Highly Selective Removal Mercury (II) from Aqueous Solution Using Silica Aerogel Modified with [1-(3,5-dicholorophenyl)-3(2-ethoxyphenyl)] triazene

This paper reported the preparation of silica aerogel (SA) adsorbent coupling with chelating ligands of [1-(3,5-dicholorophenyl)-3(2-ethoxyphenyl)] triazene (DCPEPT) and its application for highly selective adsorption of Hg (II) ion. The functionalized nanoparticles were characterized using fourier transform infrared spectra (FTIR) and thermo gravimetric analysis (TGA) measurements, nitrogen physisorption and scanning electron microscope (SEM). The adsorption of Hg (II) on these nanomaterials was studied as a function of pH, temperature, adsorbent dosage and contact time. Langmuir and Freundlich isotherm models were applied to analyze the experimental data. Moreover, the optimum pH for the adsorption was found to be 6.0 with the corresponding adsorbent dosage level of 0.05 g at 20ºC temperature. Subsequently, the equilibrium was achieved for Hg (II) with 30 min of contact time. The best interpretation for the experimental data given by the Langmuir isotherm equation and maximum adsorption capacity of the sorbent under the optimal conditions was 198.25 mgg−1. These facts indicate that modified silica aerogel with DCPEPT can be used as an inexpensive, efficient, and environmentally safe adsorbent for removal of Hg(II) from aqueous solutions.

Mohammad Saber-Tehrani, Parviz Aberoomand Azar, Shiva Motahar and Fariba Tadayon