Functionalized SBA-15 by amine group for removal of Ni(II) heavy metal ion in the batch adsorption system

Abstract

In this work, several variables that can affect the adsorption of Ni(II) using NH2-SBA-15 were studied in a batch adsorption system including; pH (1-6), contact time (0-150 min), initial concentration (20-120 mg L-1), NH2-SBA-15 dose (0.025-0.3 g) and temperature (293-333 K). The removal percentage increased with increasing the pH, the contact time, NH2-SBA-15 dose and temperature, while the increase of the initial concentrations for this metal ion reduced their percentage removal. It appeared that the Langmuir adsorption isotherm model had the best fit with R-2 = 0.99, and the maximum capacity of monolayer adsorption increased from 64.52 to 90.1 mg g(-1) as increasing in the temperature from 293 to 333 K, respectively. It was demonstrated that the kinetic studies were fitted well with the pseudo-second-order kinetic model (R-2 = 0.99). The results of thermodynamic parameters showed that the process is endothermic chemisorption (Delta H degrees = 93.8734 kJ mol(-1)) with a very little degree of disorder (Delta S degrees = 0.38812 kJ mol(-1) K-1) and whenever the temperature increased from 293 to 333 K, the process became more spontaneous (Delta G degrees = -19.098 to -34.33 kJ mol(-1) K-1).