Chemically modified activated carbon with S-benzyldithiocarbazate as a new solid-phase extractant for preconcentration of mercury prior to ICP-AES determination

Abstract

A new sorbent S-benzyldithiocarbazate (SBDTC) modified activated carbon (AC-SBDTC) was prepared and studied for preconcentration for trace mercury(II) prior to inductively coupled plasma atom emission spectrometry (ICP-AES). The experimental conditions were optimised with respect to different experimental parameters using both batch and column procedures in detail. The optimum pH value for the separation of Hg(II) on the new sorbent was 3, while the adsorption equilibrium was achieved in less than 5 min. Complete elution of the adsorbed metal ions from the sorbent surface was carried out using 5 mL of 0.25 mol L⁻¹ of HCl and 2% CS(NH₂)₂. Common coexisting ions did not interfere with the determination. The maximum static adsorption capacity of the sorbent under optimum conditions was found to be 0.55 mmol g⁻¹. The detection limit of the present method was found to be 0.09 ng mL⁻¹, and the relative standard deviation (RSD) was lower than 2.0%. The procedure was validated by analysing the certified reference river sediment material (GBW 08301, China), the results obtained were in good agreement with standard values. This sorbent was successfully employed in the separation and preconcentration of trace Hg(II) from the natural water samples yielding 80-fold concentration factor.

Keywords:

• S-benzyldithiocarbazate modified activated carbon (AC-SBDTC)
• solid-phase extraction
• mercury
• ICP-AES