Kinetic and Thermodynamic Investigations of Zn(II) Adsorption on Microcrystalline Anthracene Modified with 8‐Hydroxyquinoline and Its Application to the Preconcentration and Determination of Trace Zinc

Abstract

A new method that utilizes microcrystalline anthracene modified with 8-hydroxyquinoline as an adsorbent has been developed for the preconcentration of trace Zinc(II). The possible reaction mechanism is discussed in detail. The influences of different parameters, such as acidity, other metal ions, the amounts of 8-hydroxyquinoline and anthracene, etc. on the enrichment yield of Zn(II) have been studied to optimize the experimental conditions. The experimental data were fitted well with the pseudo-second-order kinetic model and Langmuir model at all studied temperatures and the maximum adsorption capacity was 32.58 mg·g -1 (300 K). The thermodynamic parameters (DG q , DH q and DS q ) showed the feasibility, exothermic and spontaneous nature of the adsorption at 280~320 K. Experiments indicate that Zn(II) can be completely separated from Cu(II), Co(II), Cd(II), Mn(II), Ni(II) in the eluent. The recovery of this method is in the range of 96.0%~105.0% with preconcentration factor of 100 and the limit of detection after preconcentration is 0.068 mg·L -1 . The proposed method has been successfully applied to the determination of trace Zn(II) in effluents and synthetic water sample having a composition similar to certified water sample SLRS-4 (NRC, Canada). Analytical results obtained by this recommended method were very satisfactory.