Characterization of Surface Modification, Thermal Stability, and Metal Selectivity Properties of Silica Gel Phases‐Immobilized Dithiocarbamate Derivatives

Abstract

Carbon disulphide was used to modify the surface of silica gel phases containing amine moieties for the formation of four phases-immobilized dithiocarbamate derivatives (I–IV). Characterization of the surface modification by the organic modifier was accomplished by several means of instrumental analysis. These include infrared, secondary ion mass spectrometry (SIMS), as well as, thermal desorption analysis for determination of the surface coverage values (1.051–1.501 mmol g⁻¹). The thermal stability and structure characterization of the modified silica gel phases (I–IV), along with their mercury(II) adducts, were studied and evaluated on the basis of electron impact mass spectrometric analysis (EI‐MS). The results of this study proved higher thermal stability characters incorporated into the metal adduct compared to the free silica gel phase. The selectivity properties incorporated into the modified silica gel phases for binding and interaction with a series of bi‐ and trivalent metal ions were studied and evaluated by determination of the distribution coefficient and separation factor. The results of these evaluation processes were found to point out the higher selectivity and preference of these four phases for binding with mercury(II), copper(II), and cadmium(II) compared to other metal ions.

Keywords:

• Silica gel
• Surface modification
• Thermal stability
• Metal selectivity
• Dithiocarbamate