Amidation of Purified Carbon Nanotubes for Selective Solid Phase Extraction of Mercury(II) Ions from Aqueous Solution

Raw and oxidized carbon nanotubes (CNTs) unable to adsorption of Hg(II) ions. Then carbon nanotubes were oxidized with HNO3 and oxidized CNTs were amidized with ammonium acetate solved in acetonitrile. Their physicochemical properties were investigated Boehm’s titration, Raman spectroscopy, FT-IR, thermal analysis (TGA DTA) and zeta potential measurement. In this work, amidized CNTs used as a new adsorbent for solid phase extraction (SPE) of Hg(II) from aqueous solutions. The effect of pH, type of buffer and flow rate for quantitative enrichment was also investigated. The experimental results suggest that Hg(II) adsorption capacities amidized CNTs increase due to the functional groups introduced by oxidation compared with the as-grawn CNTs. A detection limit of 5.00×10-4 ng/ml and a relative standard deviation 2.4% were obtained. The CNT–SPE preconcentration procedure showed a linear calibration curve within concentration range from 0.003 to 0.3 ng/ml for Hg(II).