Removal of copper (II) and nickel (II) from aqueous media using silica aerogel modified with amino propyl triethoxysilane as an adsorbent: equilibrium, kinetic, and isotherms study

This study focused on the adsorption of copper (II) and nickel (II) from aqueous solutions onto silica aerogel modified with amino propyl triethoxysilane as a compound containing amino functional group. The batch experiments were conducted at various conditions including contact time, pH, adsorbent dose, and adsorbate content. The results showed that the equilibrium time occurred within 5h for Ni(II) and 24h for Cu(II) and the maximum adsorption capacity for both the ions happened at a pH of 6. The kinetic and isotherm adsorption of the modified silica aerogel fitted well to pseudo-second order model and Langmuir model, respectively. The Langmuir isotherm model results showed that the maximum adsorption capacity (Q(m)) of the modified adsorbent was 47.6mg/g for Cu(II) and 27.7mg/g for Ni(II). Experimental data analysis by Dubinin-Radushkevich isotherm also illustrated that the metals adsorption onto the sorbent was physical in nature. With regard to the sorption capacity obtained by the modified silica aerogel, it can be considered as an efficient sorbent in the removal of the metal ions.