garcia-Sanchez, 2003), sepiolite for Co(II) (Kara et al, 2003), and even kaolinite for Mn(II), Co(II), Ni(II), Cu(II) (Yuvaz et al, 2003) have yielded significant adsorption. Other important results include adsorption of Cu(II) and Zn(II) on surfactantmodified montmorillonite (Lin and Juang, 2002), and of Cu(II) on 1:10-phenanthroline grafted Brazilian bentonite (De Leon et al, 2003).…”

The performance of urea-intercalated and delaminated kaolinites-adsorption kinetics involving copper and lead

“…The original K NAT sample exhibited all characteristic hydroxyl stretching bands 5 attributed to the inner-surface hydroxyls oriented towards the interlayer at 3695 cm -1 . The bands at 3622 and 3463 cm -1 are assigned to those hydroxyl groups oriented towards the vacant sites in the external layers of the kaolinite structure.…”

“…Various conventional and non-conventional adsorbents have been explored for removal of different metal ions from aqueous solutions. [1][2][3][4][5][6][7] For example, materials containing micro and macropores, such as pillared and intercalated/delaminated clays, are often employed in such operations. In particular, kaolinite and smectite group clay minerals have been successfully explored in many adsorption procedures.…”